Seroprevalence survey on Reovirus infection of broiler chickens in Tehran province

Reovirus infections are actually related to a lot of disease conditions with different clinical manifestations. Reoviruses have been isolated from a variety of tissues in poultry, suffering from different disease conditions including viral arthritis/tenosynovitis, stunting syndrome, respiratory disease, enteric disease, immunosuppression and malabsorption syndrome. Economic losses related to reoviral infections are frequently associated with increased mortality, viral arthritis/tenosynovitis and general lack of performance, including diminished weight gains, high feed conversions, uneven growth rates and reduced marketability of the affected birds. The aim of this survey was to study the prevalence of reoviral infection of broiler chickens in Tehran province. The samples were selected by cluster sampling method from sera in Razi Vaccine and Serum Research Institute. The selected sera had been collected from different slaughterhouses of Tehran province during 2004 to 2005. Commercial ELISA test was done on 582 serum samples of broiler chickens. The total number of 572 serum samples were positive and the prevalence of Reovirus infection was 98.3% (CI = 96.9-99.2%). The result shows high prevalence of antibody titre in broiler chickens. The resistance of the virus could be one of the reasons for such a high prevalence. This high prevalence put emphasis on the vaccination of the breeder flocks and shows the necessity of more studies on aspects of Reovirus infection in broiler chicken.