The Pathogenesis of the Encephalitis in Turkey Poults Produced by a Neurotropic Pleuropneumonia-Like Organism

THE pleuropneumonia-like organisms (PPLO) are capable of producing a variety of pathological processes in chickens and turkeys. In addition to aerocystitis, tracheitis and sinusitis10, inflammatory changes due to these organisms have been observed in the joints1 and brain.6 Encephalitis was described by Minard and Jungherr6 and by Groupe, Winn and Jungherr.4 They succeeded in producing the disease in chicks and poults that had been inoculated with the then poorly characterized infectious sinusitis agent. Delaplane2 found that the sinusitis agent produced nervous symptoms in some poults as a result of infection in the infraorbital sinus. Three years ago a PPLO was isolated here at the School of Veterinary Medicine by Zander from the brain of a turkey exhibiting encephalitis symptoms. Subsequent experiments indicated that this 'strain was consistently neurotropic when inoculated intravenously in turkeys. In view of these observations the following experiment was undertaken to study the pathogenesis of PPLO-induced encephalitis of turkeys.