Evaluating the role of stress and parasite load in sarcoptic mange incidence in bare-nosed wombats (Vombatus ursinus) in N.S.W., Australia

Abstract

Populations of bare-nosed wombats (Vombatus ursinus) are under threat across Australia and one of the major causes of their mortality is sarcoptic mange. Reasons for this high susceptibility are being investigated. On conducting a thorough search through literature, it was observed that although the current treatment practice can successfully restrict sarcoptic mange prevalence in small captive bare-nosed wombat populations, the same is not true for large free-ranging populations. Environmental factors such as drought, habitat degradation and anthropogenic interference can act as potential stress factors to exacerbate the effects of sarcoptic mange. During stress, the hypothalamic pituitary adrenal (HPA) axis is stimulated to release stress hormones (glucocorticoids - GC) that can influence immune function. Past research has suggested that chronic stress is associated with immunosuppression which can play a role in disease incidence. Additionally, a high prevalence of secondary endoparasitic infestations have been reported to be associated with sarcoptic mange incidence. To better comprehend the parameters that influence sarcoptic mange incidence in bare-nosed wombats, this study employed non-invasive procedures that enable evaluation of endoparasitic and stress load in these marsupials. Non-invasive faecal sampling is ideal for large nocturnal marsupials like bare-nosed wombats. Validation of species-specific enzyme immunoassay (EIA) is necessary. This thesis aimed to optimise techniques suitable for quantifying faecal cortisol metabolites (FCM) (end products of HPA axis activation) in the voided excreta of bare-nosed wombats. One in-house and one commercial EIA was successfully validated to monitor the adrenocortical activity in these marsupials. Faecal samples collected from free-ranging wombats are usually

Date of Award	2019
Original language	English