Diseases Caused by the Epizootic Hemorrhagic Disease Virus Serogroup Epizootic Hemorrhagic Disease, Hemorrhagic Disease, Ibaraki Disease, Bovine Influenza, Bovine Epizootic Fever, Bluetongue-like Disease

Epizootic hemorrhagic disease is an important disease of cervids, especially white-tailed deer. The causative virus is widespread among wild cervids in North America, where white-tailed deer are endemic, and periodically causes serious epidemics in wild and/or captive populations. Sporadic clinical cases and outbreaks have also been reported in other cervids, cattle, bison, yaks and other animals, although most infections in these species seem to be subclinical. In Japan, the illness in cattle is called Ibaraki disease, and there have been several outbreaks of varying severity, with mortality rates as high as 10%. Since 2004, other serotypes of epizootic hemorrhagic disease virus (EHDV) have caused outbreaks in cattle and some other ruminants in the Middle East, the Caribbean and North America. Some of these outbreaks were extensive, although the illness was generally milder than in whitetailed deer. In addition to occasional deaths, these epidemics resulted in significant economic losses from decreased productivity, including reduced milk yield. Disease control is difficult, as EHDV is spread by Culicoides midges, and commercial vaccines for cattle are only produced in Japan.