Leprosy, caused by Mycobacterium lepromatosis or Mycobacterium leprae, has been reported in red squirrels in Britain from Scotland to the south of England. However, there has been no attempt to determine whether lesions caused by leprosy can be detected in the skeletons of infected animals. Here, we present findings from three red squirrel skeletons (Sciurus vulgaris L., 1758) that had soft tissue lesions consistent with leprosy and were positive for M. lepromatosis. Three of six red squirrel specimens from Scotland that previously tested positive for M. lepromatosis were subjected to macro- and microscopic skeletal analyses. Erosive lesions, remodelling and porosity were found in multiple parts of the skeleton, including the podials, tarsals, distal tibiae, distal forelimbs and in the nasal bones. Additionally, porous lesions were found in the caudal vertebrae. These skeletal changes advance our knowledge of how this disease manifests in nonhuman mammals. Overall, these findings demonstrate that, despite the squirrel's significantly shorter lifespan and different metabolism, comparable patterns of skeletal lesions are observed in humans and red squirrels with leprosy.

Background: This article presents a conceptual Indigenous One Health model to assess health risks that sit at the One Health interface (across animal, human and environmental health) and implement holistic health approaches within Indigenous community settings. Methods: The model is informed by foundational research undertaken at international, national and community-levels that utilised Indigenist approaches, and involved conceptualising animal, human and environmental health considerations together in relation to Aboriginal and Torres Strait Islander health and wellbeing in Australia. Results: The conceptual Indigenous One Health model centres Indigenous cultures, values and knowledge associated with One Health in Indigenous communities and highlights structural needs and principles for implementation. Conclusion: This article discusses key considerations for the future directions of Indigenous One Health, which are required to move the Indigenous One Health research field forward and support health equity in Indigenous communities.

Infectious diseases are a leading cause of biodiversity declines, but the factors shaping the prevalence and intensity of wildlife disease outbreaks remain unresolved. Host-associated microbes are likely a key component of host resistance to infection, but a host’s ability to recruit such protective microbes may be restricted by the availability of microbes present in their immediate environment. Here we investigate the associations between the abiotic environment, skin microbiome, and infection with the Dermocystid pathogen Amphibiothecum meredithae in Palmate newts ( Lissotriton helveticus ) on the Isle of Rum, Scotland. We found more acidic ponds to be associated with higher skin microbiome diversity and lower pathogen prevalence. Predicted functional analysis of microbiota composition identified bacterially-mediated pathways linked to host immunity upregulated in skin microbiotas associated with more acidic ponds and lower infection prevalence. This study highlights the potential importance of the environment in modulating host- microbiome-pathogen relationships and patterns of infection in the wild. ### Competing Interest Statement The authors have declared no competing interest.

Buruli ulcer in southeastern Australia is a zoonosis caused by infection with Mycobacterium ulcerans. Australian native possums are a major wildlife reservoir, and infected possums shed M. ulcerans in their excreta, with mosquitoes being the major transmitting vector in this region. Buruli ulcer is geographically restricted, and this feature, combined with an average 4.8-month incubation period, makes tracking M. ulcerans environmental spread and timely identification of new Buruli ulcer endemic areas challenging. While human mobility complicates transmission tracing, we used the highly territorial behavior of native possums and high-resolution pathogen genomics to confidently identify new Buruli ulcer endemic areas in Melbourne's inner northwest and southern suburbs of Geelong. Using pathogen genomic phylodynamic modeling, we estimated that M. ulcerans was introduced to these areas 2-6 years before the emergence of human Buruli ulcer cases. This study shows how possum excreta surveys combined with pathogen genome data can pinpoint new Buruli ulcer endemic areas, thus providing critical local knowledge for targeted public health interventions to reduce exposure risk and ensure early diagnosis.IMPORTANCEBuruli ulcer is a debilitating skin disease caused by Mycobacterium ulcerans, with transmission in southeastern Australia involving native possums as wildlife reservoirs and mosquitoes as vectors. Early detection of new endemic areas is critical to preventing human disease, yet is hindered by the pathogen's long incubation period, highly focal transmission, and the mobility of human hosts. This study demonstrates how structured possum excreta surveys, combined with high-resolution pathogen genomics, can confidently identify new Buruli ulcer endemic areas in southeastern Australia. By confirming local transmission in Melbourne's inner northwest and Geelong through genome matching between possum- and human-derived M. ulcerans, we provide a framework for targeted, timely public health interventions. This integrated wildlife-environment-human approach exemplifies the power of One Health surveillance to detect and manage emerging zoonotic threats, offering a scalable model for other regions where Buruli ulcer is endemic.

Objective: This paper utilised the National Notifiable Diseases Surveillance System database to analyse the commonly notified zoonotic disease presentations in Aboriginal and Torres Strait Islander populations over 25 years, from 1996-2021. Methods: We analysed the top four zoonotic notifications using a descriptive analysis, a time series analysis assessing the trends and seasonal indices, and a de-seasonalised analysis to assess the years contributing to an increase above the trend. Results: Results show an increase in notifications for salmonellosis and campylobacteriosis over the last 10 years. On average, all diseases saw an increase in notifications above the trend in Q1 (Jan-Mar) and less so Q2 (Apr-Jun), and a decrease in notifications below the trend in Q3 (Jul-Sep) and less so in Q4 (Oct-Dec), which is aligned with increases in zoonotic notifications in Australia’s hotter and wetter months. Conclusion: The results present zoonotic notifications in Aboriginal and Torres Strait Islander populations over time and highlight potential implications of climate change due to increasing notifications, and increasing temperatures and extreme weather events in recent years. Implications for public health: The findings can inform preventative health approaches for zoonoses in Indigenous populations, with One Health approaches recommended.

Buruli ulcer (BU) is a neglected tropical disease of skin and subcutaneous tissues caused by Mycobacterium ulcerans. BU-endemic areas are highly focal, and M. ulcerans transmission dynamics vary by setting. In Victoria, Australia, BU is an endemic vector-borne zoonosis, with mosquitoes and native possums implicated in transmission, and humans incidental hosts. Despite the importance of possums as wildlife reservoirs of M. ulcerans, knowledge of BU in these animals is limited. Opportunistic necropsy-based and active trap-and-release surveillance studies were conducted across Melbourne and Geelong, Victoria, to investigate BU in possums. Demographic data and biological samples were collected, and cutaneous lesions suggestive of BU were mapped. Samples were tested for the presence of M. ulcerans DNA by IS2404 qPCR. The final dataset included 26 possums: 20 necropsied; 6 trapped and released. Most possums (77%) were common ringtails from inner Melbourne. Nine had ulcers, ranging from single and mild, to multiple and severe, exposing bones and tendons in three cases. M. ulcerans was confirmed in 73% (19/26) of examined possums: 8 with lesions and 11 without. Oral swabs were most frequently indicative of M. ulcerans infection status. Severely ulcerated possums had widespread systemic internal bacterial dissemination and were shedding M. ulcerans in faeces. The anatomical distribution of ulcers and PCR positivity of biological samples suggests possums may contract BU from bites of M. ulcerans-harbouring mosquitoes, traumatic skin wounds, ingestion of an unknown environmental source, and/or during early development in the pouch. Ringtail possums appear highly susceptible to infection with M. ulcerans and are important bacterial reservoirs in Victoria. Oral swabs should be considered for diagnosis or surveillance of infected possums. A One Health approach is needed to design and implement integrated interventions that reduce M. ulcerans transmission in Victoria, thereby protecting wildlife and humans from this emerging zoonotic disease.

Buruli ulcer is a chronic ulcerative disease of the skin and subcutaneous tissues caused by infection with Mycobacterium ulcerans. Although Australian possums are known to be susceptible to Buruli ulcer, many aspects of the disease in possums, including welfare impacts, remain largely unreported. Severe clinical Buruli ulcer was identified in four common ringtail possums (Pseudocheirus peregrinus) from Melbourne, Victoria. All four possums were euthanased due to the presence of deep ulcerative lesions on paws, with extensive tissue necrosis that exposed bones and tendons in three cases. Histologically, there was severe ulcerative necrotising pyogranulomatous dermatitis, panniculitis and myositis, with intralesional acid-fast bacteria. M. ulcerans was detected by real-time PCR in all swabs, tissues and faeces collected from all four cases. Buruli ulcer may be an important and under-recognised cause of poor possum welfare in endemic areas. The physical impacts of the severe cutaneous lesions, especially those extending to underlying bones and joints, would have directly impaired the mobility of these possums, affecting navigation of their natural environments and expression of natural behaviours including foraging and socialising. Systemic distribution of M. ulcerans throughout all major internal organs, as observed here, may further impact the health and fitness of infected possums. Faecal shedding of M. ulcerans in all four cases supports the role of possums as zoonotic reservoirs. Further research is needed to investigate the epidemiology, pathogenesis and welfare impacts of Buruli ulcer in possums and to inform the design of interventions that may protect their health and welfare.

Leprosy is a poverty-associated infectious disease in humans caused by Mycobacterium leprae or M. lepromatosis, often resulting in skin and peripheral nerve damage, which remains a significant public health concern in isolated areas of low- and middle-income countries. Previous studies reported leprosy in red squirrels in the British Isles, despite the fact that autochthonous human cases have been absent for centuries in this region. To investigate the extent of M. leprae and M. lepromatosis presence in wild red squirrels in the northern UK, we analyzed 220 blood/body cavity fluid samples from opportunistically sampled red squirrels (2004–2023) for specific antibodies against phenolic glycolipid-I, a cell wall component specific for these leprosy bacilli. Additionally, we assessed bacillus-derived DNA by real-time PCR (qPCR) in 250 pinnae from the same cohort. M. lepromatosis and M. leprae DNA were detected by qPCR in 20.4% and 0.8% of the squirrels, respectively. No cases of co-detection were observed. Detectable levels of anti-PGL-I antibodies by UCP-LFA were observed in 52.9% of animals with the presence of M. lepromatosis determined by qPCR, and overall in 15.5% of all animals. In total, 22.6% (n = 296) of this UK cohort had at least some exposure to leprosy bacilli. Our study shows that leprosy bacilli persist in red squirrels in the northern UK, emphasizing the necessity for ongoing molecular and serological monitoring to study leprosy ecology in red squirrels, gain insight into potential zoonotic transmission, and to determine whether the disease has a conservation impact on this endangered species.

Studies on normal concentration of blood constituents of free-living birds are not very common. An adequate knowledge of blood chemistry is greatly recommended for those projects involving research and management of populations as far as they can be valuable for the assessment of the nutritional levels and health status of species. No previous published reports on these parameters from this species are available. The aim of this study was to obtain representative reference measures for hematologic and biochemical values in free-living clinically healthy wild White-tailed Sea Eagle nestlings ( Haliaeetus albicilla ). In addition, we investigated potential relationships between blood parameters, sex, age and hatching dates. Blood samples were obtained as part of routine monitoring and management when wild chicks were removed from their nest as part of a reintroduction program prerelease health check. A total of 83 nestlings, 43 males and 40 females, between 41 and 66 days of age (mean = 54.22, SD = 5.7), were sampled. Significant differences between sexes were found. Among hematological parameters, MCH, lymphocytes P and thrombocytes showed significant differences between males and females. In biochemical parameters, significant differences were found only in calcium, CK and LDH between sexes. No effect was found of age of the nestling when the sample was taken in any of the analyzed hematological parameters. No other significant relationships were found between biochemical parameters and other considered explanatory variables. Hatching date showed no relationship with blood parameters excepting urea. Urea was the only variable showing a strong relationship with hatching date, with those nestlings hatching later in the season showing higher urea concentration.

Many Aboriginal and Torres Strait Islander communities face barriers in accessing animal healthcare and are exposed to disproportionate environmental health exposures leading to increased risk of disease. A One Health approach has been promoted to address public health risks and improve human, animal, and environmental health outcomes in communities. We undertook a pilot One Health study in Aboriginal and Torres Strait Islander communities in Queensland collecting animal, human, and environmental health data from 82 households. We performed a descriptive analysis and assessed the association between human and environmental health exposures and animal health outcomes. Most households were not crowded (82.9%) but did report a high level of environmental health concerns (86.6%). The majority of households owned cats and dogs (81.7%), with most animals assessed as healthy. There was no association between human and environmental health exposures and animal health outcomes. As most households experienced concerns regarding housing conditions, environmental health programs should prioritise improving household factors. There was also strong support for animal healthcare (including access to medicines and veterinarians, education programs and population management), indicating that a One Health approach is desired by communities.

IntroductionZoonoses are a health concern for Aboriginal and Torres Strait Islander peoples in Australia that face elevated risk of disease related to the environment and animals. Internationally, One Health is encouraged to effectively manage zoonoses by taking integrated approaches involving animal, human, and environmental health sectors to improve health outcomes. However, Australia’s health systems manage zoonotic diseases in animals and people separately which does not support a One Health approach. For the effective management of zoonoses, a strong evidence base and database regarding the epidemiology of zoonotic pathogens is needed. However, we currently lack this evidence limiting our understanding of the impact of zoonoses on Aboriginal and Torres Strait Islander populations.MethodsAs a first step towards building the evidence base, we undertook a descriptive analysis of Aboriginal and Torres Strait Islander zoonotic notifications in Australia from 1996 to 2021. We presented notifications as annual notification rates per 100,000 population, and percentages of notifications by state, remoteness, sex, and age group.ResultsSalmonellosis and campylobacteriosis were the most notified zoonoses with the highest annual notification rates of 99.75 and 87.46 per 100,000 population, respectively. The north of Australia (Queensland, Northern Territory and Western Australia), remote and outer regional areas, and young children (0–4 years of age) had the highest percentages of notifications.DiscussionTo our knowledge, these findings are the first national presentation of the epidemiology of zoonoses within Aboriginal and Torres Strait Islander populations. A greater understanding of transmission, prevalence and impact of zoonoses on Aboriginal and Torres Strait Islander peoples (including animal and environmental health factors) is required to inform their effective management through a One Health approach.

Abstract Birds of prey frequently feature in reintroductions and the hacking technique is typically used. Hacking involves removing large nestlings from donor populations, transferring them to captivity, feeding them ad libitum. Potentially, via the hacking method, the stress of captivity and disruption of parental feeding may be detrimental. Alternatively, the provision of ad libitum food may be advantageous. Although hacking has underpinned reintroduction project successes there has been no research on how the method may affect the health and nutritional status of translocated birds during captivity. We compared blood chemistry data from 55 young White‐tailed Eagles, translocated from Norway as part of the species' reintroduction to Scotland, from sampling soon after arriving in captivity and again (≈42 days later) before their release. Numerous significant differences between the first and second samples were found, but no significant interactions showed that the sexes responded similarly to captivity. According to hematological and biochemical metrics, individuals showed several changes during captivity, including in red blood cell parameters, plasma proteins, and white cellular parameters related to the immune system, that indicated improved health status. Captivity with ad libitum food was associated with decreased urea and uric acid values: high values can indicate nutritional stress. Urea values became more normally distributed before release, indicating that ad libitum food had reduced nutritional differences between early nestlings in the season and later ones. Despite plentiful food, both sexes lost body mass before release, suggesting an inherent physiological mechanism to improve flight performance in fledglings. We conclude that hacking improved the health and nutritional status of released eagles which is likely to enable birds to cope with greater costs of exploratory behavior which they may require in reintroduction projects. In this context, we note the absence of survival differences between hacked and wild raptors in previous research.

Abstract This case study presents the research process and learnings from undertaking One Health research within Australian Aboriginal and Torres Strait Islander community settings. One Health is relevant to Australian Aboriginal and Torres Strait Islander communities where people and animals (commonly dogs and cats) live closely together and face health risks due to barriers in accessing animal health care. One Health is an appropriate approach to understanding and addressing health disparities as it aligns with community and cultural contexts that recognise the relationships between the health of people, animals and the shared environment. However, with minimal evidence in this space, the contribution of One Health to Aboriginal and Torres Strait Islander health is not well understood limiting the ability to implement One Health approaches and address the needs of communities, families, animals and the environment. This case study describes the research approach, methodology and implications from a pilot One Health study undertaken with Aboriginal and Torres Strait Islander communities that adopted Indigenous research methodologies within a One Health framework. Information © The Authors 2023

Hybridisation between wild and domestic species poses a serious challenge to conservation management and can, potentially, lead to extinction. Alongside it, disease transmission will inevitably occur. However, the link between these two phenomena has historically been neglected. In Scotland, the European wildcat is particularly threatened by hybridisation with the domestic cat, a process promoted by long-term habitat loss, human encroachment, and persecution. Between 2015 and 2019, free-living cats (n = 120) were captured in six conservation priority areas of northern Scotland. Samples were collected for infectious disease screening (feline immunodeficiency virus, feline leukaemia virus, feline calicivirus, feline herpesvirus, Chlamydia felis, Mycoplasma felis, Bordetella bronchiseptica, Mycoplasma haemofelis, Candidatus Mycoplasma haemominutum, Candidatus Mycoplasma turicensis, and Tritrichomonas foetus) and genetic analysis. Polymerase chain reaction and reverse transcriptionPCR were used to detect infectious DNA or RNA, respectively. The hybrid score (Q) for each individual cat was determined using a 35-SNP-marker test. Statistical analysis investigated the association between Q and probability of infection, accounting for spatial clustering. The results confirmed the presence of 11 infectious agents circulating in the free-living cat population of northern Scotland, which consists of a hybrid swarm between F. silvestris and F. catus. For eight of them (feline leukaemia virus, feline herpesvirus C. felis, B. bronchiseptica, M. felis, M. haemofelis, Ca. M. haemominutum, and T. foetus), there was no significant association between infection probability and Q, supporting our hypothesis that the hybrid swarm may be functioning as a single epidemiological unit. Considering the impact of infectious diseases on health, welfare, and population dynamics of domestic cats, their presence in the extremely fragile and hybridised population of F. silvestris in Scotland could be population limiting or, potentially, contribute to local extinction. Comprehensive disease surveillance, risk analysis, and domestic cat management will be essential for the European wildcat conservation, particularly where hybridisation is increasing and anthropogenic factors are prevalent.

Toxoplasma gondii is a ubiquitous protozoan transmitted by felids and infection, morbidity, and mortality occur in numerous marsupial species. This study explores the relationship between cat exposure and Toxoplasma in burrowing bettongs (Bettongia lesueur) in the Arid Recovery Reserve (ARR), South Australia. We estimated seroprevalence, using a modified agglutination test for T. gondii-specific immunoglobulins, in cat-free and cat-exposed bettong populations. Tissue samples collected opportunistically from bettong carcasses and from cats within and around the reserve were screened for T. gondii DNA using multiplex real-time polymerase chain reaction (M-qPCR). Two cats trapped inside the ARR tested positive (50.0%; 95% CI: 15.0–85.0%). All bettongs tested from the cat-free (n = 48) and cat-exposed (n = 19) exclosures were seronegative (95% CI: 0–7.41% and 0–16.82% respectively). We found no evidence of fatal toxoplasmosis, with all bettong carcasses negative on M-qPCR (n = 11). We propose that T. gondii was not detected in bettongs coexisting with cats primarily due to low exposure of bettongs at the time of sampling, possibly due to poor oocyst viability in arid conditions or low shedding by cats. Ongoing screening throughout high and low rainfall years should be conducted to better establish the risk of Toxoplasma to bettongs in the ARR.

With limited access to animal health services, and high disease burdens among domesticated animals, Aboriginal and Torres Strait Islander communities in Australia face higher risk of disease including zoonoses. However, we lack understanding of the contribution of often preventable zoonoses to the health of these communities, which would enable us to enhance public health strategies and improve health outcomes. We conducted a scoping review to identify the current state of evidence on zoonoses in the Aboriginal and Torres Strait Islander population. We examined the size, scope and characteristics of the evidence base and analysed the zoonoses detected in the studies within a One Health framework. We identified 18 studies that detected 22 zoonotic pathogens in animals, people, and the environment, with most studies detecting pathogens in a single One Health sector and no studies investigating pathogens in all three sectors. Findings indicate that despite the strong conceptual foundations of One Health throughout the evidence base, evidence is lacking in application of this concept. There is a need to undertake further research that prioritises Aboriginal and Torres Strait Islander leadership, considers the contribution of human, animal and environmental health factors, and investigates the prevalence and impact of zoonoses in communities through a One Health approach.

The Wildlife Health Bridge was established in 2009 with the aim of improving the expertise and knowledge base of wildlife health professionals in biodiverse low- and middle-income countries. The Wildlife Health Bridge centres around partnerships among educational institutions: the Zoological Society of London, the Royal Veterinary College, the University of Edinburgh’s Royal (Dick) School of Veterinary Studies, the Wildlife Institute of India, and the University of Melbourne Veterinary School. The Wildlife Health Bridge provides quality education in wildlife health, ecosystem health, and wildlife biology, facilitates the interchange of students between collaborating countries for research studies and provides a global graduate network of wildlife health professionals. In addition to established Masters’ level wildlife health training programmes run by the partner organisations, the Wildlife Health Bridge has developed a collaborative field-based course, Interventions in Wild Animal Health, provided annually in India since 2016, which has trained 138 veterinarians to date, enhancing local and international capacity in managing emerging wildlife health issues and building global professional linkages. The Wildlife Health Bridge’s Wild Animal Alumni network facilitates networking and exchange between Wildlife Health Bridge institutions and graduates, with over 701 members from 67 countries, half of which are biodiverse low- and middle-income countries. Collaboration between educational institutions has enabled new ideas and ongoing developments in the delivery of materials and learning outcomes. The Wildlife Health Bridge is building global capacity in trained wildlife health professionals, through educational programmes and a synergised network, with the aim of impacting conservation practice to benefit human, domestic animal and wildlife health.

Red squirrels (Sciurus vulgaris) are native to most of Eurasia; in much of the United Kingdom, they have been supplanted by the non-native grey squirrel, and are considered an endangered species. Very little is known about the range of tick-borne pathogens to which UK red squirrels are exposed. As part of trap-and-release surveys examining prevalence of Mycobacterium spp. in red squirrel populations on two UK islands, Ixodes ricinus ticks were removed from squirrels and PCR screened for Borrelia spp., intracellular arthropod-borne bacteria and the parasitic wasp Ixodiphagus hookeri. At both sites, the most commonly encountered tick-transmitted bacterium was Borrelia burgdorferi sensu lato (overall minimum prevalence 12.7%), followed by Anaplasma phagocytophilum (overall minimum prevalence 1.6%). Single ticks infected with Spiroplasma were found at both sites, and single ticks infected with Borrelia miyamotoi or an Ehrlichia sp. at one site. Ticks harbouring Wolbachia (overall minimum prevalence 15.2%) were all positive for I. hookeri. Our study shows that UK red squirrels are potentially exposed to a variety of bacterial pathogens via feeding ticks. The effects on the health and survival of this already vulnerable wildlife species are unknown, and further studies are needed to evaluate the threat posed to red squirrels by Borrelia and other tick-borne pathogens.