Journal of Zoological and Botanical Gardens

Introduction: The artificial environment of zoological gardens poses risks for the transmission of parasitic diseases, among which ascarid infections in bears are exceptionally common. Due to the zoonotic potential of Baylisascaris transfuga and the morphological overlap of its eggs with other roundworms, accurate diagnosis is critical within the “One Health” framework. Materials and Methods: Following anthelmintic treatment with ivermectin and praziquantel, adult nematodes were collected from a captive brown bear (Ursus arctos) at the Sofia Zoo, Bulgaria. Detailed morphometric examination was performed for species identification, complemented by molecular-genetic and phylogenetic analyses targeting the nuclear 28S rDNA and mitochondrial COI genes. Results: Morphometric analysis revealed a specific “miniaturised” morphotype of B. transfuga, characterized by body lengths and egg dimensions that fell within or below the minimum ranges reported for wild populations. Crucially, despite the observed changes in general morphometric parameters, the male reproductive structures—specifically the spicules—exhibited high metric conservativeness (533–570 µm), confirming their reliable diagnostic value. Nuclear 28S rDNA sequences provided definitive taxonomic validation, showing a match with Palearctic lineages and distinguishing the isolate from the Nearctic cluster. At the same time, the mitochondrial COI marker captured intraspecific diversity, identifying three distinct new haplotypes co-existing within the single host. Conclusions: The observed general reduction in morphological measurements combined with reproductive metric stability demonstrates environmentally induced phenotypic variation. Furthermore, the simultaneous presence of multiple COI haplotypes highlights the cumulative nature of the infection through successive exposure over time (trickle infection), although simultaneous infection with these genetic variants cannot be entirely discarded. The global macrogeographical differentiation captured by both markers suggests noticeable genetic divergence among geographic lineages within the distribution range of the taxon, while future broad-scale investigations are required to fully clarify underlying microevolutionary patterns. These findings underscore the high adaptive potential of B. transfuga and emphasize the necessity of integrating morphometrics with molecular tools for accurate wildlife monitoring in captivity.

Pain assessment remains a major challenge in avian medicine and wildlife rehabilitation because birds frequently exhibit subtle and species-specific responses that are difficult to detect under field conditions. The objective of this study was to identify, validate and operationalise indicators suitable for assessing pain in wild birds admitted to rescue, rehabilitation and zoological facilities. A four-phase approach was used, including a literature review, expert validation, field validation and the development of a Bird Pain Index (BPI). Scientific publications indexed in Scopus and Web of Science were reviewed to identify candidate pain indicators. Then, veterinarians, wildlife rehabilitation professionals, zoo personnel, ornithologists and animal welfare specialists evaluated the relevance, magnitude and applicability of each indicator using structured questionnaires. Forty candidate indicators were initially identified through the literature review; following expert assessment, only 25 indicators exceeded the acceptance threshold (>60%) for field validation. Nine indicators were ultimately validated as Operational Pain Indicators (OPIs) based on high field feasibility: isolation behaviour (78%), half-closed eyelids (75%), anorexia (73%), stillness (70%), loss of grooming (67%), miosis/mydriasis/anisocoria (67%), seated posture (65%), ruffled feathers (64%), and pain concealment behaviour (62%). Most validated indicators were behavioural or clinical measures that could be assessed without handling the animals, while physiological indicators generally showed lower field applicability. The validated OPIs were integrated into a preliminary BPI designed to support clinical decision-making and welfare assessment.

Zoo habitats are now designed with a larger focus on animal wellbeing and the opportunities provided by more naturalistic environments. While such spaces are assumed to be beneficial for animal wellbeing, evidence to support that assumption is infrequently collected. Our primary objective was to evaluate changes in behavior for three primate species at the Saint Louis Zoo after they were moved from static, indoor habitats to larger, more dynamic outdoor ones. We also used this as an opportunity to document the effects of long-term nearby construction. We quantified behavior for the Zoo’s Guereza colobus (Colobus guereza), black-handed spider monkeys (Ateles geoffreyi), and Coquerel’s sifaka (Propithecus coquereli) indoors prior to construction (i.e., baseline), during the construction period, and after the animals moved to new outdoor habitats. In addition, sound data were collected during the baseline and construction phases of the study to quantify the potential effects of noise on behavior. Linear models were used to test differences in behavior between phases and associations of behavior with logarithmic daily average median sound levels while controlling for covariates such as group size and gate count. We observed evidence that construction may have been aversive, such as an increase in time spent inactive, a decrease in time spent locomoting, and an increase in self-directed behaviors. However, most models explained minimal variation in these behaviors, suggesting construction had a relatively weak impact on behavior. The differences observed between the baseline and new habitats phases indicated the new habitats were beneficial for animal wellbeing, including increases in some positive species-typical behaviors, decreases in agonistic behavior in the colobus and sifaka, and decreases in self-directed behaviors in the colobus and spider monkeys. This study provides evidence that large, dynamic, naturalistic habitats have beneficial effects on primate wellbeing, as measured using a combination of species-typical and self-directed behaviors.