Wildlife Rehabilitation Research Articles

Rehabilitation outcomes of bird-building collision victims in the Northeastern United States.

Building collisions are a leading threat to wild birds; however, only those that are found dead or fatally wounded are included in current mortality estimates, with injured or stunned birds largely assumed to survive long-term. Avian building collision victims are often brought to wildlife rehabilitators for care, with the hopes they can be released and resume their natural lives. We examined the wildlife rehabilitation records of over 3,100 building collisions with 152 different avian species collected across multiple seasons to identify patterns of survival and release among patients. The number of admissions varied by season; fall migration had the highest number of cases and winter had the least number of cases, and summer having the lowest release proportion and winter having the highest. The most common reported injury was head trauma and concussion. Our logistic and Poisson models found that mass had a strong positive effect on release probability, and the season of summer had a strong negative effect on release probability. Mass and winter had a strong positive effect on treatment time, and age and the seasons of fall and winter had a strong negative effect on treatment time in these models. Ultimately, about 60% of patients died in care, either by succumbing to their injuries or by euthanasia. Patients that were released remained in care for longer than patients that died. This study reports different data than carcass studies and views bird-building collisions from the perspective of surviving victims to explore longer-term effects of these collisions on mortality. Increased communication and collaboration between wildlife rehabilitators and conservation researchers is recommended to better understand building collisions and how to respond to this leading threat to wild birds. These findings, along with our estimate of delayed mortality, suggest that overall collision mortality estimates based on carcass collection far exceed one billion birds in the U.S. each year.

Collaborative wildlife disease outbreak investigation and response at Bells Swamp Victoria, February 2023.

In February 2023, a report of morbidity and mortality in waterbirds triggered a collaborative regional wildlife disease outbreak investigation and response, led by Parks Victoria. Triage, rehabilitation and diagnosis of sick and dead birds were undertaken by Zoos Victoria (ZV), Agriculture Victoria, Vets for Compassion, Wildlife Victoria and Melbourne Veterinary School (MVS). The field response focused on collection of sick and dead birds for wildlife welfare, for diagnosis, and to reduce environmental contamination. Botulism was suspected, based on clinical signs and lack of significant gross pathology, and this diagnosis was confirmed by PCR testing. Low pathogenicity avian influenza (LPAI) viruses non H5 or H7 were detected in two birds and ruled out in all in others tested. These incidental, non-clinical LPAI detections are considered part of the natural wild bird virus community in Australia. A number of elements contributed to the collaborative effort. Regional individuals had the necessary connections for reporting, collecting and transporting birds. There was rapid determination by the Victorian Department of Energy, Environment and Climate Action (DEECA) that Parks Victoria, as the land managers, should lead the response. Zoos Victoria provided capacity and expertise in wildlife triage and rehabilitation, and Agriculture Victoria, ZV and MVS were responsible for veterinary management of the response and diagnosis. Field investigation and response were conducted by Parks Victoria, Agriculture Victoria, MVS and veterinary teams from Vets for Compassion and Wildlife Victoria. Wildlife Health Australia (WHA) provided guidance and information, approved National Significant Disease Investigation Program funding and captured the event in the national wildlife health information database. Communication and media were important for community understanding of the event.

Hearing Assessment of Free-Ranging Owls and Implications for Wildlife Rehabilitation: 31 Cases (2014-2023).

Owls, members of the avian order Strigiformes, are nocturnal birds of prey that are found worldwide except for Antarctica. Traumatized, free-ranging owls are commonly presented to veterinary hospitals and wildlife rehabilitation facilities with the goal of providing medical care and rehabilitation to enable release back into their natural habitat. Minimal guidelines exist for the release of wildlife, and whereas a need for functional vision is described in raptors, assessing and evaluating hearing is usually not mentioned. This can be problematic for nocturnal predators because hearing is the primary sense utilized by owls when hunting and navigating in their dark environment. The brainstem auditory evoked response (BAER) test is a minimally invasive, objective assessment of hearing commonly used in companion animals. To the authors' knowledge, routine or standardized BAER evaluation has not been reported in traumatized, free-ranging owls. In the following retrospective study, 31 free-ranging owls presented to the University of Georgia Veterinary Teaching Hospital for known or suspected trauma or being found in a debilitated state underwent BAER testing to assess for the presence of complete sensorineural hearing loss. Similar to assessment of hearing in companion animals, the BAER test was elicited using a broad click stimulus delivered at 85 dB nHL. In all owls, qualitative assessment and peak latency measurements of the BAER test reflected hearing ability. This study highlights the importance of hearing in nocturnal raptors, how BAER testing can aid in decision making regarding rehabilitation, and provides a foundation for further investigation of hearing loss in traumatized owls. We suggest that veterinarians working with free-ranging owls in a rehabilitation setting should consider BAER testing as part of routine diagnostic testing.

Causes of admissions and mortality in patients of a wildlife rehabilitation centre in Bulgaria.

Wildlife rescue centres are specialised units with ecological, conservational and veterinary medical activities, which include treatment, rehabilitation, breeding and releasing rare and endangered wild animals into their natural habitat, as well as environmental education. These centres provide an opportunity to monitor ongoing ecological changes in wildlife, environmental pollution and emerging diseases. With the present study, we aimed to analyse the causes and conservation status of the largest wildlife rehabilitation centre in Bulgaria. A total of 18,720 patients, from 26 orders with various conservation statuses and different etiology, have been admitted to the rehabilitation centre for over 25 years. The summarised results showed that 40% of the patients were admitted with an unknown etiology and the proportion of anthropogenic causes was 18%. Natural factors related to incidents with wild animals were 32%, while a share of 10% of the wildlife which resided at the WRBC referred to a part of re-introduction programmes. This type of analysis of wildlife rehabilitation centres could provide useful information about the status of populations and ecosystems, as well as support conservation practices.

One Health and the wildlife rehabilitator

One Health and the wildlife rehabilitator

Cache like a squirrel: analysis of and recommendations for long-term storage of white oak (Quercus alba) and pin oak (Q. palustris) acorns for use in wildlife rehabilitation without fat degradation

Cache like a squirrel: analysis of and recommendations for long-term storage of white oak (Quercus alba) and pin oak (Q. palustris) acorns for use in wildlife rehabilitation without fat degradation

Baseline health parameters of rhinoceros auklets (Cerorhinca monocerata) using serum protein electrophoresis, acute phase proteins, and biochemistry.

Clinical metrics of baseline health in sentinel seabird species can offer insight into marine ecosystem dynamics, individual and population health, and assist in wildlife rehabilitation and conservation efforts. Protein electrophoresis is useful for detecting changes in acute phase proteins and immunoglobulin levels that may indicate subtle inflammatory responses and/or infectious disease. Serum biochemistry can highlight nutritional status, metabolic derangements, and organ injury and function. However, baseline values for such health parameters are largely unknown for many seabird species. Therefore, the objective of this study is to establish baseline clinical health reference intervals for serum protein electrophoresis, acute phase proteins including serum amyloid A and haptoglobin, and biochemistry parameters in the rhinoceros auklet (Cerorhinca monocerata), a key sentinel species in the North Pacific. From 2013 to 2019, 178 wild, apparently healthy breeding adult rhinoceros auklets were captured across four breeding colonies in British Columbia, Canada (Lucy Island, Pine Island, Triangle Islands, and SGang Gwaay) and from one colony in Washington, United States (Protection Island). Reference intervals were calculated for protein electrophoresis fractions and acute phase proteins (n = 163), and serum biochemistry (n = 35) following established guidelines by the American Society of Veterinary Clinical Pathology. Animals were also assessed for the presence of antibodies to the influenza A virus. Approximately 48% (70/147) of sampled birds were seropositive for influenza A virus, with a prevalence of 50% (6/12) in 2013, 75% (47/63) in 2014, and 24% (17/72) in 2019. This work provides clinical baseline health metrics of a key North Pacific sentinel species to help inform marine ecosystem monitoring, recovery, and rehabilitation efforts in the Pacific Northwest.

COVID-19 in a common woolly monkey (Lagothrix lagothricha): First evidence of fatal outcome in a nonhuman primate after natural SARS-CoV-2 infection.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was declared a pandemic by the World Health Organization in March 2020. Since then, viral spread from humans to animals has occurred worldwide. Nonhuman primates (NHPs) have been found to be susceptible to reverse-zoonosis transmission of SARS-CoV-2, but initial research suggested that platyrrhine primates are less susceptible than catarrhine primates. Here we report the natural SARS-CoV-2 infection of a common woolly monkey (Lagothrix lagothricha) from a wildlife rehabilitation center in Ecuador. The course of the disease, the eventual death of the specimen, and the pathological findings are described. Our results show the susceptibility of a new platyrrhine species to SARS-CoV-2 and provide evidence for the first time of a COVID-19-associated death in a naturally infected NHP. The putative route of transmission from humans, and implications for captive NHPs management, are also discussed. Given that common woolly monkeys are at risk of extinction in Ecuador, further understanding of the potential threat of SARS-CoV-2 to their health should be a conservation priority. A One Health approach is the best way to protect NHPs from a new virus in the same way that we would protect the human population.

Causes of Admission, Mortality and Pathological Findings in European Hedgehogs: Reports from Two University Centers in Italy and Switzerland.

European hedgehogs (Erinaceus europaeus) are nocturnal insectivores frequently found in urban areas. In the last decades, their population has declined in various European countries and human activities have emerged as significant contributors to this trend. While the literature has mainly focused on trauma as the major cause of mortality, few authors have considered pathological findings. The present study is based on the results of full post-mortem examinations performed on 162 European hedgehogs in Italy and 109 in Switzerland. Unlike in previous studies, the main cause of mortality was infectious diseases (60.5%), followed by traumatic insults (27.7%). The lungs were the main organ affected, showing mostly lymphoplasmacytic (45.9%), granulomatous (18.1%) or suppurative (8.2%) pneumonia. Nematodes were detected in 57.2% of all lungs and were significantly associated with pneumonia (p-value < 0.001). To our knowledge, this is the first study to report infectious diseases as the main cause of hedgehog death, emphasizing the need for wildlife rescue centers to adopt appropriate diagnostic and therapeutic measures. Further research is necessary to determine the broad range of infectious agents that affect this species and elucidate their interplay with the host. Finally, citizen sensitization should be implemented to promote responsible behaviors that could reduce human-related traumatic events.

Diagnosis of Orthopedic Fractures Using Craniodorsal-Caudoventral Oblique and Caudodorsal-Cranioventral Oblique Radiographic Views Made at 45° to the Frontal Plane in Four Wild Turtles

Abstract Four wild chelonians (two three-toed box turtles [Terrapene triunguis] and two red-eared sliders [Trachemys scripta elegans]) were presented to an academic wildlife rehabilitation center after presumably being hit by a car. Physical examinations revealed various carapace, bridge, and plastron fractures, as well as a lack of motor function of different limbs. A craniodorsal-caudoventral oblique view and/or caudodorsal-cranioventral oblique radiographic view made at 45° to the frontal plane (Cr45D-CdV and Cd45D-CrV oblique views, respectively), along with standard views (dorsoventral, right lateral, and craniocaudal views) were performed. The oblique views allowed for visualization of different pectoral girdle or pelvic girdle fractures that were not visualized or clearly identified on the standard views. Based on the four clinical cases described here, the addition of Cr45D-CdV and/or Cd45D-CrV oblique views to the standard views may be beneficial, especially when advance imaging such as computed tomography is not available. These oblique views can be used to better assess chelonian pectoral and pelvic girdles as these structures are superimposed in standard radiographs. Future studies investigating the diagnostic accuracy of detecting pelvic and pectoral girdle fractures using these views are warranted.

Reversed Sexual Size Dimorphism and Morphological Sex Determination of the Smallest Subspecies of Eurasian Eagle-Owls (Bubo bubo kiautschensis)

ABSTRACT The Eurasian Eagle-Owl (Bubo bubo) shows reversed sexual size dimorphism. We aimed to evaluate morphological size differences between the sexes of the smallest eagle-owl subspecies (B. b. kiautschensis), for which little morphometric information is available, and to develop a discriminant function for sex using a minimum number of morphometric parameters. We compared nine morphological measurements of 41 genetically or anatomically sexed eagle-owls admitted to a Korean wildlife rescue center and used discriminant function analysis of 29 birds (17 female, 12 male) with complete measurement data of nine biometrics. We developed four equations using three measurements (total length, head length, and weight) that had 86–96% accuracy for sexing Korean Eagle-Owls. The subspecies-specific morphometric data and discriminant functions we developed can help fill the current knowledge gap regarding the morphological characteristics of this little-known subspecies, benefiting researchers, wildlife managers, and veterinarians who work with or study this apex predator in the Korean forest ecosystem.

West Nile Virus Seroprevalence in Wild Birds and Equines in Madrid Province, Spain.

West Nile virus (WNV) is a re-emerging flavivirus, primarily circulating among avian hosts and mosquito vectors, causing periodic outbreaks in humans and horses, often leading to neuroinvasive disease and mortality. Spain has reported several outbreaks, most notably in 2020 with seventy-seven human cases and eight fatalities. WNV has been serologically detected in horses in the Community of Madrid, but to our knowledge, it has never been reported from wild birds in this region. To estimate the seroprevalence of WNV in wild birds and horses in the Community of Madrid, 159 wild birds at a wildlife rescue center and 25 privately owned equines were sampled. Serum from thirteen birds (8.2%) and one equine (4.0%) tested positive with a WNV competitive enzyme-linked immunosorbent assay (cELISA) designed for WNV antibody detection but sensitive to cross-reacting antibodies to other flaviviruses. Virus-neutralization test (VNT) confirmed WNV antibodies in four bird samples (2.5%), and antibodies to undetermined flavivirus in four additional samples. One equine sample (4.0%) tested positive for WNV by VNT, although this horse previously resided in a WN-endemic area. ELISA-positive birds included both migratory and resident species, juveniles and adults. Two seropositive juvenile birds suggest local flavivirus transmission within the Community of Madrid, while WNV seropositive adult birds may have been infected outside Madrid. The potential circulation of flaviviruses, including WNV, in birds in the Madrid Community raises concerns, although further surveillance of mosquitoes, wild birds, and horses in Madrid is necessary to establish the extent of transmission and the principal species involved.

Labor of a free-living buffy-tufted marmoset (Callithrix aurita) at a Wildlife Rehabilitation Center in southeastern Brazil.

Callithrix aurita is an endangered small primate endemic to the Atlantic Forest. The present work reports the labor of a free-living C. aurita, through observation of its length and offspring viability. A conservative treatment was used to maintain fetal viability, in view of the species conservation importance.

Potential drivers of vector-borne pathogens in urban environments: European hedgehogs (Erinaceus europaeus) in the spotlight

Vector-borne diseases (VBDs) are considered as (re-)emerging, but information on the transmission cycles and wildlife reservoirs is often incomplete, particularly with regard to urban areas. The present study investigated blood samples from European hedgehogs (Erinaceus europaeus) presented at wildlife rehabilitation centres in the region of Hanover. Past exposure to B. burgdorferi sensu lato (s.l.) and tick-borne encephalitis virus (TBEV) was assessed by serological detection of antibodies, while current infections with Borrelia spp., Anaplasma phagocytophilum, Rickettsia spp., Neoehrlichia mikurensis, Bartonella spp., Babesia spp. and Spiroplasma ixodetis were investigated by (q)PCR. Of 539 hedgehogs tested for anti-Borrelia antibodies, 84.8% (457/539) were seropositive, with a higher seropositivity rate in adult than subadult animals, while anti-TBEV antibodies were detected in one animal only (0.2%; 1/526). By qPCR, 31.2% (168/539) of hedgehog blood samples were positive for Borrelia spp., 49.7% (261/525) for A. phagocytophilum, 13.0% (68/525) for Bartonella spp., 8.2% for S. ixodetis (43/525), 8.0% (42/525) for Rickettsia spp. and 1.3% (7/525) for Babesia spp., while N. mikurensis was not detected. While further differentiation of Borrelia spp. infections was not successful, 63.2% of the A. phagocytophilum infections were assigned to the zoonotic ecotype I and among Rickettsia spp. infections, 50.0% to R. helvetica by ecotype- or species-specific qPCR, respectively. Sequencing revealed the presence of a Rickettsia sp. closely related to Rickettsia felis in addition to a Bartonella sp. previously described from hedgehogs, as well as Babesia microti and Babesia venatorum. These findings show that hedgehogs from rehabilitation centres are valuable sources to identify One Health pathogens in urban areas. The hedgehogs are not only exposed to pathogens from fleas and ticks in urban areas, but they also act as potent amplifiers for these vectors and their pathogens, relevant for citizens and their pets.

Morphological and molecular characterization of Eimeria haematopusi n. sp. (Apicomplexa: Eimeriidae) in an Australian Pied Oystercatcher (Haematopus longirostris) (Aves: Charadriiformes)

A novel Eimeria Schneider, 1875 species is described from an Australian pied oystercatcher Haematopus longirostris Vieillot, in Western Australia. The pied oystercatcher was admitted to the Kanyana Wildlife Rehabilitation Centre (KWRC), Perth, Western Australia in a poor body condition, abrasion to its right hock and signs of partial delamination to its lower beak. Investigation into potential medical causes resulted in a faecal sample being collected and screened for gastrointestinal parasites. Unsporulated coccidian oocysts were initially observed in the faeces and identified as Eimeria upon sporulation. The sporulated oocysts (n = 20) are ellipsoidal, 20–21 × 12–13 μm in shape and have thick bi-layered walls which are c.2/3 of the total thickness. Micropyle is present, robust and protruding, and occasionally has a rounded polar body attached to the micropyle. Within the oocyst, a residuum, in addition, two to five polar granules are present. There are four ellipsoidal sporocysts 9–11 × 5–6 μm with flattened to half-moon shaped Stieda bodies. Sub-Stieda body and para-Stieda body are absent. The sporocysts contain sporocyst residuums composed of a few spherules scattered among the sporozoites. Within the sporozoites, anterior and posterior refractile bodies are present, but the nucleus is indiscernible. To further characterise the novel Eimeria species from H. longirostris, molecular analysis was conducted at the 18S ribosomal RNA locus, using PCR amplification and cloning. Two cloned sequences from the novel Eimeria were compared with those from other Eimeria spp. with the highest genetic similarity of 97.6% and 97.2% from Clone 1 and 2, respectively with Eimeria reichenowi (AB544308) from a hooded crane (Grus monacha Temminck) in Japan. Both sequences grouped in a clade with the Eimeria spp. isolated from wetland birds, which include Eimeria paludosa (KJ767187) from a dusky moorhen (Gallinula tenebrosa Gould) in Western Australia, Eimeria reichenowi (AB544308) and Eimeria gruis (AB544336) both from hooded cranes. Based on the morphological and molecular data, this Eimeria sp. is a new species of coccidian parasite and is named Eimeria haematopusin. sp. after its host H. longirostris.

Exploring the Prevalence and Resistance of Campylobacter in Urban Bird Populations.

The increasing urbanization of ecosystems has had a significant impact on wildlife over the last few years. Species that find an unlimited supply of food and shelter in urban areas have thrived under human presence. Wild birds have been identified as amplifying hosts and reservoirs of Campylobacter worldwide, but the information about its transmission and epidemiology is still limited. This study assessed the prevalence of Campylobacter in 137 urban birds admitted at a wildlife rescue center, with 18.8% of individuals showing positive. C. jejuni was the most frequent species (82.6%), followed by C. coli and C. lari (4.3% each). The order Passeriformes (33.3%) showed significant higher presence of Campylobacter when compared to orders Columbiformes (0%) and Ciconiiformes (17.6%), as well as in samples collected during the summer season (31.9%), from omnivorous species (36.8%) and young individuals (26.8%). Globally, Campylobacter displayed a remarkable resistance to ciprofloxacin (70.6%), tetracycline (64.7%), and nalidixic acid (52.9%). In contrast, resistance to streptomycin was low (5.8%), and all the isolates showed susceptibility to erythromycin and gentamycin. The results underline the importance of urban birds as reservoirs of thermophilic antimicrobial-resistant Campylobacter and contribute to enhancing the knowledge of its distribution in urban and peri-urban ecosystems.

Surveillance for highly pathogenic avian influenza A (H5N1) in a raptor rehabilitation center-2022.

An ongoing, severe outbreak of highly pathogenic avian influenza virus (HPAI) A H5N1 clade 2.3.4.4b has been circulating in wild and domestic bird populations throughout the world, reaching North America in 2021. This HPAI outbreak has exhibited unique characteristics when compared to previous outbreaks. The global distribution of disease, prolonged duration, extensive number of species and individual wild birds affected, and the large impact on the global poultry industry have all exceeded historical impacts of previous outbreaks in North America. In this study, we describe the results of HPAI surveillance conducted at The Raptor Center, a wildlife rehabilitation hospital at University of Minnesota (Saint Paul, MN, U.S.A.), from March 28th-December 31, 2022. All wild raptors admitted to the facility were tested for avian influenza viruses using polymerase chain reaction (PCR) testing. All non-negative samples were submitted to the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) National Veterinary Services Laboratories for confirmatory HPAI testing and genetic sequencing. During the study period, 996 individual birds representing 20 different species were tested for avian influenza, and 213 birds were confirmed HPAI positive. Highly pathogenic avian influenza surveillance conducted at The Raptor Center contributed 75% of the HPAI positive raptor detections within the state of Minnesota, located within the Mississippi flyway, significantly augmenting state wildlife surveillance efforts. The viral genotypes observed in birds sampled at The Raptor Center were representative of what was seen in wild bird surveillance within the Mississippi flyway during the same time frame. Wildlife rehabilitation centers provide an opportune situation to augment disease surveillance at the human, wildlife and domestic animal interface during ongoing infectious disease outbreaks.

Avian Haemosporidian Infection in Wildlife Rehabilitation Centres of Portugal: Causes, Consequences, and Genetic Diversity.

In the last decade, over 40% of bird species in Europe have experienced poor and bad conservation status, with more than 30% of bird species in mainland Portugal threatened with extinction. Along with anthropogenic factors, parasites and pathogens such as avian haemosporidians have been suggested to be responsible for these avian population declines. Wildlife rehabilitation centres play an essential role in species conservation and preservation. Moreover, animals admitted for rehabilitation can provide valuable information regarding transmission and pathogenicity of many diseases that affect wild birds that are rarely sampled in nature. However, reports of haemosporidians in captive birds are still limited. Here, we explored the prevalence and genetic diversity of avian haemosporidians in 89 birds from 29 species admitted to rehabilitation centres in Portugal, showing an overall infection prevalence of 30.3%. The prevalence of infection was higher in Strigiformes and in birds admitted to rehabilitation centres due to debilitating diseases. Remarkably, 30% of the infected bird species have not been found to harbour malaria parasites in preceding studies. We detected 15 different haemosporidian lineages infecting a third of bird species sampled. Notably, 2 out of these 15 detected haemosporidian lineages have not been obtained previously in other studies. Furthermore, we also identified nine new host-parasite interactions representing new host records for these haemosporidian parasites. Finally, our results revealed that birds infected with haemosporidians require longer rehabilitation treatments, which increase the economic costs for rehabilitation and may impair their survival prospects. These findings emphasise the importance of integrating haemosporidian infection considerations into rehabilitation protocols, highlighting the challenges posed by these infections in avian conservation and rehabilitation, including economic and logistical demands.

Addressing Challenges in Wildlife Rehabilitation: Antimicrobial-Resistant Bacteria from Wounds and Fractures in Wild Birds.

Injuries and bone fractures are the most frequent causes of admission at wildlife rescue centers. Wild birds are more susceptible to open fractures due to their anatomical structure, which can lead to osteomyelitis and necrosis. Antibiotic therapy in these cases is indispensable, but the increase of antimicrobial-resistant isolates in wildlife has become a significant concern in recent years. In this context, the likelihood of antibiotic failure and death of animals with infectious issues is high. This study aimed to isolate, identify, and assess the antimicrobial resistance pattern of bacteria in wounds and open fractures in wild birds. To this end, injured birds admitted to a wildlife rescue center were sampled, and bacterial isolation and identification were performed. Then, antimicrobial susceptibility testing was assessed according to the disk diffusion method. In total, 36 isolates were obtained from 26 different birds. The genera detected were Staphylococcus spp. (63.8%), Escherichia (13.9%), Bacillus (11.1%), Streptococcus (8.3%), and Micrococcus (2.8%). Among Staphylococcus isolates, S. lentus and S. aureus were the most frequent species. Antimicrobial resistance was detected in 82.6% of the isolates, among which clindamycin resistance stood out, and 31.6% of resistant isolates were considered multidrug-resistant. Results from this study highlight the escalating scope of antimicrobial resistance in wildlife. This level of resistance poses a dual concern for wildlife: firstly, the risk of therapeutic failure in species of significant environmental value, and, secondly, the circulation of resistant bacteria in ecosystems.

Genomic insights into anthropozoonotic tuberculosis in captive sun bears (Helarctos malayanus) and an Asiatic black bear (Ursus thibetanus) in Cambodia

Contact between humans and wildlife presents a risk for both zoonotic and anthropozoonotic disease transmission. In this study we report the detection of human strains of Mycobacterium tuberculosis in sun bears and an Asiatic black bear in a wildlife rescue centre in Cambodia, confirming for the first time the susceptibility of these bear species to tuberculosis when in close contact with humans. After genotyping revealed two different strains of M. tuberculosis from cases occurring between 2009 and 2019, 100 isolates from 30 sun bear cases, a single Asiatic black bear case, and a human case were subjected to whole genome sequencing. We combined single nucleotide polymorphism analysis and exploration of mixed base calls with epidemiological data to indicate the evolution of each outbreak. Our results confirmed two concurrent yet separate tuberculosis outbreaks and established a likely transmission route in one outbreak where the human case acted as an intermediatory between bear cases. In both outbreaks, we observed high rates of transmission and progression to active disease, suggesting that sun bears are highly susceptible to tuberculosis if exposed under these conditions. Overall, our findings highlight the risk of bi-directional transmission of tuberculosis between humans and captive bears in high human tuberculosis burden regions, with implied considerations for veterinary and public health. We also demonstrate the use of standard genomic approaches to better understand disease outbreaks in captive wildlife settings and to inform control and prevention measures.