Cache Valley Fever Virus
(NY; PA) Recently we have diagnosed Cache Valley Fever virus in two sheep flocks based on the presence of antibodies to the virus in heart blood or pleural fluid from stillborn fetuses. The positive serum neutralization tests on the fetal fluids, along with the gross fetal abnormalities, which have included arthrogryposis, mandibular brachygnathism, scoliosis, and hydranencephaly together confirm the diagnosis of Cache Valley Fever. Positive antibody tests run on serum from the affected ewes only indicates exposure, but by itself is not enough to obtain a definitive diagnosis for the cause of the current abortion or stillbirth. This virus is a mosquito-transmitted cause of infertility, abortions, stillbirths and congenital abnormalities in sheep and goats. It is most commonly diagnosed in sheep and goats who are due to give birth in the winter, usually prior to February in the northeast. This corresponds to exposure of the pregnant dams (during the first 2 months of gestation) to infected mosquitoes during the late summer/early fall.