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
