A Call for One Health in Medical Education: How the COVID-19 Pandemic Underscores the Need to Integrate Human, Animal, and Environmental Health.

During the early stages of the COVID-19 pandemic in 2020, the first author, then a fourth-year student at Harvard Medical School, was enrolled in a One Health clinical experience at Zoo New England where he was introduced to a transdisciplinary approach to integrate human, animal, and ecosystem health. Seeing the vast impact of the pandemic and knowing its roots as a zoonotic disease, he realized this approach was critical to his medical education and for preparation against future novel infectious diseases. Zoonotic diseases have been emerging into human populations with increasing frequency, leading to public health emergencies such as Ebola, avian influenza, and SARS. The SARS-CoV-2 narrative, starting in bats and then mutating through an intermediate host into humans, is another striking example of the interconnectedness between human, animal, and ecosystem health that underlies these infections. Preventing future pandemics will require a transdisciplinary One Health approach, and physicians should be prepared to participate in these discussions while advocating for One Health initiatives for the benefit of their current and future patients. Integration of One Health education into medical school curricula will also prepare future physicians for other complex and urgently important health issues such as climate change, antimicrobial resistance, and the impact of biodiversity loss. As the consequences of the COVID-19 pandemic persist, education in One Health must become a priority; it is essential to break down the conventional disciplinary silos of human medicine, veterinary medicine, environmental health, public health, and the social sciences, so that future health crises can be prevented and mitigated collaboratively.

Spindly leg syndrome in Atelopus varius is linked to environmental calcium and phosphate availability.

Spindly leg syndrome (SLS) is a relatively common musculoskeletal abnormality associated with captive-rearing of amphibians with aquatic larvae. We conducted an experiment to investigate the role of environmental calcium and phosphate in causing SLS in tadpoles. Our 600-tadpole experiment used a fully-factorial design, rearing Atelopus varius tadpoles in water with either high (80mg/l CaCO3), medium (50mg/l CaCO3), or low calcium hardness (20mg/l CaCO3), each was combined with high (1.74 mg/l PO4) or low (0.36 mg/l PO4) phosphate levels. We found that calcium supplementation significantly improved tadpole survival from 19% to 49% and that low calcium treatments had 60% SLS that was reduced to about 15% at the medium and high calcium treatments. Phosphate supplementation significantly reduced SLS prevalence in low calcium treatments. This experimental research clearly links SLS to the calcium: phosphate homeostatic system, but we were unable to completely eliminate the issue, suggesting an interactive role of other unidentified factors.

The Expectations and Challenges of Wildlife Disease Research in the Era of Genomics: Forecasting with a Horizon Scan-like Exercise.

The outbreak and transmission of disease-causing pathogens are contributing to the unprecedented rate of biodiversity decline. Recent advances in genomics have coalesced into powerful tools to monitor, detect, and reconstruct the role of pathogens impacting wildlife populations. Wildlife researchers are thus uniquely positioned to merge ecological and evolutionary studies with genomic technologies to exploit unprecedented "Big Data" tools in disease research; however, many researchers lack the training and expertise required to use these computationally intensive methodologies. To address this disparity, the inaugural "Genomics of Disease in Wildlife" workshop assembled early to mid-career professionals with expertise across scientific disciplines (e.g., genomics, wildlife biology, veterinary sciences, and conservation management) for training in the application of genomic tools to wildlife disease research. A horizon scanning-like exercise, an activity to identify forthcoming trends and challenges, performed by the workshop participants identified and discussed 5 themes considered to be the most pressing to the application of genomics in wildlife disease research: 1) "Improving communication," 2) "Methodological and analytical advancements," 3) "Translation into practice," 4) "Integrating landscape ecology and genomics," and 5) "Emerging new questions." Wide-ranging solutions from the horizon scan were international in scope, itemized both deficiencies and strengths in wildlife genomic initiatives, promoted the use of genomic technologies to unite wildlife and human disease research, and advocated best practices for optimal use of genomic tools in wildlife disease projects. The results offer a glimpse of the potential revolution in human and wildlife disease research possible through multi-disciplinary collaborations at local, regional, and global scales.

The relationship between spindly leg syndrome incidence and water composition, overfeeding, and diet in newly metamorphosed harlequin frogs (Atelopus spp.).

Spindly Leg Syndrome (SLS) is a persistent animal welfare issue associated with the rearing of amphibians in captivity. We conducted two experiments to investigate the effects of diet, water composition and overfeeding on prevalence of SLS in newly metamorphosed harlequin frogs (Atelopus spp.). In our first experiment, we offered 400 full-sibling tadpoles of Atelopus certus isocaloric diets in treatments of 31%, 37%, 42% and 48% crude protein respectively. Tadpoles fed higher protein diets metamorphosed faster, but the incidence of SLS exceeded 80% in all treatments leading to the conclusion that variation in dietary protein was not responsible for causing SLS. We used 720 full-sibling Atelopus glyphus tadpoles in a second experiment to examine the effects of diet type, water composition and diet ration on SLS. We found that an overall incidence of 58% spindly leg in tadpoles reared in tap water, but reduced to about 10% in water treated by reverse osmosis and then reconstituted. It is possible that the reverse osmosis treatment removed some factor that caused the SLS, or that the reconstitution may have added a mineral lacking in the original tap water. Within tap water treatments, overfeeding tadpoles in tanks increased the incidence of SLS. We recommend further experimental research into this condition to identify the causative factors in the water. Additional research into the nutritional composition of food available to wild tadpoles would be useful in formulating captive diets, that have to date been solely based on surrogate species.

PHARMACOKINETICS, EFFICACY, AND SAFETY OF VORICONAZOLE AND ITRACONAZOLE IN HEALTHY COTTONMOUTHS (AGKISTRODON PISCIVORUS) AND MASSASAUGA RATTLESNAKES (SISTRURUS CATENATUS) WITH SNAKE FUNGAL DISEASE.

Snake fungal disease (SFD; Ophidiomyces ophiodiicola) is posing a significant threat to several free-ranging populations of pitvipers. Triazole antifungals have been proposed for the treatment of mycoses in reptiles; however, data are lacking about their safety and efficacy in snakes with SFD. Study 1 investigated in vitro susceptibility, and identified that plasma concentrations >250 ng/ml (voriconazole) and >1,000 ng/ml (itraconazole) may be effective in vivo for SFD. In Study 2, the pharmacokinetics after a single subcutaneous voriconazole injection were assessed in apparently healthy free-ranging cottonmouths (Agkistrodon piscivorus). Based on pilot-study results, four snakes were administered a single injection of voriconazole (5 mg/kg). One pilot snake and three full-study snakes died within 12 hr of voriconazole administration. All surviving snakes maintained plasma concentrations >250 ng/ml for 12-24 hr. In Study 3, two Eastern massasaugas (Sistrurus catenatus) and a timber rattlesnake (Crotalus horridus horridus) diagnosed with SFD were treated with voriconazole delivered by subcutaneous osmotic pumps. The timber rattlesnake (12.1-17.5 mg/kg/hr) reached therapeutic concentrations, whereas the massasaugas (1.02-1.6 mg/kg/hr) did not. In Study 4, the pharmacokinetics of a single 10-mg/kg per-cloaca dose of itraconazole (Sporanox®) was evaluated in seven apparently healthy free-ranging cottonmouths. Similarly, the plasma and tissue concentrations did not meet therapeutic concentrations based on in vitro data. The data presented in this report serve as an initial step toward understanding the pharmacokinetics, efficacy, and safety of triazole antifungals in pitviper species with SFD. Further study is needed to determine the appropriate dose and route of administration of triazole antifungals in pitviper species.

ASSESSMENT OF SERUM 25-HYDROXYVITAMIN D CONCENTRATIONS IN TWO COLLECTIONS OF CAPTIVE GORILLAS (GORILLA GORILLA GORILLA).

Serum 25-hydroxyvitamin D concentrations were assessed in subadult to adult captive lowland gorillas ( Gorilla gorilla gorilla) (n = 26) at two institutions with different husbandry and management practices. Serum 25-hydroxyvitamin D (25[OH]D) concentrations for gorillas managed predominantly indoors was low (14.2 ± 5.9 ng/ml), despite consuming commercial biscuits fortified with vitamin D3. Concentrations of 25(OH)D in gorillas with near daily outdoor access were significantly higher than gorillas managed indoors, although many individuals still had serum values below concentrations recommended for adult humans. Consideration should be given to assessing 25(OH)D concentrations in all captive gorillas and providing specific supplementation, particularly to juveniles without access to direct sunlight.

HYPOALDOSTERONISM IN A MATSCHIE'S TREE KANGAROO (DENDROLAGUS MATSCHIEI).

A 20-yr-old female Matschie's tree kangaroo (Dendrolagus matschiei) was diagnosed with hypoaldosteronism, a rare condition in which the body fails to produce normal amounts of the mineralocorticoid aldosterone. Aldosterone plays a key role in body salt homeostasis, increasing sodium reabsorption and promoting excretion of potassium. Hypoaldosteronism resulted in decreased appetite, lethargy, and weight loss in conjunction with hyponatremia, hyperkalemia, and hypercalcemia in this tree kangaroo. The animal was successfully managed with mineralocorticoid replacement using desoxycorticosterone pivalate. To the authors' knowledge this is the first report of hypoaldosteronism in a tree kangaroo and one of the few reports in the veterinary literature in any species.

Diagnosis and Management of Diabetes Mellitus in a Bali Mynah (Leucopsar rothschildi).

An 18-year-old female Bali mynah (Leucopsar rothschildi) was presented for polyphagia, weight loss, and incoordination. Diabetes mellitus was diagnosed based on the history and clinical findings, including persistent hyperglycemia with concurrent hypoinsulinemia and glucosuria. A treatment protocol was developed that led to improvement of clinical signs and management of hyperglycemia over several months. Because of the advanced age of the animal, difficulty in maintaining euglycemia, and the stress of handling and treatment, euthanasia was elected 167 days after initial presentation. At postmortem examination, no pancreatic lesions were detected histologically that would account for the diabetes mellitus. To our knowledge this is the first reported case of diabetes mellitus and clinical management of this condition in a passerine species.

Nutrition and health in amphibian husbandry.

Amphibian biology is intricate, and there are many inter-related factors that need to be understood before establishing successful Conservation Breeding Programs (CBPs). Nutritional needs of amphibians are highly integrated with disease and their husbandry needs, and the diversity of developmental stages, natural habitats, and feeding strategies result in many different recommendations for proper care and feeding. This review identifies several areas where there is substantial room for improvement in maintaining healthy ex situ amphibian populations specifically in the areas of obtaining and utilizing natural history data for both amphibians and their dietary items, achieving more appropriate environmental parameters, understanding stress and hormone production, and promoting better physical and population health. Using a scientific or research framework to answer questions about disease, nutrition, husbandry, genetics, and endocrinology of ex situ amphibians will improve specialists' understanding of the needs of these species. In general, there is a lack of baseline data and comparative information for most basic aspects of amphibian biology as well as standardized laboratory approaches. Instituting a formalized research approach in multiple scientific disciplines will be beneficial not only to the management of current ex situ populations, but also in moving forward with future conservation and reintroduction projects. This overview of gaps in knowledge concerning ex situ amphibian care should serve as a foundation for much needed future research in these areas.

Causes of mortality in anuran amphibians from an ex situ survival assurance colony in Panama.

The success of ex situ survival assurance populations as tools for amphibian conservation depends on the health and reproductive success of founder populations. Necropsy examination and histopathology of animals that die in assurance populations are useful for the identification of population-limiting disease problems and can help to direct applied research efforts in areas such as amphibian husbandry and nutrition. This study reviewed postmortem findings in 167 frogs from 13 species that died in a large Panamanian rescue and survival assurance population between 2006 and 2011. Common problems identified in long-term captive animals, especially in Atelopus species, were epithelial squamous metaplasia suggestive of vitamin A deficiency and a polycystic nephropathy resembling lesions seen in laboratory animals with electrolyte imbalances. Metabolic bone disease was a significant contributor to morbidity in captive-bred juvenile frogs of Gastrotheca cornuta, Hemiphractus fasciatus, and Hylomantis lemur. Findings common to multiple species included poor overall nutritional condition that was sometimes attributable to maladaptation to captive husbandry and epidermal hyperplasia and hyperkeratosis possibly reflecting environmental skin irritation. Infectious diseases and endoparasitism were most common in recently captured animals and included chytridiomycosis and Rhabdias sp. lungworms. Applied research efforts to improve sustainability of survival assurance populations should focus on elucidating optimal husbandry practices for diverse species, improving methods for nutritional supplementation of cultured insects and examination of the role of water composition in disease development.

Investigation and control of an attaching and effacing Escherichia coli outbreak in a colony of captive budgerigars (Melopsittacus undulatus).

An increase in mortality in a captive flock of budgerigars (Melopsittacus undulatus) coincided with the isolation of attaching and effacing Escherichia coli from postmortem samples. Common histologic lesions included hepatitis, enteritis, and in one case attaching and effacing lesions along the intestinal tract. Retrospective review of necropsy records and increased sampling led to the identification of several cases of E. coli with the attaching and effacing (eae) virulence gene. Factors such as environment, nutrition, and concomitant pathogens were thought to contribute to mortality in the flock. Although it is not clear whether E. coli was a primary pathogen during the period of increased mortality, the presence of the eae gene combined with associated histologic lesions supports the conclusion that this organism was a significant contributor to mortality. Manipulation of diet, environment, and the addition of probiotic supplementation resulted in a decline in mortality rate and decreased shedding of E. coli based on negative follow-up cultures of intestines, liver, and feces.

Pathogenesis, diagnosis, and treatment of amphibian chytridiomycosis.

Chytridiomycosis, caused by the chytridiomycete fungus, Batrachochytrium dendrobatidis, is an important pathogen of amphibians in captivity and is a major concern for global conservation of amphibians. The organism infects keratinized epithelial cells of amphibian skin and causes disease and mortality by interfering with important skin functions, especially electrolyte balance. Primary treatments are with antifungal medications applied in a topical bath solution, and itraconazole is the most commonly used agent, although several different options are available. Supportive treatment of the clinically ill patient is necessary for success, with particular attention to electrolyte therapy.

Multiple endocardial neurofibromas in a rosy-billed pochard (Netta peposaca).

Endocardial neoplasms are uncommon in veterinary species with most cases restricted to endocardial schwannomas in aged rats. A 15-year-old male rosy-billed pochard (Netta peposaca) was diagnosed following necropsy with numerous, proliferative endocardial masses. Histologically, these masses were composed of interlacing streams and bundles of neoplastic spindle cells supported by a fine fibrovascular stroma. Rare areas of cellular and nuclear palisading were present in the nodules. Approximately 60% of the neoplastic cells were strongly positive for S-100, whereas none of the neoplastic cells was positive for desmin, synaptophysin, neurofilament, and glial fibrillary acidic protein. The histologic features coupled with the S-100 immunoreactivity led to a diagnosis of endocardial neurofibroma.

Passive transfer of maternal antibodies to West Nile virus in flamingo chicks (Phoenicopterus chilensis and Phoenicopterus ruber ruber).

Passive transfer of maternal antibodies against West Nile virus (WNV) was studied in a captive population of Chilean (Phoenicopterus chilensis) and Caribbean flamingos (Phoenicopterus ruber ruber). Transfer of WNV antibodies from hens to chicks was documented and measured by plaque-reduction neutralization test. Hen titers were significantly correlated to chick titers. Mean half-life of maternal WNV antibodies was 13.4 days in chicks for which half-life was measurable.

Preliminary evaluation of blood lipid profiles in captive western lowland gorillas (Gorilla gorilla gorilla).

Published serum cholesterol values in captive western lowland gorillas (Gorilla gorilla gorilla) are much higher than human ranges, with a national mean of 7.36 mmol/L (284 mg/dl, n = 863). Complete blood lipid profiles were examined in 15 captive gorillas. High-density lipoprotein (HDL) was found to decrease more rapidly with age than total cholesterol, resulting in an increasing ratio of cholesterol HDL with age. The ratio of apolipoprotein B to apolipoprotein Al also increased with age. Establishment of a database of blood lipid values for captive gorillas with correlative analysis of animals with known atherosclerosis status may help to identify sensitive predictors of coronary heart disease risk.

Leptospirosis in Wied's marmosets (Callithrix kuhlii).

Two adult Wied's marmosets (Callithrix kuhlii) presented with jaundice, anemia, and weight loss. Death of one individual was attributed to renal tubular necrosis; liver and kidney were positive for Leptospira antigen by immunohistochemical (IHC) staining. The second animal was negative for antigen by IHC staining, but serologically positive for Leptospira borgpetersenii serovar ballum with an eightfold titer increase in paired samples, and was euthanized because of unresponsiveness to treatment. Environmental contamination by mice was suspected as the Leptospira source.

Cholelithiasis in four callitrichid species (Leontopithecus, Callithrix).

Medical records of three male and three female callitrichids of four species (Leontopithecus chrysopygus, Leontopithecus rosalia, Callithrix argentata argentata, Callithrix kuhlii) diagnosed with cholelithiasis were reviewed. Ages of affected animals at the time of diagnosis ranged from 2-14 yr. Definitive antemortem diagnosis of cholelithiasis was made in four of the six cases. Chronic weight loss, lethargy, and weakness were seen in all cases. Chronic intermittent diarrhea was seen in three cases. Icterus and abnormal gait were each present in two of the animals. Hematologic and serum biochemical abnormalities included leukocytosis in five cases, elevated bilirubin (direct and indirect) in four cases, and anemia in four cases. Radiographic evidence of choleliths was observed in three cases. Surgical removal of choleliths was successfully performed on two animals. Full necropsies were performed on all cases, and choleliths were believed to contribute to morbidity in all cases. However, inflammatory bowel disease was determined to be the primary cause of weight loss and mortality in at least three animals. All choleliths analyzed were pigment stones, two being primarily composed of cystine.

Successful treatment of atlantooccipital luxation in an alpaca (Lama pacos).

A 7-mo-old male alpaca (Lama pacos) presented with an abnormal lowered posture of the head and neck and reluctance to walk. Cervical radiographs demonstrated atlantooccipital luxation. Successful manual closed reduction was achieved while the animal was anesthetized, resulting in complete return to normal gait and posture.