Parasitic Infection of the Gallbladder: Cystoisospora belli Infection as a Cause of Chronic Abdominal Pain and Acalculous Cholecystitis.

Herein we describe two cases of Cystoisospora belli infection of the gallbladder in patients with chronic abdominal pain and review the published literature to date. C. belli is an intracellular protozoan parasite that typically infects the small bowel of immunocompromised hosts. Little is known of the significance of C. belli infection of the gallbladder at this point as only four cases have been reported as yet, only one of which occurred in an immunocompetent patient. It is often treatable with antibiotics, and the patient's immune status, including HIV testing, should be investigated. Neither of the patients at our institution was found to be immunocompromised, and HIV-1/2 antibody testing was non-reactive in both.