Wild animal rabies in India: Possibility of species spill over

Abstract

Background: Rabies is endemic in most parts of India, with the exception of Andaman and Nicobar and Lakshdweep islands and to some extent in Nagaland. In India, dogs play an important role in rabies transmission and maintenance, however very less is known about the role of wild animals in rabies transmission and maintenance. Phylogenetic analysis supports the evolution of lyssaviruses inbat vectorswithoccasional but regular spill over andhost switching to carnivore vectors to extend the virus host range. The present study is aimed at sequencing and phyloegnetic analysis ofwild animal rabies virus isolates by targeting thenuceloprotein gene. Methods & Materials: We collected 12 rabies suspected brain samples from different species of wild animals in India. The confirmatory diagnosis was made by direct fluorescent antibody test (dFAT) and nuceloprotien gene specific real time polymerase chain reaction (RT-PCR). The partial nucleoprotein gene was amplified and sequenced. The phylogenetic analysis was carried out with publishedN gene sequences fromwild, domestic and human origin by DNAstar software. Results: Eight out of twelve samples were found positive by dFAT andRT-PCR after runwith specific controls. The partial N gene (803bp) sequence analysis revealed the all rabies isolates were belonged to classical rabies virus of genotype 1 of rhabdovirus. These isolates were more closely related to other animal rabies virus isolates, indicating the spillover of species. Even though this event is rare, occasionally such an event can initiate a new virushost relationship in which sustained propagation and independent transmission of the virus within the new host species occurs such that thenewhost species becomes a rabies reservoir. The full length nucleotide sequence analysis is also underway along with more number of samples to knowprecise virus type and the transmission of rabies virus from the reservoir host to the other host. Conclusion: In conclusion the rabies virus isolates circulating in wild and domestic animals in India are more closely related genotypically and suggestive of species spill over.