INFECTIOUS DISEASE

Foodborne Disease Caused by Micro-organisms

2012-01-07T23:54:00.000-08:00

Foodborne disease is a public health problem which comprises a broad group of illnesses.

Among them, gastroenteritis is the most frequent clinical syndrome which can be attributed to a wide range of micro-organisms, including bacteria viruses and parasites.

Usually, the incubation period is short, from 1-2 days to 7 days.

Different degrees in severity are observed, for a mild disease which does not require medical treatment at the more serious illness requiring hospitalization, long term disability and /or death.

The outcome of exposure to foodborne diarrheal pathogens depends on a number of host factors including preexisting immunity, the ability to elicit an immune response, nutrition, age, and non specific host factors.

As a result, the incidence the severity and the lethality of foodborne diarrhea is much higher in some particularly vulnerable segments of the population, including children under five years of age, pregnant women, immuno-compromised people and elderly.

In addition to these well known predisposing conditions, new ones are regularly identified (liver disease for paraheamoliticus septicemia, thalassemia for Yersinia enterocolitica infections).

Serious complications may result from these illnesses including intestinal as well as systemic manifestations, like hemolytic uremic syndrome for 10% of Escherichia coli 0157:H7 infections with bloody diarrhea, Guillain-Barre syndrome (nerve degeneration, slow recovery and severe residual disability) after Campylobacter jejuni infection, reactive arthritis after salmonellosis and chronic toxoplasmic encephalitis.

While diarrhea is the most common syndrome following the consumption of a contaminated food some disease are more serious.

Clinical manifestations of listeriosis include bacteriemia and central nervous system infections, especially in patients with an impairment of T-cell mediated immunity and abortion in pregnant women, with an overall case fatality rate of 25%.

Food borne botulism is a result from the potent toxin by Clostridium botulinum that cause a paralysis of skeletal and respiratory muscles which, when severe may result in death in 8% of cases.

Toxoplasma gondii is also the most frequent cause of lesion in the central nervous system in patients with AIDS.

Hepatitis A is an infectious disease for which age is the most important determinant of morbidity and mortality, with severity of illness and its complications increasing with age.

The durations of illness vary but most cases are symptomatic for three weeks.

Complications during the acute illness phase are unusual, with fulminant hepatitis and death being uncommon.
Foodborne Disease Caused by Micro-organisms

What is infection?

2011-10-16T22:59:00.001-07:00

Humans live in their environment with many other species. Many members of the animal and plant kingdoms are microscopic an can cause human illness, called infection.

Infection is a disease caused by pathogen. An infection is an disease caused by pathogen.

The human body is colonized in the skin and mucosal surfaces with numerous microorganism that form the normal flora of the body.

This organism, far from causing disease, often provide benefit to the host, by competing with potential pathogens for attachment sites and nutrients.

Even potential pathogens can act as colonizers. Staphylococcus aureus, which is capable of causing severe disease, commonly exists in the surface of healthy skin.

It is only when it invades the skin tissues or the blood that it can causes an infectious disease.

Normally, it is the present of the replicating organisms, associate with tissue damage, that defines the conditions as an infection.

Tetanus occurs when Clostridium tetani multiplies on a wound, elaborating neurotoxin tetanospasmin.

Therefore, the term infection refers to the presence and multiplication of microorganisms in the tissue of a host. The host response to this invasion and replication various.

It is the task of the immune system to protect the host against invading infections agents and thereby to prevent infectious disease.

Conversely, the immune system has evolved to provide appropriate defense mechanisms at a various levels of ‘unspecific’ and ’specific’ immune response.
What is infection?

Tetanus

2011-09-13T23:34:00.001-07:00

Tetanus is a frequently fatal disease caused by the bacterium Clostridium tetani.

The disease is caused by the action of a potent neurotoxin produced during the growth of the bacteria in dead tissues.

The disease is characterized by intense painful muscle contractions, sometimes strong enough to break even the strongest bones in the body.

The word tetanus is derived from Greek term tetanus, meaning ‘to contract’.

The continue contraction of the muscle are liable to sudden increase in violence and painful paroxysm, which ceasing, leaving in a comparatively relaxed and easy state.

This disease is everyone worrying about. The repeated exposure of young children to cut scrapes and it provides a continual source of anxiety for parents on unvaccinated children.

Tetanus has been distinguished into two species, the idiopathic, including those cases where the disease appears to arise from some general cause, as exposure it damp or cold; and the traumatic or symptomatic, when it is a remote consequence of a local injury.

People of all ages can get tetanus, But the disease is particularly common and serous in newborn babies. This called neonatal tetanus. Most infants who get the disease die.

Neonatal tetanus is particularly common in rural areas where most deliveries are at home without adequate sterile procedures.

The organism responsible for tetanus is found in soils and the intestinal tracts of animals.
Tetanus

Flu Viral Infection

2011-07-19T17:09:00.000-07:00

Influenza viruses have special features that can over power a body’s immune system. It affects respiratory tract – nose, throat, bronchial tubes and lungs.

First, influenza virus are efficient travelers.

Second, they have an amazing ability to copy themselves.

And third, flu viruses are unique in that once a strain has spread in a population, its structure changes and it then is capable of causing a new form of flu because the antibodies produces to combat the original virus are not effective against the new form.

An entirely new strain appears about every 10 years.

Not only do influenza viruses travel easily from person to person, they do so secretly for part of the time.

A person with the flu may be contagious for several days before he or she know it.

When an infected person coughs or sneezes, he or she releases tiny droplets of water from the mouth and nose.

The most common way to catch the flu is by inhaling that tiny droplets. Less often it is spread when the person touch a surface such as a faucet handle or phone that has the virus on it and then touch his own mouth, nose, or eyes.

The virus’s ability to turn normal human or animal host cells into flu-copying machines is another reason influenza can take over immune systems.

After an incubation period of 1 to 4 days, people infected with influenza virus develop an abrupt fever, headache, sore throat and dry cough that can in some cases progress to viral pneumonia, respiratory failure and death.
Flu Viral Infection

Infective Parasitic Pathogen: Toxoplasma gondii

2011-07-17T18:00:00.000-07:00

Toxoplasma gondii is a protozoan parasite which can be transmitted by fecal-oral contamination. Cats are the original hosts for this protozoa. They excrete microscopic in active forms of this protozoa in their feces. Farm animals (notably sheep and pigs) become infected by consuming feed and water contaminated by barn cats’ fecal material.

Active forms of this parasite then multiply with the farm animals and encyst themselves in the brain, heart muscle, other skeletal muscle, and liver. The cysts are microscopic and can exists as long as the farm animal lives.

When these animals are slaughtered to provide meat, the raw meat contains the cysts which can then infected humans if it is eaten raw or not heated sufficiently to inactive various forms of this parasite. About 30% of all fresh pork is infected and is the main meat source of Toxoplasma gondii in the United Sates.

If cutting and grinding equipment is not thoroughly washed and sanitized, other raw meats such as ground beef can also become contaminated. About 5% of the ground beef sold in supermarket contains some pork because the grinding equipment is not properly cleaned between grinding operations. Cysts of this protozoa are also found in wild game meats such as elk, moose, and venison.

Symptoms of the disease in humans are fever, muscle aches, headaches, loss of appetite and sore throat. Other symptoms will appear, depending upon the internal organs involved. In pregnant women, these parasites can be carried by way of the placenta to fetal tissue. If fetuses are infected, spontaneous abortions may occur. Most infected infants show no obvious symptoms at birth, but will show signs of eye damage and mental retardation later in life.

It is estimated that there are over 3,300 cases of congenital Toxoplasmosis each year resulting in 450 deaths of infants and young children. Other surviving infected children are mentally retarded as a result of this parasitic infection.
Infective Parasitic Pathogen: Toxoplasma gondii

Campylobacteriosis symptoms

2011-06-30T21:36:00.001-07:00

Campylobacteriosis is the leading cause of diarrhea in the developing world, with the number of cases exceeding those of salmonellosis and shigellosis.

Campylobacteriosis is the name of the illness caused by C. jejuni. It is also often known as campylobacter enteritis or gastroenteritis.

Symptoms of illness caused by Campylobacter jejuni include: diarrhea (which may be quite severe and bloody), fever, headache, nausea and severe abdominal pain.

The illness may linger for 1 to 2 weeks and there may be a relapse when recovery seems imminent.

This illness is more severe in adults than in children and can sometimes lead to a form of reactive arthritis.

Symptoms of the illness are similar to other food borne illness caused by Salmonellosis spp, Shigella spp and Escherichia coli.
Campylobacteriosis symptoms

Gastroenteritis

2011-05-08T06:58:00.000-07:00

Gastroenteritis is one of the most common illness of humans. It is an inflammation of the stomach and intestinal lining.

Eating chemical toxins in food, drinking excessive alcohol, food allergies, foodborne illness, intestinal viruses, cathartics and other drugs can cause gastroenteritis.

Bacteria, viruses and protozoa all of which can be transmitted through contaminated food as well as from person to person.

Gastroenteritis is an acute diarrheal disease that affects both children and adults throughout the developed and developing world.

In developing countries, acute diarrheal disease illness remain one of the major causes of long term morbidity and mortality because for the majority of the population, access to clean water and safe food sources are limited.

Acute gastroenteritis causes almost 3 million deaths each year worldwide, mostly among children under 5 years of age in developing countries.

There are thousands of different organism that can cause gastroenteritis. In the United States, it is usually caused by viruses and less commonly by bacteria.

Acute gastroenteritis can follow the ingestion of pathogenic microorganisms or toxins produced by these agents.

Ingestion of contaminated food or drink is most common, but swimming or bathing in contaminated water can also result in exposure, particularly among travelers.
Gastroenteritis

Acinetobacter infection

2011-03-24T20:21:00.000-07:00

Acinetobacter is a group of gram positive, nonmotile bacteria most commonly found in the soil or water.

This bacterium has been isolated from various types of opportunistic infection. Various factors predisposing to severe infections, such as underlying disease, malignancy, burns or major surgery, have been indentified and are common to many other pathogens.

Acinetobacter most often colonize patients in intensive care units, particularly those with devices such as endotracheal tubes, indwelling urinary catheters, intravascular catheters or surgical drains.

Risk factors include recent surgery, antibiotic therapy, and immunosuppresion. Patients with serious underlying illnesses can become colonized rapidly with Acinetobacter from highly contaminated environment.

Acinetobacter is primarily spread from person to person and from fomites, such as medical equipment. It is possible that aerosolization is a route of exposure.

Acinetobacter spp can cause infection in virtually every organ system: septicemia, urinary tract infections, eye infections, meningitis, skin infections, pneumonia and endocarditis.
Acinetobacter infection

Food Infection Diseases

2010-12-12T23:52:00.000-08:00

Food Infection Diseases
The cause of food borne diseases is mainly the ingestion of infected food. Apart from gastrointestinal problems and related illness due to improper diet, nutritional deficiencies and over heating, the causes of food borne illness may be due to either
1- Food Infection
2- Food Intoxication

The entry of pathogenic organisms and parasites into the body and the reaction of the body to the presence of organisms or their metabolites cause of the body to the presence of organisms or their metabolites cause food infection.

Pathogenic organisms make their entry through the food chain i.e. by consuming foods contaminated with such organisms. Bacterial food infection refers to food borne illness cause by the entry of bacteria into the body.

Food intoxication or poisoning is cause by consuming food contaminated with toxic substances.

Food infections may be broadly sub classified into two types.

1- Those in which the contaminated food does not ordinarily support the growth of the pathogenic organisms but merely carries them. Such food infections include diseases such as diphtheria, dysentery, typhoid, cholera, tuberculosis, infectious hepatitis, etc.
2- Food infections in which the food serves as a culture medium for the growth of pathogens to increase in number and cause infection when such food is consumed leading to diseases such as salmonellosis, shigellosis, gastroenteritis, etc.

Food infections can lead to outbreak of diseases in epidemic propositions.
Food Infection Diseases

The Quinine Story

2010-08-25T03:04:00.001-07:00

The Quinine Story
Ever since is acceptance in 1640 as a proven remedy for the malaria disease, quinine has been the mainstay of malaria treatment and still is today.

Having observed Peruvians treating malaria successfully, Jesuit priests living in Peru returned to Europe with the bark of certain tree that, when boiled and the water drink, greatly improved the survival chances of a malaria victim.

Once introduced to Europe, cinchona (as it was then known) became the drug of choice after use by such famous patients as Charles II and the Archduke Leopold.

Despite its bitter taste and the fact that it sometimes produced deafness, nausea and vomiting, or that its method of action was still mysterious, quinine became known as a miraculous drug.
Its use was linked with serious risks including its association with blackwater fever, an occasional complication of malaria, but known to be one of the commonest causes of death among expatriates in Africa.

It is suspected that irregular doses of quinine used as a prophylactic may have caused this much feared disease.

Today, quinine taken with tetracycline is often the last drug used, after other drugs failed to quell malaria.
The Quinine Story

Parasites as pathogens

2010-07-09T02:01:00.000-07:00

Parasites as pathogens
The true definition of a parasite is an organism that lives on or in another organisms, deriving benefit from it but providing nothing in return.

Nor all ‘parasites’ cause disease; organisms such as Entamoeba dispar, a protozoan, live in the human gut without causing disease and are thus colonizers.

Around 500 million individuals in the world are infected with amebiasis caused primarily (90%) by E. dispar.

This closely related species E. histolytica is capable of invading the bowel wall, causing colitis and abscesses in the liver, brain and other tissues.

E. histolytica is a powerful pathogen that uses proteases to destroy hosts’ tissues, kill some hosts’ cells and “phagocyte” red cells.

Multicellular parasites such as schistosomes may also be pathogens. In the past, diseases caused by metazoan parasites, such as schistosomiasis, were sometimes called infestations. Nowadays all parasitic diseases are called infection.
Parasites as pathogens

Short History of Tuberculosis

2010-06-07T08:35:00.001-07:00

Short History of Tuberculosis
In the Paleolithic period, people lived as wanderers, did not settle in villages or permanent locations, and do not congregate in large groups.

While tuberculosis may have occurred sporadically, it an other infections disease probably did not occur in epidemic form.

Beginning in about 8000 BC, humans developed primitive agricultural techniques that allowed settlement in permanent sites and with this development came the domestication of cattle, swine and sheep.

In all probability, tuberculosis occurred more frequently in this setting, but it nevertheless remained rare.

Tuberculosis probably occurred as an endemic disease among animals long before it affected humans. Mycobacterium bovis was the most likely infecting organism and the first human infections may have been with Mycobacterium bovis.

Since Mycobacterium tuberculosis infects all primate species, it is also possible that this species existed in subhuman primates before it became established in humans.

Tuberculosis probably occurred as a sporadic and unimportant disease of humans in their early history. Epidemic spread began slowly with increasing population density.

This spread and the selective pressure it has exerted have occurred at different times around the globe.

The epidemic slowly spread worldwide as a result of infected European travelling to and colonizing distant sites.

In the 1700s and early 1800s tuberculosis prevalence peaked in Western Europe and the United States and was undoubtedly the largest cause of death.

100 to 200 years later it had spread in full force to Eastern Europe, Asia, Africa and South America.

1.6 millions death worldwide due to tuberculosis in year 2002 alone. Currently tuberculosis kills 1.8 million people each year. However scientist believed that can be averted by 2050 with better testing, drugs and vaccines.

Treatment from 1995 to 2008 saved six millions lives. However 36 millions infected with tuberculosis during 1995-2008 were cured and incidence of the lung wasting disease has begun to regress, but only by about one percent per year.
Short History of Tuberculosis

Theories about Malaria

2010-05-07T09:07:00.000-07:00

Theories about Malaria
It took a long time for the connection between malaria and swampy ground to be made.

Medieval beliefs that planet and comets rained down a fever poison or that electrical storms were responsible, had to be overcome first.

During the first half of the nineteenth century it was also believed that dew falling on the decks of ships before sunrise would produce small insects that carried the fever.

It was further thought that preferred targets were of fair complexion and were fond of alcohol.

From the middle ages up until just over 100 years ago, the dominant theory governing malaria transmission concerned the fact that swamp air contained chemical poisons released from rotting wood.

To avoid this, houses were built facing away from wetlands and lakes, and double storey houses were referred as it was thought that the air did not rise much above ground level.

Known in the Middles Ages as ‘the ague’, malaria’s connection with marshy ground was entrenched when it was eventually given the Latin name that means ‘bad air’, i.e. mal’aria.
Theories about Malaria

The definition of Pathogen

2010-04-14T03:48:00.001-07:00

The definition of Pathogen
A pathogen is defined as any organism capable of invading the body and causing diseases. Such an organism is said to be pathogenic.

Robert Koch isolated and identified organisms such as Mycobacterium tuberculosis and Bacillus anthracis, where the isolation of the organism only occurred in the presence of disease.

It is easy to define these bacteria as pathogens. They also fulfill Koch’s further definition of a pathogen, that introduction of a pure culture of the organism into a health host can cause the disease.

This definition works well for many bacteria, but does not fully describe the complex interactions between microbes and humans which more recent understanding has revealed.

For instance, Escherichia coli is found in huge numbers in the healthy human bowel, and could therefore be defined as non-pathogenic.

E. coli is also an important cause of diarrheal disease and potent enterotoxin and other pathogenicity determinants have been described on some strains.

E. coli can therefore behave as a pathogen or as a colonizer, depending on various circumstances.

Changes in medical practice mean that increasing numbers of patients are immunocompromised as the result of either disease or treatments.

In such patients organisms which are usually non-pathogenic, such as saprophytic fungi, may act as pathogens.

Intensive therapy medicine, with insertion of intravascular cannulae allows Staphylococcus epidermis, a normal part of the skin flora, to enter the cannula and cause blood borne infection: behaving as a pathogen.
The definition of Pathogen

Immunity factor in diarrheal diseases

2010-03-21T17:46:00.000-07:00

Immunity factor in diarrheal diseases
Immunity plays an important role in susceptibility to enteropathogens. Maternal antibody is provided to the infant through breast milk and this protects against a variety of enteric infections.

Transplacental antibody may also play a role in some. Immunity is actively acquired by the individual who has a diarrheal disease or in some cases even an asymptomatic infection.

There is also evidence that competence of the immune system can be compromised, such as by macronutrient deficiencies, reducing the resistance to enteric infection.

Immunocompetence in a child can be compromised by previous viral infection, such as measles or influenza, or by other infections, such as tuberculosis or typhoid fever.

These infections , along with micronutrient deficiencies, could place individual at a greater risk of diarrhea or of more severe illness through alteration in immune function or by other mechanisms.

Cholera was the first diarrheal disease for which a vaccine was available . A prenatal cholera provides approximately 50% protection lasting for less than 6 months. New killed or live V. cholera vaccines may offer greater efficiency and duration of protection.
Immunity factor in diarrheal diseases

HIV/AIDS

2010-03-02T21:33:00.001-08:00

HIV/AIDS
AIDS stands for “acquired immunodeficiency syndrome” (a syndrome being a cluster of medical conditions).

AIDS is caused y the human immunodeficiency virus, which weakens and then destroy the body’s immune systems.

HIV/AIDS has spread in the last two decades, causing massive human death and suffering, particularly in the developing world.

There is a growing recognition that HIV/AIDS is not just a serious heath issue in developing countries, but a major development catastrophe that threatens to dismantle the social and economics achievement of the past half century.

HIV/AIDS is a fatal, sexually transmitted disease or infection (STD). Once a person is infected with HIV, he or she is infected for life.

In all but a very small proportion of cases HIV/AIDS destroys a person’s immune system.

The time between becoming HIV positive and the onset of AIDS varies.

In industrialize countries, the average time between infection with HIV and the appearance of symptoms is about 10 years, but in the poorest countries of the world, without access to proper care, the time is sometimes as short as five years.

One an HIV infected person’s immune system is severely damaged, he or she becomes vulnerable in life threatening “opportunistic infections” and is diagnosed as having AIDS.

Not everybody is equally likely to become infected with HIV and to transmitted to others.

Like other STDs, HIV is difficult to spread except by sex or other direct contact with the bodily fluids of an infected person.

About three quarters of HIV transmission worldwide occurs through sexual intercourse involve sexual relations between men.

The other modes of HIV transmission are transfusion of contaminated blood products, reuse of contaminated syringes by injecting drug users, infection via birth or nursing from an HIV-positive other to her child during pregnancy, childbirth, or breast feeding, and reuse of needle in medical settings.

HIV cannot be transmitted y a sneeze, a handshake or other causal catch.
HIV/AIDS

Lower respiratory tract infection

2010-02-16T21:11:00.000-08:00

Lower respiratory tract infection
The principal function of the respiratory tract is gas exchange. It is therefore expose to the gaseous environment continuing particulate organic material such as bacteria, viruses and spores.

The entire respiratory tract is constantly exposed to air but the majority of particles are filtered out in the nasal hairs and by inertial impaction with mucus-covered surfaces in the posterior nasopharynx.

The epiglottis, its closure reflex and the cough reflex all reduce the risk of microorganisms reaching the lower respiratory tract.

Particles small enough to reach the trachea and bronchi stick to the respiratory mucus lining their walls and are propelled towards the oropharynx by the action of cilia (the mucociliary escalator).

Antimicrobial factors present to respiratory secretions further disable inhaled microorganisms.

They include lysozyme, lactoferrine and secretory IgA.

Particles in the size range 5-10 um may penetrate further into the lungs and even reach the alveolar air spaces.

Alveolar macrophages are available there to phagocytes potential pathogens. If these are overwhelmed, neutrophils can be recruited via the inflammatory response.

The defenses of the respiratory tract are a reflection of its vulnerability to microbial attack.

Acquisition of microbial pathogens is primarily by inhalation, but aspiration and mucosal and haematogenous spread also occur.

Individuals with healthy lungs rarely have any bacteria beyond the carina.

Respiratory pathogens have developed a range of strategies to overcome host defences. Influenza virus for example has specific surface antigens that adhere to mucosal epithelial cells.

The virus also undergoes periodic genetic reassortment , resulting in expression of novel adhesions to which the general population has no effective immunity.

Streptococcus pneumonia and Haemophilus influence both produce an enzymes (IgA protease) capable of disabling mucosal IgA.

Both of these species , other capsulated bacteria and mycobacteria are all resistant to phagocytosis. Penetration of local tissue is usually required before damage occurs. Although viruses using the common cold appear to be an exception.
Lower respiratory tract infection

Infectious Mononucleosis

2010-01-31T07:01:00.001-08:00

Infectious Mononucleosis
Infectious mononucleosis is an acute disease due to infection by the Epstein-Barr virus (EBV) and characterized by the tetrad of fever pharyngitis, lymphocytosis and fatigue.

Primary EBV infection may occur during childhood, adolescence or adulthood.

Approximately 50% of all children, the infection is subclinical.

When this infection occurs in adolescents and adults, it may be either subclinical or it may be recognized as infectious mononucleosis.

Once infected with virus, persons remain asymptomatically infected for life, and the virus is shed intermittently from the oropharynx.

The route of transmission for this infection is, therefore by oropharyngeal contact (usually kissing) between an uninfected and a healthy EBV-seropositive individual who is asymptomatically shedding the virus.

The virus, after having been acquired first binds to and infects the nasopharyngeal cells and then the B-lymphocytes.

Circulating B-lymphocytes carry the virus throughout the body, producing a generalized infection of lymphoid tissues.

The activated B-cells stimulate the proliferation of specific killer T-cells, giving rise to an atypical lymphocytosis associated with primary EBV infection.

These killer T-lymphocytes destroy virally infected B-cells.

Another type of T-cells released are the suppressor T-cells which inhibit the B-cell production to immunoglobulins.

The onset of this disease is marked by malaise lasting from a few days to a week followed by fever, pharyngitis (which may be severe) and adenopathy.

In other cases, enlargement of a solitary lymph node or a group of nodes may be the sole clinical manifestation.

Splenomegaly due to hyperplasia of the red pulp is observed in about 50% of cases. Because of the risk of splenic rupture, heavy lifting and contact sports should be avoided for two months after presentation, even if there is no lasting splenomegaly.
Infectious Mononucleosis

What is Tamiflu?

2010-01-14T20:05:00.000-08:00

What is Tamiflu?
This medicine contains as active ingredient oxeltamivir phosphate used in the treatment of symptoms of influenza (flu).

Tamiflu is one of the classes of antiviral drugs called neuraminidase inhibitors.

This medicine speeds recovery from the flu. When started during the first 2 days of the illness, it hastens improvement by at least a day.

It also can prevent the flu of treatment is started within 2 days after exposure to a flu victim.

As the flu virus takes hold in the body, it forms new copies of itself and spreads form cell to cell.

Neuraminidase inhibitors fight the virus by preventing the release of new copies from infected cells

Tamiflu is taken in liquid or capsule form.

Tamiflu can prevent the flu as long as continue taking this medication but getting a yearly flu shot is still the best way of avoiding the disease entirely.

For older adult, those in high risk situations such as health-care work, and people with an immune deficiency or respiratory disease, vaccination remains a must.

To provide any benefit, Tamiflu must be started within two days of the onset of symptoms or exposure to the flu.

If have the flu, continue taking it twice daily for 5 days, even of started to feel better.

To prevent the flu take it once a day for at least 7 days. Protection lasts as the medicine taken.

Unless otherwise directed by doctor or pharmacist, take this medication as directed. Do not take more of them and do not take them more often then recommended on the label.
What is Tamiflu?

Immune System

2009-12-15T22:47:00.001-08:00

Immune System
Your body’s immune system is a very complicated network of organs and cells that work together to fight deadly intruders called antigens, which are any organism that could make you sick, like bacteria, microbes, parasites and viruses.

An antigen, such as a virus, is a virus, is a parasite.

A parasite cannot survive by itself – if needs to feed off of an animal, human, or plant (also called the host) to survive.

Once inside the cells of a host, a virus tries to become active and multiply. If it successful it can eventually create so many copies of itself that it causes the cell to burst releasing the virus into the body.

Then the virus finds more cells on your body in which to live. This process can continue on and on, until the virus has attacked enough cells to make you ill.

However, a healthy and strong immune system can usually kill any viruses before they multiply to such a damaging degree.
Immune System

A Historical Perspective of Dengue

2009-11-14T21:20:00.000-08:00

A historical Perspective of Dengue
The story of dengue in many ways starts in the Americas.

Dr. Benjamin Rush made the first good clinical description of dengue.

He was in charge of hospitals under General George Washington in the Oriental Army and described for dengue outbreak in Philadelphia in 1780:

“This fever generally came on with rigor, but seldom with a regularly chilly fit. The pains which accompanied this fever were exquisitely severe in the head, back and limbs.

The pains in the head were sometimes in the back parts of it, and at other times they occupied only the eyeballs.

A few complained of their flesh being sore to the touch, in very part of the body. Its general name among all classes of people was the break-bone fever.”

Dengue today presents with the same fever, headache, eye pain, myalgia and arthralgia.

The US military’s dengue research efforts started just after the Spanish-America War, sparked by the very many dengue causalities in the Philippines.

A dengue commission was established in 1900, and Ashburn and Craig were sent to the Philippines to determine the etiology of dengue and to devise countermeasures.

Although a series of experiments they deduced that dengue was caused by “an ultra microscopic and non-filterable agent,” or a virus.

Ashburn and Craig confirmed that virus could be transmitted from person to person by both mosquito and by syringe; they made careful description of the disease to include leucopenia.

Important for vaccine development, they demonstrated that immunity following infection was absolute; they could only make healthy volunteers with dengue one time.

During World War II, Japan and the United States of America had large dengue research programs.

Dr. Hotta and Dr. Kimura in Japan isolated the dengue serotype 1 virus (DENV-1) shortly before Dr. Sabin and Dr. Schlesinger did so in Hawaii.

In the 1950s, the face of dengue changed dramatically with the widespread recognition of DHF. The army and the Air Force sent Dr. Bill Hammond to investigate the 1956 outbreak of hemorrhagic fever in the Philippines.

He worked with Philippines and Thai scientist to isolate DENV-3 and DENV-4.

The most important pathological process that distinguished DHF from dengue is plasma leakages that can lead to shock and death.

Untreated, DHF has a mortality rate of around 10%. With careful fluid management, however, mortality rates drop to below 1%.

DHF can occur in any age group, but it is most common among children living in dengue hyperendemic areas.
A historical Perspective of Dengue

Anthrax: The Disease and the History

2009-10-25T20:38:00.000-07:00

Anthrax: The Disease and the History
Anthrax is a peracute, acute or sub-acute disease primarily affecting herbivores but also encountered in other mammals, including humans, and occasionally birds.

The words ‘anthrax’ is derived from the Greek anthrakos, meaning coal, referring o the characteristics eschar in the human cutaneous form of the disease.

The familiar name ‘black bane’ and the French and Italian names for the disease charbon and carbonchio, similarly reflect this manifestation.

Names in other languages and older English names refer to other of its significant manifestations or to its sources of infection, viz Milzbrand (German) and miltvuur (Duth), meaning ‘spleen fire’, pustula maligna (Spanish), Bradford disease, woolsorter’s disease, ragpicker’s disease and so on.
Its numerous synonyms in many national languages and local dialects reflect the historical familiarity with the different syndromes before it was realized that they were manifestations of one etiological agent, Bacillus anthracis.

Fifth and sixth plaques of Egypt in the time of Moses are thought by some to have represented the earliest historical; reports of the anthrax due to respectively to systemic and cutaneous forms of the disease.

Anthrax appears to have featured in Asia Minor at the time of Siege of Troy (ca. 1200 BC) an description of the typical symptoms in the writing of Homer (ca. 1000 BC), Hippocrates (ca. 400 BC), Varro (116 – 27 BC), Virgil (70 – 19 BC and Galen (ca. 200 AD) indicate that the Greeks and Romans were well acquainted with it.

Scientifically reports began with the descriptions of malignant pustule and the disease in animals in 1700s.

The nineteenth century saw anthrax as the first disease of man and animals shown to be caused by a microorganism and as the disease on which much of the original work on bacteria and vaccines was done.
Anthrax: The Disease and the History

Measles

2009-10-04T19:41:00.001-07:00

Measles
Measles is a viral disease most commonly affecting school age children, although adults contact the ease as well.

There are two main varieties: German measles and common measles.

There is an immunization but if there are existing conditions, they may be complications.

German measles (rubella) is caused by a virus and has a rapid recovery period, but the disease must run its course and there is little that can be done medically for its treatment, German measles is a mild illness, alarming only to pregnant women.

If a woman contracts German measles during the early months of pregnancy the newborn can suffer from such malformations as heart defect, deafness, mental retardation, and blindness.

Symptoms of German measles may include fever headache and stiff joints (mainly in the neck), although most people seldom complain of any symptoms.

A rash that lasts for about three days appears on the arms, chest and forehead.

Lotion may be applied to the rash to relieve itching, and the patient should stay away from other people to avoid spreading the disease.

Common measles (rubeola) is a highly contagious disease spread by droplets from the nose throat and mouth.

The first symptoms of common measles are a fever that lasts for a couple of days followed by a cough, runny nose and inflammation of the eyes.

Stomach pains, diarrhea, and vomiting may also occur. Within twenty forty-eight hours, small red spots with white centers appear in the inside of the cheeks.

A rash which is first seen on the face and upper neck and then spreads down the back and trunk and then to the limbs, usually appears three to five days after the onset of the first symptoms.

As the rash spreads fever goes down. After about five days, the rash fades in the same order it appeared. Common measles may have been serious complications, such as ear infections, pneumonia, encephalitis and injury to the nervous system.
Measles

American Trypanosomiasis

2009-09-12T18:57:00.000-07:00

American Trypanosomiasis
American Trypanosomiasis or Chaga’s disease is caused by Trypanosomiasis cruzi, a protozoan parasite found only in the America; infects wild animals and to a lesser extent humans from southern South America to the southern United States.

An estimated 10-12 million people are infected, mostly in rural areas, resulting in about 45,000 deaths annually.

The disease is often acquired in childhood. In many countries in South America, Chaga’s disease is the most important cause of heart disease.

T. cruzi, is transmitted by reduviid (triatomine) bugs infected by ingesting blood from animals or humans who have circulating trypanosomes.

Multiplication occurs in the ingesting tract of the bug and infective forms are eliminated in feces.

Infection in humans occurs when the parasite penetrates the skin through the bite wound mucous membranes or the conjunctiva.

Transmission can also occur by blood transfusion or in utero. From the blood stream, T. cruzi invades many cell types but has a prediction for myocardium, smooth muscle and CNS glial cells.

Multiplication causes cellular destruction, inflammation, and fibrosis with progressive disease over decades.

Symptoms
The acute stage is seen principally in children and last 1-months. The earliest findings are at the site of inoculation either in the eye – Romana’s sign (unilateral edema, conjunctivitis and lymphadenopathy) – or ion the skin or a chagoma (selling with the local lymphadenopathy).

Subsequent findings include fever, malaise, headache, mild hepatosplenomegaly, and generalized lymphadenopathy.

Acute myocarditis and meningoencephalitis are rare but can be fatal.
American Trypanosomiasis

Vibrio Cholerae and Cholera

2009-08-30T00:17:00.000-07:00

Vibrio Cholerae and Cholera
The bacterium V.cholerae is a gram negative, nonsporulating, straight or curved rod. It possesses a single polar sheathed flagellum and is highly motile.

A halophiclic organism, it is found in estuarine or marine environments, and it is growth in laboratory media is generally stimulated by the presence of 5 to 90 mM sodium, depending on actual culture conditions.

Outside the human host, Vibrio Cholerae has been found free living in water and also in association with plankton, most notably copepods.

In its most severe form, cholera is capable of causing death within 3 hr after the onset of symptoms, which occurs 12 to 72 hrs after ingestion of V. Cholerae.

The distinctive feature of the disease is the profuse secretory diarrhea that results from the action of cholera toxin on cells of the intestinal epithelium.

Fluid loss by this route can reach as much as 200 ml/kg of body weight per day with total losses exceeding 100% of body weight over the course of several days.

The concomitant loss of plasma solutes such as sodium potassium and chloride ions leads to electrolyte imbalances, acidosis and ultimately death.

However, effective treatment of cholera is both simple and relatively inexpensive, consisting of oral and/or intravenous rehydration therapy couples with administration of antibiotics.

Cholera typically begins with the ingestion of V. Cholerae in contaminated food or water.

Cholera is a non invasive infection where the organism colonizes the intestinal lumen and produces a potent enterotoxin.

In severe cases, the hypersecretion of sodium, potassium, chloride and bicarbonate induced by the enterotoxin results in a profuse, pale, watery, diarrhea containing flakes of mucus, described as rice water stools.

Unless the massive losses of fluid ad electrolyte are replaced, there is a fall in blood volume and pressure, an increase in blood viscosity. Renal failure, and circulatory collapse.

In fatal cases death occurs within a few days.
Vibrio Cholerae and Cholera

Nipah Virus

2009-07-23T17:27:00.000-07:00

Nipah Virus
In 1998, Nipah virus first emerged in Malaysian pigs as a respiratory and neurology disease and then jumped to humans with lethal consequences.

Nipah virus can cause severe encephalitis and vascular disease in people, and in the Malaysia outbreak, those with virus infections had a mortality of about 40 percent.

More than 100 people died.

Essentially all of those who became infected had direct contact with pigs, either in pig-rearing facilities or in slaughter houses.

The rapid spread of Nipah virus among pig farms throughout peninsular Malaysia and into Singapore was more likely caused by an intense sell-off of infected pigs following the initial outbreak.

In order to control outbreak, millions of pigs were slaughtered, hundreds of farms were closed, and tens thousands of jobs lost Nipah virus cost the Malaysia government more than $350 million and destroyed the live-hoods of countless numbers of people.

The origin of Nipah virus has been traced back to two native species of fruit bats or “flying foxes” from the genus Pteropus (and the family Pteropodidae) the Malayan Flying Fox – Pteropus vampyrus, which is ubiquitous through peninsular Malaysia, Borneo, and Thailand, and the Variable Flying Fix – P. hypomelanus.

Pteroped bats, which do not develop clinical signs of disease when infected with Nipah virus are considered the natural reservoir for henipaviruses the vital genus to which Nipah belongs) and have most likely co-evolved with these viruses over time.

The range includes the Old World typical regions, from Madagascar eastward through Southeast Asia, Australia and the South Pacific Island.

The bats serve vital roles in tropical ecosystems acting as seed disperses and pollinators for rainforest plants.

Hunting and deforestation threaten this ecologically important group of animals throughout their range.
Nipah Virus

The 1976 Swine Flu Fiasco

2009-06-15T19:38:00.000-07:00

The 1976 Swine Flu Fiasco
Shortly after new army recruit and soldiers returning form the Christmas holidays arrived at Fort Dix, New Jersey, in January 1976, an outbreak of influenza ensued.

Most of the illness remained mild with only a few hospitalized victims. One sick recruit refuse to answer sick call died from influenza related pneumonia.

Tests showed that he and three others had been infected with and H1N1 swine virus, while all the others had been infected with a variant of the H3N2 virus hat had been circulating every year since it was introduced to human population in 1968.

There had been a few reported cases of human infection by the swine flu since 1974, but the virus had grown so adapted to pigs that it no longer adjusts well enough in the human host to be transmitted from person to person.

Fearful that the H1N1 subtype of 1918 had begun to resurface within the human population, with the prospect of a similar pandemic, scientist debated the issue and considered what should be done to prevent such a disaster.

Some scientists believed this was not the same type variant of 1918, while many others feared it could be.

President Ford at that time, following recommendations coming out of the debate announced in March the federal government’s intent to immunize the entire population of the United States against the swine flu to prevent a disastrous outbreak expected in the fall of 1976, similar to the 1918 pandemic.

Congress appropriated $135 million for the vaccination program.

Ten days after the vaccinations began, three elderly individuals with the heart conditions died shortly after receiving their shots. The news media jumped on this to create fear of the vaccine.

This prompted President Ford and his family to encourage people to take the shots by televising their own vaccinations.

Over 40 million people did receive the vaccine before the program ended in December.
The 1976 Swine Flu Fiasco

H1N1 Swine Influenza Virus

2009-05-26T16:54:00.000-07:00

H1N1 Swine Influenza Virus
Viruses of the classical H1N1 lineage were the dominant cause of influenza among pigs in North America from their first isolation.

Classical H1N1 viruses have also been isolated from pigs in South America, Europe and Asia.

There is only limited evidence of maintenance of human H1N1 influenza viruses after natural introduction into swine populations but human H3N2 viruses have been recovered frequently from pigs in Asia and Europe.

Experimental infection studies have shown that pigs can be infected with a wide range of avian influenza virus (AIVs) and naturally acquired infections of pigs with AIVs have also been documented from multiple areas of the world.

In particular, an avian H1N1 virus introduction into pigs Europe in late 1970s spread throughput much of the European continent and United Kingdom and ultimately became a dominant cause of swine flu in these areas.

These avian-like H1N1 viruses have also undergone genetic/antigenic drift and have spread from pigs to domestic turkeys.

The occurrence of influenza virus infections in pigs poses two important public health issues: zoonotic infections of people with swine influenza viruses and the potential for pigs to serve as hosts for the creation of novel viruses of pandemic potential for the human population.

Infections with swine influenza viruses is generally limited to the respiratory tract, with virus replication demonstrated in epithelial cells of the nasal mucosa, tonsils, trachea, lungs and tracheobronchial lymph nodes.

Swine flu is an acute infections and virus clearance is extremely rapid. In most experimental studies, nasal virus shedding begins on day 1 postinoculation (P1) and ceases within 7 days.

Likewise, swine influenza virus could not be isolated from lungs or other respiratory tract tissues after day 7.

Infections with H1N1, H1N2 and H3N2 subtype viruses are clinically similar, and viruses of all subtypes have been associated with acute respiratory episodes in most European countries.

Disease onset is sudden, after an incubation period of 1 – 3 days. Disease signs typically appear in a large percentage of animals of all ages within a herd or epidemiological unit.
H1N1 Swine Influenza Virus

Influenza – Major Occasional Pandemic Outbreaks

2009-04-27T00:06:00.000-07:00

Influenza – Major Occasional Pandemic Outbreaks
Influenza or simply “flu” is caused by a virus. It occurs not only in occasionally major pandemic outbreaks, but also in epidemics of variable severity almost every winter.

The term “influenza” has been derived from the Italian ‘influentia’ in the mid-1300s, indicating that, at the time, the illness was believed to result from astrological influences.

Yet, the aetiloogy of the disease and the explanation for its peculiar behavior remained elusive.

At the turn of the 19th century, influenza was thought to be due to a bacteria infection with Haemophilus influenzae.

It was not until 1931 that Richard Shope showed that swine influenza could be transmitted with filtered mucus, indicating that the causative agent was a virus.

A few years later, Smith and co-workers isolated the influenza virus from humans with respiratory illness.

The burden of influenza for the society, not only from a clinical but also from an economic perspective, is often underestimated.

This relates particularly to the recurring annual winter epidemics. Fortunately, since the virus was first discovered, efficient means to contain the infection have been developed.

Vaccination is the cornerstone of influenza prevention and control. Accordingly, the WHO (World Health Organization) has issued guidelines for implementation of influenza vaccination programs in individual countries.

Yet, in many places, implementation of vaccination programs remains woefully deficient. This implies that significant numbers of people at risk of the complications of influenza remain vulnerable to infection and possibly death.
Influenza – Major Occasional Pandemic Outbreaks

Pathogen

2009-04-13T00:14:00.000-07:00

Pathogen
A pathogen is defined as any organism capable of invading the body and causing disease.

Such an organism is said to be pathogenic.

Koch isolated and identified organisms such as Mycobacterium tuberculosis and Bacillus anthracis, where the isolation of the organism only occurred in the presence of disease.

It is to define these bacteria as pathogens.

They also fulfill Koch’s further definition of a pathogen that introduction of a pure culture of the organism into the healthy host can cause the disease.

This definition works well for many bacteria, but does nor fully describes the complex interactions between microbes and humans which more recent understanding has revealed.

For instance, Escherichia coli is found in huge numbers in the healthy human bowel, and could therefore be defined as non-pathogenic.

E. coli is also important cause of diarrhoeal disease and potent enterotoxins and other pathogenic determinants have been described in some strains.

E. coli can therefore behave as a pathogen or as a colonizer depending on various circumstances.

A broader definition of a ‘biological agent’ used in European Union legislation is: ‘any microorganism, cell culture or toxin capable of entering the human body and causing harm’.

Changes in medical practice mean that increasing numbers of patients are immunocompromised as the result of either disease or treatments.

In such patients organisms which are usually non-pathogenic, such as saprophytic fungi, may act as pathogens.

Intensive therapy medicine, with insertion of intravascular cannulae, allows Staphylococcus epidermitis, a normal part of the skin flora, to enter the cannula and cause blood-borne infection: behaving as a pathogen.
Pathogen

History of Influenza

2009-03-23T18:13:00.000-07:00

History of Influenza
Hippocrates recorded an epidemic of a flu-like infection in 412 B.C that wiped out the Athenian army.

The sixteenth century saw two flu pandemics that spread throughout Europe. The first, in 1510, infected nearly the entire population of Europe, but claimed few lives.

The second, in 1580, devastated cities and spread through the whole of Western Europe. The city of Rome, for example, had 9,000 fatalities.

At least pandemics of flu spread throughout Europe in the seventeenth century. In the past of 200 years eight great flu pandemics seized the world prior to the devastation wrought by the 1918 flu.

During a period of fourteen months beginning in the spring of 1918, half of the entire world’s population was infected with the influenza virus and nearly 41 million people died.

Every country in the world was affected, no matter how remote, and this occurred in an era before air travel and a global community existed.

Victims who died during the 1918 flu were typically healthy young adults. Among the 20 to 40 year old age group, the fatality rate from the 1918 flu was 50 percent.

The virus of 1918 was so effective at killing its host that within a short period of time it rendered itself extinct, people either immune to the virus or dead.

Since that time several other lesser pandemics have occurred across the globe, but health officials anxiously await the next deadly flu pandemic, which they predict as inevitable.

When it occurs, experts foresee millions of death, hospitals quickly flooded with cases of pneumonia, and every health care system in the world over whelmed by the volume of flu victims.
History of Influenza

Malaria in Ancient Greece and Rome

2009-03-04T10:37:00.001-08:00

Malaria in Ancient Greece and Rome
The ancient Greeks were well acquainted with malaria from about the year 500 BC when infected slaves may have carried the disease into Greece.

To a certain extend, malaria may well have contributed to the breakdown of ancient Greek civilization.

As early as 46 BC, Hippocrates described the malaria symptoms and differentiated between its various forms.

However, he incorrectly assumed that malaria was caused as a result of drinking stagnant water.

Malaria did not discriminate when choosing its victims. One famous victim was Alexander the Great.

Ancient Rome was seen to be vulnerable to the fever to the extent that Gei Febris, the fever goddess, as worshipped for her ability to cure the disease.

The fall of Rome has been attributed not only to hedonism and decadence, but also to the debilitating effects of the illness on its citizens.

Three emperors, Hadrian, Vespasian and Titus, are believed to have succumbed to malaria, while St Augustine is thought to have contracted it while carrying Christianity’s message from Rome to Britain.

Medieval Europe was well acquainted with malaria until land reclamation and improved drainage disrupted the mosquitoes’ breeding habits.

These habits were further discouraged inadvertently by the increased building of well lit and ventilated houses.
Malaria in Ancient Greece and Rome

The word of Influenza

2009-02-09T05:14:00.000-08:00

The word of Influenza
The word influenza is Italian for influence, as in the astral or occult influence of a visitation or outbreak that affects many people at the same time. First used in 1504, the word signified any disease epidemics.

In a severe flu outbreak of 1743 the word influenza was applied to the epidemic that began in Italy and spread throughout Europe.

Since then, the influenza, shortened to flu, means a serious infectious disease characterized by muscle and joint aching, prostration, and respiratory congestion with fever and headache.

It was not until 1931 that an influenza virus was identified in pigs, and finally in 1933 a human influenza virus was discovered by three researchers: Smith, Andrewes, and Laidlaw.

Both of these viruses were closely related to the Spanish flu virus of 1918. During the time of the 1918 flu pandemic, however, the suspected culprit was a bacterium named Hemophilus influenza. Viruses had not yet been discovered.

Although most people consider the flu simply and annoyance, and possibly a danger to seniors in poor health, influenza has been responsible for repeated, devastating worldwide pandemics capable of bringing entire nations to their knees.

It is hard to imagine today, but in 1918 the entire world was in the clutches of a deadly flu virus. The 1918 flu still remains the greatest plague the world has ever seen.
The word of Influenza

Pertussis

2009-01-18T17:35:00.001-08:00

Pertussis
Also known as whooping cough, pertussis is a respiratory disease caused by the bacterium Bordetella pertussis. The introduction of the whole-cell vaccines in the middle of the last century resulted in dramatic decrease in disease incidence.

The virulence factors of Bordetella pertussis can be divided into adhesions, such as pertactin and toxins, such as pertussis toxin. Adhesins attachment to the host and toxins are involved in immune evasion and possible resource extraction.

The infection is characterized by bacterial colonization of ciliated respiratory in the trachea and bronchi. The incubation period is 6 – 20 days.

Classical pertussis is an illness of three stages. It starts with a catarrhal stage, with nonspecific symptoms similar to those of the common cold (duration 1 to 2 weeks). At the paroxysmal stage (duration 2 to 6 weeks), the cough becomes more prominent with staccato attacks, postussive whooping, and vomiting.

At the convalescent stage (duration several weeks), the frequency and severity of coughing attacks gradually decrease. The most severe cases of whooping cough occur in unvaccinated children under 1 year of age. This group accounts for most deaths.

Whooping cough is presently one of the 10 most common causes of death from infectious disease. The WHO estimates it to cause 50 million illnesses and over 350,000m deaths worldwide each year.

After introduction of whole-cell vaccines in the 1950s, its morbidity and mortality were significantly reduced in the developed world, whereas in the developing countries whooping cough has remained a major cause of infant mortality.

In highly vaccinated communities, Bordetella pertussis and Bordetella parapertussis infections often go undiagnosed because pertussis is thought to be rare and adequate laboratory diagnostic tests are not used or available.
Pertussis

Mumps (Epidemic Parotitis)

2009-01-03T15:45:00.000-08:00

Mumps (Epidemic Parotitis)
Mumps was recognized as a distinct clinical entity by the ancients. In ‘Of the Epidemics’, Hippocrates described mumps as follows: ‘Swellings appeared about the ears in many on either side, and in the greatest number on both sides…. inflammations with pains seized sometimes one of the testicles, and sometimes both.’

Mumps was not considered a serious disease, although surprisingly large literature has appeared on the subject.

Contrary to measles, varicella, and pertussis, mumps is not a highly contagious disease, rarely afflicting infants. The majority of cases occur between five and ten years of age and 30 to 40 percent of the cases have inapparent infections.

Complications include testicular swelling and encephalitis, usually not succeeded by any residuals. Contrary to belief, mumps is rarely a cause of male sterility.

Because mumps is not a highly contagious disease, many children escape infection. Under certain circumstances epidemics of the disease occur among adults.
Mumps (Epidemic Parotitis)

Symptoms of measles

2008-12-22T06:37:00.000-08:00

Symptoms of measles
About ten to fourteen days after exposure to the measles virus, people infected with measles will get a rash, high fever cough, runny nose, and watery eyes. The eye symptoms can develop into conjunctivitis (pink eye), a condition that causes swelling and redness of the eye, tearing, and sensitivity to light. The skin rash often takes the form of bright red spots that are distinct and separate from each other.

They may multiply so rapidly, however that they appear to be a solid red mass. The rash usually starts behind the ears and along the hairline and then quickly spreads to the rest of the face, moving downward to the rest of the body. In addition to this red rash, light spots resembling grains of salt may appear on the inside of the patient’s cheeks near the back of the mouth. Doctors call these Koplik’s spots. These typical measles symptoms last for one to two weeks.

Most people recover form measles within ten to fourteen days. After they are well again they are no longer contagious, which means they no longer infect other people with the disease. In addition, people who have had measles develop an immunity to it – they will never catch measles again, even if someone with the disease sneezes or coughs right in their face.
Symptoms of measles

Measles

2008-12-17T06:35:00.000-08:00

Measles
Measles is a highly contagious disease. It is caused by a virus – an extremely tiny organism that can only reproduce itself by residing within living cells. Humans are the only living creatures who can develop measles, and they can only get it if they are exposed to the measles virus.

The most common way that people get infected with the disease is by breathing in tiny droplets of water vapor containing the measles virus. An uninfected person can get measles just by breathing the air in a room that was previously occupied by an infected person. The measles can live in the air for two hours after an infected person leaves the room. People can also get measles if they have direct contact with fluid from the nose or mouth of an infected person.

Once introduced into a person’s respiratory system, the measles virus proceeds to attach itself to the lining of the airways. Drawing energy from this new host, the virus begins to multiply and spread through the body.
Measles

Filariasis

2008-12-04T08:00:00.000-08:00

Filariasis
Filariasis is a helminthic infection found principally in tropical and subtropical areas in Africa, and in the South Pacific regions. The disease is transmitted from man through several genera and species of mosquitoes. The acute disease is manifested by recurrent chills and fever and by visible swelling or nodules of the lymphatics and redness of the overlaying skin due to parasitic involvement.

The illness usually subsides gradually with or without therapy. But in those who have been repeatedly infected and are chronically ill, the inflammatory reaction and scarring of the tissues surrounding the vessels may impede the flow of lymph and blood, and mammoth enlargement (“elephantiasis”) of the arms, legs, scrotum and breasts can occur. During World War II approximately fifteen thousand American military personnel became infected, but prompted withdrawal of these patients from the endemic zones prevented chronic disease and elephantiasis.

Filariasis was the first human disease described in which transmission through the skin was cause by the bites of arthropods. Doctor O. Wucherer (1868) found the embryonic filarial worms in the urine of a patient in Bahia, Brazil. T. R. Lewis (1872), working in India, observed the embryos in the urine and also in the blood, and Joseph Bancroft (1878) in Brisbane, Australia first described the adult worm. The parasite has been designated Wuchereria bancrofti.

The momentous discovery of the role of the mosquito in transmitting the disease was made by the Scotsman Patrick Mansion (1877) while he was practicing medicine in the Far East with the Chinese Imperial Maritime Customs. He became interested in the disease that confronted him, including filariasis. In that disease he recognized the parasites in peripheral blood films and also in postmortems material.

He noted the nocturnal appearance of the parasites in the peripheral blood and postulated that a blood sucking insect might be responsible for transmitting the infection. Manson proved the presence of the microfilaria in the mosquito Culex fatigans, thus supplying the missing link in the life cycle of the disease.
Filariasis

Giardiasis

2008-11-11T21:45:00.000-08:00

Giardiasis
Giardiasis is the most common intestinal protozoal infection in children in the United States and in most of the world. It is caused by Giardia lamblia. Endemic worldwide, the infection is classically associated with drinking contaminated water, either in rural areas or in areas with faulty purification systems. But even ostensibly clean urban area water supplies can be contaminated intermittently.

Persons have acquired the infection in swimming pools. Fecal oral contamination allows person-to-person spread. Day care centers have been recognized as major sources of infection, with an incidence of up to 50% reported in some centers. No symptoms occur in 25% of infected persons, facilitating spread to household contacts. Food-borne outbreaks also occur. Although infection is rare in neonates, giardiasis may occur at any age.

Symptoms
Giardia infection is followed by asymptomatic cyst passage, acute self-limited diarrhea, or a chronic syndrome of diarrhea, malabsorption and weight loss. Acute diarrhea occurs 1-2 weeks after infection and is characterized by abrupt onset of diarrhea with greasy, malodorous stools; malaise; flatulence; bloating; and nausea. Fever and vomiting occur in a minority of patients. Urticaria, reactive arthritis, biliary tract disease, gastric infection and constipation have occasionally been reported.

The disease has protracted course (more than 1 week) and frequently leads to weight loss. Patients who develop chronic complain of profound malaise, lassitude, headache, and diffuse abdominal pain in association with bouts of diarrhea – most typically foul smelling, greasy stools – intercalated with periods of constipation or normal bowel habits. This syndrome can persist for months until specific therapy is administered or until is subsides spontaneously. Chronic diarrhea frequently leads to malabsorption, steatorrhea, vitamin A and vitamin B12 deficiencies, and disaccharides depletion. Lactose intolerance, which develops in 20 – 40% of patients, can persist for several weeks after treatment and needs to be differentiated from relapsing giardiasis or reinfection.
Giardiasis

Malaria - Infectious disease

2008-11-07T18:29:00.000-08:00

Malaria - Infectious disease
Malaria kills three people every minute. Each year, it is thought that as many as 2.7 million people die from malaria and between 300 and 500 million suffer potentially fatal cases. The disease threatens 2.5 billion people, almost half the world’s population.

African countries south of the Sahara desert account for 90% of all clinical cases and nearly 90% of deaths caused by malaria. Children are most vulnerable to this major killer. In rural, tropical African areas, one child in 20 dies from malaria before he or she reaches the age of five years.

What is Malaria?
Malaria is a disease, caused by any of four species of parasite that is carried from person to person by a mosquito and transmitted by the bite of an infected female Anopheles mosquito.

Malaria is primarily a disease of the blood cells and small blood vessels. By causing the cells to become ‘sticky’ and eventually to burst, it causes blockages of the small blood vessels in the major organs of the body. This can cause severe disease and death – in case of the infection with the P. falciparum species of malaria, this can occur within 24 hrs of the disease first becoming evident.

Malaria caused by the other three parasite, namely Plasmodium vivax, P. ovale and P. malariae, is much milder and does not cause death, although they cause recurrent malaria than in itself is a debilitating disease.

The malaria parasite is found mostly in the tropical and subtropical regions of the world. Mosquito breeding is severely hampered in temperatures below 20 degree C. Optimal conditions for breeding are at temperatures around 30 degree C together with humidity levels of over 60%. Consequently, temperature and humidity largely dictate whether a country is likely to experience year-round malaria, seasonal malaria or localized break through.

The severity of malaria and its incidence is governed also by the immunity levels of the host, man. Immunity depends on constant exposure to the malaria-infected mosquito. Hence war and civil disturbances leading to an influx of non-immune workers, as well as tourism, all lead to the exposure of non immune to the malaria parasite.
Malaria - Infectious disease

Infectious Disease - Rabies

2008-10-25T18:08:00.000-07:00

Infectious Disease - Rabies
At the end of the nineteenth century, hundreds of people died from rabies every year. Almost invariably, these people got the disease from the bite of a domestic animal, usually a dog.

Because of the efforts of Louis Pasteur and many others, it is rare today for some one to die from rabies. And the few cases of rabies that arise each year almost invariably come about as a result of a bite from a wild animal, like a skunk or a bat. The rarity of the disease and the elimination of rabies from domestic animals are due largely to Pasteur’s discoveries and intense vaccination programs.

But rabies remains as a glaring example of the pain and suffering that can follow infection. And rabies is only one example of thousands of infectious diseases – diseases caused by prions, viruses, bacteria, fungi, and parasites – that make us sick and kill us. Some infectious may be essential. Others are terrifying.

A rhabdovirus virus causes rabies. There are many different types of rhabdoviruses and they cause a whole range of disease – rabies is one of the worst. The rabies is bullet shaped, covered with a large sheet of host-cell membrane and fortunately for all of us, is easily destroyed by soaps or drying. Rabies viruses are about 75 nm (nanometers) in diameter and about 150 to 300 nm long. A nanometer is one billionth of a meter, far beyond the realm human vision. These are tiny packets of trouble.

Rabid animals transmit rabies in their saliva. From the bite wound, the virus makes its way into neurons. Then it travels along the neurons to the central nervous system (brain and spinal cord) where it sets up shop. In the central nervous system, the rabies virus begins to destroy neurons as it produces more virus. Some of the new virus particles travel to the salivary gland, where they help spread the disease to others through bites.

In the process of its self-replication, the rabies virus decimates many of the neurons in the central nervous system. The result is a mental meltdown. But the virus doesn’t destroy all of the brain – just enough to drive the dog mad, just enough to make dog want to bite every other living thing it sees and pass on the infection.
Infectious Disease - Rabies

Escherichia coli

2008-09-21T16:16:00.000-07:00

Escherichia coli
Animal and human feces and untreated water are the source of Escherichia coli contamination in food. Any food product (meat, vegetables, and dry products) can become contaminated. There are 4 virulent strains of Escherichia coli; 3 of them 4 virulent strains cause mild diarrhea, cramps and fluid loss.

E.coli 0157:H7, the fourth and most virulent strain, is of current concern because of its effect: bloody diarrhea, severe abdominal pain and cramps. Hemolytic uremic syndrome, a possible complication of this illness, is the leading cause of kidney failure in children. In the past few years, under cooked ground beef products have been implicated in transference of E.coli 0157:H7.

There is estimated annual incidence of over 200,000 cases of enteric E.coli in the United States with about 400 fatalities.

The temperature range for growth of E.coli is 36 degree F to 114 degree F. E.coli are less resistant to heat than are Salmonella spp. Heating foods to temperatures that destroy Salmonella are sufficient to inactivate any E.coli which may be present.

Some critical problems which are responsible for illnesses cause by E.coli include

Animal feedlot practices which allow some animals to become colonized

The spreading of the organisms during slaughtering, processing, food preparation, and poor personal hygiene

Improper sewage treatment and disposal; use of improperly treated animal and human waste to fertilize crops

Allowing food products to remain above 36 degree F which enables this microorganism to multiply during distribution and service

Infected people who contaminate food products because they do not washed their hands and fingertips correctly after using the toilets

Escherichia coli

Food System that Lead to Salmonellosis

2008-09-12T18:47:00.000-07:00

Food System that Lead to Salmonellosis

The government sets no microbial standards or pasteurization specifications that can be used to control the presence of this microorganism in raw food in retail food operations, Meat animals and poultry are often infected as a result of the environment in which they are slaughtered. Since they often appear to be disease free, they contaminate other carcasses through cross contamination during slaughtering procedures. Salmonella are present at low levels within the yolks of eggs produced by diseased flocks of chickens. They are found in fish and seafood taken from contaminated water.

During transport and distribution, are often above 41 degree F allowing Salmonella to multiply in food products.

Food may not be heated sufficiently to destroy Salmonella. Cooks can only guess when food is cooked adequately. Hence, Salmonella spp. survive to cause illness.

There is post cooking cross contamination of cooked food when it is cut on contaminated cutting boards or with knives used to prepare raw products contaminated with Salmonella.

In spite of regulations forbidding people to work when they are ill, people who are ill or carries of Salmonella spp. continue to work in food operations. These individuals shed the microorganism in their feces and spread Salmonella to the food they prepared or touch. This occurs when they do not properly washed their fingertips and under their fingernails after defecating.

Food System that Lead to Salmonellosis

Salmonella spp.

2008-09-01T19:46:00.000-07:00

Salmonella spp.
There are over 2000 types of Salmonella, all are pathogenic to humans. This microorganism is often found in raw poultry products and may also be present on other raw meat products. It can be transmitted to other food products by cross contamination, improper food handling and poor sanitation.

Symptoms of illness include abdominal cramps, diarrhea, fever, and chills. The illness develops 8 to 72 hours after ingestion of food containing the microorganisms. Ingestion of greater than 10,000 Salmonella cells in a meal is usually necessary to cause illness in healthy people. However, as few as 4 to 5 cells per 100 grams of food can cause illness when present in foods containing higher amounts of fats such as cheese and chocolate candy. Fat in these foods provides a protective barrier around the microbial cells and prevents their disintegration by stomach acid during digestion.

Severe complications form salmonellosis include: reactive arthritis, cardiac inflammation, intracranial, and other nervous system involvement and osteomyelitis. Because of the seriousness of illness caused by Salmonella, the standard for heat destruction times and temperature for this pathogen are used as a basis for food pasteurization.

Recent news about Salmonella;
In June 2006, the BBC reported that the Cadbury chocolate manufacturer withdrew a number of products when products contaminated with salmonella caused up to 56 cases of Salmonellosis.

In February 2007, the U.S. FDA issued a warning to consumers not to eat certain jars of Peter Pan peanut butter or Great Value peanut butter due to risk of contamination with 'Salmonella Tennessee'.

July 2008, the U.S. Food and Drug Administration suspects that the contaminated food product is a common ingredient in fresh salsa, such as raw tomato, fresh jalapeño pepper, fresh serrano pepper, and fresh cilantro. It is the largest reported salmonellosis outbreak in the United States since 1985.
Salmonella spp.

Campylobacter jejuni

2008-07-28T20:38:00.000-07:00

Campylobacter jejuni
Campylobacter jejuni is considered to be a pathogen principally of veterinary significance only slightly more than decade ago, Campylobacter jejuni (formerly known as Vibrio fetus) was known to cause abortion in sheep. Following the development of procedures for detecting the organism in stool specimens, Campylobacter jejuni became recognized as a leading cause of acute bacterial gastroenteritis in humans.

Campylobacter jejuni is a gram-negative, microaerophilic, thermophilic rod that grows best at 42°C (107°F) and low oxygen concentrations. These characteristics are adaptations for growth in its normal habitat – the intestines of warm-blooded birds and mammals. Several closely related species with similar characteristics, C. coli, C. fetus, and C. upsalienis, may also cause disease in man but are responsible for less than one percent of human infections annually.

Evidence suggests that Campylobacter is responsible for at least as many cases of enteric illness as Salmonella. Indeed, it is now believed that campylobacteriosis is more common in the United States than salmonellosis and shigellosis combined. Common symptoms of campylobacter enteritis include profuse diarrhea (sometimes containing blood), abdominal cramps and nausea. Human volunteer and retrospective studies of food associated outbreaks revealed that ingesting relatively small numbers (only a few hundreds cells) of Campylobacter jejuni can produce illness.
Campylobacter jejuni

Genome of Highly Infectious Parasite, Giardia Lamblia Unlocked

2008-07-08T06:13:00.000-07:00

Genome of Highly Infectious Parasite, Giardia Lamblia Unlocked
Giardia lamblia, one of the most common human parasites in the United States, causes more than 20,000 intestinal infections a year, often through contact with contaminated drinking or swimming water. In the September 28 issue of Science, an international team led by researchers at the MBL (Marine Biological Laboratory) describes the complete genome (genetic sequence) of Giardia, which could lead to the development of new drugs to combat this persistent infection, called giardiasis.

Even though there are treatments now available, a number of people get chronic giardiasis, which is difficult to eliminate. So there is interest in new treatments. The Giardia parasite lives in the human intestine in a swimming and feeding form called a trophozoite, which is eventually expelled through the stools. Outside the body, Giardia takes the form of a highly infectious cyst that can live for weeks in water, soil, food, or on other surfaces.

Giardiasis is most common among children, especially those who are exposed to diaper changing. Swimmers, hikers, campers and others who drink untreated water are also prone to the infection (hence the nickname "backpacker's disease" or "beaver fever"), as are international travelers. Common symptoms include diarrhea, nausea, stomach cramps and gas, and usually persist two to six weeks. Because the parasite clings to intestinal cells that absorb fats and nutrients, giardiasis can lead to severe complications such as poor nutrient absorption and weight loss.

Although not life threatening, Giardia is a rather fastidious parasite and quite important from an economical viewpoint worldwide and in the United States, where it constitutes a major cause of diarrheal disease in children in daycare centers. Analysis of the Giardia genome revealed several unusual proteins that are promising drug targets. Drugs can be devised that will interfere with the parasite's ability to replicate, or to move or bind in the small intestine, or to exist at all.

The MBL team also investigated the evolutionary history of this ancient parasite. Giardia is a single-celled eukaryote, meaning its cell has a nucleus, as do the cells of humans and most other multicellular organisms. But the Giardia genome is compact compared to other eukaryotes, with simplified machinery for several basic processes, such as DNA replication and RNA processing. If the Giardia genome had originally been complex and experienced gene loss over evolutionary time, Morrison says, one would expect to see parts of the machinery intact and parts missing. This, however, wasn't the case.
Researchers embarked upon this genome project because of its importance to human health and suggestions from earlier molecular analyses that Giardia represents a very early-diverging lineage in the evolutionary history of eukaryotes. Giardia's genome content and architecture support these theories about the parasite's ancestral character.

Another important finding is that the genes that allow Giardia to evade the human immune response are organized differently than in other parasites. In the host intestine, Giardia eludes an immune system attack by shifting the proteins it displays on its surfaces. The genes for these surface proteins are scattered throughout the Giardia genome rather than found in clusters, as in other parasites.
Genome of Highly Infectious Parasite, Giardia Lamblia Unlocked
Extract from: http://www.medicalnewstoday.com

Mycobacterium tuberculosis

2008-06-09T08:50:00.001-07:00

Mycobacterium tuberculosis
Mycobacteria are aerobic and nonmotile bacteria that are characteristically acid-alcohol fast. Mycobacterium tuberculosis, along with M. bovis, M. africanum, and M. microti all cause the disease known as tuberculosis (TB) and are members of the tuberculosis species complex.

Each member of the TB complex is pathogenic, but M. tuberculosis is pathogenic for humans while M. bovis is usually pathogenic for animals. Mycobacterium tuberculosis, then known as the "tubercle bacillus," was first described on March 24, 1882 by Robert Koch. Mycobacterium tuberculosis is the etiologic agent of tuberculosis in humans. Humans are the only reservoir for the bacterium.

Mycobacterium tuberculosis is known as "acid-fast bacilli" because of their lipid-rich cell wall, which is relatively impermeable to various basic dyes unless the dyes are combined with phenol. Only about 10% of people infected with M tuberculosis ever develop tuberculosis disease. Many of those who suffer TB do so in the first few years following infection, but the bacillus may lie dormant in the body for decades.

Although most initial infections have no symptoms and people overcome them, they may develop fever, dry cough, and chest x-ray abnormalities. Tuberculosis (TB) is the leading cause of death in the world from a bacterial infectious disease. The disease affects 1.8 billion people each year which is equal to one-third of the entire world population.

In the United States Tuberculosis is on the decline. In 2007 a total of 13,293 cases were reported. The TB rate declined to 4.4 cases per 100,000 populations, the lowest recorded rate since national reporting began in 1953. Despite this overall improvement, progress toward tuberculosis elimination has slowed in recent years; the average annual percentage decline in the tuberculosis rate slowed from 7.3% per year during 1993--2000 to 3.8% during 2000--2007. Also, since 1993 there has been a gradual decline in the number of tuberculosis patients with co infection with HIV, and the number of cases of multiple drug-resistant tuberculosis has gradually dropped.
Mycobacterium tuberculosis

Evolutionary Intricacies Of Rickettsia Pathogens Revealed By Scientists

2008-05-05T18:31:00.000-07:00

Evolutionary Intricacies Of Rickettsia Pathogens Revealed By Scientists
Scientists from the Virginia Bioinformatics Institute (VBI) at Virginia Tech and the University of Maryland School of Medicine have unveiled some of the evolutionary intricacies of rickettsial pathogens by analyzing over a decade's worth of genomic data. Some species of Rickettsia are known to cause harmful diseases in humans, such as epidemic typhus (R. prowazekii) and Rocky Mountain spotted fever (R. rickettsii), while others have been identified as emerging pathogens and organisms that might possibly be used for the development of biological weapons. The new data, which are publicly available via the PATRIC project web site (patric.vbi.vt.edu), open up exciting new possibilities for future research.

Dr. Joseph Gillespie, a bioinformatician at the Virginia Bioinformatics Institute and leader of the study, remarked: "Over the past ten years, an average of one genome per year has been sequenced for the Rickettsia, which represents a considerable genomic treasure trove for evolutionary studies. We have systematically probed the genomic data available for Rickettsia to reveal how rickettsial genomes have given rise to the great diversity of organisms that we know today. This approach sheds light on the evolutionary intricacies of Rickettsia and suggests how some members of the group have developed into potent pathogens responsible for significant diseases in humans."

In the study, the researchers defined a core Rickettsia genome by looking at a large number of genes that could potentially encode for proteins in the ten genomes under investigation. This information was used to generate over 700 groups of orthologous proteins that theoretically could have originated from a common ancestor. A similar exercise yielded over 1,300 orthologous groups of proteins that define the accessory genome. Digging further into the accessory genome yielded signature proteins that define the four major rickettsial groups, as well as species infecting common arthropod hosts and species harboring plasmids. Surprisingly, and contrary to previous dogma regarding rickettsial genome evolution, the accessory genome contained many likely elements of the bacterial mobile gene pool.

VBI Director and PATRIC Principal Investigator Bruno Sobral remarked: "Virulent species of Rickettsia are of great interest both as emerging agents of infectious disease and potential bioterror agents. We believe the current work provides a robust evolutionary framework that allows for the interpretation of the genomic characteristics of the four main lineages of Rickettsia. As such it provides an ideal resource for research directed at developing vaccines, diagnostics and therapeutics for the diverse group of pathogens that constitute the Rickettsia."

Dr. Gillespie concluded: "The results obtained in this study are consistent with the recent explosion in the number of identified plasmids in Rickettsia. By making these data available we hope to enable future research into these intriguing organisms."
Evolutionary Intricacies Of Rickettsia Pathogens Revealed By Scientists
Article by: Medical News Today

New Species Of Infectious Disease Found In Amazon

2008-04-06T18:41:00.000-07:00

New Species Of Infectious Disease Found In Amazon
While investigating the tropical disease leptospirosis in the Peruvian Amazon, an infectious disease specialist from the University of California, San Diego School of Medicine has uncovered new, emerging bacteria that may be responsible for up to 40 percent of cases of the disease. Patients with severe forms of leptospirosis have jaundice, renal failure and lung hemorrhage, with high fatality rates.

Joseph Vinetz, M.D., professor of medicine in UC San Diego's Division of Infectious Diseases working in collaboration with colleagues from Universidad Peruana Cayetano Heredia in Lima, Peru, and others headed the study that led to discovery of the new species in the family of pathogens, Leptospira, which is spread from animals to humans. The findings will be published in the April 1 issue of the Public Library of Science (PLoS) journal Neglected Tropical Diseases.

Leptospirosis is a severe, water-borne disease transmitted from animals to humans, with tens of millions of human cases worldwide each year. Fatality rates can range as high as 20 to 25 percent in some regions, and it is particularly prevalent in tropical countries where poor people live under highly crowded condition, or in rural areas where people are exposed to water contaminated by the urine of Leptospira-infected animals such as rats.

The new species reflects Amazonian biodiversity, according to Vinetz, and the pathogen has apparently evolved to become an important cause of leptospirosis in the Peruvian Amazon region of Iquitos. There, Vinetz leads an international team of physicians from the U.S. and Peru in an NIH-funded training program studying malaria, leptospirosis and other infectious diseases that impact disadvantaged populations in developing countries.

The researchers found that the new species, Leptospira licerasiae cultured from a very small number of patients, as well as eight rats is significantly different from other forms of the bacteria at a genomic level and has novel biological features.

"This strain has fundamentally different characteristics," said Vinetz, adding that the next step is to sequence its genome. "We think that hundreds of patients are infected with this pathogen, which is so unique that antibodies for the disease don't react to the regular tests for leptospirosis."

In testing 881 patients in a prospective clinical study of fever, the researchers found that 41 percent of them had antibodies that reacted only to this new strain of the bacteria, showing a much higher incidence of leptospirosis than previously suspected.

"This observation is relevant to other regions of the world where leptospirosis is likely to be common, because it's necessary to identify the right strain of the Lepstospira in order to make the correct diagnosis," Vinetz said.

Since isolation of the new Leptospira in people was rare despite the high prevalence of antibodies to this strain of the bacteria in the Amazonian population, Vinetz theorizes that the individuals with positive cultures may have a previously undiscovered immune system defect, making them more susceptible to the disease.
Source: http://www.medicalnewstoday.com
New Species Of Infectious Disease Found In Amazon

Bacteria and infection

2008-02-02T21:25:00.000-08:00

Bacteria and infection
Five major groups of microorganisms are responsible for the majority of infections. They include protozoa and helminthes, or worms; both of which are considered parasites, as well as bacteria and viruses. Bacteria and viruses often are discussed, along with fungi (the fifth major group), in the context of infection and infectious diseases.

Bacteria are very small organisms, typically consisting of one cell. They are prokaryotes, a term referring to a type of cell that has no nucleus. In eukaryotic cells, such as those of plants and animals, the nucleus controls the cell functions and contains its genes. Genes carry deoxyribonucleic acid (DNA), which determines the characteristics that are passed on from one generation to the next. The genetic material of bacteria is contained instead within a single, circular chain of DNA.

Bacteria generally are classified into three groups based on their shape: spherical (coccus), rodlike (bacillus), or spiralor corkscrew-shaped (spirochete). Some bacteria also have a shape like that of a comma and are known as vibrio. Spirochetes, which are linked to such diseases as syphilis, sometimes are considered a separate type of creature; hence, Monera occasionally is defined as consisting of blue-green algae, bacteria, and spirochetes.

The cytoplasm (material in the cell interior) of all bacteria is enclosed within a cell membrane that itself is surrounded by a rigid cell wall. Bacteria produce a thick, jellylike material on the surface of the cell wall, and when that material forms a distinct outer layer, it is known as a capsule. Many rod, spiral, and comma-shaped bacteria have whiplike limbs, known as flagella, attached to the outside of their cells. They use these flagella for movement by waving them back and forth. Other bacteria move simply by wiggling the whole cell back and forth, whereas still others are unable to move at all.

Bacteria most commonly reproduce by fission, the process by which a single cell divides to produce two new cells. The process of fission may take anywhere from 15 minutes to 16 hours, depending on the type of bacterium. Several factors influence the rate at which bacterial growth occurs, the most important being moisture, temperature, and pH, or the relative acidity or alkalinity of the substance in which they are placed.

Not all bacteria are harmful; in fact, some even are involved in the production of foods consumed by humans. For example, bacteria that cause milk to become sour are used in making cottage cheese, buttermilk, and yogurt. Vinegar and sauerkraut also are produced by the action of bacteria on ethyl alcohol and cabbage, respectively. Other bacteria, most notably Escherichia coli ( E. coli ) in the human intestines, make it possible for animals to digest foods and even form vitamins in the course of their work. Others function as decomposers, aiding in the chemical breakdown of organic materials, while still others help keep the world a cleaner place by consuming waste materials, such as feces.

Despite its helpful role in the body, certain strains of E. coli are dangerous pathogens that can cause diarrhea, bloody stools, and severe abdominal cramping and pain. The affliction is rarely fatal, though in late 1992 and 1993 four people died during the course of an E. coli outbreak in Washington, Idaho, California, and Nevada. More often the outcome is severe illness that may bring on other conditions; for example, two teenagers among a group of 11 who became sick while attending a Texas cheerleading camp had to receive emergency appendectomies. The pathogen is usually transmitted through under-cooked foods, and sometimes through other means; for example, a small outbreak in the Atlanta area in the late 1990s occurred in a recreational water park.
Bacteria and infection

Yeast Infections in Children

2007-11-02T22:32:00.001-07:00

Yeast Infections in Children
We love our children and because of that love we do all that we can to provide for them. This provision for our children includes caring for their physical needs such as the giving of food, clothing and shelter. We also provide for their educational needs and do all that we can to ensure that their education is rich and full. Also, because of our love, we do our utmost to protect them from harm.

Unfortunately, we cannot isolate our children and therefore negative things do occur in our children's lives. Probably, the most agonizing negative event in our children's lives is when they become sick. We nurse them back to health through their episodes of fever, cutting teeth, colds, allergies, infections and other ailments that affect us all.

One such infection, that we may have a tendency to blame ourselves for is a yeast infection in children. Often we equate yeast infections in children with not caring properly for our child. Therefore, it is important to know what causes a yeast infection in children as well as the symptoms and steps we can take to prevent this infection from reoccurring.

Causes

It is important to remember that a child is simply a child. In other words, a child is not fully developed in all aspects of their being. They are not fully developed mentally, physically, socially and emotionally.

Therefore, a child's immune system is still in the developing stage. This fact is dramatically demonstrated in the number of colds that a child comes down with during their adolescence. This susceptibility to infection is based on the fact that their immune system is still in the process of strengthening and at this point in time does not have the capability of fighting off the various childhood diseases.

In addition, in our efforts to be good parents, we take our children to see the pediatrician and they in turn will prescribe antibiotics to fight the illness. It is this very action that is one of the major reasons for a yeast infection in children. This is due to the fact that the antibiotic will destroy the bacteria, good and bad, within the child's body. Good bacteria are necessary to maintain the proper balance of the digestive and immune system of the individual. In turn, this absence of bacteria then allows the yeast fungus, present in all individuals, to remain unchecked within the body. This created situation then allows for a higher percentage of yeast infections in children to occur.

Affected Areas

There are numerous areas of the body that are affected by a yeast infection in children. Those areas include the mouth, genital area (diaper rashes) and infections of the ear. In addition there are associated ailments of the digestive system. These ailments include excessive gas, loose stools and bloating.

Prevention

In preventing or taking measures of addressing reoccurring yeast infections in children it is important to start with building up their immune system. The best and most natural method of accomplishing this is through diet.

A child's diet should be rich in natural foods and provide the necessary vitamins and minerals to ensure the child's full development. Supplements may be indicated that provide anti-oxidants, minerals, vitamins, etc.

It is also important not to introduce foods into your child's digestive system that may contain the very elements you are trying to avoid. This element is fungus or mold. Therefore, a child's diet should be free of peanuts or peanut butter as these products may contain mold. Guaranteed organic peanut butter or peanuts is permissible.
Yeast Infections in Children

E. coli infection

2007-04-30T23:04:00.000-07:00

E. coli infection
E. coli is a common type of bacteria that can get into food. Its medical term Escherichia coli. The strange thing about these bacteria — and lots of other bacteria — is that they're not always harmful to you. E. coli normally lives inside the intestines, where it helps to body break down and digest the food.

Unfortunately, certain types (called strains) of E. coli can get from the intestines into the blood. This is a rare illness, but it can cause a very serious infection. Someone who has E. coli infection may have these symptoms: fever and chillsbad stomach cramps and belly painvomitingdiarrhea, sometimes with blood in it.
One very bad strain of E. coli was found in fresh spinach in 2006 and some fast-food hamburgers in 1993. Beef can contain E. coli because the bacteria often infect cattle. It can be in meat that comes from cattle. Most E. coli infections come from:
*Eating undercooked ground beef (the inside is pink)
*Drinking contaminated (impure) water
*Drinking unpasteurized (raw) milk
*Working with cattle

Healthy beef and dairy cattle may carry the E. coli germ in their intestines. The meat can get contaminated with the germ during the slaughtering process. When beef is ground up, the E. coli germs get mixed throughout the meat.

The most common way to get this infection is by eating contaminated food. Human can be infected with the E. coli germ if they don't use a high temperature to cook beef, or if don't cook it long enough. When human eat undercooked beef, the germs go into stomach and intestines.

The germ can also be passed from person to person in day care centers and nursing homes. If the person have this infection and don't wash hands well with soap after going to the bathroom, this can give the germ to other people when you touch things, especially food.

People who are infected with E. coli are very contagious. Children shouldn't go to a day care center until they have 2 negative stool cultures (proof that the infection is gone). Older people in nursing homes should stay in bed until 2 stool cultures are negative.
E. coli infection

Global warming and tropical diseases

2007-04-01T07:27:00.000-07:00

Global warming and tropical diseases
Tropical diseases such as malaria, dengue fever, jaundice and encephalitis will most likely be on the rise due to global warming, as mosquitoes thrive on such climatic conditions.

Global warming would increase the temperature of areas where mosquitoes could not live previously and infect more people with diseases.

Studies on global warming had revealed this. The respiratory ailments and allergies due to increased heat, air pollutants, spore and dust could also be expected to rise.

Currently, about 45% of the global population live in high-risk areas, and with the increasing temperature and release of greenhouse gases, the figure may increase to 60%.

The studies also showed that the temperature in Malaysia would rise between 0.6°C and 4.5°C while the density of the greenhouse gases would double by the year 2060.

A 1,200sq km area of Malaysia’s coastline would be under water if early measures were not taken to address the effects of global warming.

The increase in sea level will create giant waves that can destroy mangrove swamps as well as flora and fauna.

The increase in temperature and drop in rainfall by 10% will reduce water availability by between 13% and 53% during a drought.
Global warming and tropical diseases

Bird Flu :: Indonesia Latest News

2007-02-12T21:03:00.000-08:00

Bird Flu :: Indonesia Latest News

A 20 yrs. old Indonesian woman died from the avian influenza virus - H5N1 bird flu virus, in west Java on Saturday night after undergoing a two-day treatment for bird flu symptoms.

The latest mortality was Indonesia's 64th from 84 cases of the H5N1 avian influenza virus, and was the sixth death in 2007.

In

donesia has the world's highest fatality tally from the disease. Vietnam has had 42 human deaths from the virus, but none in more than a year. With the flu spreading around the world, the virus has turned up in birds in Asia and Europe, and, most recently, Africa. So far, bird flu has mostly been passed from birds either to other birds or, in isolated cases, to humans.

In June 2006, WHO reported the first case of human transference of the disease, when an Indonesian man died after catching the flu from his 10-year-old son. If the flu mutates into a strain that can pass more readily from human to human, people will have no immunity and the flu will probably pass rapidly from person to person, creating a pandemic.

Flu vaccines can only be made to protect against a particular virus, and, since the virus had yet to be passed from human to human, no vaccine has been developed.Indonesia will not share bird flu virus samples with foreign laboratories until the World Health Organisation has rules in place to ensure they are not used commercially, a senior Indonesian health official said on Friday.Indonesia on Wednesday said it would only share its H5N1 samples with those agreeing not to use them commercially.

The announcement came as it signed a preliminary agreement with a unit of pharmaceutical firm Baxter International Inc. Under the pact the health ministry's research and development institute will supply the U.S. firm specimens of H5N1; Baxter will provide technology to help develop a vaccine. Indonesia would have the right to produce and market the bird flu vaccine domestically. It is negotiating to export it to a number of countries.Bird Flu :: Indonesia Latest News

Relapsing Malaria

2007-01-12T21:37:00.000-08:00

Relapsing Malaria
Although uncommon, it is possible to develop a relapsing type of malaria months to even years after traveling to a malaria-infected country, even if you were taking the appropriate malaria medications to prevent the illness. Any returning traveler who develops a fever that lasts more than a few days requires prompt medical attention to screen for a malaria infection.

While malaria medications such as chloroquine, doxycycline, or mefloquine (Lariam) can prevent symptoms of acute malaria from developing by suppressing the infection in the bloodstream, they do not prevent relapses of infection caused by certain strains of the parasite that have a persistent liver phase.

Fortunately, the most common type of malaria is the P. falciparum strain that has no relapsing phase, so malaria medications will prevent any symptoms of this infection. However, it is necessary to continue such medications for four weeks after a possible exposure to ensure that the infection has run its course before the medication can be safely stopped.

Other strains of malaria such as P. vivax, ovale, or malariae can infect the liver and persist in a dormant state for months, or even up to several years, after exposure. Because of this risk of relapse, travelers to malarious areas are not allowed to donate blood for up to three years after returning.

In the unfortunate event that you do develop a relapsing case of malaria, it can be easily treated by suppressing the acute symptoms with chloroquine and then eradicating the liver infection with a medication called primaquine. This medication is more toxic and has more adverse effects than chloroquine, especially in individuals with an inherited deficiency in the blood enzyme G6PD that can be easily screened for with a simple blood test prior to treatment.

The best way to prevent relapsing malaria is to prevent getting infected in the first place. This is why it is very important to avoid mosquito bites by using insect repellents (containing at least 20-30% DEET) and mosquito netting in addition to taking malaria medications.

If you do develop a persistent fever and flu-like symptoms after returning from a malarious region, you need to be aware of the possibility of a malaria infection and should see a physician as soon as possible for further evaluation.
Relapsing Malaria

Dengue Infection

2006-12-10T17:11:00.000-08:00

Dengue Infection
Family: Flaviviridae
Genus: Flavivirus

Dengue is a mosquito born infection that has become a global public health concern in recent years.
Major epidemics of dengue have occurred in the Caribbean, South America, the Pacific, Asia, and Africa. Dengue is a powerful health concern in many countries, especially in areas with urban slums and breeding places for mosquitos. The power of the virus is increased by that fact that at the present time, prospects for control are poor.
Dengue is caused by one of four closely related, but antigenically distinct, virus serotypes (DEN-1, DEN-2, DEN-3, and DEN-4). Infection with one of these serotypes does not provide cross-protective immunity, so people living in a dengue-endemic area can have four dengue infections during their lifetimes.

Dengue is transmitted through the Aedes aegyptia, a domestic day biting mosquito common in the tropics. The incubation period is about two to seven days. Infection with dengue viruses produces a spectrum of clinical illness ranging from a nonspecific viral syndrome to severe and fatal hemorrhagic disease. The three clinical profiles include dengue fever, dengue hemorrhagic fever, and dengue shock syndrome.
Dengue fever is a painful but non lethal syndrome characterized by rash, sudden onset of fever, severe headache, and other flu-like symptoms. Dengue hemorrhagic fever results in fluid loss through leaky blood vessels, leading to dyhydration, hypotension, severe jaundice, gastrointestinal hemorrhages and kidney failure. This can sometimes worsen to dengue shock syndrome which is the most severe form of the disease in which a child can die of shock in hours. Important risk factors include the strain and serotype of the infecting virus, as well as the age, immune status, and genetic predisposition of the patient.

As shown by the doctrine of original antigenic sin, the body has the same immune response as its first infection, even if this is not the appropriate response. This is the problem with dengue infections. Dengue only causes serious problems such as hemorrhagic fever and shock syndrome during the second infection of a different strain of the dengue virus. Antibody dependent enhancement increases the ability for uptake of the dengue virus via Fc receptors, enhances virion replication, and therefore makes the second infection of a different strain of the dengue virus much more serous then the first strain. ?
Because of the lack of cross protection between the dengue viruses, it is necessary to develop a vaccine protecting against all four dengue serotypes. There is no licensed vaccine for dengue because none of them guard against all for strains of the virus. The most common method for control is mosquito control, however it is hard to spray using insecticides because the Aedes aegypti live in places hard to reach with pesticides. Other problems with this methods is the appearance of pesticide resistant mosquitos. Control of mosquito breeding is possible by draining stagnant water supplies.
Dengue Infection

The Infection

2006-11-20T07:00:00.000-08:00

The Infection
Infection mean growth of a parasitic organism within the body. (A parasitic organism is one that lives on or in another organism and draws its nourishment therefrom.) A person with an infection has another organism (a "germ") growing within him, drawing its nourishment from the person.

The term "infection" has some exceptions. For example, the normal growth of the usual bacterial flora in the intestinal tract is not usually considered an infection. The same consideration applies to the bacteria that normally inhabit the mouth.
The Infection