Experimental infection of badgers (Meles meles) withMycobacterium bovis

Abstract

SUMMARYThe intradermal inoculation of four badgers with small numbers of Mycobacterium bovis resulted in localized lesions with ulceration which slowly healed by 5 months after inoculation. Lesions of generalized tuberculosis were seen in three badgers, one of which died at 17 months post-inoculation and in the remaining two killed 22 months post-inoculation. In the fourth badger lesions were confined to the draining lymph node of the inoculation site but M. bovis was isolated from the liver. Monthly clinical sampling of faeces, urine, tracheal aspirate and inoculation site exudates detected only the excretion of M. bovis from the inoculation site of one badger. There were marked seasonal variations in body weight but significant weight loss was observed during the second year in all four badgers, particularly prior to death. Four badgers inoculated intratracheally with a similar inoculum of M. bovis and another two control badgers showed no evidence of infection with M. bovis.

Mycobacterium bovis in the European badger (Meles meles): epidemiological findings in tuberculous badgers from a naturally infected population

“…The marked seasonal variation in body weight of adult badgers has been previously noted from limited studies in both free-living [8,14,15] and captive animals [13,14] with the lowest body weights being found in midsummer and the highest from November to December. The extensive body weight data from the current study have allowed a far more precise estimation of this variation both by sex and age group.…”

“…These badgers tended not to survive as long as those diagnosed from other samples. This may imply a more rapidly disseminated form 16 of tuberculosis, perhaps due to haematogenous spread, following inoculation of the organism, as is seen in experimentally inoculated badgers [13]. These findings support the results of a previous study based on post-mortem examinations, in which it was considered that infection originating from bite wounds accounted for 141 % of tuberculous badgers [20] and that the post-mortem appearance in these animals suggested that a particularly severe and acute form of tuberculosis resulted.…”

“…The evidence presented suggests that badgers can cope remarkably well with the chronic infection, to the extent that cubs may be produced and a successful lactation occur. At some point this mechanism appears to fail and massive multiplication of the organism occurs [13,22]. The trigger for this is unknown, although a range of 'stress' factors, such as food shortage, may be postulated.…”

“…Visible lesions (VL) of tuberculosis were recorded and samples taken for histopathological examination. Tissue samples from all lymph nodes and major internal organs were taken for bacteriological culture [13].…”

Experimental Inoculation of North American Opossums (Didelphis Virginiana) With Mycobacterium Bovis

“…Even in laboratory studies, badgers may live several years without evidence of clinical disease (Corner and Presidente, 1980;Pritchard et al, 1987;Buddle et al, 1994). The opossum may be similarly affected when exposed to M. bovis, although its role as a reservoir host remains to be seen and our study was too short to assess long-term infection.…”