Search

Five serological tests for the diagnosis of visceral leishmaniasis (VL) were compared: a direct agglutination test (DAT) based on freeze-dried antigen (DAT-fd); a locally produced DAT (DAT-LPC); an IgG ELISA against rK39 (ELISA-rK39); an IgG ELISA for Leishmania chagasi (ELISA-L. chagasi); and an IgG IFAT against L. chagasi. Serum samples from 88 patients with VL, 20 non-infected individuals and 85 patients with others infectious diseases were evaluated. The sensitivity rates were: DAT-fd, 96.6%; DAT-LPC, 95.5%; ELISA-rK39, 88.6%; ELISA-L. chagasi, 89.8%; and IFAT, 92.0% (P>0.05). The specificity for the control groups varied from 53.3% to 100%. DAT-fd had the highest efficiency (97.4%), followed by DAT-LPC (91.7%) and ELISA-rK39 (90.7%). Our data suggest that DAT-fd, DAT-LPC and ELISA-rK39 are useful tests for the diagnosis of VL and could replace IFAT as the routine diagnostic test in Brazil.

The immunodiagnosis of human infections with Fasciola hepatica using purified parasite cysteine proteinases as antigens is reported in this paper. IgG enzyme-linked immunosorbent assays (ELISAs) with 2 cysteine proteinases of 26 kDa (Fas1) and 25 kDa (Fas2), obtained from the regurgitated material of adult worms, were evaluated with serum samples from 38 patients infected with F. hepatica, from 54 patients with other parasitic infections and from 46 healthy volunteers. The diagnostic sensitivities for detection of F. hepatica infection at a serum dilution of 1 in 500 were 89% and 95% with Fas1 and Fas2 respectively. The specificity of the ELISAs was 98% for Fas1 and 100% for Fas2. IgG ELISA with Fas2 is a highly sensitive and specific assay for the immunodiagnosis of human fascioliasis.

The species specificity of the solid phase alkaline phosphatase immunocapture assay (APIA) for the immunological detection of human immunoglobulin G antibodies to the alkaline phosphatase of adult Schistosoma mansoni was evaluated. Sera from schistosomiasis patients from South America, West Africa, south-east Asia and uninfected control subjects were compared. Only the sera of patients infected with S. mansoni gave positive results. There was no apparent difference between 2 populations infected with S. mansoni, one from South America and the other from West Africa. The results with sera from various regions of West Africa were also indistinguishable. Although the APIA was not able to discriminate the geographical origin of the S. mansoni-infected subjects, the method appeared to be specific for S. mansoni and suitable for use in the immunodiagnosis of schistosomiasis mansoni, particularly in endemic areas where mixed infections of Schistosoma spp. occur.

The sensitivity and specificity of parasite demonstration methods (smear, culture and histology) and serological assays (enzyme-linked immunosorbent assay [ELISA], direct agglutination test and immunoblot) were compared in the diagnosis of leishmaniasis in Ethiopia. Culture was found to be the most sensitive diagnostic method, followed by ELISA, for the diagnosis of cutaneous leishmaniasis (CL). When the clinical type of CL was taken into consideration, serological and parasitological methods were equally good for the diagnosis of diffuse cutaneous leishmaniasis. Overall, the serological assays were not sensitive enough to diagnose all the parasitologically confirmed cases of localized cutaneous leishmaniasis. Both groups of diagnostic methods performed equally well in the diagnosis of visceral leishmaniasis patients. In cases of CL where clinical diagnosis was a problem and histology could not give a definitive diagnosis due to the absence of demonstrable parasites, one of the serological assays, preferably ELISA, was very useful in establishing the final diagnosis.