Probable Transmission of SARS-CoV-2 from African Lion to Zoo Employees, Indiana, USA, 2021.

We describe animal-to-human transmission of SARS-CoV-2 in a zoo setting in Indiana, USA. A vaccinated African lion with physical limitations requiring hand feeding tested positive for SARS-CoV-2 after onset of respiratory signs. Zoo employees were screened, monitored prospectively for onset of symptoms, then rescreened as indicated; results were confirmed by using reverse transcription PCR and whole-genome virus sequencing when possible. Traceback investigation narrowed the source of infection to 1 of 6 persons. Three exposed employees subsequently had onset of symptoms, 2 with viral genomes identical to the lion's. Forward contact tracing investigation confirmed probable lion-to-human transmission. Close contact with large cats is a risk factor for bidirectional zoonotic SARS-CoV-2 transmission that should be considered when occupational health and biosecurity practices at zoos are designed and implemented. SARS-CoV-2 rapid testing and detection methods for big cats and other susceptible animals should be developed and validated to enable timely implementation of One Health investigations.

Provocative tests with Kisspeptin-10 and GnRH set the scene for determining social status and environmental impacts on reproductive capacity in male African lions (Panthera leo).

Understanding the hypothalamic factors regulating reproduction facilitates maximising the reproductive success of breeding programmes and in the management and conservation of threatened species, including African lions. To provide insight into the physiology and pathophysiology of the hypothalamic-pituitary-gonadal reproductive axis in lions, we studied the luteinising hormone (LH) and steroid hormone responses to gonadotropin-releasing hormone (GnRH) and its upstream regulator, kisspeptin. Six young (13.3 ± 1.7 months, 56.2 ± 4.3 kg) and four adult (40.2 ± 1.4 months, 174 ± 6 kg) male lions (Ukutula Conservation Centre, South Africa) were used in this study. Lions were immobilised with a combination of medetomidine and ketamine and an intravenous catheter was placed in a jugular, cephalic or medial saphenous vein for blood sampling at 10-min intervals for 220 min. The ten-amino acid kisspeptin which has full intrinsic activity (KP-10, 1 µg/kg) and GnRH (1 µg/kg) were administered intravenously to study their effects on LH and steroid hormone plasma concentrations, measured subsequently by ELISA and liquid chromatography tandem mass spectrometry (LC-MS/MS), respectively. Basal LH levels were similarly low between the age groups, but testosterone and its precursor levels were higher in the adult animals. Adult lions showed a significant LH response to KP-10 (10-fold) and GnRH (11-fold) administration (p < 0.05 and P < 0.001, respectively) whereas in young lions LH increased significantly only in response to GnRH. In adults alone, testosterone and its precursors steadily increased in response to KP-10, with no significant further increase in response to GnRH. Plasma levels of glucocorticoids in response to KP-10 remained unchanged. We suggest that provocative testing of LH and steroid stimulation with kisspeptin provides a new and sensitive tool for determining reproductive status and possibly an index of exposure to stress, environmental insults such as disease, endocrine disruptors and nutritional status. 272 words.

Response of lion demography and dynamics to the loss of preferred larger prey.

Large carnivores are experiencing range contraction and population declines globally. Prey depletion due to illegal offtake is considered a major contributor, but the effects of prey depletion on large carnivore demography are rarely tested. We measured African lion density and tested the factors that affect survival using mark-recapture models fit to six years of data from known individuals in Kafue National Park (KNP), Zambia. KNP is affected by prey depletion, particularly for large herbivores that were preferred prey for KNP lions a half-century ago. This provides a unique opportunity to test whether variables that explain local prey density also affect lion survival. Average lion density within our study area was 3.43 individuals/100 km2 (95% CI, 2.79-4.23), which was much lower than lion density reported for another miombo ecosystem with similar vegetation structure and rainfall that was less affected by prey depletion. Despite this, comparison to other lion populations showed that age- and sex-specific survival rates for KNP lions were generally good, and factors known to correlate with local prey density had small effects on lion survival. In contrast, recruitment of cubs was poor and average pride size was small. In particular, the proportion of the population comprised of second-year cubs was low, indicating that few cubs are recruited into the subadult age class. Our findings suggest that low recruitment might be a better signal of low prey density than survival. Thus, describing a lion population's age structure in addition to average pride size may be a simple and effective method of initially evaluating whether a lion population is affected by prey depletion. These dynamics should be evaluated for other lion populations and other large carnivore species. Increased resource protection and reducing the underlying drivers of prey depletion are urgent conservation needs for lions and other large carnivores as their conservation is increasingly threatened by range contraction and population declines.

Dynamic interactions between apex predators reveal contrasting seasonal attraction patterns.

Apex predators play important roles in ecosystem functioning and, where they coexist, intraguild interactions can have profound effects on trophic relationships. Interactions between predators range from intraguild predation and competition to facilitation through scavenging opportunities. Despite the increased availability of fine-scale GPS data, the determinants and outcomes of encounters between apex predators remain understudied. We used simultaneous GPS data from collared spotted hyaenas (Crocuta crocuta) and African lions (Panthera leo) in Hwange National Park, Zimbabwe, to determine the environmental conditions of the encounters between the two species, which species provoked the encounter, and which species dominated the encounter. Our results show that encounters between hyaenas and lions are mostly resource-related (over a carcass or around waterholes). In the wet season, encounters mainly occur at a carcass, with lions being dominant over its access. In the dry season, encounters mainly occur in the absence of a carcass and near waterholes. Movements of hyaenas and lions before, during, and after these dry-season encounters suggest two interference scenarios: a passive interference scenario whereby both predators would be attracted to waterholes but lions would leave a waterhole used by hyaenas because of prey disturbance, and an active interference scenario whereby hyaenas would actively chase lions from waterhole areas, which are prime hunting grounds. This study highlights the seasonal dynamics of predator interactions and illustrates how the relative importance of negative interactions (interference competition during the dry season) and positive interactions (scavenging opportunities during the wet season) shifts over the course of the year.

Long live the king: chromosome-level assembly of the lion (Panthera leo) using linked-read, Hi-C, and long-read data.

BACKGROUND: The lion (Panthera leo) is one of the most popular and iconic feline species on the planet, yet in spite of its popularity, the last century has seen massive declines for lion populations worldwide. Genomic resources for endangered species represent an important way forward for the field of conservation, enabling high-resolution studies of demography, disease, and population dynamics. Here, we present a chromosome-level assembly from a captive African lion from the Exotic Feline Rescue Center (Center Point, IN) as a resource for current and subsequent genetic work of the sole social species of the Panthera clade. RESULTS: Our assembly is composed of 10x Genomics Chromium data, Dovetail Hi-C, and Oxford Nanopore long-read data. Synteny is highly conserved between the lion, other Panthera genomes, and the domestic cat. We find variability in the length of runs of homozygosity across lion genomes, indicating contrasting histories of recent and possibly intense inbreeding and bottleneck events. Demographic analyses reveal similar ancient histories across all individuals during the Pleistocene except the Asiatic lion, which shows a more rapid decline in population size. We show a substantial influence on the reference genome choice in the inference of demographic history and heterozygosity. CONCLUSIONS: We demonstrate that the choice of reference genome is important when comparing heterozygosity estimates across species and those inferred from different references should not be compared to each other. In addition, estimates of heterozygosity or the amount or length of runs of homozygosity should not be taken as reflective of a species, as these can differ substantially among individuals. This high-quality genome will greatly aid in the continuing research and conservation efforts for the lion, which is rapidly moving towards becoming a species in danger of extinction.

Cross-species transmission and evolutionary dynamics of canine distemper virus during a spillover in African lions of Serengeti National Park.

The outcome of pathogen spillover from a reservoir to a novel host population can range from a "dead-end" when there is no onward transmission in the recipient population, to epidemic spread and even establishment in new hosts. Understanding the evolutionary epidemiology of spillover events leading to discrete outcomes in novel hosts is key to predicting risk and can lead to a better understanding of the mechanisms of emergence. Here we use a Bayesian phylodynamic approach to examine cross-species transmission and evolutionary dynamics during a canine distemper virus (CDV) spillover event causing clinical disease and population decline in an African lion population (Panthera leo) in the Serengeti Ecological Region between 1993 and 1994. Using 21 near-complete viral genomes from four species we found that this large-scale outbreak was likely  ignited by a single cross-species spillover event from a canid reservoir to noncanid hosts <1 year before disease detection and explosive spread of CDV in lions. Cross-species transmission from other noncanid species probably fuelled the high prevalence of CDV across spatially structured lion prides. Multiple lines of evidence suggest that spotted hyenas (Crocuta crocuta) could have acted as the proximate source of CDV exposure in lions. We report 13 nucleotide substitutions segregating CDV strains found in canids and noncanids. Our results are consistent with the hypothesis that virus evolution played a role in CDV emergence in noncanid hosts following spillover during the outbreak, suggest that host barriers to clinical infection can limit outcomes of CDV spillover in novel host species.

A pilot study evaluating the utility of commercially available antibodies for flow cytometric analysis of Panthera species lymphocytes.

BACKGROUND: The immune response against tuberculosis in lions is still poorly defined and our understanding is hampered by the lack of lion specific reagents. The process for producing antibodies against a specific antigen is laborious and not available to many research laboratories. As the search for antibody cross-reactivity is an important strategy for immunological studies in veterinary medicine, we have investigated the use of commercially available antibodies to characterize T cell subsets in African lions (Panthera leo). RESULTS: Commercially available antibodies were screened and investigated the influence of two different sample processing methods, as well as the effect of time delay on cell surface marker expression on lion lymphocytes. Using commercially available antibodies, we were able to identify CD4+, CD5+, CD8+, CD14+, CD25+, CD44+ and CD45+ T lymphocytes in samples obtained by density gradient centrifugation as well as red cell lysis of lion whole blood. Two distinct lymphocyte populations, which differed in size and phenotype, were observed in the samples processed by density gradient centrifugation. CONCLUSION: Commercially available antibodies are able to differentiate between T lymphocyte subsets including immune effector cells in African lion whole blood, and possibly give insight into unique specie phenotypes.

Detection of Simonsiella spp. in the Vagina of Lions and Leopard in Oestrus.

Reports of the vaginal flora of wild cats such as lions or leopards are scarce. The micro-organisms most commonly found in the vagina of clinically healthy cats are aerobic bacteria such as coagulase-negative Staphylococcus, Streptococcus canis, and Escherichia coli. Simonsiella spp are large Gram-negative bacteria belonging to the Neisseriaceae family, typically found in the oral cavity and upper respiratory tract of many species. To date, there are no reports of the detection of Simonsiella spp in the vaginal flora of any felid. For a period of six months, daily behaviour monitoring was performed on six captive lionesses at a South African conservation centre, in parallel with the collection of vaginal swabs and interpretation of the resultant vaginal cytologies every other day. Oestrus was identified by typical female reproductive behaviours, as well as by enlarged and separated vulvar lips, and a predominant proportion of superficial cornified cells, clearing of the background, and high bacterial presence in the vaginal smear. Simonsiella spp were identified by their characteristic morphology in 58% (60 of 103) of the vaginal samples collected during oestrus. They were also found in oral swabs of three out of three lions tested. Additionally, Simonsiella spp were opportunistically found in a vaginal smear from a zoo housed female Sri Lankan leopard in oestrus, during a routine reproduction assessment. The finding of Simonsiella spp may be more common than previously suspected, transitory, and without detectable clinical relevance. A connection between occurrence of these bacteria and oestrus was apparent.

DIAGNOSIS AND TREATMENT OF A UNILATERAL RENAL CYSTADENOMA IN AN AFRICAN LION (PANTHERA LEO).

A renal tubular cystadenoma was diagnosed in a 14-yr-old male African lion (Panthera leo). During a routine health evaluation, a left renal mass was identified via physical examination, radiographs, and abdominal ultrasonography. The mass was 30 × 15 cm in size and had a thin capsule with central hypoechoic fluid, suggestive of a perirenal cyst. An exploratory celiotomy with partial nephrectomy was performed without complications. Histologically, the tumor was characterized by a thick fibrous capsule surrounding multiple, variable-sized cysts that markedly compressed the adjacent fibrotic and atrophied renal cortex. Immunohistochemical labeling for Aquaporin-1 and Tamm-Horsfall protein was consistent with a renal tubular cystadenoma of proximal tubule origin. Renal cystadenomas are an uncommon benign epithelial neoplasm. There are only two documented case reports in domestic cats. This report represents the first documentation, to the authors' knowledge, of a renal cystadenoma in a lion.

Mucoperiosteal exostoses in the tympanic bulla of African lions (Panthera leo).

Mucoperiosteal exostoses (MpEs) of the tympanic bulla (TB), also referred as middle-ear otoliths, have been occasionally described in dogs and cats in association with clinical signs of otitis media or as an incidental finding, but they have not been recorded in other species. In this report, we describe the radiographic, gross, and histopathologic features of MpEs in 8 African lions (Panthera leo). All animals (5 males and 3 females) were adults that had been kept in captivity and had their skeletons conserved as part of an anatomic academic collection. A radiographic study revealed mineralized structures in the TB consistent with MpEs in 7 of the 16 examined TB; a computed tomography study identified MpEs in 12 of the 16 TB. Six TB from 4 lions were sectioned, and several MpEs were demineralized for histopathologic analysis. Grossly, MpEs appeared variable in number and shape. Some were globular structures that were loosely attached to the mucosal surface of the TB; others were isolated to coalescent bone spicules extending from the mucoperiosteum. Position was also variable, but MpEs frequently developed in the hypotympanum, especially on the ventromedial aspect of the TB wall. Microscopically, MpEs were composed of osteonal bone growing from the periosteum and not by dystrophic calcification of necrotic tissue debris, as is hypothesized in dogs.

Diet quality in a wild grazer declines under the threat of an ambush predator.

Predators influence prey populations not only through predation itself, but also indirectly through prompting changes in prey behaviour. The behavioural adjustments of prey to predation risk may carry nutritional costs, but this has seldom been studied in the wild in large mammals. Here, we studied the effects of an ambush predator, the African lion (Panthera leo), on the diet quality of plains zebras (Equus quagga) in Hwange National Park, Zimbabwe. We combined information on movements of both prey and predators, using GPS data, and measurements of faecal crude protein, an index of diet quality in the prey. Zebras which had been in close proximity to lions had a lower quality diet, showing that adjustments in behaviour when lions are within short distance carry nutritional costs. The ultimate fitness cost will depend on the frequency of predator-prey encounters and on whether bottom-up or top-down forces are more important in the prey population. Our finding is the first attempt to our knowledge to assess nutritionally mediated risk effects in a large mammalian prey species under the threat of an ambush predator, and brings support to the hypothesis that the behavioural effects of predation induce important risk effects on prey populations.

Effect of ecological and anthropogenic factors on grouping patterns in African lions across Kenya.

Social carnivores frequently live in fission-fusion societies, where individuals that share a common territory or home range may be found alone, in subgroups, or altogether. Absolute group size and subgroup size is expected to vary according to resource distribution, but for species that are susceptible to anthropogenic pressures, other factors may be important drivers. African lions (Panthera leo) are the only truly social felid and lion prides are characterized by fission-fusion dynamics with social groups frequently splitting and reforming, and subgroup membership can change continuously and frequently. The number of individuals in a group can be reflective of social, ecological, and anthropogenic conditions. This dynamic behavior makes understanding lion grouping patterns crucial for tailoring conservation measures. The evolution of group living in lions has been the topic of numerous studies, and we drew on these to formulate hypotheses relating to group size and subgroup size variation. Based on data collected from 199 lion groups across eight sites in Kenya, we found that group sizes were smaller when lions were closer to human settlements, suggesting that edge effects are impacting lions at a national scale. Smaller groups were also more likely when they were far from water, and were associated with very low and very high levels of non-tree vegetation. We found significant differences between the study sites, with the Maasai Mara having the largest groups (mean ± SD = 7.7 ± 4.7, range = 1-19), and Amboseli conservation area the smallest (4.3 ± 3.5, range = 1-14). While long-term studies within a single site are well suited to thoroughly differentiate between absolute group size and subgroup size, our study provides unique insight into the correlates of grouping patterns in a vulnerable species at a national scale.

Acute myeloid leukemia with neutrophilic differentiation in a 12-year-old African lion (Panthera leo).

OBJECTIVE: To describe the clinical presentation, progression, and diagnosis of acute myeloid leukemia (AML) with neutrophilic differentiation in an African lion (Panthera leo). ANIMAL: A 12-year-old male African lion kept at a zoological institution in Colombia. CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES: The lion presented for anorexia, pale mucous membranes, and a hind limb lameness of acute onset. Feline leukemia virus testing was negative, and repeated blood samples revealed severe anemia, intermittent thrombocytopenia, lymphopenia, and neutrophilia. Coinfection with Anaplasma and Mycoplasma spp and chronic kidney disease were diagnosed based on clinicopathological findings. TREATMENT AND OUTCOME: The lion received symptomatic treatment, doxycycline, and methylprednisolone or prednisolone. Euthanasia was elected due to clinical deterioration and unresponsive anemia, despite the resolution of Anaplasma and Mycoplasma spp infections. AML with neutrophilic differentiation was diagnosed based on bone marrow cytology, histopathology, and immunohistochemistry. CLINICAL RELEVANCE: AML is a rare, aggressive hematopoietic disorder in domestic cats, although it has not yet been reported in nondomestic cats. This is the first description of the clinicopathological, histological, and immunohistochemical features of AML with neutrophilic differentiation in an FeLV-negative African lion that lacked circulating blasts.

Pulmonary Langerhans Cell Histiocytosis in an African Lion: A Rare Case Report.

BACKGROUND: Feline pulmonary Langerhans cells histiocytosis (PLCH) is a rare disorder that results in progressive respiratory failure secondary to pulmonary parenchymal infiltration with Langerhans cells (LCs). A diagnosis of PLCH is proposed based on the clinical features and pathological findings and confirmed based on the infiltrating histiocytic cells. There are few documented cases of feline PLCH, and this case report of PLCH in an African Lion could present new information and aspects of this feline histiocytic disease. CASE PRESENTATION: An African lion at Hohhot Zoo showing severe hyporexia and dyspnea with subsequent mental depression and emaciation died of exhaustion after a 35-day course of illness. Empirical treatment did not have a significant effect. An autopsy revealed that the lungs were enlarged and hardened due to infiltrative lesions, with many yellowish-white foci in all the lobes and sections. Furthermore, the kidneys were atrophied and had scattered grayish-white lesions on the surface. At the same time, congestion was widely distributed in various locations, including the liver, subcutaneous loose connective tissues, serosal surface and other tissues and organs. Histologically, proliferative histiocytic cells (PHCs) were scattered in the alveolar cavities, bronchioles and submucosa of bronchioles, with evident cellular and nuclear pleomorphism, and thus the alveolar septa were obliterated. The histopathological changes in other organs included chronic sclerosing glomerulonephritis, proliferated Kupffer cells in the liver, adrenal edema and interstitial connective tissue hyperplasia, as well as atrophy of the small intestines and spleen. Furthermore, immunohistochemical analysis results were strongly positive for CD1a, vimentin, S100 and E-cadherin in the membrane or cytoplasm of PHCs, supporting an LC phenotype. CONCLUSIONS: Here, we present a rare pulmonary Langerhans cell histiocytosis case in an African lion.

Ungulate co-occurrence in a landscape of antagonisms.

Protected areas largely now exist as coupled natural-human ecosystems where human activities are increasingly forcing wildlife to adjust behaviors. For many ungulate species that rely on protected areas for their persistence, they must balance these anthropogenic pressures amid natural regulators. Here, we investigated the pressures exerted from humans and livestock, apex predators, and within guild competitors on ungulate co-occurrence patterns in a fragile protected area complex in West Africa. Specifically, we used multi-species occupancy modeling to quantify co-occurrence among four ungulates (Tragelaphus scriptus, Redunca redunca, Kobus kob, Phacochoerus africanus) and applied structural equation models to discern the relative contributions of pressures on co-occurrence patterns. We observed a strong spatial gradient across with higher co-occurrence in the wetter western portion of our ~13,000 km2 study area. Co-occurrence patterns among ungulate dyads ranged from 0.15 to 0.49 with the smallest body sized pair showing highest levels of sympatry, warthog and reedbuck. We found that anthropogenic pressures, namely cattle had the greatest effect in reducing sympatry among wild ungulates more strongly than the presence of African lions that also exhibited negative effects. Humans, hyenas, and competitors showed positive effects on ungulate co-occurrence. In a region of the world ongoing rapid socio-ecological change with increasing threats from climate and environmental instability, protected areas in West Africa represent a major safeguard for wildlife and human livelihoods alike. Our findings highlight the need for effective interventions that focus on large carnivore conservation, habitat restoration, and containment of livestock grazing to promote the coexistence of biodiversity and socio-economic goals within the region.

Lion (Panthera leo) movements in a multiuse area of the eastern Panhandle of the Okavango Delta, Botswana.

As global large carnivore populations continue to decline due to human actions, maintaining viable populations beyond protected area (PA) borders is critical. African lions (Panthera leo) ranging beyond PA borders regularly prey on domestic livestock causing humans to retaliate or even preemptively kill lions to minimize impacts of lost livestock. To understand how lions navigate high-conflict areas in human-dominated landscapes, lions were observed and monitored in the eastern Panhandle of the Okavango Delta between October 2014 and December 2016, and five lions were fitted with GPS satellite collars from August 2015 to December 2016. Lion prides and coalitions were small, with all prides having four or fewer females and all coalitions having two or fewer males. Home range size varied between the sexes but was not statistically different (males: x¯ = 584 km2, n = 3; females: x¯ = 319 km2, n = 2). There was considerable spatial overlap in home ranges as nonassociating, neighboring collared individuals utilized high levels of shared space (female-female overlap = 152 km2, representing 41-56% of respective home ranges; male-male overlap = 125-132 km2, representing 16-31% of respective home ranges). However, neighboring lions varied use of shared space temporally as evidenced by low coefficients of association (< 0.08), avoiding potentially costly interactions with neighboring individuals. Highest levels of overlap occurred during the wet and early dry seasons when flood waters minimized the amount of available land area. All collared individuals minimized time in close proximity (< 3 km) to human habitation, but some individuals were able to rely heavily on areas where unmonitored livestock grazed. While most lions exist within PAs, anthropogenic impacts beyond PA boundaries can impact critical populations within PAs. Studying systems beyond park boundaries with high levels of human-lion conflict while also establishing conservation programs that account for both ecological and sociocultural dimensions will better aid lion conservation efforts moving forward.

African or Asiatic origin? Genome analyses solved the mystery of the hybrid origin of the rescued lion cub.

Species assignment of any seized material using DNA analysis has been a routine and widely accepted standard procedure in providing scientific advisory for the legal prosecution of wildlife cases. Scientific advancements and rigorous application of genetic tools have led to the development of a variety of molecular markers with their defined efficacy in wildlife forensics. However, in a few unusual cases where a hybrid needs to be identified or assignment need to be made at sub-species level, mitochondrial markers often fail or else provide biased results, which can affect the overall judgment in the court of law. Here, we report one such challenging case of lion cub rescued by the law enforcement from illegal trafficking. Phylogenetic assessment based on complete mitogenome assigned rescued lion cub with African lion (Panthera leo leo). However, the TSPY gene of the Y chromosome established that the lion cub shared its paternal lineage from Asiatic lion (Panthera leo persica). With the use of maternally and paternally inherited markers, we conclude a hybrid origin of the rescued lion cub which shared ancestry from both Asiatic as well as African lion. The present study exhibits the application of genome sequencing in thinking beyond routine identification and contributes to the operating procedures of wildlife forensics.

Lions in a coexistence landscape: Repurposing a traditional field technique to monitor an elusive carnivore.

Throughout Africa, lions are thought to have experienced dramatic population decline and range contraction. The greatest declines are likely occurring in human-dominated landscapes where reliably estimating lion populations is particularly challenging. By adapting a method that has thus far only been applied to animals that are habituated to vehicles, we estimate lion density in two community areas in Kenya's South Rift, located more than 100 km from the nearest protected area (PA). More specifically, we conducted an 89-day survey using unstructured spatial sampling coupled with playbacks, a commonly used field technique, and estimated lion density using spatial capture-recapture (SCR) models. Our estimated density of 5.9 lions over the age of 1 year per 100 km2 compares favorably with many PAs and suggests that this is a key lion population that could be crucial for connectivity across the wider landscape. We discuss the possible mechanisms supporting this density and demonstrate how rigorous field methods combined with robust analyses can produce reliable population estimates within human-dominated landscapes.

Current State of In Vitro Embryo Production in African Lion (Panthera leo).

In the last 30-40 years, in vitro maturation (IVM) and fertilization (IVF) of domestic cat oocytes have been established as part of the panel of assisted reproduction technologies. As a representative of wild felids, the African lion is not yet considered endangered. Nevertheless, the zoo population management of the African lion itself as well as other closely related felids would benefit from the establishment of an IVF system. Here, we aimed to investigate the transferability of domestic cat IVF technology to the African lion. From the ovaries of 42 lionesses aged between 0.75 and 15 years, a total of 933 IVF-suitable oocytes were retrieved and subjected to IVM and IVF. The overall maturation rate was 40.6% and 18.9% of these oocytes cleaved after fertilization, respectively. Embryos were generated by intracytoplasmic sperm cell injection as well as co-culture with epididymal sperm. Improvements in the model system also led to an improved outcome with in vitro produced embryos in the lion. Compared to domestic cats, the transportation of gonads to a specialized laboratory was time-consuming and influenced oocyte quality negatively. In conclusion, the domestic cat IVF system is adoptable for the African lion, although success rates are still lower.

Comparison of interferon gamma release assay and CXCL9 gene expression assay for the detection of Mycobacterium bovis infection in African lions (Panthera leo).

Mycobacterium bovis (M. bovis) infection has been identified in both domestic and wild animals and may threaten the conservation of vulnerable species including African lions (Panthera leo). There is a need to develop accurate ante-mortem tools for detection of M. bovis infection in African big cat populations for wildlife management and disease surveillance. The aim of this study was to compare the performances of two immunological assays, the QuantiFERON®-TB Gold Plus (QFT) Mabtech Cat interferon gamma release assay (IGRA) and QFT CXCL9 gene expression assay (GEA), which have both shown diagnostic potential for M. bovis detection in African lions. Lion whole blood (n=47), stimulated using the QFT platform, was used for measuring antigen-specific CXCL9 expression and IFN-γ production and to assign M. bovis infection status. A subset (n=12) of mycobacterial culture-confirmed M. bovis infected and uninfected African lions was used to compare the agreement between the immunological diagnostic assays. There was no statistical difference between the proportions of test positive African lions tested by the QFT Mabtech Cat IGRA compared to the QFT CXCL9 GEA. There was also a moderate association between immunological diagnostic assays when numerical results were compared. The majority of lions had the same diagnostic outcome using the paired assays. Although the QFT Mabtech Cat IGRA provides a more standardized, commercially available, and cost-effective test compared to QFT CXCL9 GEA, using both assays to categorize M. bovis infection status in lions will increase confidence in results.