Distribution and habitat use patterns of the endangered Central American clouded oncilla (Leopardus pardinoides oncilla) in Costa Rica.

Montane cloud forests are highly threatened ecosystems that are vulnerable to climate change. These complex habitats harbor many species that suffer the negative consequences of this global phenomenon, such as shifts in their distribution and habitat use. The Central American clouded oncilla (Leopardus pardinoides oncilla) is the smallest and most endangered wild cat in Mesoamerica and is primarily reported in cloud forests throughout its distribution. The species is poorly understood, with no studies conducted in Central America assessing its habitat preferences. To bridge this knowledge gap, we sampled two mountain ranges in Costa Rica with camera traps and conducted an occupancy analysis to understand the anthropogenic and environmental features that influence oncilla habitat use within them. Additionally, we conducted spatial predictions of habitat use across its northern and southern range in Costa Rica to identify priority conservation areas for the species. We found that Central American clouded oncilla habitat use is driven primarily by environmental factors. Our results showed that oncillas select habitats with denser tree cover at high elevations, closer to permanent water sources, which may provide them with high prey density and a favorable habitat structure for their survival. Spatial predictions identified two main regions as conservation priority areas where threat mitigation efforts and monitoring should be implemented: the Caribbean slope of the Talamanca mountains, and the Arenal-Monteverde forest complex. The occupancy modeling approach turned out to be very useful to assess the spatial associations of the species with the environment and mapping the conservation priority areas. Future research and mitigation actions should focus on potential threats that could negatively impact Central American clouded oncilla populations and habitat use, including the role of mesopredators and feral species.

First record of Hydatigera taeniaeformis in Geoffroy's cat (Leopardus geoffroyi) in Brazil.

Leopardus geoffroyi (Geoffroy's cat) is a neotropical feline considered globally threatened. In Brazil, it occurs exclusively in the Pampa biome. Its predatory habits contribute to the infection, dispersion, and continuation of the life cycle of various pathogens, including helminths, within ecosystems. However, few studies involving cestodes in wild felines are found in the literature, especially in Brazil. Therefore, we aimed to report the first case of parasitism by Hydatigera taeniaeformis in L. geoffroyi. The helminths were found in the small intestine of the necropsied feline. Specimens were analyzed morphometrically and subjected to molecular analyses for taxonomic identification. The molecular phylogeny based on the analysis of the mitochondrial gene (COX1) allowed the identification of these parasites. Thus, this is the first description of H. taeniaeformis parasitizing L. geoffroyi in Brazil. Consequently, the number of known host species parasitized by this helminth in the country and the world is increased. Additionally, a new molecular sequence is being provided, contributing to the knowledge of Hydatigera in South America.

SERIAL CHANGES IN METABOLIC ACID-BASE STATUS IN THREE SPECIES OF ANESTHETIZED CAPTIVE LARGE FELID.

Determination of acid-base status contributes important information about patient health, including for patients under anesthesia. There is a paucity of information about the determinants of acid-base status of large felids managed under anesthesia, and advancement of such knowledge may contribute to patient safety. This study serially monitored the individual metabolic acid-base status of 11 large felids, including lions (Panthera leo), tigers (Panthera tigris), and cheetahs (Acinonyx jubatus), under general anesthesia. We analyzed the contributions of measured strong ions (sodium, chloride, potassium, lactate), weak acids and buffers (albumin, phosphate and bicarbonate), and unmeasured anions to standardized extracellular base excess (SBE). A general linear model assessed for species differences in these parameters, with time since immobilization, SBE, and mean arterial pressure as covariates. By employing a Stewart-based analytical approach, it was possible to separate chloremic and unmeasured anion contributions to metabolic acid base status. This provided a basis for identifying mixed metabolic processes, generating differentials for underlying causes. Using normal acid base parameters for domestic felids, metabolic acidosis was found to be prevalent. Frequent evidence of unmeasured anion accumulation was also found, with unmeasured anions occasionally exceeding 5mmol/L. These findings warrant further inquiry into the drivers and clinical significance of metabolic acidosis and unmeasured anion accumulations in anesthetized large felids, encouraging further anion identity studies to elucidate possible causes. Reference ranges need to be established for acid-base parameters in large felids as a foundation for interpreting more controlled, prospective research into determinants of metabolic acid-base status in these animals under anesthesia.

USE OF SOLENSIA (FRUNEVETMAB) IN NONDOMESTIC FELIDS (PANTHERA TIGRIS, LYNX RUFUS, PANTHERA UNCIA) GUIDED BY PROTEIN SEQUENCE ANALYSIS.

Osteoarthritis and degenerative joint disease affect many species of nondomestic felid and negatively impact quality of life in managed care settings. Previously, pain management options were limited because of the frequency of comorbidities such as renal disease and common difficulty encountered in medication administration. SolensiaTM (frunevetmab) is a felinized monoclonal antibody that binds to nerve growth factor in arthritic joints, thereby inhibiting pain response cascades, and produces marked improvement in clinical signs and quality of life in domestic cats diagnosed with osteoarthritis. Protein sequence analysis was performed to inform the application of frunevetmab in four individuals from three nondomestic felid species (Panthera tigris, Lynx rufus, and Panthera uncia) diagnosed with degenerative joint disease to predict safety, contraindications, and likely response to treatment. Patients were then treated utilizing doses extrapolated from domestic cats and following manufacturer guidelines for administration, and clinical response was evaluated over a minimum 2-mon period. Significant improvement was noted in clinical signs in all four animals, resulting in marked improvement in mobility, lameness, activity level, demeanor, and overall quality of life. Frunevetmab presents an excellent adjunctive therapeutic alternative for nondomestic felids suffering from degenerative joint disease and may complement or decrease the need for other conventional therapeutic regimens.

Clinical and diagnostic evaluation of a wild ocelot (Leopardus pardalis) specimen.

Background: Monitoring the health of wild animals under the principles of one health contributes to the prevention of diseases and the preservation of human and animal health, thus contributing to the conservation of species. Aim: The current study describes the clinical and paraclinical status of an ocelot (Leopardus pardalis) captured in Buriticá, Antioquia, Colombia, for research purposes with the aim of contributing to the construction of animal health reference values in the wild, considering the scarcity of published data for the country on capture, management, and paraclinical parameters related to this species. Methods: For this, hematological parameters, blood chemistry, urine cytochemical analyses, and coprological examinations were carried out. Results: The hematological values of the captured individual do not show relevant differences concerning those reported in the literature in both captive and free specimens. However, differences were identified between the reference blood chemistry and urine cytochemical values between reports of animals in captivity and the wild, revealing the need to develop reference standards for animals in the wild that guarantee adequate management of these species and favor their conservation. A possible picture of renal failure and multiple parasitic infections of epidemiological importance was found. Conclusion: This study reports for the first time a urine infection by Capillaria sp. and an infection by Dicrocoelium spp. in fecal matter for the species.

Selective extraction of genomic DNA from leopard cat (Prionailurus bengalensis), hairy-crowned deer (Elaphodus cephalophus) and muntjac (Muntiacus reevesi) using hydrophobic magnetic deep eutectic solvents.

Wild animals, as a vital component of our natural world, serve a crucial role in preserving ecological equilibrium and biodiversity. By delving into the genetic constitution of wild animal populations, the evolutionary history, genetic diversity, and adaptation mechanisms could be explored, thereby informing conservation strategies and safeguarding the future of these species. In order to study the genetic information of wild animals, it is necessary to extract high purity and high concentration of wild animal genomic DNA. In this work, a hydrophobic magnetic deep eutectic solvent (HMDES) based vortexed extraction was developed for the extraction of genomic DNA from leopard cat (Prionailurus bengalensis), hairy-crowned deer (Elaphodus cephalophus) and muntjac (Muntiacus reevesi) muscle tissue, respectively. Extraction conditions like the pH value, extraction time, temperature and the amount of HMDES used were optimized by single-factor experiments. Under the optimized condition, genomic DNA could be selectively extracted from the three animal tissues. The limits of detection (LOD) and limits of quantification (LOQ) of the proposed method were 2.86 ng/µL and 8.66 ng/µL, respectively. Meanwhile, the relative standard deviation (RSD) of the method precision and repeatability were 1.64 % and 5.57 % at 20 ng/µL, showing the method has good precision and repeatability. After extraction, the DNA extracted into the HMDES droplets can be quickly recovered and the HMDES can be recycled and reused. The method proposed is a fast, environmental-friendly and high efficient extraction strategy for purification and enrichment of genomic DNA from leopard cat, hairy-crowned deer and muntjac tissues.

Molecular detection using hybridization capture and next-generation sequencing reveals cross-species transmission of feline coronavirus type-1 between a domestic cat and a captive wild felid.

Feline coronavirus (FCoV) infection normally causes mild or subclinical signs and is common in domestic cats. However, in some cats, FCoV infection can also lead to the development of feline infectious peritonitis (FIP)-a typically lethal disease. FCoV has two serotypes or genotypes, FCoV-1 and FCoV-2, both of which can cause FIP. The main difference between the genotypes is the viral spike (S) protein that determines tropism and pathogenicity, crucial mechanisms in the development of FIP. Subclinical infection and FIP have both been reported in wild felids, including in threatened species. Due to the high genetic variability of the S gene and the technical challenges to sequencing it, detection and characterization of FCoV in wild felids have mainly centered on other more conserved genes. Therefore, the genotype causing FIP in most wild felids remains unknown. Here, we report a retrospective molecular epidemiological investigation of FCoV in a zoological institution in the U.Ss. In 2008, a domestic cat (Felis catus) and a Pallas' cat (Otocolobus manul) sharing the same room succumbed to FIP. Using in situ hybridization, we detected FCoV RNA in different tissues of both felids. Using hybridization capture and next-generation sequencing, we detected, sequenced, and characterized the whole genome of the FCoV infecting both felids. Our data show for the first time that FCoV-1 can be transmitted between domestic and wild felids and extends the known host range of FCoV-1. Our findings highlight the importance of identifying the genotype causing FIP, to develop effective control measures. IMPORTANCE: Feline coronavirus (FCoV) is highly prevalent in domestic cats worldwide and has also been reported in wild felids, including endangered species, in which it has caused substantial population declines. Characterizing the genetic diversity of FCoV is crucial due to recent reports of novel pathogenic recombinant variants causing high mortality in feral cats in Cyprus. In this retrospective molecular epidemiology study, we used archived samples collected in a zoological institution in the U.S. in which a domestic and a wild felid succumbed to FCoV. Using hybridization capture (HC) and next-generation sequencing, we show for the first time that FCoV can be naturally transmitted between domestic and wild felids. We demonstrate the efficacy of HC for detecting and sequencing the whole genome of FCoV, which is essential to characterize its different genotypes.

Protein quality of a small mammal prey and its body organs for felids.

This study evaluated the protein quality of small mammalian prey and its body organs by analyzing amino acid (AA) composition and digestibility of wild adult rats and their body organs (skin/fur, bone, muscle, intestine, liver, kidney, spleen, brain, heart, and lung) utilizing an in vitro digestion method. The average dry matter (DM) digestibility of whole rats was 89.9%. The digestibility of total AA (TAA), total indispensable AA (TIAA), and total dispensable AA (TDAA) in whole rats was 85.6, 87.0, and 87.6%, respectively. Differences in DM digestibility were observed among rat organs, ranging from 59.0% in bone to 99.8% in muscle (P < 0.001). Highly digestible organs generally exhibited AA digestibility exceeding 90%, except for cysteine (Cys) in the intestine and kidney (83.8% and 88.9%, respectively). The digestibility of AAs in skin/fur ranged from 19.7% for Cys to 81.0% for glycine (Gly). In bone, the digestibility spanned from 56.9% for Gly to 81.1% for tyrosine (Tyr). Additionally, examining the digestible indispensable AA score (DIAAS) gives us an idea of the protein quality of small mammalian prey and their body organs. Our results complement information on AA supply and digestion during prey ingestion by felids.

As obligate carnivores, free-ranging felids consume prey and rely on nutrients from animal organs. Studies in adult carnivores such as domestic cats have demonstrated the importance of the dietary amino acid profile. Therefore, this research used rats as a small prey model to analyze the amino acid composition and digestibility of whole prey and its body organs through in vitro digestion methods. Our results add information on amino acid supply and digestion during natural food intake in felids.

High-resolution computed tomographic (HRCT) image series from 413 canid and 18 felid skulls.

Computed tomography (CT) is a non-invasive, three-dimensional imaging tool used in medical imaging, forensic science, industry and engineering, anthropology, and archaeology. The current study used high-resolution medical CT scanning of 431 animal skulls, including 399 dog skulls from 152 breeds, 14 cat skulls from 9 breeds, 14 skulls from 8 wild canid species (gray wolf, golden jackal, coyote, maned wolf, bush dog, red fox, Fennec fox, bat-eared fox), and 4 skulls from 4 wild felid species (wildcat, leopard, serval, caracal). This comprehensive and unique collection of CT image series of skulls can provide a solid foundation not only for comparative anatomical and evolutionary studies but also for the advancement of veterinary education, virtual surgery planning, and the facilitation of training in sophisticated machine learning methodologies.

Cytauxzoon brasiliensis sp. nov. (Apicomplexa: Theileriidae), a new species infecting a little-spotted-cat (Leopardus tigrinus) (Carnivora: Felidae) from Brazil.

Cytauxzoon spp. have been detected in Brazil infecting mainly asymptomatic domestic cats and wild felids. However, the supposed genetic similarity with the pathogenic Cytauxzoon felis is questionable because it is based on analysis of short sequences of the 18S rRNA gene. Herein, we describe a novel Cytauxzoon species infecting an asymptomatic little-spotted-cat (Leopardus tigrinus) based on morphological, histopathological, and molecular analyses. The animal was attended presenting a history of a run-over with multiple traumas. Although the little-spotted-cat was stabilized, he died a few days later. Ring-shaped merozoites within erythrocytes were found on blood smears and in the abdominal effusion. In addition, schizonts were observed in histiocytes in the liver. Phylogenetic analyses based on both near-complete 18S rRNA and cytb genes positioned the obtained sequences in a unique clade, albeit closely related to Cytauxzoon felis from the USA. Genetic divergences ranging from 0.004 and 0.067-0.068 were found between the near-complete 18S rRNA and cytb sequences of Cytauxzoon sp. detected in the little-spotted-cat and C. felis, respectively. This study evidenced the circulation of a novel Cytauxzoon species, herein named Cytauxzoon brasiliensis sp. nov., in an asymptomatic wild felid species from Brazil. Further studies are necessary to identify Cytauxzoon species from domestic and wild felids in the country.

Evolution: Bridging the sabertooth gap(e).

Saber-toothed felids are models of how extreme biomechanical specialization can evolve. A new study reveals a continuous morphological spectrum between sabertooths and modern cats, with specialization acting as a macroevolutionary ratchet.

Evolutionary patterns of cat-like carnivorans unveil drivers of the sabertooth morphology.

The sabertooth morphology stands as a classic case of convergence, manifesting recurrently across various vertebrate groups, prominently within two carnivorans clades: felids and nimravids. Nonetheless, the evolutionary mechanisms driving these recurring phenotypes remain insufficiently understood, lacking a robust phylogenetic and spatiotemporal framework. We reconstruct the tempo and mode of craniomandibular evolution of Felidae and Nimravidae and evaluate the strength of the dichotomy between conical and saber-toothed species, as well as within saber-toothed morphotypes. To do so, we investigate morphological variation, convergence, phenotypic integration, and evolutionary rates, employing a comprehensive dataset of nearly 200 3D models encompassing mandibles and crania from both extinct and extant feline-like carnivorans, spanning their entire evolutionary timeline. Our results reject the hypothesis of a distinctive sabertooth morphology, revealing instead a continuous spectrum of feline-like phenotypes in both the cranium and mandible, with sporadic instances of unequivocal convergence. Disparity peaked at the end of the Miocene and is usually higher in clades containing taxa with extreme sabertoothed adaptations. We show that taxa with saberteeth exhibit a lower degree of craniomandibular integration, allowing to exhibit a greater range of phenotypes. Those same groups usually show a burst of morphological evolutionary rate at the beginning of their evolutionary history. Consequently, we propose that a reduced degree of integration coupled with rapid evolutionary rates emerge as key components in the development of a sabertooth morphology in multiple clades.

Two Lineages of Papillomaviruses Identified from Caracals (Caracal caracal) in South Africa.

Papillomaviruses (PV) infect epithelial cells and can cause hyperplastic or neoplastic lesions. In felids, most described PVs are from domestic cats (Felis catus; n = 7 types), with one type identified in each of the five wild felid species studied to date (Panthera uncia, Puma concolor, Leopardus wiedii, Panthera leo persica and Lynx rufus). PVs from domestic cats are highly diverse and are currently classified into three genera (Lambdapapillomavirus, Dyothetapapillomavirus, and Taupapillomavirus), whereas those from wild felids, although diverse, are all classified into the Lambdapapillomavirus genus. In this study, we used a metagenomic approach to identify ten novel PV genomes from rectal swabs of five deceased caracals (Caracal caracal) living in the greater Cape Town area, South Africa. These are the first PVs to be described from caracals, and represent six new PV types, i.e., Caracal caracal papillomavirus (CcarPV) 1-6. These CcarPV fall into two phylogenetically distinct genera: Lambdapapillomavirus, and Treisetapapillomavirus. Two or more PV types were identified in a single individual for three of the five caracals, and four caracals shared at least one of the same PV types with another caracal. This study broadens our understanding of wild felid PVs and provides evidence that there may be several wild felid PV lineages.

Comparative anatomy of the caudate nucleus in canids and felids: Associations with brain size, curvature, cross-sectional properties, and behavioral ecology.

The evolutionary history of canids and felids is marked by a deep time separation that has uniquely shaped their behavior and phenotype toward refined predatory abilities. The caudate nucleus is a subcortical brain structure associated with both motor control and cognitive, emotional, and executive functions. We used a combination of three-dimensional imaging, allometric scaling, and structural analyses to compare the size and shape characteristics of the caudate nucleus. The sample consisted of MRI scan data obtained from six canid species (Canis lupus lupus, Canis latrans, Chrysocyon brachyurus, Lycaon pictus, Vulpes vulpes, Vulpes zerda), two canid subspecies (Canis lupus familiaris, Canis lupus dingo), as well as three felids (Panthera tigris, Panthera uncia, Felis silvestris catus). Results revealed marked conservation in the scaling and shape attributes of the caudate nucleus across species, with only slight deviations. We hypothesize that observed differences in caudate nucleus size and structure for the domestic canids are reflective of enhanced cognitive and emotional pathways that possibly emerged during domestication.

Identification and genomic characterization of feline calicivirus from a leopard cat (Prionailurus bengalensis) in Taiwan.

The leopard cat (Prionailurus bengalensis) is an endangered wildlife that is protected under Taiwan's regulations. The body of a road-killed leopard cat was found to contain sequences of feline calicivirus (FCV), designated W109-1443. Analysis of the complete genomic sequence revealed that it shared approximately 81% similarity with a Chinese strain of FCV found in a domestic cat. Phylogenetic analysis of the VP1 gene indicated that the W109-1443 isolate belonged to genogroup II. Recombination analysis revealed that the W109-1443 isolate may have resulted from recombination between two FCV strains. Given the potential impact of FCV on the health and survival of wild felids, further investigation is necessary to assess its pathogenicity in the leopard cat population.

Dirofilaria immitis and Onchocercidae spp. in wild felids from Brazil.

Among the species described within the Onchocercidae family, Dirofilaria immitis is regarded as the most common worldwide, causing severe and often fatal conditions in dogs, cats, and occasionally humans. Dirofilaria spp. are vectored by mosquitoes, simulids, and culicoids, with their epidemiology dependent on the geographical distribution of competent vectors. Eight species of Dirofilaria have been reported so far in Brazil, of which six parasitize non-human primates, deer, procyonids, and marsupials. Here, we investigated the occurrence of Onchocercidae in wild felids (i.e., Panthera onca, Puma concolor, Herpailurus yagouaroundi, Leopardus geoffroyi, Leopardus guttulus, Leopardus pardalis, Leopardus wiedii, Leopardus munoai) from different locations in Brazil. Overall, 82 samples (n = 63 blood; n = 19 tissues) were molecularly screened for cytochrome c oxidase subunit-1 (cox1) gene. Four (i.e., 4.8%) wild felid samples were positive, and at BLAST analysis, the obtained sequences showed varying percentage of nucleotide identity with the genera Brugia (i.e., 87-88%), Setaria (i.e., 89%), and D. immitis (i.e., 94.4%). Phylogenetic analyses clustered sequences obtained into three distinct clades, one with D. immitis and the remaining two with other Onchocercidae spp. Data herein obtained highlight the need for a more comprehensive understanding of the diversity and biology of Onchocercidae in South America in order to assess the potential impact that these species may have for domestic and wild animals, as well as humans.

NONDOMESTIC FELID ABC BLOOD PHENOTYPING, GENOTYPING, AND CROSSMATCHING.

Based upon previous clinical experience with domestic cats (Felis catus), the ability to assess ABC blood types and blood (in-)compatibilities of nondomestic felids, and adequately consider and plan for blood transfusions, may be important. Although nondomestic felids appear to have an ABC blood group system similar to domestic cats, typing with point-of-care kits and by CMAH genotyping for domestic cats have not been reported. In this study, 162 blood samples from 18 different nondomestic felid species (cheetah [Acinonyx jubatus, n = 42], lion [Panthera leo, n = 33], tiger [Panthera tigris, n = 23], Canada lynx [Lynx canadensis, n = 11], snow leopard [Uncia uncia, n = 10], puma [Puma concolor, n = 7], clouded leopard [Neofelis nebulosa, n = 6], serval [Leptailurus serval, n = 5], jaguar [Panthera onca, n = 5], fishing cat [Prionailurus viverrinus, n = 4], Pallas cat [Felis manul, n = 3], bobcat [Lynx rufus, n = 3], ocelot [Leopardus pardalis, n = 3], black footed cat [Felis nigripes, n = 2], leopard [Panthera pardus, n = 2], African wildcat [Felis lybica, n = 1], caracal [Caracal caracal, n = 1], and sand cat [Felis margarita, n = 1]) were ABC blood typed by laboratory and point-of-care tests, genotyped for four known CMAH variants for type B and type C (AB) phenotypes, and crossmatched with one another and domestic type A cats. Traditional tube typing identified blood type A (n = 106), type B (n = 8), type C (n = 43), and no discernible ABC type (n = 4). Several discrepancies were found between point-of-care and traditional typing test results. None of the tested felids possessed the four CMAH variants responsible for type B and C (AB) in domestic cats. Crossmatch incompatibilities (≥2+ agglutination) were identified within and between nondomestic felid species and beyond ABC incompatibilities. Of 26 crossmatches performed between domestic cats and various nondomestic felids, only 7 (27%) were compatible. In conclusion, point-of-care typing kits and CMAH genotyping, successfully used in domestic cats, may not identify the correct ABC blood type in nondomestic felids. Prior crossmatching is recommended to increase the likelihood of compatible transfusions between any nondomestic felids.

Fleas of wild carnivores in Romania: diversity, distribution, and host-associations.

BACKGROUND: Fleas are important hematophagous insects, infesting mammals and birds with a worldwide distribution. Fleas of medical importance have been reported from various carnivores worldwide, such as felids, canids, or mustelids. Romania hosts a wide carnivore diversity, but very little is known about flea species that parasitize these animals in Romania. This study aimed to provide a better understanding of the fleas' diversity and their distribution in a relatively large and diverse number of wild carnivore hosts from Romania. METHODS: From 2013 to 2021, 282 carcasses of wild carnivores from different locations in Romania were collected and examined for the presence of ectoparasites. All collected fleas were morphologically identified using specific keys and descriptions. An analysis of the co-occurrence networks was performed. RESULTS: A total of 11 flea species were identified: Pulex irritans (41.09%), Paraceras melis (20.11%), Ctenocephalides felis (7.33%), Ctenocephalides canis (7.83%), Monopsyllus sciurorum (11.11%), Chaetopsylla trichosa (21.96%), Chaetopsylla homoea (5.5%), Chaetopsylla tuberculaticeps (100%), Chaetopsylla rothschildi (13.33%), Chaetopsylla sp. (14.34%), Chaetopsylla globiceps (5.12%), Echidnophaga gallinacea (10%). The statistical analyses showed a significant difference between the infestation of Martes foina with females being more frequently infected than males (66% versus 33%). Paraceras melis infesting Meles meles had a significantly higher prevalence in female badgers than in males (× 2 = 7.7977, P < 0.01) and higher intensities of infestations in males than in females (t = 1.871, P < 0.05). CONCLUSIONS: This is the first large-scale study investigating the distribution and diversity of flea species infesting wild carnivores in Romania. Three flea species were identified for the first time in Romania (E. gallinacea, C. homoea, and C. tuberculaticeps).

Mortality associated with SARS-CoV-2 in nondomestic felids.

Between September and November 2021, 5 snow leopards (Panthera uncia) and 1 lion (Panthera leo) were naturally infected with severe acute respiratory coronavirus 2 (SARS-CoV-2) and developed progressive respiratory disease that resulted in death. Severe acute respiratory syndrome coronavirus 2 sequencing identified the delta variant in all cases sequenced, which was the predominant human variant at that time. The time between initial clinical signs and death ranged from 3 to 45 days. Gross lesions in all 6 cats included nasal turbinate hyperemia with purulent discharge and marked pulmonary edema. Ulcerative tracheitis and bronchitis were noted in 4 cases. Histologically, there was necrotizing and ulcerative rhinotracheitis and bronchitis with fibrinocellular exudates and fibrinosuppurative to pyogranulomatous bronchopneumonia. The 4 cats that survived longer than 8 days had fungal abscesses. Concurrent bacteria were noted in 4 cases, including those with more acute disease courses. Severe acute respiratory syndrome coronavirus 2 was detected by in situ hybridization using probes against SARS-CoV-2 spike and nucleocapsid genes and by immunohistochemistry. Viral nucleic acid and protein were variably localized to mucosal and glandular epithelial cells, pneumocytes, macrophages, and fibrinocellular debris. Based on established criteria, SARS-CoV-2 was considered a contributing cause of death in all 6 cats. While mild clinical infections are more common, these findings suggest that some SARS-CoV-2 variants may cause more severe disease and that snow leopards may be more severely affected than other felids.

Catcalls: exotic cats discriminate the voices of familiar caregivers.

Background: The ability to differentiate familiar from unfamiliar humans has been considered a product of domestication or early experience. Few studies have focused on voice recognition in Felidae despite the fact that this family presents the rare opportunity to compare domesticated species to their wild counterparts and to examine the role of human rearing. Methods: We tested whether non-domesticated Felidae species recognized familiar human voices by exposing them to audio playbacks of familiar and unfamiliar humans. In a pilot study, we presented seven cats of five species with playbacks of voices that varied in familiarity and use of the cats' names. In the main study, we presented 24 cats of 10 species with unfamiliar and then familiar voice playbacks using a habituation-dishabituation paradigm. We anticipated that human rearing and use of the cats' names would result in greater attention to the voices, as measured by the latency, intensity, and duration of responses regardless of subject sex and subfamily. Results: Cats responded more quickly and with greater intensity (e.g., full versus partial head turn, both ears moved versus one ear twitching) to the most familiar voice in both studies. They also responded for longer durations to the familiar voice compared to the unfamiliar voices in the main study. Use of the cats' name and rearing history did not significantly impact responding. These findings suggest that close human contact rather than domestication is associated with the ability to discriminate between human voices and that less social species may have socio-cognitive abilities akin to those of more gregarious species. With cats of all species being commonly housed in human care, it is important to know that they differentiate familiar from unfamiliar human voices.