The immunological consequences of challenge with bovine tubercle bacilli in badgers (Meles meles)

Abstract

SUMMARYOptimal conditions were determined for performing antibody measurements (ELISA), lymphocyte transformation tests and, to some extent, skin tests in badgers. These parameters, together with the bacteriological and pathological studies reported previously (Pritchard et al. 1987), were used to follow the course of intradermal and intratracheal challenge of badgers with bovine tubercle bacilli. Two challenge doses were used for each route of infection and two animals received each dose. None of the four animals challenged by the intratracheal method showed any evidence of infection, suggesting that adult badgers may have some resistance to challenge by this method. All four animals challenged intradermally developed lesion of tuberculosis.Immunologically the disease passed through three phases. There was an early phase in which lymphocyte transformation to whole BCG steadily and significantly increased, and skin tests to tuberculin became positive but there was little change in antibody levels. This was followed by an intermediate phase of variable skin responses, fluctuating lymphocyte transformation and significant increase in antibody levels. The final phase, which was only seen in two animals with extensive disease, was associated with changing skin reactions and falling lymphocyte responses, together with a sudden increase in antibody levels.This paper presents the first formal evidence of cell-mediated immunity to tuberculosis in the badger, which may delay onset and prolong the survival of challenged animals.

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

“…The badger is an efficient reservoir for bovine tuberculosis and is responsible for maintaining M. bovis in parts of Ireland and the United Kingdom. However, unlike the brush-tailed possum, badgers may shed organisms for long periods through urine, feces, and respiratory secretions while showing neither internal lesions nor outward signs of debilitation (Little et al, 1982;Mahmood et al, 1987).…”

Experimental infection of badgers (Meles meles) withMycobacterium bovis

“…Ltd) and tracheal aspirate together with swabs of bite wounds or other lesions were taken for bacteriological examination. Blood was collected aseptically from the jugular vein for use in LTT and ELISA tests and also collected in EDTA for haematological examination which will be reported separately (Mahmood et al 1987). Badgers were marked using coloured plastic ear-tags and tattooed on the ventral surface of the lower abdomen using Indian ink (Cheeseman & Harris, 1982).…”

“…The immune response of these badgers was monitored by lymphocyte transformation test (LTT) to whole BCG bacilli, skin tests and ELISA tests, the results of which are reported in a succeeding paper (Mahmood et al 1987). …”

Rehabilitating and releasing badgers in England

“…However, intradermal skin tests, as used in cattle, are ineffective in badgers (Mahmood and others 1987) and should not be used. IFN-g tests for badgers are not currently commercially available and culture of clinical samples takes considerable time (around 12 weeks), so neither option is practical in a rehabilitation situation.…”