PRESUMPTIVE REOVIRUS INFECTION IN BROILER BREEDERS

Tenosynovitis is one of the pathological manifestations of avian reovirus infection and are of economic importance, special in one of the most important stages of the poultry industry, i.e., broiler breeders. In late May 2012, an outbreak of unilateral lameness occurred in a broiler breeder flock (15,000 birds divided by two houses) of a multi-age farm, with a total of four broiler breeder flocks (65,000 birds in total). Birds aged from 20 to 30 weeks presented joint lesions. Morbidity ranged between 5 and 10%. Routine postmortem examination of 30 birds revealed a range of visible joint lesions, typically unilateral in distribution. After postmortem examination, samples of tendons, heart and liver were collected for histopathology, bacteriological culture and polymerase chain reaction analysis. Microscopic examination of the tendons revealed changes consistent with a reovirus infection and, to the authors’ knowledge, these are the first reported cases of viral arthritis in broiler breeders in Portugal.