Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 9/21/2001
Publication Date: N/A
Technical Abstract: Bordetella bronchiseptica and Haemophilus parasuis are common agents recovered from swine respiratory disease. B. bronchiseptica has been shown to predispose to other bacterial infections such as Pasteurella multocida and Streptococcus suis. The objective of this study was to determine if B. bronchiseptica would predispose to colonization or disease with H. parasuis. Three groups of 3-week-old conventional pigs (10 pigs/group) were inoculated intranasally with either B. bronchiseptica (10**6 pfu), H. parasuis (serovar 4, 10**6 pfu), or B. bronchiseptica followed by H. parasuis one week later. One group served as a PBS inoculated control group. Five pigs from each group were necropsied 1 and 2 weeks post inoculation with H. parasuis. Mean nasal colonization by H. parasuis was significantly (p=0.003) higher in the coinfected group (10**6.9 cfu/g of tissue) as compared to the group infected with H. parasuis only (10**5.7 cfu/g of tissue). Mean nasal colonization by B. bronchiseptica was significantly (p=0.04) lower in the coinfected group (10**4.9 cfu/g of tissue) as compared to the group infected with B. bronchiseptica only (10**6.1 cfu/g of tissue). No lesions of polyserositis were seen in any of the pigs inoculated with H. parasuis. Pneumonia, from which either H. parasuis or B. bronchiseptica was isolated, was present in 6/10 pigs in the coinfected group, 2/10 pigs in the H. parasuis only group, and 0/10 pigs in both the B. bronchiseptica only and the control groups. Thus, B. bronchiseptica increased colonization of the upper respiratory tract with H. parasuis and may have predisposed to the development of pneumonia.