Mycobacterium bovis infection in the brush-tailed possum (Trichosurus vulpecula): II. Comparison of experimental infections with an Australian cattle strain and a New Zealand possum strain

Experimentally induced M. bovis infection in brush-tailed possums (Trichosurus vulpecula) with a possum-adapted strain from New Zealand, produced a more rapidly progressive, severe disease than did that induced by an Australian cattle strain. Possums infected with either strain excreted large numbers of mycobacteria in urine, faeces and discharges from abscesses. Aerosol transmission of infection occurred only with the New Zealand possum strain. The infectious aerosol most probably was of respiratory origin but urine may have been the source.All possums had focal interstitial nephritis consistent with Leptospira infection. Histopathological evidence of severe stress was observed in only one possum; the remainder had either mild or no stress-associated lesions.