TUBERCULOUS MYCOBACTERIOSIS IN TERRESTRIAL AUSTRALIAN MAMMALS
Three TM species are known to cause disease in Australian mammals: M. bovis, M. tuberculosis and M. pinnipe- dii. Tuberculosis in pinnipeds is covered in Chapter 45.
Species of significance to terrestrial Australian mammals are M.
tuberculosis and M. bovis, although M. tuberculosis infection has been rarely reported in Australian mammals, most being historic and unconfirmed, with the most recent in three red-necked wallabies (Nota- macropus rufogriseus) (Hime and Jones 1972). Mycobacterium bovis (bovine tuberculosis) is an economically important, serious disease of bovids worldwide. In NZ, M. bovis is endemic and introduced Australian free- ranging common brush-tailed possums are the primary wildlife reservoir (WHA 2017b). It has never been diagnosed in a common brush-tailed possum in Australia; M. bovis has been reported in a rufous bettong (Aepyprym- nus rufescens) and a group of red-necked wallabies from London Zoo and Zurich Zoo, respectively (Potkay 1977).TM are host-dependent and therefore rely on host-to- host transmission, which is usually via the respiratory route. Tuberculous mycobacteriosis in Australian mammals resembles that seen in other species, namely pyo- granulomatous nodular pneumonia and/or lymphadenitis. Infection may disseminate systemically (Hime and Jones 1972; Potkay 1977; Nugent et al. 2013). Intralesional AFB may be noted, but TM lesions can have very few microscopically detectable organisms and therefore suspected samples should also be submitted for culture and/or PCR for confirmation or confident exclusion. Reports of treatment of Australian mammals with tuberculous mycobac- teriosis are limited and historic (Teuscher 1957, cited in Potkay 1977). In nearly all cases the appropriate management is euthanasia, given the animal welfare implications of long-term treatment and isolation, zoonotic risk and socioeconomic implications of a diagnosis of bovine tuberculosis in Australia. Diseased possums in NZ are not treated (WHA 2017b).
3.