Review of epizootic hemorrhagic disease in cattle and a study defining seroprevalence of epizootic hemorrhagic disease virus serotype 2 in Texas cattle

Abstract

Epizootic hemorrhagic disease virus is an orbivirus transmitted by Culicoides spp. In North America, it is recognized as a major cause of disease affecting white-tailed deer, but it can impact other wildlife species as well as domestic cattle. Although minimal clinical disease had been noted in Texas, periodic outbreaks in other states caused Texas cattle producers to question the risks to their cattle. The objective of this study was to estimate the proportion of Texas cattle exposed to epizootic hemorrhagic disease virus serotype 2 by observing seroprevalence in auction markets. Serum samples collected from cattle >18 mo of age sold through 11 Texas auction markets were collected during June of 2014. Antibody levels were measured using the virus neutralization test as the diagnostic protocol. Market sampling indicated 97.08% of adult cattle had been exposed to epizootic hemorrhagic disease virus serotype 2. There were no significant differences in mean titers between individual markets. However, when markets were grouped there was a significant mean titer difference between groups, increasing in the southern and western regions. The lack of clinical disease is likely related to enzootic stability as a result of high viral infections in cattle and white-tailed deer and the abundance of Culicoides vectors.