[Intestinal parasitic infections and leishmaniasis in patients with HIV infection]

Intestinal parasite infections are very frequent in HIV patients with severe immunodeficiency (CD4 < 100/mm3) causing chronic diarrhea and malabsorption in the majority of cases. The most frequent microorganisms are microsporidia and Cryptosporidium parvum while Cyclospora cayetanensis and Isospora belli are more prevalent in subtropical and tropical areas and rare in industrialized areas. The diagnosis can be obtained by stool examination (differences in size and form of cysts), although microsporidia is frequently demonstrated by intestinal biopsy and/or duodenal aspirate. The treatment with cotrimoxazole for C. cayetanensis and I. belli is very effective and does not present any problems in the acute phase, however, due to a high percentage of relapses the treatment must be maintained while the patient is in a severe immunodeficiency state. E. intestinalis usually responds satisfactorily to albendazole while E. bieneusi is resistant to some drugs except in some cases (albendazole, atovaquone ad fumagillin). C parvum is also resistant to most medicaments but shows an adequate or partial clinical: response to paramomicine (< 50%). When there is no response, it is advised to administer octreotide since in half the cases the response is positive either total or partial. Nowadays with the use of protease inhibitors in the antiretroviral treatment a decrease in the incidence of these infections has been observed (microsporidia and C. parvum) even in the stools samples taken from the patients who had them before. As primary prophylaxis for C. parvum, it is better to avoid been exposed to the microorganism taking into account the 1997 preventive measures recommended by the USPHS/IDSA Prevention of Opportunistic Infections Working Group. The coinfection Leishmania-HIV is frequent in the mediterranean area. The most common specie is L. infantum. The incidence is most frequent in immunosuppressed patients (CD4 < 200 mm3) and in parenteral drug addicts. The symptomatology is similar to the one from immunocompetent patients, although in some cases it appears to be subclinical. A chronic development with relapses is frequent. The most effective diagnostic method for the finding of the parasites is thru bone marrow puncture and the culture in Novy-McNeal-Nicolle (NNN) medium. Serological tests have a low sensibility and the PCR is useful in asymptomatic cases, for therapeutical control and in relapses. The treatment is similar to that of immunocompetent patients, using primarily antimonials or amphotericine B (standard or lipid or liposomal forms). Relapses are very frequent, therefore, it is important to perform a secondary prophylaxis. However, no treatment has been completely effective. Mortality rate is high (approximately 25%) during the first month after diagnosis. This fact may be related to the severe immunodeficiency state and/or to the toxicity of the drugs used. The main priority for the future is to find a first line treatment with higher efficacy, decrease in relapses and a lower toxicity.