Giardia lamblia is considered to be one of the leading causative agents of diarrhea in both children and adults.
The life cycle of Giardia species is simple and it is included of two active trophozoite and cystic forms. This parasite transmits via fecal-oral route through direct or indirect ingestion of infectious cysts.
The cyst is relatively inert, allowing prolonged survival in a variety of environmental conditions. After exposure to the acidic environment of the stomach, cysts ex-cyst into trophozoites in the proximal small intestine.
Trophozoites attach actively to the epithelium of the small intestine and exhibit antigenic variation of variant surface proteins (VSPs) in their protein surface coat. It causes symptoms of diarrhea and malabsorption.
The incubation period varies from 9 to 15 days after ingestion of cysts.
Mode of infection:
*Contaminated food or water.
*Flies and food handlers.
*Fecal-oral.
Giardia lamblia
