European Zoos Research Articles

Inactivated Toxoplasma gondii nanovaccine boosts T-cell memory response in a seropositive Yellow-footed rock wallaby (Petrogale xanthopus) – a case report from Copenhagen Zoo

Toxoplasma gondii is a ubiquitous parasite causing significant mortality in captive wildlife, especially marsupials. Historically, treatment has been unrewarding and no vaccine was available. An intranasal vaccine based on purified inactivated T. gondii was developed for toxoplasmosis prevention. A vaccination campaign started in early 2017 and was successful in preventing toxoplasma-related mortality in marsupials in many European and South American zoos. Amongst the vaccinated wallabies, about 30% were T. gondii seropositive before the vaccination, and no toxoplasma-related deaths were observed since the administration of the vaccine. The objective of this case study was to assess the potential effect of the vaccination on a seropositive wallaby. It is important to note that this vaccine doesn’t induce any humoral response in sheep, and squirrel monkeys but induces a strong T-cell response. A T. gondii seropositive Yellow-footed rock wallaby (Petrogale xanthopus) from Copenhagen Zoo received two doses of the aforementioned intranasal vaccine. Blood samples were collected before each vaccination and used for peripheral blood mononuclear cell isolation. The impact of the vaccination on the lymphocyte phenotype was characterized by flow cytometry. Cell size, represented by forward scatter, and granularity, represented by side scatter parameters were analyzed. Two doses of the vaccine induced a respective 30.1 and 25.6% increase in cell size and granularity in lymphocytes stimulated with T. gondii antigens, as assessed by flow cytometry. These changes were likely correlated with T-cell activation, which indicates that two doses of the vaccine might have boosted the already-existing T-cell memory response against T. gondii in a seropositive animal. No morphological changes were observed in lymphocytes from an unvaccinated seronegative wallaby. This is the first documented case of boosting an already-existing cellular immune response against toxoplasmosis by the vaccine in a seropositive Yellow-footed rock wallaby.

Liver and Let Die? A Retrospective Analysis of Secretarybird Mortality in European Zoos.

The secretarybird (Sagittarius serpentarius) is a threatened African raptor species, and as such requires conservation attention. While the species is managed under a European Association of Zoos and Aquaria (EAZA) Ex-situ Programme (EEP), no studies of mortality are currently available. A retrospective mortality project was therefore conducted to identify the most common causes of death in captive secretarybirds, with a view to informing management decisions. Data were collected by requesting the postmortem reports from zoos where secretarybirds had died and combining this with the existing data recorded in the Zoological Information Management System. Overall, 167 birds were recorded as having died within the EEP population, of which post-mortem information was available for 51 (30.54%) individuals. Trauma was the most common cause of death identified (22 birds, 13.17%), with infection appearing as the second most prevalent cause (15 birds, 8.98%). One incidental finding at postmortem was that many (9) birds showed evidence of liver damage, with reports of bacterial hepatitis, staphylococcal infection, lesions, and dark coloration. Further research into liver complications and diet composition for secretarybirds may therefore have value in reducing mortality. Similarly, investigating strategies to reduce trauma caused by other enclosure occupants or conspecifics may have value in lengthening lifespans for this endangered species.

Morphological and molecular characterisation of the nematode parasite Graphidioides affinis (Secernentea: Trichostrongylidae) in Patagonian maras, Dolichotis patagonum, kept in a zoo in Sofia, Bulgaria

Abstract Introduction Patagonian maras, rodents endemic to South America, are classified as a near-threatened species. Various factors affect their health including parasitic diseases. The aim of this study was to perform morphometric, molecular and phylogenetic characterisation of one such parasitic disease agent, the nematode Graphidioides affinis, specimens of which were found in captive Patagonian maras. Material and Methods In March 2023, 18 Patagonian maras kept at the Sofia Zoo in Bulgaria were investigated with the use of coprological methods. Following the investigation, the animals were dewormed with the use of albendazole. Dead adult nematodes found in the faeces of dewormed maras were collected and preserved in 70% ethanol, and morphometrically, molecularly and phylogenetically analysed. Results The morphometric analyses confirmed the nematodes to be Graphidioides affinis. The partial nucleotide sequences of the small subunit ribosomal rDNA (SSU), the internal transcribe spacer 2 (ITS2) and the large subunit ribosomal DNA (LSU) of G. affinis were obtained. These are the first available nucleotide sequences of this parasite. The phylogenetic analyses of the species showed its distinctiveness in comparison to other gastrointestinal nematodes, as it was grouped separately. Conclusion The Patagonian maras kept in a European zoo retained their original parasitofauna which are related to South America.

Present status and trends of “ex situ” Cercopithecinae monkey populations worldwide

Primates are one of the most threatened mammalian taxa and are also one of the most commonly exhibited in zoological gardens. The information from the Zoological Information Management System (ZIMS) was used to provide an overview of the species of Primates belonging to the subfamily Cercopithecinae currently held in zoos. A total of 56 species (71.79 %) are kept in ZIMS institutions. Of these, 27 (48.31 %) are threatened. Zoos do not show any preference in keeping threatened species or non-threatened ones. In the case of threatened species, only five of them are represented by more than 200 individuals while the non-threatened ones are nine. In the past 12 months, 17 non-threatened species and 16 threatened ones managed to breed. At a regional level, Asia, Europe, and North America have the highest number of species however the highest number of individuals is found in European zoos which also have a higher rate of threatened individuals to non-threatened ones. The population trends of the last 20 years indicate that Europe has the highest number of increased threatened populations (10) followed by Asia (eight) and North America (four). The latter features the highest number of increased non-threatened populations (11). Europe has the highest number of decreased threatened and non-threatened populations (16 and 17) whilst North America lost the highest number of species in the last 20 years. The analysis indicates that European zoos are at the forefront of the ex situ conservation of threatened Cercopithecinae. Although trends in zoo design and philosophy make unlikely a future increase of space for threatened cercopithecids, a better integration of conservation priorities in zoos’ master planning process may arrest the decline of space available to threatened taxa.

Current social management practices contribute to reproductive failure in zoo-housed guenons

Recent emphasis on reflecting natural behaviour and wild group composition in zoo-housed social animals has resulted in substantial improvement in captive breeding and welfare. We investigated studbook data for four guenon species housed in European zoos to assess the role of zoo management practices in the reproductive success of social species. We hypothesized that group dynamics reflecting wild living, including early social experience, would be associated with greater reproductive success. Our findings are presented in a standardized qualitative risk assessment with an additional certainty measure in the form of literature evidence. We found that greater reproductive success was associated with more potential breeding partners in L’Hoest’s, Roloway and Diana monkeys and with larger group sizes in all species studied here, providing support that mimicking wild group size, composition, and dynamics under captive conditions can improve reproductive success. Unexpectedly, greater reproductive success was associated with earlier first inter-facility transfers in female L’Hoest’s and Diana monkeys, and with more frequent inter-facility transfers in male L’Hoest’s and Diana monkeys. Furthermore, for male Diana monkeys and female and male L’Hoest’s monkeys, mothers with less reproductive and rearing experience tended to produce offspring that in turn had greater reproductive success, hinting at more complex and sex-differentiated mechanisms underlying sub-optimal reproduction in zoo guenons. Our findings highlight the importance of carrying out species-specific studies, and demonstrate that zoo management and husbandry practices can inadvertently impact reproductive success. We recommend that zoos holding guenons consider reducing the number of guenon species they hold in favour of increasing group size to improve reproductive success.

GUT MICROBIOME DIVERSITY OF THREE RHINOCEROS SPECIES IN EUROPEAN ZOOS.

The wild rhinoceros populations have declined drastically in the past decades because the rhinoceros are heavily hunted for their horns. Zoological institutions aim to conserve rhinoceros populations in captivity, but one of the challenges of ex situ conservation is to provide food sources that resemble those available in the wild. Considering that the mammalian gut microbiota is a pivotal player in their host's health, the gut microbiota of rhinoceros may also play a role in the bioavailability of nutrients. Therefore, this study aims to characterize the fecal microbiome composition of grazing white rhinoceros (WR; Ceratotherium simum) and greater one-horned rhinoceros (GOHR; Rhinoceros unicornis) as well as the browsing black rhinoceros (BR; Diceros bicornis) kept in European zoos. Over the course of 1 yr, 166 fecal samples in total were collected from 9 BR (n = 39), 10 GOHR (n = 56), and 14 WR (n = 71) from 23 zoological institutions. The bacterial composition in the samples was determined using 16S rRNA gene Illumina sequencing. The fecal microbiomes of rhinoceros clustered by species, with BR clustering more distantly from GOHR and WR. Furthermore, the data report clustering of rhinoceros microbiota according to individual rhinoceros and institutional origin, showing that zoological institutions play a significant role in shaping the gut microbiome of rhinoceros species. In addition, BR exhibit a relatively higher microbial diversity than GOHR and WR. BR seem more susceptible to microbial gut changes and appear to have a more diverse microbiome composition among individuals than GOHR and WR. These data expand on the role of gut microbes and can provide baseline data for continued efforts in rhinoceros conservation and health status.

Demographic and conservation genomic assessment of the threatened marbled teal (Marmaronetta angustirostris).

Genetic assessment of species that have experienced dramatic population declines provides critical information that is instrumental for the design of conservation recovery programs. Here, we use different sources of molecular data (mtDNA and ddRAD-seq) to evaluate the genetic status of wild and captive populations of marbled teal (Marmaronetta angustirostris), a duck species classified as critically endangered in Spain and near threatened at a global scale. First, we determined the evolutionary and demographic trajectories of the wild population from Spain and the currently much larger population from Iraq, which is also the documented source of European zoo stocks. Second, we evaluated the suitability of the different captive populations for ongoing restocking programs in Spain and assessed their potential impact on the genetic composition of wild populations. Populations from Spain and Iraq were assigned to distinct genetic clusters, albeit with an overall low level of genetic differentiation, in line with their recent divergence (<8000 years ago) and lack of phylogeographic structure in the species. Demogenomic inferences revealed that the two populations have experienced parallel demographic trajectories, with a marked bottleneck during the last glacial period followed by a sudden demographic expansion and stability since the onset of the Holocene. The wild population from Spain presented high levels of inbreeding, but we found no evidence of recent genetic bottlenecks compatible with the human-driven decline of the species during the past century. The captive populations from the two Spanish centers involved in restocking programs showed genetic introgression from European zoos; however, we found limited evidence of introgression from the zoo genetic stock into the wild population from Spain, suggesting captive-bred birds have limited breeding success in the wild. Our study illustrates how ex situ conservation programs should consider the genetic distinctiveness of populations when establishing breeding stocks and highlights the importance of genetically assessing captive populations prior to reinforcement actions.

Admixture and reproductive skew shape the conservation value of ex situ populations of the Critically Endangered eastern black rhino

Small populations of endangered species risk losing already eroded genetic diversity, important for adaptive potential, through the effects of genetic drift. The magnitude of drift can be mitigated by maximising the effective population size, as is the goal of genetic management strategies. Different mating systems, specifically those leading to reproductive skew, exacerbate genetic drift by distorting contributions. In the absence of an active management strategy, reproductive skew will have long-term effects on the genetic composition of a population, particularly where admixture is present. Here we examine the contrasting effects of conservation management strategies in two ex situ populations of the Critically Endangered eastern black rhino (Diceros bicornis michaeli), one managed as a semi-wild population in South Africa (SAx), and one managed under a mean-kinship breeding strategy in European zoos. We use molecular data to reconstruct pedigrees for both populations and validate the method using the zoo studbook. Using the reconstructed pedigree and studbook we show there is male sex-specific skew in both populations. However, the zoo’s mean-kinship breeding strategy effectively reduces reproductive skew in comparison to a semi-wild population with little genetic management. We also show that strong male reproductive skew in SAx has resulted in extensive admixture, which may require a re-evaluation of the population’s original intended role in the black rhino meta-population. With a high potential for admixture in many ex situ populations of endangered species, molecular and pedigree data remain vital tools for populations needing to balance drift and selection.

Design and test of novel scent enrichments to enhance breeding of zoo-housed lemurs.

Zoos use environmental enrichments, including scents, which may have applications to improve breeding success for taxa, such as lemurs, which rely heavily on olfactory communication. We aimed to develop novel, biologically-relevant scent enrichments to trigger mating behaviours of zoo-housed lemur species, which are critically endangered in the wild and show a low success rate in captive breeding programmes. We examined anogenital odour secretions, released by female gentle ( Hapalemur alaotrensis) and ruffed ( Varecia variegata) lemurs, using solid-phase microextraction and gas chromatography-mass spectrometry techniques. We identified the key compounds distinguishing the volatile chemical profile of female lemurs during the breeding season and used them to develop species-specific scent enrichments. We then tested the scent enrichments, made up of synthesized mixtures conveying information about female lemur fertility, on unsuccessful breeding pairs of lemurs hosted in European zoos. We evaluated the effects of the newly designed scent enrichments on their target species by combining behavioural observations with faecal endocrinology. We identified and reproduced fertility-specific signals associated with female scents. These scent mixtures triggered male sexual behaviours, including mating, during and after the enrichment condition. We also found effects on faecal testosterone levels, with increased levels after the enrichment condition albeit not statistically significant. Our findings suggest that biologically-relevant scent enrichments may trigger natural species-specific behaviours, with potential implications for conservation breeding of zoo-based endangered lemur species, and highlight that combining more assessment methods may assist with evaluating the impact of environmental enrichments.

Low gH/gL (Sub)Species-Specific Antibody Levels Indicate Elephants at Risk of Fatal Elephant Endotheliotropic Herpesvirus Hemorrhagic Disease.

Elephant endotheliotropic herpesviruses (EEHVs), of which eleven (sub)species are currently distinguished, infect either Asian (Elephas maximus) or African elephants (Loxodonta species). While all adult elephants are latently infected with at least one EEHV (sub)species, young elephants, specifically those with low to non-detectable EEHV-specific antibody levels, may develop fatal hemorrhagic disease (EEHV-HD) upon infection. However, animals with high antibody levels against EEHV(1A) gB, an immunodominant antigen recognized by antibodies elicited against multiple (sub)species, may also occasionally succumb to EEHV-HD. To better define which animals are at risk of EEHV-HD, gB and gH/gL ELISAs were developed for each of the Asian elephant EEHV subspecies and assessed using 396 sera from 164 Asian elephants from European zoos. Antibody levels measured against gB of different (sub)species correlated strongly with one another, suggesting high cross-reactivity. Antibody levels against gH/gL of different subspecies were far less correlated and allowed differentiation between these (sub)species. Importantly, while high gB-specific antibody levels were detected in the sera of several EEHV-HD fatalities, all fatalities (n = 23) had low antibody levels against gH/gL of the subspecies causing disease. Overall, our data indicate that (sub)species-specific gH/gL ELISAs can be used to identify animals at risk of EEHV-HD when infected with a particular EEHV (sub)species.

Incorporating Art Events Into Marketing Activities - Good Practice By European Zoos

Abstract Research purpose. In today's business world and for over a hundred years, art events have been used to develop a brand, promote awareness, and increase the number of customers. Art is a useful tool for a company to promote and advertise its products. As some authors mentioned, arts can enhance the company's image: in marketing and selling, art can brand a company's culture and products; arts can also act as a social connector in the workplace and beyond and in marketing, art can brand a company's culture and products, it helps to further community relations (Anderson, 2017). Companies can use not only art events to attract customers and diversify target audiences but also institutions such as zoos. Attracting visitors through art events is especially important for those zoos that cannot afford rare animal species or special spaces and landscapes. Nowadays, most cultural activities in zoos are done under the educational programs - educational activities provided by zoos not only concern animals, biodiversity and the environment but may have cross-academic roots, like arts, geography, theatre, engineering and technology, physical and mental health, even math (Zareva-Simeonova et al., 2014.) Social media development gives the zoos an excellent opportunity to make these activities visible and allows them to incorporate art, music, crafts, games, and storytelling into the zoo experience. Videos, artistic content and online read-alongs can draw kids and their families into the zoo community long before stepping foot into the zoo. (Softplay, 2023). The most active in attracting visitors with art and culture activities are USA zoos, from the usual placement of art objects in the zoo territory and celebration of various holidays to master classes with professional artists who teach visitors to draw animals and art residencies. This research aims to identify European best practice examples of zoos using art events that attract more local visitors and tourists and classify art events in zoos. Design / Methodology / Approach. Using the document analysis method, the home pages of different zoos worldwide were analysed. In antiquation, partly structured interviews with zoo representatives and artists were made. Findings. The results of the research will be presented at the conference. Originality / Value / Practical implications. The research summarises the experiences of different zoos in organising art events. It creates a typology of art events that can be used by representatives of different zoos when planning additional activities.

Nocturnal behavioral patterns of African ungulates in zoos.

Currently, most studies on ungulates' behavior are conducted during the daylight hours, but their nocturnal behavior patterns differ from those shown during day. Therefore, it is necessary to observe ungulates' behavior also overnight. Detailed analyses of nocturnal behavior have only been conducted for very prominent ungulates such as Giraffes (Giraffa camelopardalis), African Elephants (Loxodonta africana), or livestock (e.g., domesticated cattle, sheep, or pigs), and the nocturnal rhythms exhibited by many ungulates remain unknown. In the present study, the nocturnal rhythms of 192 individuals of 18 ungulate species from 20 European zoos are studied with respect to the behavioral positions standing, lying-head up, and lying-head down (the typical REM sleep position). Differences between individuals of different age were found, but no differences with respect to the sex were seen. Most species showed a significant increase in the proportion of lying during the night. In addition, the time between two events of "lying down" was studied in detail. A high degree of rhythmicity with respect to this quantity was found in all species. The proportion of lying in such a period was greater in Artiodactyla than in Perissodactyla, and greater in juveniles than in adults.

Taxa Richness Differences in European Zoos between 1959 and 2016: Establishment Period and the Iron Curtain Matter

Zoos represent a social construct, whose form is influenced by societal development. During the 20th and at the beginning of the 21st century, they have been transformed from assembled collections to internationally managed insurance (ex situ) populations, and these transformations required some changes in taxa numbers and composition. Previous studies have already identified the trend of reducing the number of taxa kept in zoos worldwide. The aim of the present study is to verify this trend in Europe in more detail and therefore to identify the changes in taxa richness and mammalian taxa richness from 1959 to 2016 in the same set of 67 European zoos while considering their opening period (before 1900 and 1900–1960) and location with respect to the former Iron Curtain (Eastern vs. Western Bloc). There was no significant decrease in taxa richness; on the contrary, there was a significant increase in taxa richness for the former Eastern Bloc zoos. There was a significant decrease in mammalian taxa richness for zoos opened before 1900 and those of the former Western Bloc. These results demonstrate that mammalian taxa have declined in numbers to some extent and that the decline mostly concerns older zoos and those that have historically reached a different stage of development. This suggests that European zoos have not been subject to trends uniformly and should apply different and appropriate strategies when facing future (not only conservation) challenges.

DISEASES OF THE GIANT ANTEATER (MYRMECOPHAGA TRIDACTYLA) IN CAPTIVITY: STUDY OF MEDICAL DATA FROM 99 INDIVIDUALS IN EUROPEAN ZOOS.

The giant anteater (Myrmecophaga tridactyla) is one of the three species in the family Myrmecophagidae of the suborder Vermilingua. It is the only species of the genus Myrmecophaga. The species, subject to increasing threats in its natural environment, is classified as vulnerable on the International Union for the Conservation of Nature Red List of Threatened Species. European zoos are involved in the ex situ conservation of the giant anteater, which is essential for its long-term viability. However, the diseases encountered by European captive populations of giant anteaters are not well documented, and best practice guidelines are not yet available for the species. An online two-part survey was conducted among European institutions hosting or having housed anteaters over a 20-yr period concerning the current management of captive populations and the diseases encountered. Medical data were collected from 99 giant anteaters from 30 institutions. Among the study population, 4% of the individuals were born in the wild and 96% were born in captivity. Seventy animals (71%) were still alive at the time of data collection, with an average age of 8 yr. A predominance of digestive (20%), dermatologic (20%)-with mainly wounds-and internal parasitism (18%) disorders was observed, followed by behavioral (13%), musculoskeletal (12%), respiratory (11%), nutritional (10%), and ocular (9%) disorders. Mortality mainly concerns the most extreme age categories: very young individuals, mostly secondary to trauma, and older individuals with no main cause identified. This paper details all the medical conditions reported in the European captive giant anteaters included in the study. It allows us to formulate some medical and zootechnical recommendations for the species management and to envisage new research perspectives.

A large-scale study on the nocturnal behavior of African ungulates in zoos and its influencing factors

IntroductionThe nocturnal behavior of many ungulate species has currently not been sufficiently studied. However, the behavioral patterns of large herbivores vary greatly between day and night, and knowledge about species’ behavior is not only scientifically interesting, but also required for successful animal management and husbandry.Material and methodsIn the current study, the nocturnal behavior of 196 individuals of 19 ungulate species in 20 European zoos is studied, providing the first description of the nocturnal behavior of some of the species. The importance of a wide range of possible factors influencing nocturnal behavior is discussed. Specifically, the behavioral states of standing and lying were analyzed, evaluating the proportion and number of phases in each behavior. The underlying data consist of 101,629 h of video material from 9,239 nights. A deep learning-based software package named Behavioral Observations by Videos and Images Using Deep-Learning Software (BOVIDS) was used to analyze the recordings. The analysis of the influencing factors was based on random forest regression and Shapley additive explanation (SHAP) analysis.ResultsThe results indicate that age, body size, and feeding type are the most important factors influencing nocturnal behavior across all species. There are strong differences between the zebra species and the observed Cetartiodactyla as well as white rhinos. The main difference is that zebras spend significantly less time in a lying position than Cetartiodactyla.DiscussionOverall, the results fit well into the sparse existing literature and the data can be considered a valid reference for further research and might help to assess animal's welfare in zoos.

Geckos in zoos: A global approach on distribution patterns of threatened geckos (Gekkota) in zoological institutions

According to the One Plan Approach to Conservation, proposed by the IUCN SSC Conservation Planning Specialist Group (CPSG), there is, besides in situ conservation measures, also increased need for ex situ conservation breeding of threatened taxa. To gain a better overview of the current situation, we have compiled information from the zoo databases ZIMS (Zoological Information Management System) and ZTL (Zootierliste) on the husbandry of gecko species (suborder Gekkota) worldwide. Only 9.3 % (n = 201) of the 2151 currently recognized gecko species from seven families were kept according to ZIMS, of which about 20.4 % (n = 41) were classified as threatened. Most species were kept in European, North American and Australian zoos. Many of the species were kept outside the natural distributional range hotspots of geckos. However, institutions in Oceania kept mainly native geckos. The species richness of the natural distributional ranges of zoo-kept geckos was highest in Australia, Southeast Asia, Madagascar and lowest in South America. About 38.0 % (n = 25) of zoo-kept species with a successful breeding record were threatened, and most reproductive successes of threatened species have been recorded from only one institution per species. Although Gekkota is the most species-rich group among lizards (Sauria), they are still relatively poorly represented in zoological institutions, and most of the kept species are not threatened. Zoos inside and outside the distributional range can play a key role in conservation (breeding) programs, when they continue to provide their expertise and resources for the buildup of insurance colonies for threatened taxa. Preferably this is carried out in cooperation with experts and conservation centers from the species’ range countries and also in cooperation with Citizen Conservation programs.

Visually assessed body condition shows high heritability in a pedigreed great ape population.

Body condition, a measure for relative fat mass, is associated with primate health, fitness, and overall welfare. Body condition is often influenced by dietary factors, age, and/or sex, but several body condition measures (body weight, weight-to-height ratios, and so on) also show high heritability across primate species, indicating a role of genetic effects. Although different measures for body condition exist, many require direct handling of animals, which is invasive, time-consuming, and expensive, making them impractical in wild and captive settings. Therefore, noninvasive visual body condition score (BCS) systems were developed for various animal species, including macaques and chimpanzees, to visually assess relative fat mass. Here we evaluate the utility of a visual BCS system in bonobos by assessing (1) inter-rater reliability, (2) links with body mass, a traditional hands-on measure of condition, and (3) the factors driving individual variation in BCS. We adapted the chimpanzee BCS system to rate 76 bonobos in 11 European zoos (92% of the adult population). Inter-rater reliability was high (s* = 0.948), BCSs were positively associated with body mass (β = 0.075) and not predicted by diet, sex, or age, nor were they associated with a higher abundance of obesity-related diseases. Instead, BCSs showed high levels of heritability (h2 = 0.637), indicating that a majority of body condition variation in bonobos is attributable to genetic similarity of the individuals. This is in line with reported h2 -values for traditional body condition measures in primates and provides support for the reliability of visual BCS systems in great apes. The results of this study emphasize an often unanticipated role of genetics in determining primate body fat and health that has implications for the management of captive primates. Application of this tool in wild populations would aid to unravel environmental from genetic drivers of body condition variation in primates.

Higher convergence of human-great ape enteric eukaryotic viromes in central African forest than in a European zoo: a One Health analysis

Human-animal pathogenic transmissions threaten both human and animal health, and the processes catalyzing zoonotic spillover and spillback are complex. Prior field studies offer partial insight into these processes but overlook animal ecologies and human perceptions and practices facilitating human-animal contact. Conducted in Cameroon and a European zoo, this integrative study elucidates these processes, incorporating metagenomic, historical, anthropological and great ape ecological analyses, and real-time evaluation of human-great ape contact types and frequencies. We find more enteric eukaryotic virome sharing between Cameroonian humans and great apes than in the zoo, virome convergence between Cameroonian humans and gorillas, and adenovirus and enterovirus taxa as most frequently shared between Cameroonian humans and great apes. Together with physical contact from hunting, meat handling and fecal exposure, overlapping human cultivation and gorilla pillaging in forest gardens help explain these findings. Our multidisciplinary study identifies environmental co-use as a complementary mechanism for viral sharing.

Results of the re-introduction of the Griffon Vulture (Gypsfulvus) in Vrachanski Balkan Nature Park, Bulgaria - completion of the establishing phase 2010-2020.

The current study analyses and presents the results of the ten-year establishment phase of the Griffon Vulture (Gypsfulvus) local re-introduction in Vrachanski Balkan Nature Park, north-western Bulgaria. Between 2010 and 2020, 61 rehabilitated and captive-bred Griffon Vultures from Spain, France and several European zoos were released from an acclimatisation aviary. The first successful breeding in the wild was reported in 2015. Thus, the species has been restored as a nesting species in the area after more than 60 years of absence. In 2020, the local population accounted for some 55-70 individuals, consisting of about 20-23 breeding pairs in three-five separate colonies and two frequently-used roosting sites. Forty-two chicks fledged from 2010 to 2020, at an average breeding success of 0.46 chicks/territorial pair and productivity of 0.62 fledglings/breeding pair. The mortality rate is calculated at 0.34; an additional 0.07 of the released individuals have never been seen or found. The local nucleus of the Griffon Vulture now covers a territory of 1,478.58 km², calculated as a 95% home range, while the 50% core area is 9.07 ± 5.73 km2 (range 2.12-22.89 km2). With these results, we consider the establishment phase of the re-introduction of the species in Vrachanski Balkan Nature Park as completed.

First results from the releases of Cinereous Vultures (Aegypiusmonachus) aiming at re-introducing the species in Bulgaria - the start of the establishment phase 2018-2022.

The current work presents the preliminary results of the Cinereous Vulture (Aegypiusmonachus) releases in the Balkan Mountains in 2018-2022, aiming at the species re-introduction in Bulgaria, where it was listed as locally extinct since 1985. The first imports and releases of Cinereous Vultures in Bulgaria started in 2018. Until mid-2022, 72 individuals were released in the Eastern Balkan Mountains (Kotlenska Planina SPA and Sinite Kamani Nature Park) and Vrachanski Balkan Nature Park. Of them, 63 immatures imported from Spain were released from aviaries and nine juveniles captive-bred in European zoos were released by hacking (fledging from an artificial nest). We compared the success in survival and establishment between the different release sites and methods used to adjust the ongoing technics and tactics and to support knowledge improvement for future similar projects. From the nine Cinereous Vultures released by hacking, the results were as follows: 1.00 fledging success, but only 0.22 survival in the first six months - combined period of acclimation, first migration and the first winter. All survivors from that period reached maturity into the wild, but all emigrated from the release site and settled elsewhere. Of the 63 individuals released by aviaries, 32 individuals were released in the Eastern Balkan Mountains (18 individuals are still alive - 0.56 survival; 14 individuals settled in the area, which accounts for 0.44 of all released birds and 0.78 of the survivors). Thirty-one individuals were released in Vrachanski Balkan Nature Park (23 individuals are still alive - 0.74 survival; 22 individuals settled in the area - 0.71 of all released birds and 0.96 of the survivors). Based only on aviary method comparison, the settling of the individuals in the release area was alike in the two sites. However, the Vrachanski Balkan Nature Park performed better in survival - both in acclimation and establishment periods. While comparing the release methods - hacking and release from the aviary - the following results were observed: the survival rate during acclimation was 0.86. Due to more considerable losses during the first migration and dispersal in the individuals released by hacking, the survival rate of 0.22 was significantly lower compared to 0.73 for the birds released from the aviary. Additionally, in both methods, a similar pattern in the first winter and spring migration dispersal was observed. Although the survival was equal in the released-by-hacking or aviary birds after the first year onwards, it is essential to note that the emigration of the hacked birds from the release site was 1.00. In comparison, the birds released from aviaries largely remained and settled in the release area (> 0.77 of the survivors). The cost of release and related acclimation, settling, dispersal and the first winter was the greatest: 0.12-0.17 per period, or cumulatively, it was about 0.27. Survival increased and stabilised to > 0.90 after the first year in the wild and reached nearly 1.00 after two years in the wild onwards. Two distinct nuclei of the Cinereous Vulture were established along the Balkan Mountains - the Eastern Balkan Mountains with 18-23 individuals and four formed pairs using a territory of about 642.74 km2 - 95% home range and 85.72 km2 - 50% core area with center being the town of Kotel; and Vrachanski Balkan Nature Park with present 23-29 individuals, of which 2-3 pairs formed so far, using a territory of about 1,143.66 km2 - 95% home range and 22.89 km2 - 50% core area with center being the village of Zgorigrad. The species readily accepted breeding in artificial nest platforms built by professional arborists on different tree species - oak, beech, sycamore and pine. The only naturally built nests were on the ground (n = 2) (unsuccessful) and in Scots Pine (n = 1) (successful). In 2021 and 2022, in each of the two sites, the first successful reproductions were recorded, which marked the return of the Cinereous Vulture as breeding species - 28 years after the last occasional record of a single breeding pair in the country and 36 years after it was officially listed as locally extinct in Bulgaria.