Panthera Tigris Altaica Research Articles

О находке клещей Rhipicephalus leporis (Arai, Ixodidae) в Южном Прибалхашье

Иксодовые клещи являются переносчиками многих трансмиссивных инфекций, в том числе особо опасных. Хотя медицинское и ветеринарное значение этой группы кровососущих членистоногих трудно переоценить, тем не менее, известно, что интенсивное изучение фауны иксодовых клещей Ка-захстана пришлось на советский период, а после распада СССР исследования фауны и систематики иксодовых клещей носили лишь эпизодический характер. Сегодня фауна иксодовых клещей Респуб-лики Казахстан насчитывает 42 вида кровососущих паукообразных, при этом зачастую сведения по некоторым видам клещей носят фрагментарный характер. Так, авторами в результате обследования, проведенного на территории Иле-Балхашского резервата на флаг, всего было собрано 65 экземпляров иксодовых клещей. В ходе идентификации удалось установить, что собранные клещи принадлежали к роду Rhipicephalus, а при видовой дифференциации все собранные клещи оказались Rh. leporis. Клещи концентрировались в основном вокруг жилых помещений, но наибольшая численность была отмечена около вольера, где содержались бухарские олени (Cervus elaphus bactrianus). Примечательным являет-ся тот факт, что ранее этот вид клеща для данной территории не указывался, и обнаружен авторами здесь впервые. Получение новых сведений о фауне иксодовых клещей, обитающих на территории резервата «Иле-Балхаш», может иметь важную роль для планируемой интродукции амурского тигра (Panthera tigris tigris), поскольку иксодовые клещи переносят большое количество зоонозных заболеваний. Таким образом, это будет способствовать комплексной оценке рисков для интродукции тигра и может повысить успех планируемого мероприятия.

Addressing the impact of canine distemper spreading on an isolated tiger population in northeast Asia.

The continuation of the isolated Amur tiger (Panthera tigris altaica) population living along the China-Russia border is facing serious challenges due to factors such as its small size (including 38 individuals) and canine distemper virus (CDV). We use a population viability analysis metamodel, which consists of a traditional individual-based demographic model linked to an epidemiological model, to assess options for controlling the impact of negative factors through domestic dog management in protected areas, increasing connectivity to the neighboring large population (including more than 400 individuals), and habitat expansion. Without intervention, under inbreeding depression of 3.14, 6.29, and 12.26 lethal equivalents, our metamodel predicted the extinction within 100 years is 64.4%, 90.6%, and 99.8%, respectively. In addition, the simulation results showed that dog management or habitat expansion independently will not ensure tiger population viability for the next 100 years, and connectivity to the neighboring population would only keep the population size from rapidly declining. However, when the above three conservation scenarios are combined, even at the highest level of 12.26 lethal equivalents inbreeding depression, population size will not decline and the probability of extinction will be <5.8%. Our findings highlight that protecting the Amur tiger necessitates a multifaceted synergistic effort. Our key management recommendations for this population underline the importance of reducing CDV threats and expanding tiger occupancy to its former range in China, but re-establishing habitat connectivity to the neighboring population is an important long-term objective.

Fatal balamuthosis in a Siberian tiger and a literature review of detection options for free-living amoebic infections in animals.

Free-living amoebae are rare causes of morbidity and mortality in humans and animals around the globe. Because the route of exposure and clinical progression of disease caused by different species of amoebae may vary in people and animals, determining the species of amoeba present is important. We describe here a fatal infection by the free-living amoeba Balamuthia mandrillaris in a Siberian tiger (Panthera tigris altaica). The 17-y-old patient had a rapid clinical decline after a peracute onset of severe lethargy, dull mentation, and anorexia. Autopsy did not identify a cause of death. Histology revealed inflammation associated with amoebic trophozoites in the brain, lungs, and iris of one eye. These amoebae were confirmed to be B. mandrillaris based on a PCR assay and sequencing. Although there are subtle morphologic differences between cyst stages of Acanthamoeba spp., B. mandrillaris, and Naegleria fowleri when present and identified on routine staining, other modalities, including PCR, immunofluorescence, electron microscopy, and immunohistochemistry, are typically utilized to confirm the pathogen involved in these cases. We review the reports of balamuthosis in animals.

AF‐TigerNet: A lightweight anchor‐free network for real‐time Amur tiger (Panthera tigris altaica) detection

AbstractMonitoring the critically endangered Amur tiger (Panthera tigris altaica) is crucial for the conservation of the natural environment. This paper proposes a novel lightweight deep‐learning network for detecting Amur tigers in mobile and resource‐constrained environments, like those using unmanned aerial vehicles. The network uses an anchor‐free mechanism with modified CSPNet and cross stage partial (CSP)‐path aggregation network (PAN) structures, which improves the model's feature extraction capabilities. Label assignment strategy is also improved to stabilize the model training process. Additionally, the random Mosaic and Mixup data augmentation strategy is utilized to address the overfitting issue due to insufficient data in the data set. The model achieves 55.5% mean average precision (mAP [0.5:0.95]) with only 0.617 million parameters and 73.58 frames per second on mobile CPU with pixels input. Results show that the model is an accurate, fast, and practical detector of the Amur tiger, serving as a reference for wildlife detectors of other species.

The Borderlands

The Borderlands

Canine Distemper Virus in Tigers (Panthera tigris) and Leopards (P. pardus) in Nepal.

From wild dogs (Lycaon pictus) in the Serengeti to tigers (Panthera tigris altaica) in the Russian Far East, canine distemper virus (CDV) has been repeatedly identified as a threat to wild carnivores. Between 2020 and 2022, six Indian leopards (P. pardus fusca) presented to Nepali authorities with fatal neurological disease, consistent with CDV. Here, we report the findings of a serosurvey of wild felids from Nepal. A total of 48 serum samples were tested, comprising 28 Bengal tigers (P. t. tigris) and 20 Indian leopards. Neutralizing antibodies were identified in three tigers and six leopards, equating to seroprevalences of 11% (CI: 2.8-29.3%, n = 28) and 30% (CI: 12.8-54.3%, n = 20), respectively. More than one-third of seropositive animals were symptomatic, and three died within a week of being sampled. The predation of domestic dogs (Canis lupus familiaris) has been posited as a potential route of infection. A comparison of existing diet studies revealed that while leopards in Nepal frequently predate on dogs, tigers do not, potentially supporting this hypothesis. However, further work, including molecular analyses, would be needed to confirm this.

Anatomical and topographic features of the quadriceps femoris muscle in the Amur tiger

The article presents the specific features of the anatomical design of the quad- riceps femoral muscle in the Amur tiger. The aim of the study is to establish anatomical and topographic features and skeletotopic landmarks of the quadriceps femoral muscle in the Amur tiger, as well as to assess the functional significance of the studied structures. It was found that its straight head in its distal part has a muscle-tendon method of attachment to the kneecap. It is shown that the terminal tendons of the lateral and medial heads of the quadriceps femoris fuse with the plate-shaped tendons of the lateral and medial parts of its intermediate head. A more extensive area of fixation is characterized, in comparison with other heads, by the lateral head extending to the top of the cranial tubercle of the kneecap. The intermediate head with its distal end, together with the joint capsule, is fixed in the area of the articular surface of the kneecap. The study was performed at the Department of Anatomy and Histology of Animals named after Professor A.F. Klimova, Moscow State Academy of Veterinary Medicine and Biotechnology – MBA named after K.I. Scriabin. The object of study was the Amur tiger. The material for the study was pelvic limbs, without external signs of pathologies. We used methods of conventional and fine anatomical dissec- tion of muscles under the control of a binocular magnifier “Micromed HR 350 S”, as well as biomechanical modeling of a static-locomotor act. Based on the conducted studies, we have identified additional collateral lateral and medial menisco-femoral ligaments in the tiger, which stabilize the menisci and strengthen the knee joint. The revealed features of the mac- roarchitecture of the kneecap in a tiger can provide optimal conditions for the functioning of the quadriceps femoral muscle and biomechanical perfection of the knee joint

ПРИМЕНЕНИЕ ГЕОИНФОРМАЦИОННЫХ СИСТЕМ В ИЗУЧЕНИИ ЛОКАЛЬНОЙ ПОПУЛЯЦИИ АМУРСКОГО ТИГРА С ПОМОЩЬЮ ФОТОМОНИТОРИНГА В ЗАПОВЕДНИКЕ «БАСТАК» И НА СОПРЕДЕЛЬНЫХ ТЕРРИТОРИЯХ

Photo monitoring with the help of camera traps has proven itself as one of the key methods in the study of the Amur tiger, which allows obtaining up-to-date information on the population condition, its number, and its sex and age structure. In the Bastak Nature Reserve, 50 camera traps are installed and operate year-round. They form trapping stations of paired cameras recording a tiger on both sides and correctly identifying it. Based on the obtained photo and video materials for 2022, the authors have analyzed the Amur tiger visits to trapping stations in the cluster «Central» of the reserve Bastak. With the interpolation module, the data analysis was carried out in the QGIS program, which allowed to determine a place most visited by Amur tigers. The site is located in the upper reaches of the Ikura River (Rocky Hill ridge), where adults are most often recorded. A male Bastak (20 meetings), females Cinderella (10 meetings) and Tala (8 meetings) were identified and reflected on the GIS layer. The male named Bastak is regularly noted in the upper reaches of the river with the same name. According to the study results, there is a need in increase of the trapping stations number. It is created the stations location model to fully embrace the Amur tiger habitat by photo monitoring in the cluster “Central” and its protection zone. The data obtained makes the basis for a further study of the predator’s food supply, for getting up-to-date information about the habitat areas and peculiarities of the Amur tiger daily and seasonal activity in the Bastak Reserve and adjacent territories.

Анатомо-топографическая характеристика мышц тазовой конечности у тигра

The aim of the present study was to establish anatomical and topographic features of the muscles of the thigh region of the Amur tiger and to assess the functional significance of the studied structures. The research was carried out at the Department of Anatomy and Histology of Animals named after Professor A. F. Klimov of the Moscow State Academy of Veterinary Medicine and Biotechnology – MBA named after K.I. Scriabin. The object of study was the Amur tiger. The material is pelvic limbs of mature animals, without external signs of pathologies. We used methods of conventional and fine anatomical dissection of muscles under the control of a binocular magnifier «Micromed HR 350 S», as well as biomechanical modeling of a static-locomotor act. The specific anatomical and topographic features of skeletal thigh muscles in the Amur tiger are presented. Thus, the first muscle layer, located between the leaves of the deep fascia, is represented from the lateral surface by the biceps femoris muscle, with the medial – tailor's and slender muscles. The topical features of the fixation of muscles acting on the knee and metatarsal joints, which are absent in the available literature, are presented. The features indicating the anatomical and functional integration of the organs of the musculoskeletal system of the pelvic limb in a representative of the feline family (the tiger), which must be taken into account when assessing the status-locomotor act, in the diagnosis of arthro-desmo and myopathologies, are revealed.

Сетевой подход в изучении пространственной экологии крупных хищников и копытных юго-восточного Сихотэ-Aлиня (Приморский край)

Network analysis has proven to be an effective tool for understanding patterns and predicting consequences in the study of complex systems on a local, regional and global scale. In the south of the Russian Far East exists one of the highest levels of biodiversity in Russia. This paper presents mainly theoretical study, its results includes maps and of spatial structure distribution schemes in the winter of the Amur tiger and the main objects of its food interest—ungulates. The research model area situated within the mountain-forest territory of Southeastern Sikhote-Alin Mountains (Primorsky Krai). This region is home to species of worldwide conservation significance, including the Amur tiger (Panthera tigris altaica). The results of the study show the interpenetration of places of human activity and infrastructure into the main habitats of large animals in winter. The factors threatening the existence of large predators can be divided into three types: anthropogenic (related to the presence of man and his economic activity); technogenic (caused by implemented technological systems, for example, transport and fuel and energy infrastructure); natural (natural disasters, as well as relief and landscape conditions that prevent the existence of living organisms of wildlife). The work presents: 1) network models and geoinformation mapping of the winter distribution of the Amur tiger, which is the result of using the proximity threshold as a key variable parameter of the network model; 2) maps of the distribution of ungulates have been compiled by recalculating the total number of animals by their population density in hunting grounds; 3) network models of the human-occupied space (roads, settlements) of the model territory have been prepared and distribution of hunting enterprises. The applied synergy of geoinformation modeling and network analysis provides effective analytical tools for research in the spatial ecology of animals.

РЕЗУЛЬТАТЫ МОНИТОРИНГА УРОЖАЙНОСТИ ДУБА МОНГОЛЬСКОГО – ОСНОВЫ КОРМОВОЙ БАЗЫ КОПЫТНЫХ ЖИВОТНЫХ В ЗАПОВЕДНИКЕ «БАСТАК»

The Mongolian oak Quercus mongolica Fisch. ex Ledeb. along with the Korean pine, Pinus koraiensis Siebold et Zuss form the ecosystem integrity basis at the Bastak Reserve. The study of these species productivity is important and relevant. Currently, a number of articles have been published on the Korean pine nut productivity in the protected area. However, the information concerning the Mongolian oak yield is available only in the Annals of Nature. This paper presents the assessment data on the Mongolian oak acorns yield as a fodder base for a number of wild animals being the nutrition for the Amur tiger. This species productivity monitoring has been carried out at Bastak Nature Reserve since 2015. However, the first acorn harvest was obtained only in 2017. The assessment is made on permanent transects in different areas of the reserve. The research shows that monitoring of the Mongolian oak harvest in the Bastak reserve is carried out irregularly. The productive and lean years alternation trend has not been determined yet, unlike in the Lazovsky Reserve. Perhaps, because of a short monitoring period. The Mongolian oak acorns yield is significantly influenced by the weather conditions, primarily, the absence of rainy days during the flowering period. It is noted that in the absence of Mongolian oak acorns yield there is a good harvest of pine nuts partially compensating the absence of acorns as a nutrition for ungulates. However, maintaining a stable density of ungulates needs certain bio-technical measures, such as feeding grounds.

Is the Lesser Khingan Suitable for the Amur Tiger Restoration? Perspectives with the Current State of the Habitat and Prey Base

The Amur tiger (Panthera tigris) has a status of being endangered on the world's IUCN red list. The northwestern part of its range is situated in Russia and China, where tigers were exterminated by humans in the 1950-1970s. To restore tiger population within a historical range, an estimation of the habitat suitability is firstly needed. The Lesser Khingan mountains (Heilongjiang) was analyzed. Habitat types were mapped by satellite images analysis and field proven. The potential habitats of the main tiger's prey species (wild boar (Sus scrofa), roe deer (Capreolus pygargus), and red deer (Cervus elaphus xanthopygus) were also assessed. Maximum entropy and linear discriminant analysis methods were applied and compared for species distribution modeling (SDM). Species distribution maps were used to design an ecological network. The fragmentation of habitat patches was evaluated by spatial ecological metrics. The habitat patches with the best metrics were assigned as cores for the ecological network, which were connected by calculated corridors. The least cost distance method (based on distance to roads and settlements) was used. The recovery of the Amur tiger in habitats of China's Lesser Khingan is shown to be possible. Types of habitats were calculated as natural corridors for moving tigers. They are mainly located at the forests' edges and characterized with various canopy structures and high variability in the tree species composition. Three potential transboundary corridors are described: (a) foothills and low mountains of the northern Lesser Khingan; (b) connection between the southeast Lesser Khingan and the western part of the Wandashan mountain system; and (c) corridor within foothills and low mountains of the eastern part of Lesser Khingan. It is recommended to establish protected areas for the important tiger core habitats, and the main optimal ways for their migrations are described during the current investigation. Moreover, it is necessary to implement habitat recovery activities for key areas.

Wild Terrestrial Animal Re-Identification Based on an Improved Locally Aware Transformer with a Cross-Attention Mechanism.

The wildlife re-identification recognition methods based on the camera trap were used to identify different individuals of the same species using the fur, stripes, facial features and other features of the animal body surfaces in the images, which is an important way to count the individual number of a species. Re-identification of wild animals can provide solid technical support for the in-depth study of the number of individuals and living conditions of rare wild animals, as well as provide accurate and timely data support for population ecology and conservation biology research. However, due to the difficulty of recording the shy wild animals and distinguishing the similar fur of different individuals, only a few papers have focused on the re-identification recognition of wild animals. In order to fill this gap, we improved the locally aware transformer (LA transformer) network structure for the re-identification recognition of wild terrestrial animals. First of all, at the stage of feature extraction, we replaced the self-attention module of the LA transformer with a cross-attention block (CAB) in order to calculate the inner-patch attention and cross-patch attention, so that we could efficiently capture the global information of the animal body's surface and local feature differences of fur, colors, textures, or faces. Then, the locally aware network of the LA transformer was used to fuse the local and global features. Finally, the classification layer of the network realized wildlife individual recognition. In order to evaluate the performance of the model, we tested it on a dataset of Amur tiger torsos and the face datasets of six different species, including lions, golden monkeys, meerkats, red pandas, tigers, and chimpanzees. The experimental results showed that our wildlife re-identification model has good generalization ability and is superior to the existing methods in mAP (mean average precision), and obtained comparable results in the metrics Rank 1 and Rank 5.

‘I know the tiger by his paw’: A non-invasive footprint identification technique for monitoring individual Amur tigers (Panthera tigris altaica) in snow

Apex predator populations are in decline around the world. Many exist at low density and are elusive, making the acquisition of reliable data on their numbers and distribution a considerable challenge. The Amur tiger (Panthera tigris altaica) is the largest of the five extant sub-species of tiger. The single most significant, contiguous population, an estimated 550 animals, exists in the Russian Far East, with smaller populations on the far eastern Sino-Russian border. For the last few decades, active efforts on the part of Chinese authorities have encouraged the recolonization of these populations back to their former ranges in Northeast China. Reliable data on Amur tiger numbers and distribution are required to assess population recovery at the landscape scale. Footprints, ubiquitous in the snow over range areas, could inform on these baseline data. This paper describes a statistically robust, cost-effective and non-invasive footprint identification technique (FIT) to identify individual tigers from footprints in snow. It is based on a rigorous data collection and data-processing protocol, combined with a cross-validated discriminant analysis method. A Ward's clustering technique provides a visual output of individual classification. The analytical tools are packaged in a user-friendly analytical interface. Between December 2011 and December 2012, we collected a series of 605 footprint images from 44 captive individual Amur tigers for a reference database from which to derive a classification algorithm. The 23 females and 21 males ranged in age from 3 to 13 years (female mean age 7.95 +/− 0.18; male mean age 8.08 +/− 0.19). 128 measurements (areas, lengths and angles) were taken from each print and analyzed with the FIT add-in to JMP software. The derived classification algorithm was then applied to 21 footprint trails collected from an unknown number of free-ranging Amur tigers during 2012 and 2015/2016. The algorithm predicted 7 Amur tigers at the site surveyed in 2012, and 4 tigers surveyed at two sites in 2015/16. We demonstrate that the footprint identification technique translates traditional tracking methodologies into a statistically robust and objective analytical tool that can be deployed by both scientists and local communities to monitor the recovery of big cat populations.

Seroprevalence and risk factor analysis of Toxoplasma gondii infection in Siberian tigers (Panthera tigris altaica) and giant pandas (Ailuropoda melanoleuca) in China.

Toxoplasmosis, caused by Toxoplasma gondii, is a worldwide zoonosis. The aim of the present study was to detect the seroprevalence of T. gondii infection and associated risk factors among Siberian tigers (Panthera tigris altaica) and giant pandas (Ailuropoda melanoleuca) in China. Blood samples from 112 Siberian tigers and 22 giant pandas were tested for immunoglobulin G (IgG) against T. gondii by enzyme-linked immunosorbent assay (ELISA). The seroprevalence of T. gondii infection was 7.14% among Siberian tigers and 9.09% among giant pandas. No risk factors were found to be significantly associated with seroprevalence (P > 0.05). This is the first study to evaluate T. gondii infection in Siberian tigers on a large scale in China, and it also updates the information regarding the positivity rate of T. gondii infection among giant pandas in China.

Mitochondrial genomes assembled from non-invasive eDNA metagenomic scat samples in the endangered Amur tiger Panthera tigris altaica.

The Amur or Siberian tiger Panthera tigris altaica (Temminck, 1844) is currently restricted to a small region of its original geographical range in northwestern Asia and is considered 'endangered' by the IUCN Red List of Threatened Species. This solitary, territorial, and large top predator is in major need of genomic resources to inform conservation management strategies. This study formally tested if complete mitochondrial genomes of P. tigris altaica can be assembled from non-enriched metagenomic libraries generated from scat eDNA samples using the Illumina sequencing platform and open-access bioinformatics pipelines. The mitogenome of P. tigris altaica was assembled and circularized using the pipeline GetOrganelle with a coverage ranging from 322.7x to 17.6x in four different scat eDNA samples. A nearly complete mitochondrial genome (101x) was retrieved from a fifth scat eDNA sample. The complete or nearly complete mitochondrial genomes of P. tigris altaica were AT-rich and composed of 13 protein coding genes (PCGs), 22 transfer RNA genes, two ribosomal RNA genes, and a putative control region. Synteny observed in all assembled mitogenomes was identical to that reported before for P. tigris altaica and other felids. A phylogenomic analysis based on all PCGs demonstrated that the mitochondrial genomes assembled from scat eDNA reliably identify the sequenced samples as belonging to P. tigris and distinguished the same samples from closely and distantly related congeneric species. This study demonstrates that it is viable to retrieve accurate whole and nearly complete mitochondrial genomes of P. tigris altaica (and probably other felids) from scat eDNA samples without library enrichment protocols and using open-access bioinformatics workflows. This new genomic resource represents a new tool to support conservation strategies (bio-prospecting and bio-monitoring) in this iconic cat.

Additional evidence of tigers (Panthera tigris altaica) as intermediate hosts for Toxoplasma gondii through the isolation of viable strains.

Toxoplasmosis is one of the most common zoonotic diseases in the world. Felines excrete Toxoplasma gondii oocysts, which play a key role in the transmission of this protozoon. Pathological diagnoses were performed on four carcasses of captive tigers collected from 2019 to 2021 in China, and T. gondii was surveyed using serology, molecular analysis, and aetiology. Striated muscle samples of the tigers (n=4) were bioassayed in mice. DNA derived from T. gondii tachyzoites was isolated and characterized using PCR-RFLP. The pathological diagnoses revealed that ageing, declined immune function, liver, and kidney failures caused the deaths in the tigers examined. A modified agglutination test (cut-off: 1:25) revealed that IgG antibodies to T. gondii were 100% (4/4) in the captive tigers. Two viable T. gondii strains (TgTigerCHn3 and TgTigerCHn4) were isolated from tiger striated muscles and seeded on the Vero cell culture for further propagation. The genotypes of TgTigerCHn3 and TgTigerCHn4 were ToxoDB#20 and ToxoDB#2, respectively. The two strains were avirulent for Swiss mice, which matched the ROP18 and ROP5 gene alleles of TgtigerCHn3 (3/4) and TgtigerCHn4 (3/3). Few brain tissue cysts (0-213) were observed in the mice after inoculation with TgTigerCHn3 and TgTigerCHn4. This is the first documented isolation of T. gondii ToxoDB#20 and ToxoDB#2 from tigers. The results provide additional direct evidence of tiger as intermediate hosts for T. gondii. Tigers in the zoos may potentially transmit T. gondii to other animals and humans.

Developmental stage variation in the gut microbiome of South China tigers.

South China tigers (Panthera tigris amoyensis, SC) are the most threatened tiger subspecies in the world. All the living SCs are captive in zoos or reserves and depend on artificial feeding. The composition of the gut microbiome plays an important role in sustaining the health of the host. A comprehensive understanding of the composition and development of the microbial community of SC is helpful to improve the feeding of captive SC. In this study, we collected 47 fecal samples, 37 of which were from SC of three developmental stages, 5 from adult Amur tigers (Am), and 5 from adult Bengal tigers (Bg), which were all housed in the same zoo. We investigated the diversity, richness, and composition of the bacterial microbiomes and we found that the gut microbiome of SC is strongly affected by host aging. The composition of the gut microbiome of juvenile SC experienced dramatic changes from 5 months old to 1 year old, and it showed much less difference when compared to the samples of 1 year old and the subadult. No significant differences were observed between the samples of subadult and the adult groups. The predominant phylum of 5-month-old SC is Fusobacteriota (33.99%) when the juvenile tigers were older than 5 months, and Firmicutes, but not Fusobacteriota, became the predominant phylum of bacteria in their gut. The gut microbiome of SC, Am, and Bg is possibly affected by their genetic variation; however, the core microbiome of these three subspecies is the same. Our data suggest that the gut microbiome of SC undergoes a developmental progression: a developmental phase (cub), a transitional phase (subadult), and a stable phase (adult). These results expand our understanding of the role of age in the development of the gut microbiome of SC.

Multiple renal and liver cysts in a Siberian hybrid tiger

Polycystic kidney disease (PKD) is an inherited disease commonly reported in cats, but rarely in big cats. It is associated with formation of cysts in the kidneys. This article describes the clinical, pathology and immunohistochemistry findings of PKD in a Siberian hybrid tiger. A 16-year-old female captive Siberian hybrid tiger showed inappetence, weight loss, polyuria, and polydipsia. Within six months, its body weight and hydration status were progressively declining. Although hematology parameters were normal, serum creatinine and urea levels were elevated. Ultrasonography of the kidneys showed the presence of cysts. The animal was euthanized and necropsied, revealing multiple cysts in both kidneys and liver. These samples were subjected to histopathology using routine stain, special histochemistry, and immunohistochemistry. The cysts were lined by various types of epithelial cells. Most renal tubular epithelium showed severe vacuolar degeneration, accompanied by bacterial colonies in the renal pelvis. Masson’s trichrome stain demonstrated presence of mesenchymal stroma at the periphery of the cysts in the kidneys and liver. Immunohistochemistry showed different staining intensity of β-catenin, E-cadherin, and vimentin in the various parts of renal tubules, suggesting the involvement of epithelial-mesenchymal transformation. The tiger was diagnosed with PKD based on clinical and pathological examination. This is the first report of PKD in a tiger, potentially useful for future study in wildlife medicine and conservation.

The year of the tiger and the year of tiger genomes!

Tigers are endangered apex predators. They typify endangered species because they are elusive, rare, and face numerous threats across their range. Tigers also symbolize conservation. However, it is very difficult to study tigers because of their stated nature. Also, tiger conservation is a geopolitically sensitive topic, making it difficult to use the studies to propose evidence-based management that allows their recovery, especially in the context of conservation genetics. Zhang et al. (Mol. Ecol. Resour., 2022) have created very valuable and rare resources to aid the community in conserving tigers. First, they present chromosome level genome assemblies of a South China tiger and an Amur tiger. Second, they present whole genome sequences of 16 captive South China tigers. Additionally, by using the assemblies they model the demographic history of these populations, estimate inbreeding and the potential threats they face in captivity. This approach is particularly important because genetic management is now the only remaining option for South China tigers, because they are extinct in the wild. In other words, captive individuals are our only hope for some day restoring the wild populations of South China tigers.