The data support the value of standard fecal examinations in human immunodeficiency virus-infected patients, even in the absence of diarrhea, since these examinations easily can be performed, with low costs, and frequently disclose treatable conditions.

Amongst the causes of diarrhea in developing countries, those of a parasitic origin are prominent in patients with AIDS.Opportunistic infections caused by intestinal parasites also vary according to the geographical area and the endemic levels in each location.The progressive decline of immunological and mucous defense mechanisms predisposes patients to early, intermediary and late gastrointestinal manifestations of HIV infection. 6 At later stages of the disease, the alterations in non-specific defense mechanisms in the production of Ig A and the reduction in local immune cell response also progress, thus increasing the susceptibility to a number of intestinal opportunistic pathogens, among which Cryptosporidium parvum, Isospora belli and Microsporidia species are the most prominent. 7After the emergence of AIDS, these parasites, until then known solely in veterinary medicine, were no longer considered as commensal organisms and are nowadays recognized as opportunistic pathogens common to these patients. Infections by these agents constitute a major secondary aggravating factor of the disease, often responsible for worsening the general health conditions, due to manifestations of diarrhea which are difficult to control, sometimes resulting in the death of the patient. CRYPTOSPORIDIASISCryptosporidiasis, a disease caused by an intracellular protozoan named Cryptosporidium sp, was described for the first time in 1907 by Tyzzer. This parasite was considered a commensal up to 1975, when it was identified as the cause of diarrhea in animals. 8 The first manifestation of cryptosporidiasis was reported by Nine et al. in 1976, and the disease became a major concern when the notification of the first 21 patients was given, 14 of whom died of chronic diarrhea caused by Cryptosporidium sp infection. 9 It is worth noting that outbreaks of epidemic linked to contaminated water are of extreme importance for the dissemination of this parasite such as the 1993 Milwaukee (USA) cryptosporidiasis outbreak, in which 403,000 human cases were reported, thereby becoming a relevant public health concern.10-12 After this outbreak, it was recommended that immunocompromised patients should be extremely careful with water, foodstuffs and contact with animals.Cryptosporidiasis is distributed over all continents. In Haiti and the African continent the prevalence is 50%, 13 while in the USA it ranges from 3 to 4%.14 In Brazil, due to the continental size of the country, the rates of incidence vary with the location. In the city of São Paulo, for instance, reports have referred to levels around 12.1 to 24.44%. [15][16][17] However, the latest epidemiological report on Brazil, dated February 1998, shows a cryptosporidiasis rate of only 3.5%. 18Cryptosporidiasis in AIDS patients usually causes chronic, bulky and intermittent diarrhea, with liquid non-bloody stools, accompanied by pain and abdominal colic, and a noticeable loss of weight can be observed. 8Asymptomatic cases are rarely described, occurring mostly in developing countries with pati...

We conducted a cohort survey on 200 AIDS patients in São Paulo, SP, Brazil, to verify if the presence of enteroparasites is associated with the various risk factors for HIV infection. Diarrhea was significantly more frequent in the group of patients presenting enteroparasitosis (p < 0.00001). Giardia lamblia, found in 32 (16%) cases, was the most prevalent parasite. The presence of parasites in the stool samples was not significantly associated with risk factors for HIV infection, mainly when considering Giardia lamblia and Cryptosporidium parvum (p = 0.99 and 0.69, respectively). The controversy found in the literature indicates that additional studies should be done in the different geographical regions of the country.