Nonsuppurative Encephalomyelitis of Calves Caused by Akabane Virus Genogroup Ⅱ

Abstract

Two calves showed neurological symptoms such as astasia, dysstasia and ataxia in Fukui Prefecture during the wide-ranging epidemic of Akabane disease from Kyushu to Hokuriku regions in 2008. Nonsuppurative encephalomyelitis was observed in the calves by histopathological examination. Akabane viral antigen and genome were consistently detected from the central nervous system of the calves through immunohistochemistry and RT-PCR, respectively, and the virus was isolated from one of them. Based on these findings, these two calves were diagnosed with postnatal Akabane virus infection. Through phylogenetic analysis, the isolate was classified into genogroup Ⅱ, which has not been isolated from Akabane viral encephalomyelitis in cattle by postnatal infection.