A guinea pig model of low-dose Mycobacterium bovis aerogenic infection

In order to develop a model of Mycobacterium bovis infection with pathogene tical relevance, a modified version of the Henderson apparatus was used to deliver infectious aerosols directly to the snouts of guinea pigs. Aerosols generated from 10(6), 10(7), 10(8) CFU/ml M. bovis suspensions established disease in every animal, with estimated retained doses of 10, 100, 1000 CF U, respectively. For comparison, other guinea pigs were inoculated with 100 CFU M. bovis intramuscularly (i.m.). Pathology and bacterial colonisation of lungs and spleen varied according to the dose and route of inoculation. Animals inoculated i.m. gave a significant cutaneous tuberculin hypersensit ivity reaction earlier after testing than those infected aerogenically. A s erological response to M. bovis antigens was detected in all infected anima ls. Intensity of antigen recognition was dose-dependent and although the ra nge of antigens recognised varied between animals, a 25 kDa antigen present in the cell fraction was serodominant. Thus, a reproducible guinea pig mod el has been defined that may be suitable for virulence, vaccination, and im munological studies. Crown Copyright (C) 2001 Published by Elsevier Science B.V. All rights reserved.