An epidemic of Getah virus infection among racehorses: isolation of the virus.

During the autumn of 1978 a disease characterised by fever and occasionally by exanthema and/or oedema of the limbs was seen in approximately 13 per cent of horses in a training stable in the Kanto district of Japan. A virus was isolated by the intracerebral inoculation of one-day-old mice from blood and nasal swabs taken from naturally and experimentally infected horses. The virus was subsequently passaged in two monkey kidney cell lines in which it produced complete cytopathic changes. Infected horses developed neutralising, complement fixing and haemagglutinin inhibiting antibodies to the virus and the results of serological investigations indicated that approximately 56 per cent of horses in the training centre had been infected. The virus was subsequently identified as Getah virus, a member of the alphavirus subgroup of Togaviridae.