Congenital anomalies in cattle associated with an epizootic of bluetongue virus (serotype II)

Abstract

Outbreaks of bluetongue occurred in several ruminant species in Oklahoma between December, 1983, and May, 1984. Bluetongue virus (BTV) was isolated from 9 of 20 specimens from cattle fetuses and newborn calves. The viral isolates were serotyped as BTV 11. Serotype 11 of BTV was also identified in 2 sheep fetuses and in a 1-month-old addax, a 1-day-old Nubian ibex, a 1-day-old Cape buffalo and a 1-day-old Sable antelope. Serotype 17 of BTV was identified in a newborn lamb. The ability to isolate BTV from clinical specimens was enhanced by increasing the adsorption time of virus onto cell cultures. An increase in congenital anomalies in cattle was associated with the outbreak of BTV. The most prominent histological lesion of BTV was found in the brain of the affected animals.