Epidemiological investigations into the ecology and transmission of environmental mycobacteria.

Abstract

Part 1: Investigations of Mycobacterium ulcerans. Real-time PCR investigations have detected M. ulcerans DNA in a variety of Australian environmental samples, including the faeces of native possums with and without clinical evidence of infection. Characterisation of the disease in possums and attempts try to ascertain what role, if any, possums may have as reservoir hosts for this organism were undertaken. It was found that there is a significant disease burden in Pseudocheirus peregrinus (especially males) in some areas of Victoria and that these animals may become systemically, and potentially fatally affected. Some mildly affected Trichosurus vulpecula and Trichosurus cunninghami can spontaneously overcome the infection. Subclinical gut carriage of M. ulcerans DNA in possums is common and in some T. vulpecula and T. cunninghami this is transient. Culture of M. ulcerans from the gut contents of clinically affected possums was successful on two occasions. Localised infection caused by M. ulcerans in seven dogs and two alpacas is also described.

Part 2: Investigations of fastidious mycobacteria causing cutaneous nodular disease in cats (feline leprosy). A detailed and comparative molecular and clinical epidemiological description of feline leprosy disease in 145 cats referable to Candidatus ‘Mycobacterium tarwinense’, Mycobacterium lepraemurium and Candidatus ‘Mycobacterium lepraefelis’ is presented.