Sources of morbidity in lorises and pottos in North American zoos: A retrospective review, 1980-2010

A SYSTEMATIC REVIEW OF RETROSPECTIVE MORBIDITY AND MORTALITY STUDIES ON CAPTIVE WILDLIFE SPECIES

Zoological institutions manage animals for conservation, education, entertainment, and research purposes. Zoological staff have a responsibility to safeguard the welfare of animals in their care. Retrospective morbidity and/or mortality studies (MMSs) can be useful tools to highlight common diseases in captive wildlife populations. There is currently no standardized methodology for conducting MMSs. Variation in the methodology of MMSs, particularly the categorization of diseases, can make comparisons between studies challenging and may limit the applicability of the results. A Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) compliant systematic review was performed, which identified 67 MMSs describing 146 species of captive wildlife. These MMSs are becoming more common and were predominantly performed on mammals (76/146). Prospective authors are encouraged to perform MMSs on amphibians, birds, reptiles, fish, and invertebrates. The studied animals were mostly managed at institutions in the United States of America (28/67, 41.2%) and Europe (14/67, 20.9%). Classifying individuals into age groups facilitates the identification of disease trends within age classes. Only 22/67 (32.8%) studies cited justification for their age classification; classifications should be based on a referenced source on the breeding biology of the studied species. There is variation in the body systems used by authors and into which system a disease is categorized, which makes study comparisons challenging. Diseases were predominantly categorized by etiology and body system (28/77, 36.4%). Because of its ubiquity, the use of the categorization system employed by the pathology module of the Zoological Information Management System is recommended as a useful standard. This system is imperfect, and amendments to it are suggested. The results and recommendations of this study were discussed with a panel of zoo and wildlife experts; guidelines have been formulated for prospective authors aiming to conduct MMSs in captive wildlife.

CLINICAL FINDINGS OF DENTAL DISEASE AND POTENTIAL CONTRIBUTING FACTORS IN PYGMY SLOW LORISES (NYCTICEBUS PYGMAEUS) UNDER HUMAN CARE

Dental disease is a common finding in pygmy slow lorises (Nycticebus pygmaeus) under human care, but the etiology is not fully understood. The small oral cavity in this species can make diagnosis of dental disease difficult. This retrospective study evaluated medical records and diet and husbandry protocols from 18 participating institutions with the objective of describing the signalment, clinical signs, physical exam findings, tooth type, tooth location, diagnostics used, and treatments performed to help guide care for dental disease. In addition, the study aimed to identify potential contributing factors to dental disease in this species. Of 59 animals with medical records evaluated, 42 (71.2%) had dental disease: 19 (44.2%) males, 20 (46.5%) females, and 3 (9.3%) without gender documented. Average age at onset of dental disease was 7.6 yr in males and 9 yr in females. Multiple lorises with dental disease (n = 12; 28.6%) had no premonitory clinical signs, and dental disease was found incidentally on examination. On dental examination, 30 lorises (71.4%) had evidence of gingivitis. In 13 cases skull radiographs were taken, but the majority of images (n = 8; 61.5%) were nondiagnostic for pathologic dental changes. A small proportion of cases with dental abnormalities (n = 4; 9.5%) were diagnosed using computed tomography. In total, 175 teeth were extracted from 31 patients; molars were the most frequently extracted tooth (n = 55; 31.4%). No substantial differences in diets were noted among many of the participating institutions, and not all slow lorises evaluated developed dental disease (n = 17; 28.8%). This retrospective study provides clinical findings on slow loris dental disease and guidance for the veterinary care and management of slow lorises under human care.

Slowly Making Sense: A Review of the Two-Step Venom System within Slow (Nycticebus spp.) and Pygmy Lorises (Xanthonycticebus spp.)

Since the early 2000s, studies of the evolution of venom within animals have rapidly expanded, offering new revelations on the origins and development of venom within various species. The venomous mammals represent excellent opportunities to study venom evolution due to the varying functional usages, the unusual distribution of venom across unrelated mammals and the diverse variety of delivery systems. A group of mammals that excellently represents a combination of these traits are the slow (Nycticebus spp.) and pygmy lorises (Xanthonycticebus spp.) of south-east Asia, which possess the only confirmed two-step venom system. These taxa also present one of the most intriguing mixes of toxic symptoms (cytotoxicity and immunotoxicity) and functional usages (intraspecific competition and ectoparasitic defence) seen in extant animals. We still lack many pieces of the puzzle in understanding how this venom system works, why it evolved what is involved in the venom system and what triggers the toxic components to work. Here, we review available data building upon a decade of research on this topic, focusing especially on why and how this venom system may have evolved. We discuss that research now suggests that venom in slow lorises has a sophisticated set of multiple uses in both intraspecific competition and the potential to disrupt the immune system of targets; we suggest that an exudate diet reveals several toxic plants consumed by slow and pygmy lorises that could be sequestered into their venom and which may help heal venomous bite wounds; we provide the most up-to-date visual model of the brachial gland exudate secretion protein (BGEsp); and we discuss research on a complement component 1r (C1R) protein in saliva that may solve the mystery of what activates the toxicity of slow and pygmy loris venom. We conclude that the slow and pygmy lorises possess amongst the most complex venom system in extant animals, and while we have still a lot more to understand about their venom system, we are close to a breakthrough, particularly with current technological advances.

Breaking the constraint on the number of cervical vertebrae in mammals: On homeotic transformations in lorises and pottos

Mammals almost always have seven cervical vertebrae. The strong evolutionary constraint on changes in this number has been broken in sloths and manatees. We have proposed that the extremely low activity and metabolic rates of these species relax the stabilizing selection against changes in the cervical count. Our hypothesis is that strong stabilizing selection in other mammals is largely indirect and due to associated pleiotropic effects, including juvenile cancers. Additional direct selection can occur due to biomechanical problems (thoracic outlet syndrome). Low metabolic and activity rates are thought to diminish these direct and indirect effects. To test this hypothesis within the primates, we have compared the number of cervical vertebrae of three lorisid species with particularly low activity and metabolic rates with those of more active primate species, including with their phylogenetically closest active relatives, the galagids (bushbabies). In support of our hypothesis, we found that 37.6% of the lorisid specimens had an abnormal cervical count, which is a higher percentage than in the other nine primate families, in which the incidence varied from zero to 2.2%. We conclude that our data support the importance of internal selection in constraining evolvability and of a relaxed stabilizing selection for increasing evolvability. Additionally, we discuss that there is no support for a role of the muscularized diaphragm in the evolutionary constraint.

Bioacoustics as a tool to monitor the estrus cycle in a female slow loris (Nycticebus sp.)

Evidence-based husbandry leading to increased reproductive success and strengthening of ex situ populations of slow lorises (Nycticebus spp.) living in zoos is highly important. Better fulfillment of their social needs is one of the main priorities in achieving these objectives. We performed 21-month long acoustic monitoring of a zoo-kept female slow loris (Nycticebus sp.) housed either singly or with one of two males to examine whether her estrus cycle potentially could be detected based on her vocal activity. We found a regular cycle of remarkably increased whistle production that lasted approximately 31.2 days in a nocturnal exhibit and approximately 39 days in an off-show room. The regular cycle of increased vocal activity corresponded to a previously described estrus cycle of slow lorises and was observable in the presence of both males as well as when the female was housed singly. Additionally, vaginal smears collected from the female close to the peak period of her vocal activity showed signs of proestrus and estrus. The acoustic properties of the whistles, specifically that they did not overlap with or were loud enough to exceed background noise commonly occurring in zoos, made them perfect candidates for analyses involving automatic processing of a large number of recordings. We conclude that bioacoustics represents a promising, completely noninvasive and relatively easily applicable tool that allows detection and anticipation of the estrus cycle in some females, thus improving the social management of slow lorises living in zoos.