Causes of Morbidity and Mortality in Platypus (Ornithorhynchus anatinus) From Tasmania, With Particular Reference to Mucor amphibiorum infection

Over a twelve month period, 25 platypuses (Ornithorhynchus anatinus) were presented for necropsy. The most common causes of mortality were dog predation (40%), road trauma (28%), starvation and/or exposure (16%) and Mucor-mycosis (8%). Mucor amphibiorum is the only disease agent known to cause significant morbidity and mortality in free-living O. anatinus in Tasmania. This fungus causes a severe, granulomatous, commonly ulcerative, skin condition in this species. A study was conducted to define the nature and extent of the granulomatous dermatitis caused by M. amphibiorum. The mycotic granulomatous dermatitis of O. anatinus appears to be confined to streams in the north and midlands. The prevalence of the disease at two infected sites was 36% (n=36) and 66% (n=3). Lesions included abscesses, ulcers, granulation tissue and nodules. Of the 17 diseased animals captured, II were adult male, 5 were adult female and 1 was a juvenile female. Thirteen isolates of M. amphibiorum were cultured from skin lesions, all were of the positive mating type. Mucor amphibiorum was not isolated from 40 faecal or 8 skin samples from O. anatinus. No M. amphibiorum was isolated from 14 environmental samples. Mucor circinelloides and M. saturninus were isolated from soil, and M. circinelloides and M. hiemalis were isolated from faecal samples from O. anatinus.