Zoological Gardens Research Articles

Advancing zoo animal welfare through data science: scaling up continuous improvement efforts.

Advancing zoo animal welfare through data science: scaling up continuous improvement efforts.

Body Shape Analysis in Reticulated Giraffe, Okapi, and Black Rhinoceros Using Three-Dimensional Laser Measurements

Health management in captive animals is difficult for various unknown reasons presumably related to physiological functions, disease, and diet. Generally, abnormal conditions are diagnosed based on body weight; however, zoos lack appropriate scales for megafauna. Body shape evaluation is often used to evaluate the nutritional status of breeding animals; however, this is inaccurate for zoo animals because of inter-observer variability, especially in megafauna. Previously, three-dimensional laser measurements were used to analyse body shape of reticulated giraffe, but further studies are required to examine its effectiveness in more individuals, and other species. Here, we applied this method to seven reticulated giraffe (Giraffa reticulata), five okapi (Okapia johnstoni), and three black rhinoceros (Diceros bicornis) individuals for which cross-sectional area, width, and height in transverse section were determined. Relative change rates of each variable in relation to measurements at the axillary region revealed changes in body shape for each individual. Further, scatter plots and corresponding fitted curves and correlation coefficients showed a correlation between body length and approximate volume. The accuracy of three-dimensional laser measurements was demonstrated in three animal species, whereby we propose its use as an alternative method to evaluate body shape in megafauna without the inter-observer variability. In addition, this handheld device may be applied for various zoos without the scale for megafauna.

Antimicrobial resistance of commensal Escherichia coli and Enterococcus faecalis isolated from clinically healthy captive wild animals in Seoul zoo.

Despite the importance of antimicrobial resistance, only a few studies on the antimicrobial susceptibility on wild animals have been conducted owing to their population, accessibility, and characteristics. The objective of this study was to investigate the prevalence and characteristics of antimicrobial resistance pattern in Escherichia coli and Enterococcus faecalis isolated from the feces of captive wild animals in a zoo. A total of 61 captive wild animals were included in this study. E. coli was isolated from 58 of the 61 animals and E. faecalis was isolated from 29 animals. Among the isolated E. coli strains, ampicillin exhibited the highest resistance rate (27/29, 93.1%). Of these, 18 strains (18/29, 62%) showed multidrug resistance. The multilocus sequence typing (MLST) test showed that only ST155 was detected twice, while the other 16 strains showed different ST types. Among the E. faecalis strains, two were susceptible to all tested antimicrobials, whereas the remaining 27 strains showed resistance to one or more antimicrobials. Nine strains (9/27, 31%) showed multidrug resistance. Among the E. faecalis strains, resistance to quinupristin/dalfopristin was the highest at 96.3% (26/27), while the MLST of the nine MDR strains showed no predominant ST. Genetic association with human isolates or livestock products was observed in the isolated ST types. This indicates that antibiotic resistance in the zoo is responsible for the use of antibiotics and the partial horizontal transmission between humans and animals through feeding or contact.

Mosquito (Diptera: Culicidae) Fauna of a Zoological Park in an Urban Setting: Analysis of Culex pipiens s.l. and Their Biotypes.

Mosquito-borne diseases (MBDs) are important emerging diseases that affect humans and animals. Zoological parks can work as early warning systems for the occurrence of MBDs. In this study, we characterized the mosquito fauna captured inside Lisbon Zoo from May 2018 to November 2019. An average of 2.4 mosquitos per trap/night were captured. Five mosquito species potentially causing MBDs, including Culex pipiens biotypes, were found in the zoo. The sympatric occurrence of Culex pipiens biotypes represents a risk factor for the epizootic transmission of West Nile virus and Usutu virus. The mosquito occurrence followed the expected seasonality, with the maximum densities during summer months. However, mosquito activity was detected in winter months in low numbers. The minimum temperature and the relative humidity (RH) on the day of capture showed a positive effect on Culex pipiens abundance. Contrary, the RH the week before capture and the average precipitation the week of capture had a negative effect. No invasive species were identified, nor have flaviviruses been detected in the mosquitoes. The implementation of biosecurity measures regarding the hygiene of the premises and the strict control of all the animals entering the zoo can justify the low prevalence of mosquitoes and the absence of flavivirus-infected mosquitoes.

Intestinal parasites infecting captive non-human primates in Italy.

Non-human primates (NHPs) living in captive conditions are susceptible to intestinal parasites that can contribute to mortality and morbidity, and cause zoonotic infections. Thus, parasite surveys on NHP populations under human care are relevant as part of the evaluation of NHPs welfare and in the zoonotic disease risk assessment, as well as in the exploration of parasite transmission pathways, according to the One-Health concept. This study aimed to identify intestinal parasites infecting NHPs living in two wildlife recovery centers and in a zoological garden, in Italy. Ninety-three fecal samples from Macaca tonkeana, Macaca fascicularis, Sapajus apella, Chlorocebus aethiops, Macaca fuscata, Macaca sylvanus, and Cebus capucinus were collected at Piano dell'Abatino Park (Lazio), and fecal smears and flotation were performed in order to identify parasites according to morphological keys. Additionally, one carcass of M. fuscata from the Bioparco Zoological Garden of Rome (Lazio) and one of M. fascicularis from the Center for the Recovery of Exotic and Maremma Wild Animals (Tuscany) were necropsied and intestinal adult nematodes were collected and characterized at morphological and molecular level, using the mitochondrial cox1 and rrnL markers. Protozoans (Entamoeba coli, Iodamoeba bütschlii, Dientamoeba fragilis-like, Giardia sp.), chromists (Balantidium/Buxtonella sp.) and nematodes (Capillaria sp., Trichuris sp., strongyliform larvae and Oesophagostomum sp.) were found through fecal smears and flotation. The collected adult nematodes from dead NHPs were morphologically identified as whipworms (genus Trichuris). Phylogenetic analyses grouped Trichuris specimens into the Trichuris trichiura complex of species, with specimens from M. fuscata clustering into a host-specific branch, and whipworms from M. fascicularis clustering within a clade formed by Trichuris infecting several primate species, including humans. The results here collected revealed the presence of potentially zoonotic parasites circulating in captive primates in Italy, providing useful information for the formulation of management and care plans for captive NHPs, and for the elaboration of safety measures for visitors and animal keepers.

МОНИТОРИНГ ВОЗБУДИТЕЛЕЙ ОСНОВНЫХ ПАРАЗИТОЗОВ ВОДНЫХ ПТИЦ НА ИЗОЛИРОВАННОЙ ПРИРОДНОЙ ТЕРРИТОРИИ НАЦИОНАЛЬНОГО ПАРКА «ЛОСИНЫЙ ОСТРОВ»

An important point in the conservation of biological diversity and avifauna resources on the territory of national and zoological parks, reserves, as well as commercial breeding poultry enterprises is the study of the bioecology of parasitosis pathogens. In this study, for the first time in a long time, the results of bioecological monitoring of the main parasitoses of aquatic birds living in the isolated natural territory of NP "Losiny оstrov" are presented. The main focus of the work was the study of the spread of the invasive origin in intermediate, additional and final hosts, as well as the conservation potential of aquatic bird species and other components of the biogeocenosis. The article presents the results of helminthological studies of feces of birds of the gull families (lake gull Larus Ridibundus) and duck (mallard Anas Platyrhynchos); helminthological studies of the gastrointestinal tract of fish of the cyprinid family (bream Abramis Brama) and firebrand (perch Perca Fluviatilis); mollusks of the family Lymnaeidae and the family Planorbidae. 85 and 86 individuals of fish and shellfish, respectively, and 116 samples of bird droppings were studied. The number of identified samples from seagulls was 23, from ducks – 47, the remaining 46 samples were defined as «blind samples». The main composition of intestinal parasites of aquatic birds and aquatic organisms has been revealed. Data were obtained on the infection of aquatic birds with associative helminth-protozoal mixinvasion: genera – Eimeria and Trichomonas and helminths of genera: Capillaria, Amidostomum, Heterakis. At the same time, the presence of mixed invasion was noted in 64.28% of the total number of samples. Data were obtained on the infection of fish and shellfish, the helminth fauna of which is represented by the families Echinoctomatidae and Diplostomum sp. The extent of monoinvasion of mollusks of the species Lymnaea stagnalis by cercariae and metacercariae of trematodes of the family Echinoctomatidae was 62.16%.

Haematological and serum biochemical analysis of Bengal tigers from Arignar Anna Zoological Park (AAZP), Chennai, India

Haematological and serum biochemical analysis of Bengal tigers from Arignar Anna Zoological Park (AAZP), Chennai, India

Investigation of symmetric dimethylarginine as a serologic marker for kidney function in striped skunks (Mephitis mephitis).

Kidney disease is prevalent among veterinary species, including zoo animals; however, investigations into this condition in striped skunks (Mephitis mephitis) are scarce. Diagnostic tools for kidney diseases in this species also remain limited. This study aimed to assess the utility of symmetric dimethylarginine as a biomarker for kidney disease in captive striped skunks in Korea. This retrospective study analysed 11 striped skunks housed at the Everland Zoo between 2017 and 2021. Blood samples were collected during health checks. Kidney function was assessed through blood analysis and diagnostic ultrasound, with necropsies conducted on deceased animals. Symmetric dimethylarginine levels were measured in 27 plasma samples collected from 11 skunks. Over the study period, seven skunks were diagnosed with kidney disease. Analysis of 27 blood samples revealed a concurrent increase in SDMA levels with concentrations of blood urea nitrogen and blood creatinine. In 3 of the 7 skunks with kidney disease, symmetric dimethylarginine exceeded 14 µg/dL prior to the elevation of blood urea nitrogen and blood creatinine above the upper reference limit. To our knowledge, this is the first study investigating symmetric dimethylarginine in captive striped skunks in Korea. Our findings suggest that symmetric dimethylarginine may serve as an early and consistent biomarker for renal dysfunction in striped skunks. Further studies with larger clinical sample size from striped skunks are needed to validate the clinical utility of blood symmetric dimethylarginine concentration.

Human-animal interactions and machine-animal interactions in animals under human care: A summary of stakeholder and researcher perceptions and future directions

Abstract Animals under human care are exposed to a potentially large range of both familiar and unfamiliar humans. Human-animal interactions vary across settings, and individuals, with the nature of the interaction being affected by a suite of different intrinsic and extrinsic factors. These interactions can be described as positive, negative or neutral. Across some industries, there has been a move towards the development of technologies to support or replace human interactions with animals. Whilst this has many benefits, there can also be challenges associated with increased technology use. A day-long Animal Welfare Research Network workshop was hosted at Harper Adams University, UK, with the aim of bringing together stakeholders and researchers (n = 38) from the companion, farm and zoo animal fields, to discuss benefits, challenges and limitations of human-animal interactions and machine-animal interactions for animals under human care and create a list of future research priorities. The workshop consisted of four talks from experts within these areas, followed by break-out room discussions. This work is the outcome of that workshop. The key recommendations are that approaches to advancing the scientific discipline of machine-animal interactions in animals under human care should focus on: (1) interdisciplinary collaboration; (2) development of validated methods; (3) incorporation of an animal-centred perspective; (4) a focus on promotion of positive animal welfare states (not just avoidance of negative states); and (5) an exploration of ways that machines can support a reduction in the exposure of animals to negative human-animal interactions to reduce negative, and increase positive, experiences for animals.

Molecular and Serological Studies on Potential SARS-CoV-2 Infection among 43 Lemurs under Human Care-Evidence for Past Infection in at Least One Individual.

In the setting of the recent COVID-19 pandemic, transmission of SARS-CoV-2 to animals has been reported in both domestic and wild animals and is a matter of concern. Given the genetic and functional similarities to humans, non-human primates merit particular attention. In the case of lemurs, generally considered endangered, they are believed to be susceptible to SARS-CoV-2 infection. We have conducted a study for evidence of SARS-CoV-2 infection among the 43 lemurs of Mundomar, a zoological park in Benidorm, Spain. They belong to two endangered lemur species, 23 black-and-white ruffed lemurs (Varecia variegata) and 20 ring-tailed lemurs (Lemur catta). Health assessments conducted in 2022 and 2023 included molecular analyses for SARS-CoV-2 RNA of oral and rectal swabs using two different RT-qPCR assays, always with negative results for SARS-CoV-2 in all animals. The assessment also included serological testing for antibodies against the receptor-binding domain (RBD) of the spike protein (S) of SARS-CoV-2, which again yielded negative results in all animals except one black-and-white ruffed lemur, supporting prior infection of that animal with SARS-CoV-2. Our data, while not indicating a high susceptibility of lemurs to SARS-CoV-2 infection, show that they can be infected, adding to the existing information body on potential ways for SARS-CoV-2 virus spreading in zoos, highlighting the need for animal surveillance for the virus.

Development of Explorative Behavior and Neophobia in Captive Sun Bears (Helarctos malayanus)

Neophobia is the aversion to novelty and is a widespread phenomenon in the animal kingdom. In bears (Ursidae) neophobic responses seem to develop around the age of 5 months, and disturbance of this development may be the cause of rehabilitation failures. However, little is known about the behavioral development of bear cubs, which may be helpful for successful rehabilitation as well as for zoo animal management. Here, the development of explorative behavior and neophobia is investigated in two captive sun bear cubs (Helarctos malayanus). The behavior of the animals is observed between the ages of 4 to 6 months and neophobic responses are tested during general observations and in novel object tests. It would be expected that explorative behavior decreases while neophobia increases and that this development is in parallel with a growth in (social) distance to their mother. The results show that there is no decrease in explorative behavior of the cubs and no evidence for the development of neophobia is found. However, the distance to the mother does increase between the ages of 4 to 6 months, indicating that this would be an evident timeframe for neophobia to develop. These findings suggest that either no development of neophobia occurs in the sun bear, or the captive environment has disturbed their natural development. Further research comparing captive and wild cubs should clarify this.

Diurnal Activity Patterns of Burchelli Zebra (Equus burchelli) in Captivity at Zoological Garden, Alipore, Kolkata, India

A study was conducted on the diurnal behavioural pattern and activity time budget of a captive female burchelli zebra (Equus burchelli) in the Zoological Garden, Alipore, West Bengal, India, from 10.00 to 17.00 h between October 2022 to June 2023including winter and summer seasons by using focal sampling method with 25,200 minutes of observations. Data were analyzed by assessing mean time spent percentage for different activities in different hours and different seasons. Differences in the seasonal and hourly time budget were tested using one-way ANOVA, followed by DMRT. Grazing was dominant with significantly (P<0.05; DMRT) maximum time spent, followed by standing, feeding of offered feed, resting and then locomotion during both the seasons. Between seasons, significantly higher (P<0.05; DMRT) grazing (32.72%±0.92), walking (7.58%±0.77) and sleeping (7.18%±0.24) behaviours were observed during summer, while the other activities during the winter. During summer, from 12:00-13:00 h, grazing was the lowest, while resting was most. During winter, resting was more in the 1st hour of observation. The zebra devoted 2.12% to 2.21% of their time towards vigilance behaviour which was with higher rate during winter. This individual-based behavioural study on captive zebra will be useful for taking a well comprehensive management plan to ensure its successful in-situ conservation as well as its welfare.

Genomics insights into a Mycobacterium pinnipedii isolate causing tuberculosis in a captive South American sea lion (Otaria flavescens) from Italy.

Tuberculosis (TB) affects humans and other animals, and it is caused by bacteria within the Mycobacterium tuberculosis complex (MTBC). In this study, we report the characterisation of Mycobacterium pinnipedii that caused a TB case in a sea lion (Otaria flavescens) kept in an Italian zoo. The animal died due to severe, progressive disorders involving the respiratory and gastro-enteric systems and the skin. At necropsy, typical gross lesions referable to a TB generalised form were found. In particular, nodular granulomatous lesions were detected in the lungs and several lymph nodes, and colonies referable to Mycobacterium spp. were isolated from lung, mesenteric, and mediastinal lymph nodes. The isolate was identified by PCR as a MTBC, had a spoligotype SB 1480 ("seal lineage"), and was characterised and characterised by whole-genome sequencing analysis confirming that the MTBC involved was M. pinnipedii. The analysis of the resistome and virulome indicated the presence of macrolide and aminoglycoside resistance genes intrinsic in M. tuberculosis [erm-37 and aac(2')-Ic] and confirmed the presence of the region of difference 1 (RD1), harbouring the esxA and esxB virulence genes, differently from its closest taxon, M. microti. As for other MTCB members, M. pinnipedii infection can spill over into non-pinniped mammalian species; therefore, zoological gardens, veterinary practitioners, and public health officers should be aware of the hazard posed by tuberculosis from marine mammals. Since the isolate under study, as well as all available genomes of M. pinnipedii investigated in this study retains almost all the M. tuberculosis virulence genes, it could indeed cause infection, lesions, and disease in other animal species, including humans.

Global avian influenza situation (2019–2022). Host range expansion asevidence of high pathogenicity avian influenza virus evolution

High pathogenicity avian influenza has a significant negative impact on poultry farming, international trade and health of wild bird populations, therefore the infection requires the utmost attention of the entire international community. The article investigates the evolutionary and epidemic processes observed in recent years in many countries of the world where avian influenza outbreaks occur; describes the ways of the infection spread; the prevalence of the virus types for the last several years, as well as the expansion of the host range, including among representatives of the Mammalia class. The change in the ratio between the virus types starting from 2020, when H5N8 subtype was responsible for the overwhelming number of the disease outbreaks reported, until 2022, when an obvious predominance of H5N1 subtype was detected is demonstrated. A noticeable expansion of the disease-affected areas in Central and South America, the influence of migration, anthropogenic and other factors on influenza spread are highlighted. The conditions facilitating the occurrence of the infection outbreaks affecting mammals, wild animals and livestock, zoo and companion animals are described. Cases of mammals’ infection on the North American and Eurasian continents in zoos, nature parks, backyards and fur farms, asa rule, coincide in time with the infection outbreaks in waterfowl populations. The WAHIS data were analyzed and the high ability of the virus to spillover from birds to mammals, such as martens (minks, otters, ferrets, badgers), cats (domestic cats, cougars, leopards, lynxes), pinnipeds (common seals, grey seals), bears (brown, grizzly, American black), bottlenose dolphins, skunks, foxes, opossums, raccoons was demonstrated. Changes in the habitats of both migratory birds and mammals, including due to some human economic activities, add an ecological and urban component to the complex task of the control and prevention of the epidemic, also posing a potential threat to humans.

Visual and acoustic exploratory behaviors toward novel stimuli in Antillean manatees (Trichechus manatus manatus) under human care.

Exploratory behaviors describe the actions performed by an animal to obtain information on an object, environment, or individual by using its different senses. Exploration is described in some marine mammals, but not yet in manatees. Our study investigated behavioral and acoustic responses of two groups of Antillean manatees (N = 12 and N = 4) housed in zoological parks toward various stimuli involving three sensory modalities: visual, tactile, and auditory. Simultaneous audio and video recordings were collected during three periods of time (i.e., before, during, and after the presentation of all stimuli). Behaviors related to interest, social behaviors, the number and type of calls produced, and their frequency and duration were recorded and analyzed. Manatees reacted more to submerged stimuli than to out-of-water and sound stimuli, with an increase in approach, social contacts, and number of vocalizations. The proportion of squeaks and squeals call types also varied according to stimuli, and call entropy and F0 range varied according to periods. Our results suggest that manatees display sensory preferences when exploring stimuli, with more interest in manipulable stimuli, supporting the importance of their somatic perception. We highlight the need for particular enrichment programs (i.e., involving submerged objects) in zoological facilities. By displaying social contacts and by producing vocalizations, manatees communicate information such as their motivational state. The increase in call rate, harsh calls, and entropy values could be valid indicators of heightened arousal. We encourage further studies to associate acoustic recordings with ethological data collection to increase the understanding of manatees' behaviors andperception. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Sequence capture identifies fastidious chytrid fungi directly from host tissue

The chytrid fungus Batrachochytrium dendrobatidis (Bd) was discovered in 1998 as the cause of chytridiomycosis, an emerging infectious disease causing mass declines in amphibian populations worldwide. The rapid population declines of the 1970s-1990s were likely caused by the spread of a highly virulent lineage belonging to the Bd-GPL clade that was introduced to naïve susceptible populations. Multiple genetically distinct and regional lineages of Bd have since been isolated and sequenced, greatly expanding the known biological diversity within this fungal pathogen. To date, most Bd research has been restricted to the limited number of samples that could be isolated using culturing techniques, potentially causing a selection bias for strains that can grow on media and missing other unculturable or fastidious strains that are also present on amphibians. We thus attempted to characterize potentially non-culturable genetic lineages of Bd from distinct amphibian taxa using sequence capture technology on DNA extracted from host tissue and swabs. We focused our efforts on host taxa from two different regions that likely harbored distinct Bd clades: (1) wild-caught leopard frogs (Rana) from North America, and (2) a Japanese Giant Salamander (Andrias japonicus) at the Smithsonian Institution’s National Zoological Park that exhibited signs of disease and tested positive for Bd using qPCR, but multiple attempts failed to isolate and culture the strain for physiological and genetic characterization. We successfully enriched for and sequenced thousands of fungal genes from both host clades, and Bd load was positively associated with number of recovered Bd sequences. Phylogenetic reconstruction placed all the Rana-derived strains in the Bd-GPL clade. In contrast, the A. japonicus strain fell within the Bd-Asia3 clade, expanding the range of this clade and generating additional genomic data to confirm its placement. The retrieved ITS locus matched public barcoding data from wild A. japonicus and Bd infections found on other amphibians in India and China, suggesting that this uncultured clade is widespread across Asia. Our study underscores the importance of recognizing and characterizing the hidden diversity of fastidious strains in order to reconstruct the spatiotemporal and evolutionary history of Bd. The success of the sequence capture approach highlights the utility of directly sequencing pathogen DNA from host tissue to characterize cryptic diversity that is missed by culture-reliant approaches.

Land Snails at the Zoo: A Biodiverse Community with Conservation and Educational Potential

The combination of animals and plants in zoological gardens provides the opportunity for conservation within the grounds. An example is pollination gardens that support free-moving butterflies and bees. Pollination gardens and other areas with plants also support a wide range of other non-captive animals, including soil-associated invertebrates. This study targeted land snails, a species-rich group that links the brown decomposition food web and the plant-based web that is preyed upon by fireflies and birds, among others. A survey of 24 sites within the Oklahoma City Zoo and Botanical Garden revealed a diverse snail fauna of 23 species. The majority were native species but included 10 non-native species that are common regional urban species, likely introduced through the plant trade. No distributional pattern of snails was evident, probably because of the similar management scheme throughout the zoo. Snails and other observed soil-associated invertebrates (e.g., isopods, millipedes, and earthworms) support non-captive birds and other animals. Lightly managed areas with leaf litter and downed wood are especially conducive to snails and other soil-associated invertebrates and are nesting sites for bees. These communities can form conservation demonstration areas that can be the basis of educational programs, including outreach programs.

Diversity, prevalence and risk factors associated to gastrointestinal tract parasites in wild and domestic animals from Pakistan.

The gastrointestinal tract (GIT) of animals contains various helminth parasites, responsible for subclinical and clinical parasitism. The health situation of animals is seriously affected by these parasites and leads massive financial losses for the livestock trade. The present study was conducted to determine the prevalence and associated risk factors of GIT parasites in small and large ruminants of Mardan district and zoo animals of Golden Life Safari Park Khyber Pakhtunkhwa. A total of 419 fecal samples were collected including 117 from goats, 110 from cattle, 80 from sheep, 66 from buffaloes, 40 from birds, four from deer, and two from leopards. The fecal samples were subjected to sedimentation and floatation to identify parasite eggs. Of a total of 419 fecal samples, 215 (51.31%) were found positive for GIT parasites eggs. The prevalence of GIT parasites was high in sheep (65%), followed by goats (62.39%), cattle (42.70%), and buffaloes (37.87%). In birds, GIT parasite eggs were identified in 11 (45.83%) and 7 (43.75%) fecal samples of Pheasant and Peacock, respectively. However, an absence of infection was noted in fecal samples from deer and leopards. Eggs of GIT Parasites belonging to one superfamily and four different genera were recognized in fecal samples of domestic animals and buffaloes, which were Trichostrongyloidea (19.81%), Strongyloides (9.31%), Trichuris (7.77%), Monezia (6.44%), and Fasciola (4.53%). For bird, the coccidia group comprises the highest representation of parasites (2.63%), followed by the Trichuris genus (1.67%). Settlement, management system, anthelminthic medications and body condition score were significantly associated with the occurrence of GIT parasites in feces (P < 0.05). Animals from rural settlements, rearing under poor management systems, with thin (poor) body condition and under warmed were more affected by GIT parasites. The diversity and the high prevalence of GIT parasites reported in this study highlights the urgent need for intervention through treatment and modification of management practices in the investigated areas of Pakistan.

Unveiling a novel parasitosis: Trichostrongylus colubriformis infection in captive ring-tailed lemurs (Lemur catta)

Ring-tailed Lemur (Lemur catta) is the only surviving semi-terrestrial diurnal lemur in Madagascar. Despite being the most intensively studied of lemur taxa, only a few helminths have been described in this species. In this study we describe a persistent infection due to Trichostrongylus colubriformis in a captive population of L. catta hosted in a zoological park of northern Italy. In the context of a parasitological survey on zoo animals, we investigated parasites in a captive colony of ring-tailed lemurs within a zoological park. Parasitological analysis included necropsy of a deceased lemur in 2019, subsequent fecal sample collections in 2021–2022, followed by coprological examination and coprocolture. Morphological and molecular analyses were conducted on adult helminths, larvae and eggs, involving microscopy, scanning electron microscopy (SEM), and sequencing of the ITS rDNA region. Trichostrongylidae parasites were primarily found after necropsy in the intestine of the lemur. Morphological and molecular investigations on adults and eggs/larvae recovered from feces collected at different times from lemurs of the same captive population, allowed to properly identify the parasite as T. colubriformis. To the best of our knowledge this is the first description of T. colubriformis in L. catta. Although its presence in wild populations is not necessarily implied by our finding, this parasitosis represent a cause of concern in captive lemurs, considering the possibility of interspecies transmission and the zoonotic implications.

Getting to the Meat of It: The Effects of a Captive Diet upon the Skull Morphology of the Lion and Tiger

Zoo animals are crucial for conserving and potentially re-introducing species to the wild, yet it is known that the morphology of captive animals differs from that of wild animals. It is important to know how and why zoo and wild animal morphology differs to better care for captive animals and enhance their survival in reintroductions, and to understand how plasticity may influence morphology, which is supposedly indicative of evolutionary relationships. Using museum collections, we took 56 morphological measurements of skulls and mandibles from 617 captive and wild lions and tigers, reflecting each species’ recent historical range. Linear morphometrics were used to identify differences in size and shape. Skull size does not differ between captive and wild lions and tigers, but skull and mandible shape does. Differences occur in regions associated with biting, indicating that diet has influenced forces acting upon the skull and mandible. The diets of captive big cats used in this study predominantly consisted of whole or partial carcasses, which closely resemble the mechanical properties of wild diets. Thus, we speculate that the additional impacts of killing, manipulating and consuming large prey in the wild have driven differentiation between captive and wild big cats.