Comparison of serological methods (ELISA, DAT and IFA) for diagnosis of visceral leishmaniasis utilizing an endemic strain.

Abstract

The causative agent of visceral leishmaniasis (VL) in Iran is Leishmania infantum (L. infantum) (Mediterranean type) and its major reservoir host is the dog. To compare the serological methods including direct agglutination test (DAT), indirect immunofluorescent-antibody test (IFA) and enzyme-linked immunosorbent assay (ELISA) for serodiagnosis of endemic strain of L. infantum. 61 blood samples from VL patients referred to Shiraz hospitals and 49 blood samples from control group were collected. Native strain of the parasite isolated from a VL patient from the region was cultured and characterized. Antigens from this L. infantum parasite were used in ELISA and IFA system. Anti-Leishmania antibody was detected in 43 (70.5%), 49 (80.3%) and 51(83.6%) cases using DAT, IFA and ELISA, respectively. Based on these results, sensitivity and specificity of DAT was found to be 70.5% and 100%, respectively. Sensitivities of IFA and ELISA in diagnosis of VL were 80.3% and 83.6% and their specificity was 90.5%. Results of this study showed that DAT and ELISA have the highest specificity and sensitivity in diagnosis of VL. DAT is a simple, cost-effective and field applicable test. Thus, it can be recommended for early and accurate diagnosis of VL, especially in regions where malaria, brucellosis and tuberculosis are prevalent.