Evaluation of vaccines for atrophic rhinitis--a comparison of three challenge models.

We compared three challenge models for the assessment of atrophic rhinitis (AR) vaccines: combined infection with Bordetella bronchiseptica (Bb) and Pasteurella multocida (Pm); application of acetic acid (AA) to the nasal mucosa followed by Pm infection; and Bb infection alone. Two vaccines were tested using standardized criteria, notably nasal lesion scores. The vaccines provided different levels of protection in the Bb and the AA/Pm challenges, but were similar in the combined (Bb/Pm) challenge. It is clear that the AA/Pm model shows the protective value of only the Pm component, whereas the single Bb challenge reflects the protective value merely of the Bb component of a combined vaccine. These results suggest that the best assessment of protection is provided if the two specific challenges are performed separately.