Application for Scientific Permit – Available for Public Comment
Public comment on the following application for a Scientific Research (Fauna) Permit is open until 3 August.
Applicant: University of Tasmania
Species/Taxon: Bare-nosed wombat (Vombatus ursinus)
Aim 1: Two sites (A and B) on private land in Tasmania
Aim 2: Tasmania-wide on private (pending land manager approval)/reserved/Crown land
Title of research: Field trials to treat and control sarcoptic mange in free-living bare-nosed wombats (BNW)
Aims of project:
Aim 1: To develop techniques for, perform, and evaluate the success of, population-scale treatment of sarcoptic mange in BNW using fluralaner.
Aim 2: To evaluate the effects of opportunistic single dose fluralaner treatments (topical administration at 25mg/kg) on individual free-living mange-affected BNWs in Tasmania in collaboration with the Tasmanian State Government (DPIPWE).
Sarcoptic mange, caused by infection with Sarcoptes scabiei, is the most important infectious disease of the bare-nosed wombat (BNW). Occurring across the species’ range, BNWs commonly suffer the most severe form of disease, termed parakeratotic mange, which is associated with severe clinical signs, protracted animal welfare compromise, and high mortality rates that can limit population growth and lead to marked local declines.
To date, the success of managing sarcoptic mange in free-living BNWs has been limited by the absence of a clinically proven and feasibly conducted therapeutic protocol. This is predominantly because the drugs currently available for mange treatment (moxidectin/ivermectin) provide protection for <7 days and are ineffective against mite eggs. As such, repeated weekly treatments for up to four months are required to ensure clinical recovery and prevent re-infection while mites die out in the local environment, which our research and other literature suggests is not effective for disease control in free-living animals at the individual or population level.
As an alternative, fluralaner (Bravecto®; MSD Animal Health) has recently been described as an effective and long-lasting single dose treatment for sarcoptic mange in several species of domestic and wild animal, including the BNW. This is because it: confers ongoing protection while breaking the life-cycle of S. scabiei in the environment; alleviates the need to repeatedly and reliably identify and re-treat individuals; and, can feasibly be applied to free-living BNWs in its topical formulation. As such, fluralaner represents a revolutionary development in our ability to treat and potentially control sarcoptic mange in free-living BNW, at the individual and population level. The present study, therefore, will advance our understanding of the efficacy of fluralaner in treating BNWs in-situ, with varying degrees of mange, and at the population level, while informing future treatment guidelines and improving the health, welfare, and conservation status of BNWs throughout their range.
Maximum likely numbers of individuals involved: 440 (Aim 1 will involve up to 400 wombats (max. 300 at site A, max. 100 at site B) and Aim 2 up to 40 BNWs)
Activities undertaken and methods:
Aim 1. Field trials for population-level mange control
A. Surveying: wombats will be observed from a distance via walking (dawn/dusk) and driving transects (dusk/spotlight at night). No direct interactions will occur, but the spotlight may cause mild disturbance. Camera traps will be placed on stakes facing BNW burrows (average distance ~5m). Cameras will not be baited or impede movement/ access. Sarcoptic mange scores will be assigned to all BNWs as per Simpson et al. (2016).
B. Population-scale treatment: burrow flaps/pole and scoop methods will be used to treat BNWs with 25mg/kg fluralaner (Bravecto Spot-on for Large Cat; MSD Animal Health). Future modifications to this application may be made for the use of remote treatment delivery methods. Post-treatment, all animals will be monitored intermittently over ~12 weeks as per the methods described in A.
C. Sub-set of BNWs to be captured (max. 40 per site):
i. Selected BNWs (~80% mild/moderately diseased, ~20% healthy) will be captured in a hand net, whereby 2-5 people surround and quietly approach a BNW, then catch it in the net once disturbed. Mascot traps (dimensions: 53 x 53 x 106 cm) set in burrow openings may be used as an alternative trapping method if required: up to 8 would be set while BNWs are inactive, baited with grass/hay, insulated with hessian sacks, and checked every two hours.
ii. Captured BNWs will be anesthetised with intramuscular tiletamine/zolazepam (3 mg/kg) and medetomidine (40 μg/kg). Routine anaesthetic monitoring will take place throughout anaesthesia and animals will be subjected to physical examination and body condition and mange severity scoring. Sampling with then take place as follows: up to 5ml of blood will be collected from the femoral or jugular vein using aseptic technique; four skin swabs will non-invasively sample bacterial skin flora from the lateral abdomen and extremities; and, dry skin scrapes will be taken using routine methodology from a maximum of four sites.
iii. 25mg/kg of fluralaner (Bravecto® Spot-on for Large Cat; MSD Animal Health) will be administered to the interscapular epidermis. Healthy individuals will not receive treatment to act as controls.
iv. Wireless Identification Devices (WID) (WildSupply) will be inserted into the auricular cartilage, using aseptic technique, to allow for future identification and monitoring of treatment response. WIDs are sheep ear tags, modified to enable radio tracking, that weigh approx. 5g (dimensions: 24 x13 x 10mm, <0.005% of BNW weight) and are smooth in texture so will not snag in burrows.
v. Anaesthesia will be reversed with intramuscular atipamezole and animals will be placed in darkened insulated Mascot traps where routine indirect observational monitoring of BNWs will take place until complete recovery and release at capture site before dawn.
i. Tagged animals will be re-captured up to twice during the study period, at approx. two- and six-weeks post-treatment, on which occasions steps i., ii. and v. will be repeated.
Aim 2. Opportunistic treatment of individual mange-affected BNWs throughout Tasmania
Under the supervision of DPIPWE veterinarians/UTAS staff, single 25mg/kg fluralaner doses will be applied topically to up to 40 mange-affected wild BNWs using non-invasive methods (pole and scoop or burrow flap). At the time of treatment, BNWs will be scored for mange severity and photographed (bilaterally where possible) to enable future identification using distinctive patterns of alopecia. These patterns will remain for long enough duration to allow intermittent monitoring for up to three months post-treatment via direct observation (e.g. by binocular or spotting scope at dusk and by using spotlights)/camera traps.
Fate of animals: Sarcoptic mange is frequently fatal in BNWs, with past research showing that this can be up to 100% of diseased individuals. However, we hope to decrease this to <2% sarcoptic-mange associated mortality in study animals over the monitoring period (12-18 months). While our anaesthetic-associated mortality rate has been 0% to date and we expect all animals to recover fully, we have included a 5% anaesthetic death risk as a matter of caution.
Likely impact on species involved (including any by-catch): Observational surveys and camera trapping: minimal impact. Capture and sampling: moderate acute stress (capture), mild post-procedural pain (ear-tagging), minimal impact (all other sampling procedures). Fluralaner treatment: clinical resolution of sarcoptic mange disease, no adverse side effects anticipated.