Parasites of the bridled nailtail wallaby (Onychogalea fraenata) (Marsupialia : Macropodidae)

Abstract

The bridled nailtail wallaby (Onychogalea fraenata), an endangered macropod, has been reintroduced into the wild after a captive-breeding program. As part of a management program to assess the risks to its survival O. fraenata were trapped and examined for ecto- and endoparasites. From February to September 1996, 55 wallabies from Taunton National Park, central Queensland, some trapped more than once, were visually examined for ectoparasites. The blood of 39 O. fraenata was tested for antibodies against Toxoplasma gondii and Echinococcus granulosus and a total of 82 faecal samples were examined microscopically. In addition, in a second study a complete carcase, three complete gastro-intestinal tracts, and a single stomach, obtained from various sources, including Idalia National Park, were examined for helminth parasites. The most prevalent ectoparasites were the ticksAmbylomma triguttatum and Haemaphysalis bancrofti. Other ectoparasites included four species of trombiculid mites and a louse, Heterodoxus sp. A single instance of the nippoboscid fly, Ortholfersia minuta, was found. From the serological surveys, antibodies against Toxoplasma and Echinococcus were detected in 15% and 21% respectively. No trematode or cestode eggs or protozoal cysts were found in faeces. Nematode eggs had a prevalence of 92% with a mean egg density of 500 eggs per gram. Strongyloides sp. (larvae) was the most prevalent nematode in faeces. In the postmortem study, seven nematode species (Cloacina polyxo, Hypodontus macropi, Labiostrongylus onychogale, Macropostrongyloides baylisi, Macropoxyuris sp., Rugopharynx australis and Zoniolaimus buccalis) and four cestode species (Progamotaenia bancrofti, P. zschokkei, P. abietiformis and larval E. granulosus) were found. Six of the nematode species are new host records. The presence of infection with the introduced parasites T. gondii and E. granulosus, both recognised as serious pathogens, is of management significance. Since the definitive hosts of these parasites are cats and canids respectively, control of cat, dog and dingo populations within the Park will lessen the incidence of infection with these parasites.