A new PCR–ELISA for diagnosis of visceral leishmaniasis in blood of HIV-negative subjects

Abstract

The PCR-ELISA represents a promising advance for diagnosis of visceral leishmaniasis (VL) in blood samples. However, the method has been validated mostly with HIV-positive patients who are known to have high levels of parasitaemia. We developed a new PCR-ELISA assay for specific detection of Leishmania in patients' blood and validated it in Nepalese subjects with clinically suspected VL, almost all of whom were HIV-negative. For blood samples, PCR-ELISA was more sensitive (83.9%) than conventional PCR (73.2%), and demonstrated 100% and 87.2% specificity when using healthy controls who had never travelled to a VL-endemic area and controls from a VL-endemic area as references, respectively. We have demonstrated the ability of PCR-ELISA to detect parasites in blood of HIV-negative patients. The method could be used for epidemiological as well as clinical purposes, as it reduces the need for traumatic bone marrow sampling and risky spleen aspiration.