Epidemiology, clinical manifestations, and diagnosis of Cystoisospora (Isospora) infections
- Karin Leder, MBBS, FRACP, PhD, MPH, DTMH
Karin Leder, MBBS, FRACP, PhD, MPH, DTMH
- Section Editor — Travel Medicine
- Head of Infectious Diseases Unit
- Monash University, Australia
Cystoisospora belli (formerly known as Isospora belli) is a gastrointestinal protozoan. In patients with AIDS and other immunodeficiencies, it is an opportunistic pathogen that can cause watery diarrhea and weight loss. Like other enteric pathogens such as Cryptosporidium and Cyclospora, C. belli is a coccidian, unicellular protozoan parasite that primarily infects the intestinal epithelium .
Cystoisospora belli is found worldwide, but infections are more common in tropical and subtropical areas . In India, Cystoisospora infections are the most common parasitic cause of diarrhea in HIV-infected subjects [3,4]. Among HIV-infected patients living in France, Cystoisospora infections were seen more commonly among patients who had emigrated from sub-Saharan Africa .
Gastrointestinal infections secondary to Cystoisospora are uncommon in the United States, but can be acquired by travelers to endemic countries [6-9]. In a study of more than 16,000 HIV-infected patients between 1985 and 1992 in Los Angeles County, the prevalence of Cystoisospora infections was highest in foreign-born patients, particularly those from Mexico and El Salvador, and among persons of Hispanic ethnicity . Cystoisospora can also be identified as a copathogen with other enteric organisms, such as Enterocytozoon bieneusi, in geographic regions with high levels of fecal contamination of surface water .
In contrast, a history of treatment or prophylaxis with trimethoprim-sulfamethoxazole for Pneumocystis infection in an HIV-infected patient is associated with a decreased risk of developing cystoisosporiasis [6,11].
Cystoisospora has also been reported in immunocompetent patients as well as in patients with other cellular immunodeficiencies, such as human T-lymphotropic type 1 infection , lymphoblastic leukemia, adult T-cell leukemia, Hodgkin's disease, and non-Hodgkin lymphoma . It has also been reported in patients taking immunomodulators such as TNF-inhibitors .To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:
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