Background: Swine atrophic rhinitis (AR) is a multiple chronic respiratory diseasemainly caused by porcine Bordetella bronchiseptica (Bb) and Toxigenic Pasteurella multocida (T+Pm). There are two challenge models using Bordetella bronchiseptica and Pasteurella multocida. The first model is to treat pigs with Bordetella bronchiseptica followed by Toxigenic Pasteurella multocida infection. Another model is to inoculate pigs with Bordetella bronchiseptica and Pasteurella multocida simultaneously. So far, there is no report about comparison of these two challenge models as for their effectiveness to establish infection.
Methods: Thirteen 42 day-old piglets were divided into three groups. Pigs in the first group were challenged with Bordetella bronchiseptica followed by Toxigenic Pasteurella multocida infection (model 1). Pigs in the second group were challenged with Bordetella bronchiseptica and Pasteurella multocida at the same time (model 2). Pigs in the third group worked as sterile controls. Clinical symptoms, turbinate lesions, lung lesions and daily bodyweight gain were used as parameters to evaluate the effectiveness of above challenge models.
Results: All challenged piglets showed different degrees of clinical symptoms, turbinate lesions, lung lesions and loss of average daily bodyweight gain. There was no significant difference in clinical symptoms and lung lesions between two challenge models. However, significant differences in turbinate lesion score and average daily gain were observed between these two challenge models.
Discussion and Conclusion: Turbinate lesions score of piglets in first group ranged from 4 to 10 and only 1/5 of piglets had a total turbinate score of 10. By contrast, turbinate lesions score of piglets in the second group ranged from 8 to 16 and 4/5 of piglets had a total turbinate score of equal or above to 10. Therefore, all above data indicated that co-infection of Bordetella bronchiseptica and Pasteurella multocida was more suitable for to establish AR infection model.