Sero-evidence of silent Japanese Encephalitis Virus infection among inhabitants of Ilorin, North-central Nigeria: a call for active surveillance

Infection by Japanese Encephalitis Virus (JEV) causes viral encephalitis in humans. It is endemic in Asia and western Pacific regions with no reported case in Nigeria so far. This study aimed at detecting evidence of circulation and pattern of exposure of individuals in Ilorin, Nigeria to JEV. A total of 139 febrile patients attending outpatient departments of Sobi specialist hospital, Civil service hospital and University of Ilorin health center participated in the study. About 5 ml of venous blood was collected from each participant and the plasma tested for the presence of anti-JEV IgG antibody using Enzyme Linked Immunosorbent Assay (ELISA) technique. Anti-JEV IgG antibody was detected in 32% (45/139) of the participants. Males were more exposed (37%) than female participants (27.3%). Similarly, participants with travel history outside of the country were more exposed (44.4%) than those without travel history (29.5%). Further analysis on the basis of age, marital and working status showed no statistical association between these variables and anti-JEV positivity (p˃0.05). This study has provided serological evidence of the circulation of JEV among Ilorin inhabitants and therefore calls for active surveillance for the infection in order to forestall any future major outbreak.