Bordetella avium: an opportunistic pathogen in leghorn chickens.
In the 2 experiments, groups of young commercial turkeys and SPF chickens, respectively, were challenged at 2 weeks of age with one of 7 different isolates of Bordetella avium and 2 isolates of B. avium-like bacteria. Isolates of B. avium with the smooth colony type were pathogenic in turkeys but not in chickens. The B. avium-like bacteria and B. avium isolates with rough colony morphology were nonpathogenic. In a third experiment, SPF leghorn chicks were vaccinated at 1 day of age with infectious bronchitis virus, Newcastle disease virus, or both and then challenged with B. avium at 7 days of age. Chickens vaccinated and challenged with B. avium developed clinical signs and lesions similar to bordetellosis in turkeys. No clinical signs developed in unchallenged chickens. It is concluded that B. avium is an opportunistic pathogen in SPF leghorn chickens.