Current status and future prospects of epizootic haemorrhagic disease of deer - a review

Epizootic haemorrhagic disease virus (EHDV), a member of the Orbivirus genus in the family Reoviridae, is related to bluetongue virus (BTV) and Palyam serogroup of orbiviruses. The EHDV infects domestic and wild ruminants in many parts of the world. Ten serotypes of EHDV designated (EHDV-1 through EHDV-10) are recognized worldwide. Currently, there is little information about the epidemiology of EHDV serogroup of orbiviruses. Cattle are susceptible to EHDV infection, but the disease is usually subclinical. Whereas the disease is fatal in North American white-tailed deer (Odocoileus virginianus), no information is available about the disease in African deer populations. Unfamiliarity with the ecology, biology and molecular epidemiology of EHDV serogroup has led to major barriers in international trade of livestock and associated germplasm. The surge of new techniques in cellular immunology and molecular biology should provide an excellent opportunity for understanding the molecular epidemiology of EHDV serogroup members. A vaccine that will provide protective immunity against multiple serotypes, or even a single serotype of EHDV serogroup, is yet to be produced. This article is intended to review the biology, distribution, transmission, pathogenesis, diagnosis, economic importance, import/export regulatory implications, and prevention as well as control measures of these viruses.