EN
Avian reoviruses are members of the Orthoreovirus genus in the Reoviridae family. They were first isolated from the respiratory tract of chickens with chronic respiratory disease. Reovirus infections can spread horizontally by direct contact among infected birds or indirectly by water, feed and feces. In the case of chickens the viruses cause arthritis/tenosynovitis, reovirosis, pericarditis, miocarditis, malabsorption syndrome, enteritis, hepatitis, atrophy of the bursa Fabricii and thymus, and acute and chronic respiratory tract diseases. Reoviruses are also isolated from turkeys with arthritis and malabsorption syndrome. In the case of geese and Muscovy ducks they cause diarrhorea and hepatitis. The viruses have an immunosuppressive ability and are frequently found in chickens with latent infections that were initially clinically normal. Prevention and control are achieved through vaccinating the parent flocks and broilers, as well as by disinfection.