Mucormycosis in the platypus and the anuran (frogs and toads) is a serious fungal disease caused by the dimorphic Mucorale, Mucor amphibiorum. M. amphibiorum was first reported from a German Zoo in 1972, where it resulted in a disseminated mycosis in a green tree frog imported from Australia. In Australia, M. amphibiorum has been reported naturally infecting wild cane toads and frogs from Queensland and Northern Territory and captive frogs from Melbourne and Perth. The agent grows and sporulates in soil, with transmission between anurans by the oro-faecal route. Positive and negative mating types have been isolated from mainland cane toads. Mucor amphibiorum has not been isolated from frogs or their faeces from Tasmania. A severe ulcerative skin condition was first reported in platypuses from the Elizabeth River in Tasmania in 1982, but the causative agent was not confirmed as M. amphibiorum until a decade later. The granulomatous and ulcerative dermatitis may progress to involve underlying muscle or disseminate to internal organs. The route of entry is by cutaneous wounds caused by injuries and tick attachment, although the respiratory route has also been proposed. The sudden emergence of mucormycosis in Tasmanian platypuses may have been by accidental introduction with ‘banana box frogs’ from Queensland or due to an endemic Tasmanian strain that mutated becoming pathogenic for platypuses. Only positive mating types have been isolated from platypuses. The distribution of the disease in Tasmania appears to be expanding, but mucormycosis has not been confirmed in platypuses on the Australian mainland to date. The ecologic niche of M. amphibiorum in Tasmania (other than platypus lesions) is currently unknown. The use of molecular tools to detect M. amphibiorum in the environment, in tissue lesions and other aquatic vectors, would improve our understanding of mucormycosis epidemiology, leading to better surveillance and control.
Full conference title:
- ISHAM 19th (2015)