# Food and Drinking Water as Sources of Pathogenic Protozoans: An Update
## 12 _Cystoisospora belli_
### Diseases Caused by C. belli  
_C. belli_ infection in immunocompetent hosts can be asymptomatic or cause self-limiting watery diarrhea. However, it causes prolonged diarrhea or chronic diarrhea with relapses in immunocompromised patients, such as those infected with HIV, sometimes associated with headache, fever, malaise, abdominal pain, vomiting, dehydration, and weight loss. Moreover, in these patients, it can cause extra-intestinal complications with monozoic tissue cyst-like stages involving the liver, spleen, gallbladder, biliary tract, trachea-bronchial tract, and lymph nodes. This parasite can also infect epithelial cells of bile ducts and gallbladder, especially in severely immunocompromised patients. Other patients at risk are transplant recipients under immunosuppressive therapy [269; 270; 271].  
Often, patients infected with _C. belli_ are asymptomatic carriers before contracting HIV and may become symptomatic once infected with HIV regardless of the CD4 count, suggesting the absence of a protective CD4 count threshold [45]. Cystoisosporiasis recurrence is observed in HIV/AIDS patients and could be related to the reactivation of tissue cysts formed in extra-intestinal organs or the lamina propria of the intestine. Diagnosis is made difficult by intermittent shedding in stools and there is no reported serological test at present [269].  
Infections and even fatal cases have been sporadically reported in immunocompromised patients, including those with Hodgkin's and non-Hodgkin's lymphoma, and acute lymphoblastic leukemia and in human T-cell leukemia virus type 1 (HTLV-1) infected patients [271]. Prevalence rates in HIV-infected patients range between 0.4% and 28% [269].  
Recent cases in immunocompromised patients regarded a 66-year-old male with myeloma in Turkey [271]; six HIV-infected patients, including a 25-year-old kidney-transplanted male patient with deteriorated renal function [269]; a 45-year-old Nigerian woman with disseminated Kaposi sarcoma [19]; a 57-year-old man in Colombia [45]; a 34-year-old woman also with chronic hepatitis B and latent tuberculosis; a 61-year-old male with a very low CD4 cell count who had a dramatic weight loss and presented multiple erosions and ulcers in the colon [273]; and a 27-year-old male patient in Cameroon who contracted the infection in Morocco and required hemodynamic support in an intensive care unit (ICU) [274]. In five of the reported cases, the patients experienced prolongeddiarrhea, even for one year, and in all cases, _C. belli_ infection was successfully treated with TMP-SMX [45; 269; 271; 273; 274] which should be administered as a long-term maintenance therapy in HIV patients [19].  
Misdiagnoses were also reported for this parasite, namely, ovoid perinuclear cytoplasmic structures composed of dense fibrillar aggregates in the gallbladder of pediatric patients [275] and aggregates of degenerated cytoplasmic components in the gallbladder in immunocompetent individuals were reported as _C. belli_ infection in a large series of studies but not confirmed by molecular and ultrastructural analysis [276].