BORDETELLA-AVIUM - AN OPPORTUNISTIC PATHOGEN IN LEGHORN CHICKENS

Experiments were conducted in order to produce bordetellosis in specif ic pathogen-free (SPF) leghorn chickens. In the first and second of th ree experiments, young turkeys and chickens, respectively, were allott ed into groups and challenged at 2 weeks of age with one of seven diff erent isolates of Bordetella at avium and two isolates of B. avium-lik e bacteria. Isolates of B. avium with the smooth colony type were path ogenic in turkeys but not in chickens. The B. avium-like bacteria and B. avium isolates B. with rough colonial morphology were nonpathogenic . In the 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 vacc inated and then challenged with B. avium showed clinical signs and les ions similar to bordetellosis in turkeys. No clinical signs were obser ved in unchallenged chickens. Thus, we conclude that B. avium is an op portunistic pathogen in SPF leghorn chickens.