Effects of avian reovirus on Marek's disease (MD). I. Suppression of MD development

The effects of an avian reovirus on the development of acute Marek's disease (MD) were studied by exposing chickens to Reo-W isolant of avian reovirus before infecting them with an oncogenic MD herpesvirus (MDHV). Four separate trials were made in a similar manner, 2 trials with an experimental line of White Leghorn (WSU-VS) highly susceptible to MD, and 2 trials with a commercial strain of meat-type (C-MT) chicken. MD mortality and/or incidence of gross MD lesions were consistently reduced by preexposure to avian reovirus. The suppression was more apparent in the WSU-VS than in the C-MT birds, and appeared greater with exposure to reovirus via the respiratory route than with the alimentary route.