Cystoisospora belli, liver disease and hypothesis on the life cycle

Abstract

Cystoisospora belli causes chronic diarrhoea, acalculous cholecystitis, cholangiopathy and disseminated cystoisosporosis in patients with AIDS. Clinical manifestations and histological stages during C. belli infection in a patient with AIDS and liver disease were described. It was possible to identify sporozoite-like structures in the villus epithelium of the duodenum, close to the vascularization that underlies the basal membrane and unizoite tissue cysts near to the vascularization in the lamina propria. Unizoite tissue cysts were found inside of sinusoids in the liver communicating with the central vein and with a bile canaliculus and portal spaces. Based on these findings a hypothesis on C. belli life cycle could consider that the route of migration of unizoite tissue cysts up the liver is via the portal blood. The unizoite tissue cysts located in hepatic portal vein could migrated via sinusoid to central vein and general circulation through the venous system. The unizoite tissue cysts could also return via bile canaliculus to bile duct to portal triad. This hypothesis allows to understand the presence of unizoite stages in blood, the pathway by which the bile ducts become infected and unizoites in the liver being able to behave like hypnozoites that favour relapses and treatment failures.

Detection of Cystoisospora belli among Children in Sulaimaniyah, Iraq

“…As with another coccidian, C. belli has a sexual and asexual life cycle. Humans are the only known host for this parasite, and the infection is acquired through the ingestion of sporulated oocysts through contaminated water and food [5]. After the invasion of the small intestinal epithelium and completes its life cycle within the cytoplasm of the enterocytes, Oocysts (diagnostic stage) are excreted with the faeces and develop outside the host into mature cysts, each with two sporocysts which contain four sporozoites each (infective stage) [6].…”

Detection of Cystoisospora belli among Children in Sulaimaniyah, Iraq

“…Also, studies shown that C. belli does not require an intermediate host and it can be transmitted directly from person to person through the ingestion of sporulated oocysts from contaminated water and food [5]. After the invasion of the small intestinal epithelial cells and completes its life cycle within the cytoplasm of the enterocytes, oocysts (diagnostic stage) are excreted with the feces and develop outside the host into mature Journal homepage www.jzs.univsul.edu.iq…”