Meningoencephalitis in commercial meat turkeys associated with Mycoplasma gallisepticum.

Mycoplasma gallisepticum (MG) infection was diagnosed in three different flocks of 12-to-16-week-old commercial meat turkeys displaying torticollis and/or opisthotonos. MG was isolated from the brain, air sacs, trachea, and sinus of one bird with neurological signs. Histological examination of brains in all three cases revealed moderate-to-severe encephalitis with lymphoplasmacytic cuffing of vessels, fibrinoid vasculitis, focal parenchymal necrosis, and meningitis. Birds with neurological signs were seropositive for MG by the serum-plate agglutination and hemagglutination-inhibition tests. The encephalitic form of MG has been described previously but is rarely mentioned in the current literature.