Given the epidemiology of human leishmaniasis and AIDS in Brazil, numerous cases of Leishmania/HIV co-infection might be expected. Relatively few Brazilian cases have been reported, however, even from regions where the overall incidences of HIV and Leishmania infection are both relatively high. Many cases of co-infection probably go undetected because of a lack of awareness among clinicians or limited access to appropriate diagnostic methods. In contrast to the situation in Europe, intravenous-drug users do not predominate among those exposed to HIV infection in Brazil. The success of the Brazilian programme for the free and universal distribution of antiretroviral drugs has decreased the prevalences of the commoner opportunistic infections among HIV-positives and increased the longevity of AIDS cases. Recent changes in the epidemiological patterns of HIV and Leishmania infections are likely to lead to a greater degree of overlap and a greater risk of co-infection and they justify increased alertness. This review of the co-infection in Brazil addresses three main topics: the current situation, in terms of the epidemiology of AIDS and Leishmania infection; the related epidemiological trends and their likely impact on the co-infection; and the co-infection cases reported in Brazil by June 2003.

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This study aims at estimating the prevalence of Leishmania infection among HIV-infected patients through the use of non-invasive tests. The study was conducted in three Infectious Diseases Services in two large Brazilian cities, both endemic areas for visceral leishmaniasis. Three hundred and eighty-one asymptomatic patients were enrolled whose ages ranged from 19 to 58 years old; 63.5% were men; mean TCD4+ was 380 cells/μl; and mean viral load was 153800 copies/ml. All individuals were tested for Leishmania infection through: ELISA using crude Leishmania infantum (ELISA), ELISA using the recombinant K39 antigen (rK39), indirect fluorescent antibody test (IFAT) and PCR targeted to kDNA region. The tests' positivity were: 10.8% (ELISA), 3.9% (IFAT), 0.8% (rK39), 6.3% PCR and 20.2% (overall, at least one positive test), with no statistical correlation between positivity and clinical and laboratorial variables. Concordance among tests was low (Kappa <0.20). Prevalence of Leishmania asymptomatic infection was high in this population, reinforcing the need for attention in the evaluation of HIV patients from endemic areas. New efforts are needed to develop more specific and sensitive tests to diagnose Leishmania asymptomatic infection. Highly active antiretroviral therapy (HAART) seems to have a protective role against disease progression in co-infected individuals.

A polymerase chain reaction (PCR) assay for the detection of Leishmania spp. DNA in peripheral blood was optimized and evaluated for the diagnosis of human visceral leishmaniasis (VL) in Brazil during May 2001 to December 2002. Optimization of the technique resulted in a detection limit of 1.65 fg of purified L. (L.) chagasi DNA, equivalent to 1.65 x 10(-2) parasites. Leishmania DNA was detected in the blood of 48 of 53 patients with parasitologically-confirmed VL, which corresponds to a sensitivity of 91%. No DNA was detected in the peripheral blood of 15 healthy, non-exposed volunteers, giving a specificity of 100%. We conclude that detection of parasite DNA in peripheral blood offers a non-invasive, sensitive and rapid method for the detection of VL caused by L. (L.) chagasi.

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