Mutations in the gene called OAS1 contribute to a horse's ability to fight West Nile Virus (WNV), reported a group of researchers led by David Adelson, PhD, Professor and Chair of Bioinformatics and Computational Genetics from the University of Adelaide in South Australia.

Previous research in mice indicated that the OAS genes played a role in immunity to flaviviruses (such as WNV). Horses also have OAS genes that produce proteins known to break down viral genetic material.

"Since animals' susceptibility to the West Nile Virus is variable and horses are particularly susceptible to severe infections, this study was conducted to determine if mutations in the OAS genes contribute to a horse's ability to fight off the virus," explained Adelson.

Indeed, OAS1 gene mutations were identified in the 44 horses that succumbed to fatal WNV infection during the initial US epidemic in 2001 and 2002