It consists of a large group called Apicomplexa; some of its members are intestinal parasites while others are associated with the blood and tissue parasites. Ingestion of infective oocysts in food and water is the most common mode of transmission.


Isospora Belli

Physiology and Structure:

I. Belli is a coccidian parasite of the intestinal epithelium. Both sexual and asexual reproduction occurs in the intestinal epithelium. the end product of gametogenesis is the oocyst, which is the diagnostic stage present in fecal specimen. The oval oocysts of I. Belli measures up to 30 micrometres by 10-17 micrometers. An immature oocyst contains a single central mass and delvelps into two sporocysts after further muturation.


Extracted from: Essentials of Human Parasitology


Life Cycle:


Extracted from: Essentials of Human Parasitology


Clinical Syndromes:

  • Infected individuals may be asymptomastic carries or suffer mild to severe gastrointestinal disease such as mimics giardiasis or malabsorption syndrome characterized by loose, foul-smelling stools.
  • Chronic infection may occur and some patients are asymptomatic. Moreover, infections may occur in the liver, lungs and other organs but these are usually rare.


Treatment and Prevention:

  • Prevention of infection involves adequate sanitation measures, good personal hygiene.
  • Unprotected homosexual contact should be avoided.