Effects of Habitat, Host Sex and Age on the Parasites of Trichosurus Caninus (Marsupialia: Phalangeridae) in North-Eastern New South Wales.

Abstract

The condition of 57 Trichosurus caninus (Ogilby), and their ectoparasites, endoparasites and associated pathology were examined; ages and habitat status of these animals were known. Condition scores for females were greater (P<0.005) than those for males. Seven ectoparasite species (two ticks, five mites), two protozoan and seven helminth (one cestode, six nematodes) species were identified in T. caninus from both preferred and peripheral habitats. Prevalence of Amplicaecum robertsi (Sprent & Mines) larvae and the oxyurid nematode Adelonema trichosuri (Johnston & Mawson) were greater (P<0.05) in T. caninus from peripheral habitat than in preferred-habitat animals. Greater burdens (P<0.05) of the tick Ixodes holocyclus Neumann, two mites Trichosurolaelaps dixoa Domrow and 7. crassipes Womersley, and the trichostrongylid nematode Paraustrostrongylus trichosuri Mawson were found in peripheral-habitat T. caninus. Subadult males harboured greater Paraustrostrongylus burdens (P<0.05) than did subadult females or adult animals. Three Trichosurus vulpecula (Kerr) sympatric with peripheral-habitat T. caninus were also examined. One tick I. trichosuri Roberts, one mite T. crassipes and four helminth species: Bertiella trichosuri Khalil, A. robertsi, Paraustrostrongylus trichosuri and Parastrongyloides trichosuri Mackerras, were identified. The cestode B. trichosuri was recovered from the three T. vulpecula and four peripheral-habitat T. caninus, but only from one T. caninus from preferred habitat. Larval A. robertsi caused focal eosinophilic cholangiohepatitis with dilatation of affected bile ducts in livers of both Trichosurus spp. Eosinophilic vasculitis of hepatic portal veins was associated with ?Sprattia venacavincola (Spratt & Varughese) and focal granulomatous splenitis with sequestered microfilariae in T. caninus. Also, ?Marsupostrongylus minesi Spratt in dilated alveoli caused mild pulmonary inflammation. There were no pathological changes associated with intestinal tract parasites. Free corticosteroid levels in preferred-habitat female T. caninus were greater (P<0.05) than in those from peripheral habitat. This correlated with hyperplastic changes in adrenal glands of these females, but not with parasite burdens.