Influence of feed on the course of tenosynovitis caused by REO virus infection in broilers

The first outbreak of tenosynovitis caused by infection with REO virus in the Netherlands, involving 15 broiler flocks, is described. The disease could be reproduced easily by subcutaneous, oral and contact infection of susceptible broilers with the isolated virus. The 15 affected flocks all came from one broiler parent flock and were fed with feed from one mill (A). Twenty other flocks, also coming from this parent flock and reared in the same period on feed from another feed mill (B) did not suffer from tenosynovitis. The parent flock showed no disease symptoms but seroconversion to REO virus occurred after the onset of the problems in the offspring. The influences of the different feeds on the course of the synovitis could be reproduced experimentally, but with less extreme differences than observed in the field. The possible ways in which feeds may influence tenosynovitis causing REO virus infection are discussed.