An Outbreak of Infectious Laryngotracheitis in Commercial Poultry Flocks in Ontario

An outbreak of infectious laryngotracheitis was observed in Ontario commercial poultry flocks from September 1974 to June 1975. Fifty-five flocks, totalling over 848,770 birds were clinically affected by this disease in the southern region of the province. Sixty-nine percent (38/55) of the exposed flocks were in Wentworth country and the regional municipality of Niagara. Hemorrhagic tracheitis with histological evidence of intranuclear inclusion bodies in syncytia of tracheal epithelial cells were the salient pathological findings.