Molecular Detection of Hepatitis E Virus in Rattus norvegicus in Lagos, Nigeria

Hepatitis E virus (HEV) is an important cause of acute viral hepatitis globally which is mainly transmitted through fecal-oral routes. HEV has also been reported in animal hosts like swine, rabbit, mouse, and wild rodents from different parts of the world. Wild rodents trapped within human dwellings around Ikotun, Alimosho Local Government Area of Lagos State, Nigeria were screened to determine their contribution to HEV epidemiology in the country. In this cross-sectional study in an urban setting, twenty small mammals including, Rattus norvegicus (12) and Crocidura dolichura (8) were captured, anesthetized with chloroform and euthanized by cervical dislocation. Viral RNA was extracted from blood, liver, kidney, heart and lung tissues and amplified by Nested reverse transcription Polymerase chain reaction (RT-PCR) and amplicons detected by 1.8% agarose gel electrophoresis. Eight out of twenty rodents (40%) identified as Rattus norvegicus were positive for HEV. The viral genome was detected in various organs of the rat including blood (50%), kidney (25%), lungs (33.3%), liver (50%), and heart (41.7%). Non-parametric Kruskal-Wallis test shows no significant difference in HEV among the tissues (P=0.0790; α = 5%). HEV RNA was not detected from C. dolichura. The high prevalence (40%) of HEV RNA detected in R. norvegicus, makes rodents an obvious target for further investigations for their roles in HEV epidemiology in Nigeria. Genome sequencing and comparison with human HEV sequences will help explain whether these rodents pose zoonotic threats.