Atrophic rhinitis: appraisal of infection pressure on gnotobiotic piglets infected with Bordetella bronchiseptica.

With the use of 16 gnotobiotic piglets inoculated at day 4, 5 and 6 of life with defference concentrations (3.10(4) to 3.10(9) colony forming units of Bordetella bronchiseptica per mL), it was possible to establish a minimal infective dose (3.10(5) CFU/mL). With a lower dose, it was not possible to induce any of the typical gross lesions of atrophic rhinitis. The authors discuss some factors which can modify the infection pressure in the field.