Comparative seroepidemiological surveillance of visceral leishmaniasis and its association with diabetes co-morbidity in Osun State, Nigeria

Abstract

Visceral leishmaniasis is the most severe form of leishmaniasis and the second largest parasitic killer in the world after malaria. This sero-epidemiology surveillance was carried out to ascertain visceral leishmaniasis incidence in Osun State, Southwestern Nigeria. Methods A total of 272 volunteers from different towns of the State were enrolled for participation in this study. They were grouped viz.: Control, Diabetic, Diabetic Foot Ulcer in order to investigate the incidence of VL and the association of the disease co-morbidity with diabetes viz-a-viz implication on biochemical parameters of kidney (Urea and Creatinine) and liver (ALT and AST) functions. Using standard protocols of ELISA, Buffy coat and thin film techniques, VL was diagnosed for each volunteer. Results Following screening, the Buffy coat (least recommended) technique did not detect the Leishmania parasite (0%), whereas the thin film examination (sensitivity: 2.3%, specificity: 99.6%, negative predictive value: 84.1%, positive predictive value: 50%) detected 2 (2.1%) while ELISA (the gold standard) detected 44 (16.2%) leishmaniasis cases among the participants. The results revealed statistically significant (p <0.05) decreased urea, increased creatinine, elevated ALT and AST levels in participants found to be infected with Leishmania species compared to those not infected. It is interesting to note that urea, creatinine, ALT and AST levels of participants having a co-morbidity of VL-diabetes and VL-diabetic foot ulcer did not change significantly compared to the Leishmania-infected participants without diabetes or the foot ulcer. Conclusions These findings indicate that Leishmania infection is the singular factor that perturbs the kidney and liver enzymes considered in this study. Therefore VL does not show association with diabetes or diabetic foot ulcer co-morbidity in the population studied. There has not been any reported case of visceral leishmaniasis in Osun State prior to this study. It therefore suffices that the infectious disease has hitherto remained un- or mis-diagnosed. Keywords: Visceral leishmanisis, diabetes, diabetic foot ulcer, kidney function, liver function.