A Preliminary Study on Bat Lyssavirus in Assam, India

Rabies is a zoonotic disease caused by Lyssavirus of the family Rhabdoviridae, affecting all warm-blooded animals. Although a vast majority of the cases are canine-mediated, many cases of bat-mediated rabies in humans have been documented since the early part of the 20^th century. Different lineages of Lyssavirus have been detected in bat populations across Africa, Eurasia and Australia. Although there is no direct evidence of the prevalence of bat Lyssavirus in India thus far, indirect evidences are emerging of late. This has significant public health implications considering the not so infrequent human bat interactions in a country like India. In view of the absence of any systematic surveillance of bat rabies especially in the context of Assam state, a preliminary study was conducted to determine the prevalence of bat lyssavirus in Assam.

34 brain samples belonging to nine species of bats were collected from fourteen locations in eight districts of Assam, for detection of bat Lyssavirus by Lateral Flow Assay (LFA), Direct Fluorescent Antibody Technique (DFA) and One-step PCR at KVAFSU-CVA Rabies Diagnostic Laboratory, WOAH Rabies Reference Laboratory, Veterinary College, Bengaluru, Karnataka-560 024.

None of the samples were positive for lyssavirus indicating absence of an active lyssaviral infection in the representative bat population under study. However, considering the small sample size mere absence of the lyssavirus antigen among bats in the present study does not preclude the pathogen’s presence in bat populations across the state or occurrence in the future, considering the rapidly dynamic state of ecology and environment. Continuous surveillance through One-Health collaboration is essential to monitor the status of bat rabies in India.