ABSTRACT. In efficacy tests, 7 primary specific-pathogen-free piglets vaccinated with the Bordetella bronchiseptica and type D Pasteurella multocida bacterin-toxoid were challenged with B. bronchiseptica and type A P. multocida. Severe or moderate nasal turbinate atrophy was produced in the non-vaccinated pigs, whereas, only one of the 4 pigs in the vaccinated group had slight turbinate atrophy. Other immune sera against crude toxin of P. multocida type A or D were cross neutralized. bronchiseptica was done in a 0.5 ml suspension instilled into each nostril on the post-vaccination week (PVW) 4, and P. multocida was done in the same manner as with B. bronchiseptica starting from PVW 5 for four consecutive days. The pigs were observed daily for clinical signs of AR. Nasal swab samples were taken from all pigs immediately before vaccination and at regular time intervals after vaccination. For the recovery of B. bronchiseptica, samples were plated on MacConkey agar (Eiken Chemical Co., Ltd., Tokyo) containing 25 µg/ml of furazolidone, 0.5 µg/ml gentamicin, 4 µg/ml of fradiomycin and 2 µg/ml of clindamycin, and were incubated for 3 days at 37°C. The samples were also cultured for P. multocida using DS agar (Difco Lab.) containing 0.1 µg/ml gentamicin and 30 µg/ml vancomycin for 18 hr at 37°C. Suspected colonies of B. bronchiseptica or P. multocida were identified using conventional biochemical tests [6,21]. Blood samples were collected from pigs at the same times as the nasal swab samples were taken. ELISA tests for the detection of antibodies against pure DNT of B. bronchiseptica [8,9] and pure DNT of P. multocida serotype D [18] were performed. Each pure DNT antigen showed a single band of nearly 160 kd or 140 kd by sodium dodecyl sulfate-polyacrylamide disc gel electrophoresis. The pigs were sacrificed using an intravenous injection of thiopental sodium (Tanabe Pharmaceutical Co., Osaka) on PVW 7. The snouts were cut transversely between the first molar and the canine tooth, and the turbinate atrophy was recorded as: = normal, + = slight, ++ = moderate and +++ = severe according to the criteria described by Maeda et al. [15].The relationship between clinical atrophic rhinitis (AR) of swine and infections with Bordetella bronchiseptica and/ or toxigenic capsular serotype D Pasteurella multocida has been reported by many investigators [2, 3, 23, 27-30, 32, 35]. In addition, it has been reported that capsular serotype A P. multocida is isolated predominantly from pneumonic lung in swine [26,37]. Previous experiments have shown that the dermonecrotic toxin (DNT) of B. bronchiseptica and P. multocida are virulence factors producing AR [7,11,12]. Therefore, the bacterin and/or toxoid [22] containing B. bronchiseptica and toxigenic capsular serotype D P. multocida were developed, and these vaccines were prophylactic against experimental AR with B. bronchiseptica and toxigenic capsular serotype D P. multocida [1,14,24,36]. Although there is little information about toxigenic capsular serotype A P. multocida associated wi...
