Canine distemper virus in Northeast India: Genetic diversity and spillover potential in the Indo-Burma biodiversity hotspot.

Abstract

Canine distemper is a highly contagious multisystemic disease of domestic and wild carnivores worldwide. The constantly expanding host range of canine distemper virus (CDV) raises serious implications not only for domestic dogs and cats but also for wildlife conservation. This study investigated the molecular epidemiology of CDV circulating in Northeast India, part of the Indo-Burma Biodiversity Hotspot. Bayesian phylogenetic analysis of the complete H gene from fourteen different isolates of CDV revealed the co-circulation of Asia-1 and Asia-5 lineages. The concurrent detection of Asia-1 and Asia-5 lineages in this specific geographic area underscores Northeast India's potential role as a convergence zone for CDV lineages and a corridor for viral exchange. The study also recorded one Asia-5 isolate from a wild jackal, underscoring potential wildlife spillover. Deduced amino acid analysis of the H gene showed several lineage specific substitutions including at key receptor binding sites, while N-glycosylation site analysis revealed inter and intra-lineage variations. The findings emphasize the need for a holistic approach to CDV surveillance, including targeted sampling across diverse host species and genomic analysis. This study provides the first comprehensive report of CDV circulating in Northeast India and underscores the importance of surveillance at cross border and human-wildlife interface.