Oral Presentation 64th International Conference of the Wildlife Disease Association 2015

A multi-disciplinary approach to investigation of the emerging fungal pathogen Paranannizziopsis australasiensis in Tuatara (Sphenodon punctatus) (#30)

Sarah Alexander 1 2 , Nick Holford 3 , Sharon Paterson 4 , Sharon Humphrey 5 , Hye Jeong Ha 5 , Richard Jakob-Hoff 1 , Andrew Dopheide 6 , Merran Govendir 7 , Andrew McLachlan 8 , Ros Podmore 9 , Carly Holyoake 2 , Lian Yeap 2 , Kris Warren 2
  1. Auckland Zoo, Western Springs, New Zealand
  2. School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia
  3. Department of Pharmacology & Clinical Pharmacology, University of Auckland, Auckland, New Zealand
  4. Toxicology, Canterbury Health Laboratories, Christchurch, New Zealand
  5. Animal Health Laboratory, Ministry for Primary Industries, Upper Hutt, New Zealand
  6. Plant and Food Research, Auckland, New Zealand
  7. Faculty of Veterinary Science, University of Sydney, Sydney, New South Wales
  8. Faculty of Pharmacy, University of Sydney, Sydney, New South Wales
  9. Microbiology, Canterbury Health Laboratories, Christchurch, New Zealand

Captive tuatara (Sphenodon punctatus) in the North Island of New Zealand have recently been discovered to be affected by the emerging primary fungal pathogen Paranannizziopsis australasiensis (PA), the cause of an ulcerative dermatitis often fatal in other reptile species. The affected tuatara were part of a national breeding program, and the presence of this emerging disease has prevented their planned release.  Our objectives are to develop a safe, effective treatment protocol for PA in tuatara, and to improve diagnostic and surveillance capabilities for detecting PA in both captive and wild populations. A multi-disciplinary, collaborative approach is being taken to investigate this emerging disease.  Methods include an in vitro and in vivo pharmacokinetics study of two anti-fungal drugs (itraconazole and voriconazole) previously used to treat mycoses in reptiles but for which pharmacological studies in these animals is extremely limited.  Simultaneously the focus of collaborators has been on the development of a PCR to enable surveillance of potential environmental reservoirs and identification of asymptomatic carriers.Results to date show significant differences in antifungal pharmacokinetics at high and low ends of the tuatara’s optimal temperature zone, with both antifungals exceeding target MICs for PA.  A PCR has been developed which has shown that PA DNA can be successfully amplified when spiked into soil DNA extracts, and work is ongoing to detect naturally occurring PA infections from soil samples.The pharmacokinetic study will enable the development of an evidence-based treatment regime. This, in combination with the further use of PA-specific PCR testing, will allow us to better understand the risks of this disease to captive and free-living tuatara, and develop appropriate treatment and risk mitigation protocols.