Kristin Warren

Exploitation of bears via the illegal wildlife trade risks exposing them to pathogens unlikely to be encountered in the wild, through conditions inherent to capture, transit, and ongoing captivity. Tuberculosis (TB), a disease of humans and livestock that requires close contact to spread, is a prime example of this risk, particularly in regions with high human TB endemism alongside the trade in, and rescue of, bears. This thesis aimed to explore the origin/s and epidemiology of an outbreak of TB in a population of sun bears (Helarctos malayanus) and Asiatic black bears (Ursus thibetanus) at a bear rescue centre in Cambodia, and the utility of locally available diagnostic methods for management of such outbreaks. Confirmed TB of human origin had not previously been described in either species. Between 2009 – 2024, Mycobacterium tuberculosis was isolated from 35 cases (31 sun bear, three Asiatic black bear, and one staff member). Using isolates from the first 32 cases (occurring between 2009 and 2019), alignment of antimicrobial susceptibility testing and genotyping of isolates revealed two clusters, which were confirmed and further explored with whole genome sequencing. We combined epidemiolocal data with single nucleotide polymorphism analysis and exploration of mixed base calls to indicate the evolution of each cluster. We established a likely transmission route in one cluster where the human case acted as an intermediatory between bear cases. Results from testing of 344 bears at three regional bear rescue centres were used to build a Bayesian latent class model to explore the accuracy of available tests for diagnosing pulmonary TB in bears. Five tests were included; microscopy, PCR, and culture of respiratory tract samples, thoracic radiography, and a patient-side lateral flow test designed to detect antibodies to key Mycobacterium tuberculosis complex antigens in serum from elephants and cervids. Our model demonstrated the high specificity and suboptimal sensitivity of the microbiological tests, and a need for caution when interpreting the serological test results. Thoracic radiography was the only diagnostic method with both sensitivity and specificity estimated by the Bayesian latent class model to be above 90%. Finally, we explored the use of thoracic radiography as a screening tool for sun bears at risk of TB, using radiographs from a subpopulation of confirmed TB cases and control (apparently healthy) sun bears. Our results supported the high specificity of radiographic changes for TB diagnosis, and highlighted sensitivity challenges when radiographic changes are subtle, extra-pulmonary, or there are concurrent differential diagnoses to explain changes. The results of this thesis drive evidence-based recommendations to support veterinary and husbandry staff managing bears in resource-poor, high human TB settings, where the surveillance for, and response to, TB outbreaks can have significant consequences for animal welfare, public health, and conservation goals.

Wildlife health data can be a powerful contributor to conservation outcomes, disease surveillance, and the broader objectives of One Health – an aim to achieve optimal health for people, animals, and the environment. Collections of wildlife necropsy reports are a common source of such data. However, the nature of these data creates a resource barrier between acquisition and analysis, resulting in sporadic extraction to inform such outcomes. To evaluate challenges and opportunities provided by wildlife health data, necropsy records for all the culturally, economically, and ecologically significant Sphenisciformes within the Wildbase Pathology Register of Aotearoa New Zealand were extracted, validated, and analysed. This manual process highlighted the dominance of a threatened and arguably cryptic species in the database (hoiho or yellow eyed penguin, Megadyptes antipodes), and that infectious/ inflammatory diagnoses were the most frequently encountered across all reviewed reports (35.7%, 523/1463). The free-text nature of many fields complicated analysis through high rates of typographical variance requiring manual resolution. The manual review shed light on threats to Sphenisciformes in Aotearoa, but also highlighted the temporal cost of knowledge extraction. Using these insights, an application was developed to facilitate time sensitive knowledge extraction, via text-mining and a dashboard approach to analyse and display information akin to the manual necropsy review. Simple algorithms were used to derive categorical fields such as species, and sex, while more complex query-based algorithms were used to quantify subjective elements, such as the prevalence of specific clinicopathologic findings. To evaluate the performance of this application nine professionals in wildlife health were recruited to a pilot study, to quantify the occurrence of four clinicopathological findings across two species datasets extracted from the Wildbase Pathology Register. Results from the testers were compared to the manual review (a “gold standard”), to determine the proportion of false negative and false positive records returned by each tester across the four clinicopathological findings that had been assigned to find. Mean F1-scores, which infer the level of agreement between the tester and the manual review, ranged from 0.63-0.93. Agreement was affected by tester, and the clinicopathologic finding being examined. The majority of misclassification (false positive or false negative records) was attributed to inappropriate search term selection and differences in interpretation of records. Further, the linguistically simple clinicopathologic findings (e.g., ‘oiled’) performed more consistently across users and in greater agreement with the manual review when compared to the other findings tested. The value of the application was affirmed in the pilot testing, however highlighted the potential for individual users, and clinicopathological findings with high rates of synonymy (e.g., “Starvation”), to impact performance. Overall, the development and testing of this application demonstrates the under-recognised value of automated methods in the extraction of knowledge from painstakingly acquired wildlife health data. This utility may be improved through the implementation of more sophisticated semantic-based techniques for data extraction as compared to the relatively simple term-based approaches utilised here. With early warning a recognised precursor to the success of any intervention, be it for conservation or infectious disease purposes, approaches that fast-track evidence-based adaptive management are a global priority for wildlife health.

The south-west of Western Australia (SWWA) is home to three species of threatened endemic black cockatoos. Anthropogenic activities including urbanisation and agriculture have led to the loss of at least 70% of pre-colonial native vegetation and much of what remains exists in a highly fragmented state within a matrix of human modified landscapes. The black cockatoos of SWWA interact in varying degrees with these modified landscapes, with consequences to fitness that are largely unknown.

In this project, I used modern tracking technologies to study the ecology of Carnaby’s cockatoo (CC) and the forest red-tailed black cockatoo (FRBC) in modified habitats. Using GPS units with integrated accelerometer devices, I gained insight into the fine-scale habitat use of these birds, as well as informing the interaction between habitat, behaviour, and energy expenditure. In addition, I analysed foraging resources for energetic content to further inform patterns of activity revealed by tracking data.

FRBC were tracked in both their natural forest habitat and the urban environment into which they have recently expanded. Urban birds were found to expend 25% more energy per day, with little evidence that this was adequately offset by foraging on exotic foods of higher calorific value. CC were also tracked in the urban area where birds spending more 􀆟me utilising the smallest fragments of remnant vegetation were found to travel significantly further each day. Daily distance travelled was in turn associated with greater energetic expenditure. Breeding CCs were tracked in the wheatbelt where the recent introduction of canola to the diet has been associated with improved reproductive outcomes. The existence of an upper limit to canola foraging was discovered, even when high temperatures reduced time available for foraging on native vegetation.

The research undertaken for this thesis has added to our understanding of the ecology of both species and the fitness consequences imposed on each by interaction with modified landscapes. The information herein will contribute to the conservation of Carnaby’s cockatoos and forest red-tailed black cockatoos by directly informing their respective Recovery Plans.

The aim of this project was to determine the prevalence of bornavirus, nidovirus, sunshinevirus and Mycoplasma spp. in pythons in Western Australia. Two captive cohorts were screened: snakes which had been confiscated by the Department of Biodiversity Conservation and Attractions (DBCA) (n=38) and snakes from Perth Zoo (n=15), for which longitudinal samples were also available for all 15 individuals for 2015 and 2017. A third cohort comprised free-living pythons captured and sampled from various locations within Western Australia (n=17). The majority of the pythons in the study were Antaresia spp., Morelia spp. and Aspidites spp.

Deep oesophageal, oral and cloacal swabs, and blood samples were collected. The swabs were screened using conventional and/or quantitative Polymerase Chain Reaction (PCR). Where relevant, positive amplicons were sequenced.

Sunshinevirus and bornavirus were not detected in any of the pythons sampled in this study. All pythons from Perth Zoo tested negative for nidovirus. Two pythons from the confiscated cohort (5.3%; 95% CI: 0.6%, 17.7%) were positive for nidovirus. All of the free-living pythons tested negative for nidovirus, with the exception of one individual which had inconclusive results. Sampling confirmed that Mycoplasma spp. were present in all three cohorts. The highest rates of Mycoplasma spp. detection occurred within the Perth Zoo cohort in 2015 (73.3%; 95% CI: 44.9%, 92.2%) and 2017 (86.7%; 95% CI: 58.5%, 98.3%) followed by the confiscated population (52.6%; 95% CI: 35.8%, 69.0%), and finally the free-living population (35.3%; 95% CI:14.2%, 61.7%). Mycoplasma spp. were detected in snakes with a range of clinical examination findings, with the majority in clinically normal individuals. Additional studies are necessary to determine the clinical significance of Mycoplasma spp. in snakes. This research is one of only a few studies reporting virology and bacteriology screening in free-living pythons in Australia, and is the first report of Mycoplasma spp. detection in freeliving Australian python species.

This thesis addresses the mitigation of opioid-induced respiratory depression in wild African antelope species.

Potent opioids such as etorphine or thiafentanil are often used for the immobilisation of wild herbivores. One disadvantage of using these potent opioids is that they can cause clinically significant respiratory depression which is due to their potent effect on mu-opioid receptors. Activation of mu-opioid receptors in the respiratory centres of animals depresses neurons that generate the normal respiratory rhythm. At the same time activation of mu-opioid receptors on chemo receptors in the brain stem, on the aortic arch and carotid bodies depresses the normal respiratory drive as these chemo receptors become less sensitive to activation by hypercapnia, hypoxaemia and acidaemia. This effect in turn leads to a reduction of the respiratory frequency and tidal volume. Furthermore, pulmonary vasoconstriction, caused by the sympathomimetic actions of etorphine, decreases pulmonary perfusion. This effect leads to impaired diffusion of oxygen through the alveolar membrane. Studies have found that serotonergic ligands, specifically 8-hydroxy-2-(di-n-propylamino) tetralin (8-OHDPAT), improved blood oxygenation by reducing opioid-induced respiratory depression and improving pulmonary perfusion through their serotonergic effects on the lungs and brain. More specifically, 8-OH-DPAT binds to 5-HT1A and 5-HT7 serotonin receptors in the lungs and brain. This binding results in smooth muscle relaxation and improved pulmonary perfusion without affecting catatonia and sedation caused by opioids. It was thought that the use of the R-enantiomer of 8-OH-DPAT (R-8-OH-DPAT) in comparison to the racemic form (RS-8-OH-DPAT), might produce even better results because of its high specificity at the 5- HT1A receptors.

Although some literature on the pharmacokinetic data of 8-OH-DPAT in rats and marmosets existed, there was no published literature available on the pharmacokinetics of 8-OH-DPAT in ungulates.

Therefore, the investigation into the pharmacokinetics and bioavailability of R-8-OH-DPAT in goats served as the first step in a series of experiments to understand the viability of adding R-8-OH-DPAT to an opioid-based immobilisation protocol for wild antelope species in order to alleviate respiratory depression. It was hypothesised that the pharmacokinetics and bioavailability of R-8-OH-DPAT in goats would be similar but different to that reported in other species. It was established that the bioavailability of R-8-OH-DPAT when injected intramuscularly (IM) into goats was 66%. At the dosage used in this experiment (0.1 mg kg- 1), signs of serotonin toxicity were observed in some of the goats. The bioavailability results, as well as the encountered side effects in goats, guided the choice of three experimental R-8- OH-DPAT dosages for the next experiment.

The second experiment aimed to determine the ability of R-8-OH-DPAT, when administered in combination with etorphine in a dart, to prevent opioid-induced respiratory depression in blesbok (Damaliscus pygargus phillipsi) and impala (Aepyceros melampus). The experiment also aimed to establish the most clinically effective dosage of R-8-OH-DPAT, in these species.

Blesbok and impala were chosen for the second experiment as they were abundant and readily available in the study area. Both are antelope species commonly immobilised with potent opioids. Impala are regularly used in immobilisation experiments. It was hypothesised that R-8-OH-DPAT would mitigate opioid-induced respiratory depression in wild ungulates without affecting the quality of immobilisation. R-8-OH-DPAT did not influence induction, immobilisation or recovery scores in either of the species. However, this experiment revealed that there were substantial differences between the two antelope species and their physiological changes after the administration of etorphine alone as well as etorphine in combination with 0.005, 0.02 and 0.07 mg kg-1 R-8-OH-DPAT respectively. Surprisingly, opioid-induced hypoxia was substantially more severe in impala compared to blesbok. Respiratory rate in blesbok, but not impala, increased with an increasing dosage of R-8-OHDPAT but this did not translate into clinically relevant improvements in partial arterial oxygen pressure (PaO2) values in blesbok.

In impala, the medium and higher dosages of R-8-OH-DPAT combined with etorphine led to an improved PaO2 and decreased opioid-induced tachycardia during the first ten minutes of immobilisation.

It was concluded that species-specific effects and the possibility of serotonin toxicity at higher dosages, which seemed most effective, might not allow the routine use of R-8-OHDPAT at appropriate dosages for wildlife immobilisation.

These results lead to the third experiment which aimed at comparing physiological effects of two commonly used potent opioids, namely etorphine and thiafentanil, in both antelope species. It was hypothesised that the time to recumbence, immobilisation quality and physiological variables during immobilisation of blesbok and impala respectively would differ between the two potent opioids.

The results of this experiment demonstrate that both opioids used in high dosages are suitable for immobilisation of blesbok and impala without the addition of any sedative or tranquillisers. Both, blesbok and impala developed hypertension with either of the opioids. The thiafentanil treated animals of both species developed higher systemic blood pressure compared to the etorphine treated animals. The healthy animals used for these experiments recovered from hypertension without apparent adverse consequences.

Thiafentanil in impala achieved a faster time to recumbence compared to etorphine but thiafentanil also was responsible for more incidences of prolonged apnoea during the beginning of the monitoring period in impala. Overall, there were large differences in the reaction of individual impalas to the opioid immobilisation, which seemed to result in unpredictable immobilisation.

In blesbok, opioid-induced respiratory depression, hypoxia and hypercapnia were much less pronounced than in impala. Thiafentanil treated blesbok had higher respiratory rates, higher PaO2 and lower partial arterial carbon dioxide pressure (PaCO2) compared to etorphine treated blesbok. There was no difference in time to recumbence between the two opioids in blesbok.

In conclusion, for short term management procedures of impala and blesbok, both opioids are suitable. No matter which opioid is used, both cause hypoxaemia to a greater or lesser degree and oxygen supplementation should be considered for both species.

Veterinarians should also be aware that in some species, such as impala, thiafentanil can achieve a faster time to recumbence than etorphine. However, this statement cannot be applied across all species as in blesbok there was no significant difference between both drugs with regards to time to recumbence. In addition, time to recumbence has to be weighed against potential negative respiratory, pulmonary and cardiovascular side-effects of the drug.

While these experiments did not give the desired positive results with regards to the use of R-8-OH-DPAT to alleviate opioid-induced respiratory depression, they led to insights into differences between the two opioids which will enable veterinarians to make a more educated decision as to which opioid should be used preferentially.

New insights into the differences between blesbok and impala with respect to reaction and physiological changes caused by opioids will also enable researchers to make decisions with regards to species selection for wildlife trials. It may also explain some of the difficulties encountered when immobilising impala.

The current state of sea turtle health in the Indian Ocean is largely unknown, especially for the endemic flatback turtle (Natator depressus) which is listed as ‘vulnerable’ in Western Australia (WA) and ‘data deficient’ globally. Anecdotally, the causes of illness, injury, and death in Western Australian turtles are comparable to those in other parts of Australia and the world (e.g., spirorchiidiasis, fibropapillomatosis, and marine debris interaction) but scientific studies to validate these reports are particularly limited in this region. To address these knowledge gaps, causes of both live and dead turtle strandings in WA were investigated through an array of veterinary diagnostic techniques including necropsy, clinical pathology, diagnostic imaging, histopathology, parasitology, microbiology, toxicology, and molecular analyses. Health assessments were conducted on live animals to determine baseline levels of health and disease for specific populations, predominately nesting and foraging flatback turtles.

Through these health and disease investigations, baselines were developed, along with the discovery of new diseases in flatback turtles including a novel haemoparasite, Haemocystidium spp., occurring specifically in the foraging life stage; a potentially emerging zoonotic bacterium, Streptococcus iniae associated with a multi-species mass mortality event involving post-hatchlings; as well as spirorchiidiasis, previously unreported in this species. Other unusual and emerging diseases were also reported in sea turtles in this study, including microsporidial myopathy, salt gland adenitis, gout, and pseudogout.

In this study, natural disease-related causes of mortality occurred more frequently than direct anthropogenic causes, with parasitoses the most frequently occurring natural disease. Spirorchiidiaisis was the most common cause of mortality (32.0%) with a prevalence of 93.2% in turtles susceptible to the disease (i.e., excluding the post-hatchling life stage). The next most common cause of mortality was unknown (17.3%), followed by trauma (13.3%), endoparasitosis (10.7%), infectious disease (6.7%), and pneumonia (6.7%), with the remaining mortality categories each accounting for less than 5% of cases (including systemic inflammation, osmoregulatory disorder, gastrointestinal impaction, gastrointestinal foreign body, fibropapillomatosis, and metabolic disorder).

We developed the first flatback turtle reference intervals (RIs) in Reference Value Advisor (RefVal v2.1) following the American Society of Veterinary Clinical Pathology (ASVCP) guidelines. We found flatback turtle RIs were generally similar to other published sea turtle RIs and reference values (RVs) but detected significant differences in our study for the various boundary conditions including life stage (nesting or foraging), as well for measurement methodology (field or laboratory tests), justifying the establishment of separate RIs/RVs for nesting and foraging flatbacks, and for field and laboratory techniques.

This study was the first sea turtle health and disease investigation in WA and the eastern Indian Ocean to offer broader insights into sea turtle health and disease status on a regional scale. These essential baselines provided a number of crucial functions which include serving as a reference point for future studies to monitor changes in population health and disease levels. Specifically, these baseline data will be useful for future comparative studies of the same population where changes are an indication of a changing environment. The blood RIs can be used for disease diagnosis, monitoring progress and assessing prognosis of clinical flatback turtle cases in rehabilitation. Considering that diseases in the marine environment are predicted to rise with increasing anthropogenic pressures, detection of new and emerging diseases is of significance to the global knowledge of sea turtle diseases; and for understanding and mitigating disease threats to sea turtle populations. Finally, this study provided a framework to integrate health into future conservation management decisions to ensure the long-term survival of sea turtles.

Historically it has been difficult to gain information on the movement ecology of psittacine species in Australia. Using a novel double-tagging telemetry method, this research, aimed to: investigate regional differences in movement of the three black cockatoo species endemic to Western Australia; identify key roost and foraging sites for these species across regions; and estimate home range sizes for flocks in resident areas, using a combination of GPS and satellite PTT tags.

Tagged birds served as markers of flock movement once integrated into a wild flock of conspecifics, which was confirmed through means of behavioural change point analysis and field observations. Linear mixed models were used to determine differences in movement across regions, revisitation analysis was used to identify key habitat sites, and an auto-corrected Kernel density estimator was used to estimate the home ranges.

Results showed that key roosts sites for the three species predominantly occurred on public green space and private property. These were closely associated with foraging habitat which mainly occurred as remnant vegetation in the landscape or as nature reserves. Riparian zones and roadside vegetation were shown to play a crucial role as foraging habitat and in providing connective landscape structures. Daily movement distances differed both between and within regions depending on habitat matrix, resulting in varying home range sizes. These results suggest that movement for the three black cockatoo species is region specific, driven by food resources in the landscape. In addition, between species, movement varied as each species uses the landscape in different ways, depending on seasonal movements and ecological requirements.

This research has provided critical baseline data required to address knowledge gaps listed in Recovery Plans for these species of black cockatoo. Further research is now required to include these data in resource and habitat selection models to identify how the landscape matrix affects movement, which will facilitate adaptive habitat management and conservation plans for black cockatoos in Western Australia.

Lumpy jaw is a well-recognised cause of morbidity and mortality in captive macropods (Macropodidae) worldwide. The extent and causes of the disease are largely unknown, although multiple risk factors associated with a captive environment are thought to contribute to the development of clinical disease. Identification of risk factors associated with lumpy jaw would assist with the development of preventive management strategies, potentially reducing mortalities.

A cross-sectional study was undertaken from 2011 to 2015, to determine prevalence and risk factors for this disease through the distribution of a survey to 527 institutions across Australia and Europe; two regions where macropods are popular exhibits. Veterinary and husbandry records from the period 1st January 1995 up to and including 28th November 2016 (the last date when data were extracted from zoo records) were analysed in a retrospective cohort study, examining risk factors for developing disease and treatments used, over time. Computed tomography was used to examine disease occurrence in wild macropods using skulls from population management culls.

The prevalence of lumpy jaw was found to differ between the two regions (p < 0.0002). A review of 6178 records for 2759 macropods housed within eight zoos across the Australian and European regions, found incidence rates and risk of infection differed between geographic regions and individual institutions. Risk of developing lumpy jaw increased with age, particularly for macropods >10 years (Australia IRR 7.63, p < 0.001; Europe IRR 7.38, p < 0.001). Treatment approach varied and prognosis was typically poor with 62.5% mortality for Australian and European regions combined. Lumpy jaw was detected in all captive genera examined, but was absent from the wild populations studied.

Geographic region influenced the incidence of lumpy jaw, the risks associated with developing clinical disease, and preferred treatment approach. Despite advances in antibiotic therapy and surgical techniques, treatment of lumpy jaw is largely unrewarding for the individual and should be approached on an individual basis. This research provides new information about this refractory disease and makes practical recommendations to reduce disease risk. This information may assist institutions in providing optimal long-term health management for captive macropods; such efforts having a positive impact on both welfare and conservation, including but not limited to captive breeding and translocation programs.

The three black cockatoo species endemic to south-west Western Australia – Carnaby’s cockatoo (Calyptorhynchus latirostris), Baudin’s cockatoo (C. baudinii) and forest red-tailed black cockatoo (C. banksii naso) are threatened and have Recovery Plans guiding conservation efforts. Threats include habitat loss due to land clearing for urban, agricultural and industrial development; competition with other species for nest hollows; poaching; disease; vehicle-strike and illegal shooting.

This research built on previous black cockatoo research with an overall aim to develop and validate reliable methods to track all three species, to gain insight into their movement, distribution, habitat use, activity and behaviour.

In an initial proof of concept trial, we attached tail-mounted tags to two Baudin’s cockatoos. Both birds were successfully tracked for several months after release, demonstrating satellite telemetry can be used to locate and track forest species.

We then developed a double-tag mounting protocol to attach a tail-mounted ARGOS PTT satellite tag and back-mounted solar-powered UvA-BiTS GPS tag to captive black cockatoos. The combination of UvA-BiTS back mount and ventral tail mounted Telonics tags was the best tolerated and provided excellent GPS and ARGOS satellite location data with no interference between the two types of tag.

The focus then moved to the development of an automated classifier tool that used accelerometer data from UvA-BiTS GPS tags to remotely identify behaviours and calculate activity budgets. Using accelerometer data from 15 birds post-release, we determined black cockatoos spend most of their time at rest, interspersed with foraging activity through the day and some movement between roost sites and feeding habitat.

To maximise the retention time of tail-mounted tags, the tail feather life span and time of moulting was studied using moulted tail feathers from captive cockatoos and tagged bird post-release. Captive cockatoos had a mean feather lifespan of 410 days, suggesting tail feathers do not always moult annually. Peak tail feather moulting occurs from December to March, the non-breeding period. The optimal time to attach tail mounted tags is from May to September.

The development and optimisation of tracking methodologies for use on black cockatoos has facilitated the tracking of all three species in the wild. This research has provided data which have enabled identification of key roosting, foraging and breeding habitat and determination of flock movement patterns and habitat use at a landscape scale across the species’ distribution ranges. This information is being used to guide black cockatoo conservation management in relation to habitat protection and restoration.

Tuatara (Sphenodon punctatus) are unique, cold-adapted reptiles endemic to New Zealand. Recently, captive tuatara have been found to be affected by an emerging fungal pathogen, Paranannizziopsis australasiensis. P. australasiensis causes dermatitis in tuatara, and has caused fatal systemic mycosis in a bearded dragon (Pogona vitticeps), and in aquatic file snakes (Acrochordus spp). The discovery of P. australasiensis infections has prevented the release of tuatara from several captive institutions to offshore islands, and has negative implications for the long-term health and welfare of the animals.

A review of the literature revealed that infections caused by organisms related to P. australasiensis are being recognised worldwide as emerging pathogens of reptiles. Little is known about the epidemiology of these often-fatal infections, and treatment with a range of antifungals has met with varying success. There has been little research on antifungal use in reptiles, and none on how environmental temperature affects the pharmacokinetics of antifungals.

This study investigated the microbiological characteristics of P. australasiensis, primarily the growth rate of the fungus at different temperatures, and the Minimum Inhibitory Concentration (MIC) of various antifungal agents for P. australasiensis. It was determined that the optimal growth temperature for P. australasiensis encompasses the range from 20oC-30oC, with scant growth at 12oC, moderate growth at 15oC, and no growth at 37oC. The MICs of antifungals were tested at room temperature and at 37oC, and were not found to be significantly different. MICs of itraconazole and voriconazole for three isolates of P. australasiensis were found to be low, at 0.12mg/L for itraconazole and <0.008mg/L for voriconazole.

The single and multiple dose pharmacokinetics of itraconazole and voriconazole in tuatara were investigated at 12 and 20oC; these are the high and low ends of the tuatara’s preferred optimal temperature zone (POTZ). Results showed statistically significant differences in antifungal elimination half-life between temperatures. With the aid of population pharmacokinetic modelling, optimal dosing regimes for both antifungals were developed for tuatara of different weights. It was established that tuatara should be treated at 20oC, at the high end of POTZ, to facilitate rapid attainment of therapeutic antifungal concentrations, improve clinical outcomes and reduce the risk of adverse effects.

While itraconazole demonstrated more predictable pharmacokinetics than voriconazole in tuatara, itraconazole treatment was associated with significant adverse effects. These included elevated bile acids and uric acid concentrations, and weight loss. While voriconazole appears to be safer, its pharmacokinetics are less predictable, with high inter-individual variability in tuatara administered the same dose rate (a phenomenon also observed in humans). While voriconazole may be a useful antifungal in clinically affected tuatara where dosage can be adjusted based on the response to treatment, its use in an asymptomatic quarantine setting may be limited. The use of higher voriconazole doses may increase the likelihood of maintaining therapeutic concentrations in all treated animals, however the risk of adverse effects increases concomitantly. Furthermore, there are currently no published reports of successful treatment of P. australasiensis in tuatara with voriconazole.

This study also established haematologic and biochemical reference ranges in a group of tuatara. These demonstrated variability in several parameters based on sex and season, and will be a useful tool for assessing health and disease in these and other tuatara.