MOLECULAR EVOLUTION OF ORBIVIRUSES

Authors: Wilson, William - Bill; Mecham, James

Submitted to: United States Animal Health Association Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/1/2000
Publication Date: 3/1/2000
Citation: Wilson, W.C., Mecham, J.O. 2000. Molecular evolution of orbiviruses. United States Animal Health Association Proceedings. 104:169-180.

Interpretive Summary: Arboviruses (insect-transmitted viruses) comprise one third of the Office of Intermational des Epizooties List A diseases. These are infectious diseases that have the potential for very serious and rapid spread, irrespective of national borders. Two fifths of these arboviruses are of the Reoviridae family, orbivirus genus. Among these orbiviruses that are transmitted by biting midges in the genus Culicoides, Bluetongue virus (BTV) has the greatest economic impact, with losses attributed to effects on animal health and productivity, as well as non-tariff trade restrictions that affect the sale and movement of animals. Losses to U.S. livestock industries attributed to BTV have been estimated at $120 million annually, and losses worldwide attributed to BTV have been estimated at $3 billion annually. BTV causes an infectious, noncontagious disease that occurs in domestic and wild ruminants. Once infected, a sheep may have high fever and distinctive lesions in the mouth including a tongue that becomes severely affected and turns dark blue. The disease has significant economic consequences. The cost of this disease is due to a number of factors including high mortality in infected flocks, lowered production in meat, milk and wool, decreased reproductive performance in the survivors, and restriction of livestock and germplasm movement from the disease-occurring areas such as the U.S. to disease-free countries. This paper described the current status of genetic informaton available for these viruses.

Technical Abstract: Arboviruses (insect-transmitted viruses) comprise one third of the Office of Intermational des Epizooties List A diseases. These are infectious diseases that have the potential for very serious and rapid spread, irrespective of national borders. Two fifths of these arboviruses are of the Reoviridae family, orbivirus genus. Among these orbiviruses that are transmitted by biting midges in the genus Culicoides, Bluetongue virus (BTV) has the greatest economic impact, with losses attributed to effects on animal health and productivity, as well as non-tariff trade restrictions that affect the sale and movement of animals. Losses to U.S. livestock industries attributed to BTV have been estimated at $120 million annually, and losses worldwide attributed to BTV have been estimated at $3 billion annually. BTV causes an infectious, noncontagious disease that occurs in domestic and wild ruminants. Once infected, a sheep may have high fever and distinctive lesions in the mouth including a tongue that becomes severely affected and turns dark blue. The disease has significant economic consequences. The cost of this disease is due to a number of factors including high mortality in infected flocks, lowered production in meat, milk and wool, decreased reproductive performance in the survivors, and restriction of livestock and germplasm movement from the disease-occurring areas such as the U.S. to disease-free countries. This paper described the current status of genetic informaton available for these viruses.