Mixed infection of turkeys withMycoplasma synoviaeand reovirus: Field and experimental observations

Abstract

Mycoplasma synoviae and a reovirus were isolated from hock joints of commercial turkeys affected with severe synovitis. One day old turkey poults were inoculated with the mycoplasma and the virus into the left and right foot pads respectively. Other groups were given a single infection of either mycoplasma or virus, plus a sham inoculation of sterile medium into the other foot pad. Uninfected controls received sterile medium only. Although the birds were kept for 15 weeks there were no signs of clinical disease and on postmortem examination, there were no gross lesions, apart from occasional slight excess of synovial fluid in the hock joint. Microscopic lesions in the joints were minimal. M. synoviae was recovered only once and this was not until 15 weeks, despite regular attempts to reisolate the organism from a number of tissues, There was serological evidence of M. synoviae infection in some birds, with a greater number of reactors in the dual than the single infection. The virus could be recovered for no more than three weeks from either virus-infected group but neutralising antibodies developed in all birds and persisted until the end of the experiment. Results were similar for the single and dually-infected groups. Factors that may have influenced the outcome of this experiment include the age of bird at infection, the route of infection and possibly the timing of the infections with respect to each other.