CILIA-ASSOCIATED RESPIRATORY (CAR) BACILLUS INFECTION IN CONVENTIONALLY REARED RABBITS

This study was designed to investigate the prevalence of Cilia-associa ted respiratory (CAR) bacillus infection in rabbits reared for meat pr oduction in Italy and to correlate the presence of CAR bacillus with i nflammatory lesions of the respiratory tract. Seventy healthy, 3-month -old, New Zealand White rabbits, raised in 10 different rabbitries in Northern Italy were randomly selected at slaughter. No gross lesions w ere found at necropsy in any rabbit. In each animal, the trachea and l ungs were sampled, fixed in 10% formalin, embedded in paraffin and sta ined with the Warthin-Starry method to evaluate the presence of CAR ba cillus, and with haematoxylin and eosin to evaluate the presence of in flammatory lesions. CAR bacillus was present in 50 out of 70 rabbits ( 71.4%) with a prevalence of the infection that varied from 30% to 100% in the seven rabbitries. CAR bacillus was present both in the trachea and bronchi in 23 cases (32.8%), only in the trachea in 24 cases (34. 3%) and only in the bronchi in three cases (4.3%). Inflammatory lesion s were found in the trachea (22 cases, 31.4%) and the bronchi (58 case s, 82.8%). There was a strong, statistically significant correlation b etween the presence of CAR bacillus in the bronchi and bronchial infla mmatory lesions (P < 0.0001). This study indicates that CAR bacillus i nfection is widespread in conventionally reared rabbits in Italy and t hat a possible correlation exists between the presence of CAR bacillus and bronchial inflammatory lesions.