We conducted a retrospective observational study to investigate exposure history, clinical signs, and onward transmission of animals infected with SARS-CoV-2 in US zoological institutions. We analyzed animal surveillance data collected through voluntary national surveillance during 2020 to 2023, including a descriptive epidemiologic analysis of surveillance data, comparative genomic analysis of SARS-CoV-2 sequences from zoo animals and the US human population, and comparison of impacts at the human-animal interface for a subset of zoological institutions (n = 12) with a SARS-CoV-2 animal outbreak. During 2020 to 2023, 170 animals in zoological institutions were confirmed positive for SARS-CoV-2. These animals consisted of 13 species in 28 US jurisdictions. Of affected animals, 72.4% presented with clinical signs, most commonly cough (60.0%). The likely source of SARS-CoV-2 in animals was a known infected caretaker in 44.7% of cases. Some zoological institutions participated in an in-depth analysis of outbreaks; these institutions implemented an average of 48.7 and 52.9 of 88 recommended biosecurity practices in the month before and after an outbreak, respectively, in their facility. Zoological institutions were a high-risk setting for SARS-CoV-2 transmission via spill-back from people to animals. Genomic analysis supported that zoo animals became infected with SARS-CoV-2 variants circulating in humans at the time, with no evidence of significant viral evolution in zoo populations. Mitigating emerging infectious disease threats in these facilities is critical for protecting vulnerable animal populations and public health.
The genus Moniezia comprises globally distributed parasitic cestodes that cause significant economic losses in domestic ruminants, yet its molecular characterization in wildlife remains limited. This study provides the first molecular confirmation of M. expansa in zoo animals in Taiwan. Specimens were obtained from a captive-born common eland (Tragelaphus oryx) and a domestic goat (Capra hircus); those from the eland underwent morphological examination of gravid proglottids, while all samples were analyzed genetically. Using the 18S ribosomal RNA, 28S ribosomal RNA, cytochrome c oxidase subunit 1, and NADH dehydrogenase subunit 1 (nad1) gene regions, we found identical strains of M. expansa in both the common eland and domestic goat in Taiwan, suggesting a local infection event. Notably, the eland-derived sequences clustered within lineages predominantly reported from Caprinae hosts, providing preliminary evidence of a potential spillover event, which aligns with the known broad host specificity of M. expansa. Haplotype network analysis further identified a novel nad1 haplotype within our sampled dataset and revealed high genetic diversity, which may support the hypothesis of complex expansion history of M. expansa. These findings underscore the value of molecular tools in clarifying parasite ecology in mixed wildlife-livestock settings and highlight the need for ongoing surveillance in zoological institutions.
The limitations of biohybrid and mechanical robots, including insufficient control accuracy, limited flexibility, long-term stability, and endurance, have spurred considerable research interest in cyborg animals, which leverage the innate locomotion capabilities, physiological systems, and natural intelligence of organisms to perform tasks with high adaptability, superior performance, and extended endurance. This study provides a comprehensive overview of cyborg animals within the framework of animal taxonomy, summarizing the current state of research from a zoological perspective. Subsequently, the effect of different control techniques on the locomotion performance of cyborg animals was examined, with a special emphasis on 2 prominent research areas: brain-computer interfaces and muscle-receptor electrical stimulation. In addition, the role of advances in electronic backpack design and navigation control algorithms in enabling closed-loop control and applications, including swarm robotics, environmental exploration, and human-machine interaction, is also introduced, offering valuable insights for developing cyborg animals. This study highlights 4 critical aspects essential for the future advancement of cyborg animals by synthesizing recent progress and clarifying technical distinctions: adaptation between control strategies and animals, biocompatibility and stability of electronic backpacks, construction of interactive hybrid robotic systems, and ethical and welfare considerations related to the experimental animals, with the hope of facilitating the optimization and application of cyborg animal systems.
The Siberian moth, Dendrolimus sibiricus Tschetverikov, is one of the most destructive conifer pests in Northern Asia, causing severe ecological and economic losses. In Russia, its range overlaps with that of the closely related pine-tree lappet Dendrolimus pini (L.), and this raises the potential for hybridization and complicates accurate identification, particularly in the context of the potential westward expansion of D. sibiricus. Here, we present the first comprehensive morphometric analysis of male genitalia aimed at distinguishing these two major forest pests and their hybrids. The study was based on D. sibiricus and D. pini specimens collected during the last 130 years (1894-2024) across Europe and Asia, including their hybrids reared indoors by crossing D. pini females with D. sibiricus males in 1956 and preserved in the collection of the Zoological Institute of the Russian Academy of Sciences (St. Petersburg, Russia). Overall, 70 permanent genitalia slides were prepared (33 D. sibiricus, 33 D. pini, and 4 hybrids), and the following genital structures were measured: valva and harpe length, aedeagus width and length, and cornuti length. Dendrolimus sibiricus had significantly larger genital structures compared to D. pini: 74% longer harpe, 32% longer valva, and a 28% wider and longer aedeagus. In contrast, in D. sibiricus cornuti were 21% shorter than in D. pini. Hybrids displayed intermediate values for valva, harpe, and aedeagus lengths, and for these parameters, they significantly differed from both parental species. The following diagnostic indices were suggested to distinguish between the two species and their hybrids: Harpe Length/Valva Length Index (HL/VL) and Cornuti Length/Aedeagus Length Index (CL/AL). Decision-tree analysis identified HL/VL as the strongest predictor for separating the parental species and the Combined Genital Proportion Index (CGPI), which integrates harpe, valva, aedeagus, and cornuti lengths, as the strongest predictor for identifying hybrids. The morphometric criteria developed here have practical applications for monitoring programs and quarantine diagnostics, particularly in sympatric zones and regions at risk of D. sibiricus expansion.
The biodiversity of euplotid ciliates in high-latitude regions has long been underestimated due to a historical research focus on mid- to low-latitude areas. This study describes three new species collected from high latitudes, Euplotes aspergilliformis sp. nov., E. borealis sp. nov., and E. verebkovi sp. nov. Euplotes aspergilliformis sp. nov. is characterized by medium body size (60-85 × 40-60 μm). It possesses nine frontoventral cirri, two marginal cirri and two caudal cirri with forked distal ends. It also has eight dorsal kinetids (with 13-17 dikinetids in the mid-dorsal kinety) and a double-eurystomus type silverline system. Euplotes borealis sp. nov. is a medium-sized (45-55 × 25-35 μm) freshwater ciliate. It can be recognized by nine frontoventral cirri, one marginal and two caudal cirri. It has nine dorsal kineties with about nine basal bodies in the mid-dorsal kinety, and a double-eurystomus type silverline system. Euplotes verebkovi sp. nov. features an elongated oval body (40-54 × 22-31 μm). It has ten frontoventral, five transverse, one marginal, and two caudal cirri. It possesses seven dorsal kineties with eight or nine bristles in the mid-dorsal row, seven conspicuous dorsal ridges, and a double-eurystomus type dorsal silverline system. Phylogenetic analyses based on molecular data revealed the systematic positions of the three new taxa and confirmed the validity of the three organisms as distinct species.
Mitochondria exhibit a complex spatially organized distribution within muscle, tailored to the energy requirements of ATPases and contractile filaments, which exhibit precise intracellular positioning. Mitochondrial distribution varies across longitudinal and transverse axes as well as based on fiber composition within the muscle. The differential mitochondrial capacity can be localized in muscle by succinate dehydrogenase (SDH) activity. Given the distinct energy requirements of the fore-limb and hind-limb muscles, this study aimed to investigate the distribution of mitochondrial activity within individual fibers and their composition within fascicles across different tetrapod taxa. We analyzed pectoralis and gastrocnemius from toad, garden lizard, duck, pigeon, quail, chicken, rat, rabbit, goat, and buffalo. The study revealed unique patterns of mitochondrial activity distribution within the same muscle across various tetrapods. Toad and lizard muscles showed mostly fibers with intermediate SDH-activity (SDHInt) in both muscles. The muscles only from birds and mammals exhibited fibers with negligible SDH-activity termed SDHLow, which might indicate that such fibers are evolutionarily more recent. Interestingly, avian pectoralis showed a very unique fiber composition compared to mammals, which displayed a mosaic pattern of different fibers. Among mammals, slow-grazers (buffaloes, goats) had higher percentages of SDHHigh and SDHInt fibers, whereas sprint-runners (rats, rabbits) possessed a high abundance of SDHLow fibers. These findings provide evidence for localized mitochondrial enrichment as an adaptation strategy to create muscle group heterogeneity. SUMMARY STATEMENT: This study characterizes the spatial distribution of mitochondrial activity in skeletal muscle across tetrapods, from the single-fiber scale to the fascicular level.
Rapid global changes in climate and habitats lead to shifts in species' geographic ranges. Range contractions experienced by numerous species may result in local extinctions and connectivity disruptions. In some species, range expansions have been observed instead, suggesting the enlargement of suitable habitats and/or adaptations to changing environments. Despite its importance for wildlife management, our understanding of the factors influencing species' spatial responses to rapidly changing environments remains limited. The golden jackal serves as an excellent model to address this knowledge gap, given its ongoing rapid range expansion. In this study, we investigated environmental factors contributing to genetic connectivity and local adaptation across the expanding range of the golden jackal, based on a comprehensive sampling scheme across Eurasia (n = 363), a high-quality set of genomic markers (19,746 SNPs), and a landscape genomics framework. At the continental scale, geographic distance emerged as the predominant factor. At finer spatial scales, genetic connectivity was best explained by climatic predictors, specifically high annual and seasonal variations in precipitation and temperature, which can shape the species' spatial genetic structure by constraining gene flow. Our connectivity models for current and future climatic conditions show that the species' northward expansion is facilitated by changes in these variables in central and northern Europe promoting high connectivity. Precipitation and temperature were also responsible for most local adaptation signals. Given the potential role of hybridization with domestic dogs in shaping range expansion patterns, we investigated the association between environmental conditions and dog admixture proportions. We found no significant trends, indicating a limited effect of dog admixture on habitat choice. Collectively, our findings suggest that the golden jackal has the potential to continue its expansion across Eurasia in response to ongoing global climate change, providing an example of a species that rapidly tracks the expansion of its suitable habitats.
Deep-sea methane seeps host diverse and abundant animal communities, including an extensive undescribed diversity of small cryptic invertebrates. We describe a new genus and species of neomphalid snail, Levinaespira georgesnyderi gen. et sp. nov., from the Mound 12 methane seep at 1000 m depth on the Pacific margin of Costa Rica, and we report a closely related singleton specimen from the Hydrate Ridge seep off Oregon, USA, at ca. 600 m depth. Molecular phylogenies based on the mitochondrial cytochrome c oxidase subunit I (COI) gene and the complete mitochondrial genome support the placement of the new genus within Neomphalidae (Gastropoda: Neomphalida), a group originally described from hydrothermal vents. Levinaespira georgesnyderi gen. et sp. nov. is separated from species in other described genera by at least 15.2% COI distance. It is morphologically distinctive in having lateral projections on the anterior foot, a lobe-shaped right cephalic lappet, and bilaterally symmetric cephalic tentacles without obvious reproductive modifications. This species represents the first genetically confirmed record of Neomphalidae at methane seeps and the shallowest known occurrence of this group at any environment. The new genus is named in honor of Professor Emerita Lisa Levin and the new species is named in memory of Collection Manager H. George Snyder (1931-1990) for their contributions to deep-sea invertebrate biology.
Goiter or thyroid enlargement has been frequently reported at postmortem examination in Eastern bongos (Tragelaphus eurycerus isaaci). It has been hypothesized that associated thyroid hormone disturbance may be a cause of poor reproductive performance in captive bongos, but thyroid histology or hormone analysis are rarely described. Thyroid glands from 39 individuals within the European captive population were examined grossly, with goiter observed in 64.1% (n = 25) of individuals, of which 96.0% (24/25) had multinodular lesions. Older animals were significantly more likely to develop goiter (P = 0.004), with goiter present in individuals from 6 yrs of age. There was no correlation between the presence of goiter and reproductive success or body condition. Thyroid glands from 16 bongos were examined histologically by a board-certified veterinary pathologist. Histologic lesions were identified in all 16 samples and included giant colloid follicles (100.0%), interstitial fibrosis (93.8%), hyperplastic collapsed follicles (75.0%), papillary fronds (62.5%), inflammation (25.0%), and mineralization (12.5%). No neoplasia was found. Multinodular colloid goiter appears to be the most common thyroid lesion within the European Eastern bongo population. Serum samples collected within 30 d prior to death were available for 25/39 animals, both with and without goiter. Total triiodothyronine (tT3), free triiodothyronine (fT3) and total thyroxine (tT4) concentrations were validated and analyzed by competitive inhibition enzyme immunoassay using bovine ELISA kits. No thyroid hormone levels correlated to goiter presence. Findings suggest that although highly prevalent, colloid goiter is euthyroid and does not impact on reproductive success or body condition in Eastern bongos. The cause of goiter in this species remains unknown.
The study aimed to characterize, through imaging examinations-including radiographs and computed tomography-the hip joint and the bones of the thigh, leg and feet in Lowland tapirs (Tapirus terrestris). Ten pelvic limbs were collected, two from juveniles and the remaining from adults. The femoral head exhibited a rounded morphology with a well-defined fovea capitis and a short, thick neck. Three trochanters were identified, with the greater and third trochanters being particularly prominent. The femoral diaphysis was elongated and straight, and the distal end displayed a globular medial condyle and a flatter lateral condyle. The femoral trochlea consisted of medial and lateral trochlear crests of similar size, separated by a well-defined trochlear groove. The proximal tibia showed slightly concave tibial plateaus, with the lateral condyle being wider and a prominent intercondylar eminence. The fibula was positioned laterally along the entire tibia, with the interosseous space preserved. The talus presented a well-defined trochlea and a head articulating with the central tarsal bone. Tarsal bones I, III and IV were identified, with tarsal IV being elongated. Three metatarsals (II, III and IV) were observed, with metatarsal III relatively more developed. The third digit was larger than both the second and fourth digits. The Norberg angle, femoral head-neck inclination angle, mechanical lateral distal and proximal femoral angles, and anatomical medial proximal and lateral distal tibial angles were similar between the two imaging methods. In conclusion, the imaging examinations were complementary, enabling the characterization of morphological features reflecting the species' functional adaptations for cursorial and semi-aquatic locomotion.
Birdsong variation among populations within species has been regarded as a possible precursor for variation between species and may play a role in speciation. However, acoustic variation between 2 populations of the same or different species can have a variable impact on mutual responsiveness, and we currently lack sufficient insight into the underlying reasons. We report here on geographic song variation and responsiveness to playback for the light-vented bulbul (Pycnonotus sinensis), a species with recent range expansion in China. We recorded songs in 4 historical populations in the south and 6 newly established populations in the north. We tested responsiveness in 2 southern and 2 northern locations to songs from southern and northern birds. Besides songs from the other distribution range (south to north and north to south), we used recordings for playback from local, near-by, and far-away dialects from within their own distribution range. We confirmed distinct dialectal differentiation in the south and a more gradual pattern of geographic song divergence in the north. Birds in the south showed very little response to almost all nonlocal songs. In contrast, birds in the north showed a strong response to a wide-range of stimuli, just gradually fading from local, near-by, to far-away northern dialects, which may be related to song type sharing or individual mobility and aggression associated with the recent range expansion. We hereby add an asymmetric response pattern in responsiveness to the literature and review the current insights about the potential impact of song variation on avian speciation.
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Understanding whether a species' distribution results from recent and/or anthropogenic events or ancient vicariant factors is critical for conservation planning. The Endangered Sanje mangabey (Cercocebus sanjei), endemic to Tanzania's Udzungwa Mountains, is currently divided into two populations located approximately 100 km apart. These represent distinct evolutionary lineages that diverged around 0.77 million years ago (MYA). We aimed to investigate i) the phylogeographic history and recent changes in size and range of the two Sanje mangabey populations, and ii) whether lack of suitable habitat between populations and consequent difficulty to disperse may have influenced the 0.77 MYA divergence time. We used 64 mitochondrial control region sequences obtained from non-invasive DNA. The probability of suitable habitat across Tanzania and the Udzungwa Mountains was modelled at three time points: Mid-Holocene (6,000 YA), Last Glacial Maximum (22,000 YA), and the Last Interglacial period (120,000-140,000 YA). We found six haplotypes, clustered into two haplogroups. Significant differentiation was estimated between populations, which show no evidence for recent range expansion or contraction. The ecological niche modelling revealed fluctuating extents of suitable habitat across southern Tanzania. Large genetic differentiation between populations may have been influenced by a general trend in aridification in East Africa across the last 40,000 years, resulting in a shift of montane forests to gradually higher elevations. Intermediate populations may have become extinct as suitable habitat retracted, leaving relict populations with relatively stable demographic histories ancestral to the present-day populations. This study supports their preliminary designation as separate evolutionary significant units, a conclusion with conservation management implications.
Refractory chronic diabetic wounds severely threaten patient survival; however, current treatments do not adequately promote healing. Cathepsin K (CTSK), a collagen-degrading protease upregulated in early diabetic wounds, presents a potential therapeutic target, and human umbilical cord mesenchymal stem cell-derived extracellular vesicles (hUMSC-EVs) show promise in regeneration but are associated with challenges related to production yield and stability. This study hypothesized that combining a stable CTSK inhibitor with hUMSC-EVs could enhance therapeutic efficacy and overcome these challenges. The hypothesis was tested using diabetic wound models in db/db mice with high glucose-exposed human dermal fibroblasts and human umbilical vein endothelial cells. The combination of a CTSK inhibitor and hUMSC-EVs at half doses outperformed full-dose monotherapies, accelerating wound healing through superior effects on collagen synthesis, cell proliferation, migration, and angiogenesis. Mechanistically, the combined treatment promoted wound healing by inhibiting ferroptosis. This strategy demonstrates accelerated wound healing with a lower hUMSC-EV dosage, suggesting promising clinical application potential. A half-dose combination of a cathepsin K and human umbilical cord mesenchymal stem cell-derived extracellular vesicles (hUMSC-EVs) achieved superior diabetic wound healing compared with full-dose monotherapies. The combined therapy more potently suppressed ferroptosis in diabetic wound tissue as well as in high glucose-exposed fibroblasts and endothelial cells. Ferroptosis inhibition enhanced cell survival, migration, angiogenesis, and mitochondrial function in high glucose-exposed fibroblasts and endothelial cells. This dual-target strategy has the potential to reduce the hUMSC-EV dosage while improving wound healing outcomes, thus enhancing clinical potential.
Five new species of Plateros Bourgeois, 1879 are discovered from Hainan Island, China, and described as P. hainanensis sp. nov., P. sinuatus sp. nov., P. elongatus sp. nov., P. dentaticornis sp. nov., and P. spinulosus sp. nov. Three previously known species, including P. belokobylskyi Kazantsev, 2011, P. binhanus (Pic, 1925), and P. bachmaensis Kazantsev & Pham, 2026, are recorded to China for the first time. Females of P. belokobylskyi and P. incurvusimimus Fang, Yang, Yang & Liu, 2024 are identified for the first time. These species are illustrated with their habitus and male genitalia. An identification key to the Plateros species found on Hainan Island, China is provided.
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Large whale strandings along the east coast of the USA have increased in recent years, resulting in unusual mortality event (UME) declarations for several species. Endangered sperm whales Physeter macrocephalus have not been included in a UME; however, recent strandings have shown commonalities that warrant investigation. We analyzed 4 live-stranded sperm whales ('case' whales) in waters of the southeastern USA from 2020-2022 to determine if common factors contributed to death and to inform future management decisions. Thorough investigations were performed, including necropsy, histopathology, and infectious disease and biotoxin testing. Major findings were related to emaciation; there was no evidence of infectious disease or significant toxin exposure. Two of the whales had ingested fishing gear and other marine debris that may have contributed to emaciation. Prey identification and stable isotope analysis (SIA) of these whales combined with SIA of 4 additional sperm whales ('reference' whales) provided further life history data for this species. Prey consumed were primarily cephalopods from families consistent with known sperm whale diets in other parts of the world, and SIA suggested that case whales had similar foraging habitats and trophic levels compared to reference whales. The common finding of emaciation in case whales despite typical prey consumption emphasizes the need for continued research on factors that may influence foraging efficiency or prey availability and quality in this region. Furthermore, finding ingested fishing gear in 2 whales supports continued efforts to monitor and mitigate human impacts to support long-term survival and recovery of sperm whale populations.
Ageing is the primary risk factor for many chronic, degenerative, and life-threatening disorders, yet the translational pipeline for geroprotective interventions remains comparatively sparse. Short‑lived, experimentally tractable models with conserved ageing pathways, particularly Caenorhabditis elegans, Drosophila melanogaster, and the African turquoise killifish (Nothobranchius furzeri), have expanded discovery beyond traditionally mammalian-centric pipelines. By leveraging advances in automation, high-content imaging, and artificial intelligence (AI), these models have shifted the field from low-throughput, reductionist assays to scalable, mechanistically informed in vivo phenotypic discovery. Here, we review recent advances in middle- to high-throughput screening (HTS) technologies across these models, review key phenotypic and molecular biomarkers, such as motility, cognition and memory, intestinal integrity, mitochondrial function, and immune response, and discuss their strengths and limitations. We further evaluate the expanding role of AI from in silico screening, automated and high-content phenotyping, to integrative multi-layer mechanistic inference. Key challenges, including data standardisation, reproducibility across laboratories, limited cross‑species pharmacokinetic comparability, AI model interpretability, and the translational gap between invertebrate hits and vertebrate or mammalian efficacy, are also discussed. By highlighting recent developments in in vivo disease models, HTS methodologies, and AI integration, this review provides a comprehensive resource for developing effective models and screening strategies to accelerate therapeutics for ageing and age-related diseases.
Pharmaceutical agents, such as antiepileptic medications, can cross fetal barriers and affect the developing brain. Prenatal exposure to the antiepileptic drug valproate (VPA) is associated with an increased risk of neurodevelopmental disorders, including congenital malformations and autism spectrum disorder. In animal models and neural organoids, VPA has been shown to alter signaling pathways, such as Wnt pathway, providing insights into VPA-induced neurodevelopmental defects. Here, we exposed dorsal forebrain organoids to VPA for 30 days and examined effects at the tissue, cellular, and molecular level. VPA treatment disrupted ventricular-like regions, indicating defects in cell-cell and cell-matrix interactions. Transcriptomics analysis confirmed altered expression of extracellular matrix (ECM) genes and single cell RNA sequencing analysis identified genes involved in microenvironment sensing, such as cellular mechanosensing and Hippo-YAP/TAZ signaling pathway. Finally, proteomics analysis corroborated that VPA alters the microenvironment of the human dorsal forebrain organoids by disrupting the secretion of ECM proteins. Altogether, our study suggests that VPA-treated dorsal forebrain organoids serve as a model to investigate the role of extracellular processes in brain development and to understand how their disruptions might contribute to neurodevelopmental disorders.
The evolution of body size and its role in structuring communities has long been of interest. Here, we investigated the relationship between body size, phylogeny and spatial patterns of distribution in three aquatic frog genera that have undergone extensive diversification in the Western Ghats of India. We used a comprehensive sampling protocol designed to uncover fine-scale divergence between allopatric and parapatric lineages. First, we found that body size differences between sympatrically distributed lineages were significantly greater than expected in the stream-adapted genera, Nyctibatrachus and Micrixalus, with few assemblages across the entire Western Ghats containing two lineages of the same size. This pattern was not seen in Hylarana where sympatric species typically occupied different habitats, such as streams and ponds. Body size showed significant phylogenetic signal, but we found little overall evidence of phylogenetic clustering or overdispersion in all the genera. We also show that body size evolution in all three frog groups was not strongly affected by character displacement across closely related lineages. Taken together, this provides striking evidence for the potential role of species sorting, where competition leads to spatial assortment of body size, structuring frog assemblages in this tropical biodiversity hotspot.