The crucial contribution of veterinarians to conservation biology.

Conservation biology is a relatively new (began in the 1980s), value-based discipline predicated on the belief that biological diversity-from genes to populations to species to communities to ecosystems-is good and extinction is bad. Conservation biology grew from the recognition that the Earth has entered its sixth great extinction event, one that differs from previous great extinctions in that a single species-Homo sapiens-has caused this biodiversity crisis. A diverse, interacting set of variables drive current extinctions. As such, to succeed, conservation efforts usually require broad-based, interdisciplinary approaches. Conservationists increasingly recognize the importance of contributions by veterinary science, among many other disciplines, to collaborative efforts aimed at stemming the loss of biodiversity. We argue that, to improve success rates, many wildlife conservation programs must incorporate veterinarians as part of an interdisciplinary team to assess and address problems. Ideally, veterinarians who participate in conservation would receive specialized training and be willing to work as partners as part of a larger team of experts who effectively integrate their work rather than work independently (i.e., work as interdisciplinary, as opposed to multidisciplinary, teams, respectively). In our opinion, the most successful and productive projects involve interdisciplinary teams involving both biological and nonbiological specialists. Some researchers hold multiple degrees in biology and veterinary medicine or the biological and social sciences. These experts can often offer unique insight. We see at least 3 major areas in which veterinarians can immediately offer great assistance to conservation efforts: (1) participation in wildlife capture and immobilization, (2) leadership or assistance in addressing wildlife health issues, and (3) leadership or assistance in addressing wildlife disease issues, including using wildlife as sentinels to identify new and emerging diseases or epidemics of old diseases. We cover each of these main topics in detail.

Veterinary assessment for free-ranging Eurasian Black Vulture (Aegypius monachus) chicks in southeastern Mongolia.

Working as a veterinarian in remote field locations can be physically and intellectually challenging. A collaborative multi-disciplinary approach is often required for successful data collection. Technologies and methodologies frequently need to be modified to work in these harsh field environments. This article will describe a collaboration in southeastern Mongolia collecting blood for sera analytes and physiologic data from Eurasian Black Vulture (Aegypius monachus) chicks during a tagging operation.

25-OH-D(3), calcium, phosphorus, and alkaline phosphatase content in sera from captive polar bear (Ursus maritimus) cubs at the Denver Zoological Foundation.

After the development of rickets in two hand-reared polar bear (Ursus maritimus) cubs at the Denver Zoological Foundation we initiated a project opportunistically evaluating sera 25-OH-D(3), calcium, phosphorus, and alkaline phosphatase levels in seven mother-reared polar bear cubs. From one to three serum samples were obtained while the cub was still in the den with no access to natural sunlight and one after the cub exited the den. The sera 25-OH-D(3) increased as the cubs grew (108+/-37 nmol/L [n=7] while in den, 184.6+/-48.3 nmol/L [n=7] out of the den) but were substantially lower then captive adults (348+/-215 nmol/L [n=36]) or free-ranging adults (360+/-135 nmol/L [n=56]). We found that age was correlated significantly with 25-OH-D(3) levels but den status (in or out) was not significant. Sera calcium and phosphorus values were highest in denned cubs (calcium, 2.9+/-0.4 mmol/L [n=13]; phosphorus, 3.1+/-0.5 mmol/L [n=13]) and then declined as the cubs matured and left the den (calcium, 2.5+/-0.1 mmol/L [n=7]; phosphorus, 2.4+/-0.4 mmol/L [n=7]). The enzyme alkaline phosphatase (presumably the bone isoenzyme) was high in denned growing cubs (831+/-426 IU/L [n=13]) and then declined gradually as the cubs aged and exited the den (96+/-83 IU/L [n=7]). Zoo Biol 0:1-7, 2007. (c) 2007 Wiley-Liss, Inc.

Myasthenia gravis in a polar bear (Ursus maritimus).

A 14.6-yr-old, female, multiparous polar bear (Ursus maritimus) acutely developed an apparent hind limb weakness. Physical examination and diagnostic tests including a hemogram, serum biochemistry, electrolytes, radiographs, and myelogram did not provide a definitive diagnosis. No improvement in condition was noted during 4 days of supportive care, and the bear was euthanized. An ovoid mass was present in the anterior mediastinum, and a thymoma was confirmed histologically. Compared with control polar bears, elevated serum acetylcholine receptor (AChR) antibodies (0.13 +/- 0.06 nmol/L vs. 0.86 nmol/L) were detected by immunoprecipitation radioimmunoassay, which is consistent with myasthenia gravis (MG) in other species. Although the AChR antibody test has not been validated in the polar bear, we are confident in the postmortem diagnosis of MG, which is commonly associated with thymoma in other species.

Intracapsular lens removal in a Przewalski's wild horse (Equus caballus przewalskii).

A 11.5-yr-old female Przewalski's wild horse (Equus caballus przewalskii) presented for unilateral blepharitis and drainage from the left eye. The left cornea was not ulcerated, and intraocular evaluation was hampered by severe corneal edema. The left eye appeared to respond positively to treatment with anti-inflammatories and a topical mydriatic agent. During the ensuing 2 yr, there were minor episodes of epiphora from the left eye. The discharge then increased, and a luxated lens was noted during an examination by a veterinary ophthalmologist as part of the preshipment examination. Initially, the lens was located in the anterior compartment but was in the vitreal compartment at the time of surgery, complicating the intracapsular extraction. After successful removal of the lens, the horse was transferred to a new institution without incident, where it appears to have adapted well to its probable loss of vision in the left eye. No further episodes of uveitis, corneal edema, or epiphora have been reported, and the horse has successfully foaled at the new institution.

Negative-pressure pulmonary edema complicated by acute respiratory distress syndrome in an orangutan (Pongo pygmaeus abelii).

A 22-yr-old, 86-kg, morbidly obese female orangutan (Pongo pygmaeus abelii) was immobilized and transported to the Denver Zoological Gardens hospital for a routine physical examination. Immediately after arriving at the hospital, cyanosis and apparent inadequate ventilatory efforts were noted. Clinically significant hypoxia occurred despite attempts to ventilate the orangutan through face mask, and attempts to place an endotracheal tube began. A large volume of pink-tinged frothy fluid flowed from the trachea when the laryngoscope was inserted into the oropharynx. Severe pulmonary edema due to negative-pressure pulmonary edema, precipitating life-threatening hypoxia was suspected. The orangutan was maintained on a mechanical ventilator using the neuromuscular blocking agent cisatracurium besylate and sedation with periodic doses of isoflurane and midazolam for 48 hr. Positive end-expiratory pressure was used while the orangutan was ventilated mechanically to improve respiratory function. The edema and hypoxia improved, but respiratory arrest ensued 30 min after extubation, when the orangutan was removed from mechanical ventilation. Necropsy and histopathology demonstrated that serious lung injury had led to acute respiratory distress syndrome.

Toxoplasmosis in Pallas' cats (Otocolobus felis manul) at the Denver Zoological Gardens.

In May 1996 the Denver Zoological Gardens obtained two male and two female Pallas' cats (Otocolobus felis manul) that were wild-caught in the Ukraine. These animals were part of a group of 16 wild-caught adults (eight male and eight female) imported to the United States and Canada between 1995 and 1996. The Denver Zoological Gardens cats were quarantined at the zoo hospital for approximately I mo. During the quarantine period they were immobilized for physical examination, and sera were obtained from them to evaluate for exposure to Toxoplasma gondii. All cats were positive for T. gondii antibodies by latex agglutination (titers from 1:512 to 1:1,024). After being paired for breeding, one pair produced two litters, and another pair produced four litters, a total of 17 kittens between 1997 and 2001. Four kittens and two young adults died from a disseminated granulomatous and necrotizing inflammation consistent with toxoplasmosis. Toxoplasma gondii infection was confirmed in all six deceased cats by polymerase chain reaction performed on formalin-fixed tissues. An additional five kittens disappeared and were not available for necropsy. The fatality rate from toxoplasmosis was 35.3% (6/17) for cats that were available for necropsy and could have been as high as 64.7% (11/17) if it were assumed that the disappeared kittens were also affected. The Pallas' kitten survival rate at the Denver Zoological Gardens was 35.3%. This article describes the clinical and pathologic features of toxoplasmosis in a group of Pallas' cats at the Denver Zoological Gardens.