a vaccine for animals subject to bordetella bronchiseptica infection comprises an aqueous suspension of viable cells of the modified bordetella bronchiseptica previously identified as strain 55 and now further identified as atcc strain no . 31437 . strain 55 is not merely attenuated and avirulent but has been modified so that it will colonize the respiratory mucosa of animals for only a limited time before it is cleared , causing no adverse effect on the animals . during the limited period of growth on the respiratory mucosa , however , strain 55 is capable of inducing local resistance to b . bronchiseptica infection . swine are thereby protected against atrophic rhinitis and turbinate atrophy and dogs against tracheobronchitis .