Combining host and vector data informs emergence and potential impact of an Usutu virus outbreak in UK wild birds.

Following the first detection in the United Kingdom of Usutu virus (USUV) in wild birds in 2020, we undertook a multidisciplinary investigation that combined screening host and vector populations with interrogation of national citizen science monitoring datasets to assess the potential for population impacts on avian hosts. Pathological findings from six USUV-positive wild passerines were non-specific, highlighting the need for molecular and immunohistochemical examinations to confirm infection. Mosquito surveillance at the index site identified USUV RNA in Culex pipiens s.l. following the outbreak. Although the Eurasian blackbird (Turdus merula) is most frequently impacted by USUV in Europe, national syndromic surveillance failed to detect any increase in occurrence of clinical signs consistent with USUV infection in this species. Furthermore, there was no increase in recoveries of dead blackbirds marked by the national ringing scheme. However, there was regional clustering of blackbird disease incident reports centred near the index site in 2020 and a contemporaneous marked reduction in the frequency with which blackbirds were recorded in gardens in this area, consistent with a hypothesis of disease-mediated population decline. Combining results from multidisciplinary schemes, as we have done, in real-time offers a model for the detection and impact assessment of future disease emergence events.

CONSERVATION CHALLENGES: THE LIMITATIONS OF ANTEMORTEM TUBERCULOSIS TESTING IN CAPTIVE ASIATIC LIONS (PANTHERA LEO PERSICA).

Genetic diversity of captive wild animals can be enhanced by moving those individuals with valuable genes between collections and through introduction of a new pair from a range country. This requires movement of animals, which is inherent with disease risks, such as the introduction of pathogenic Mycobacterium sp. (MTBC) into a zoological collection. Decisions need to be made based on the outcome of perimovement disease screening using an array of tests, the majority of which are unvalidated in the species. A pair of endangered Asiatic lions (Panthera leo persica) imported from India to the United Kingdom were screened for MTBC using the comparative intradermal tuberculosis (TB) test, the feline interferon-γ blood test, and the experimental bacteriophage assay. Reactions on all three tests prompted screening of the three resident Asiatic lions using the same tests, all of which were negative for MTBC. Based on these test results, the decision had to be made to exclude the genetically valuable pair from the current collection. MTBC could not be identified using further tests, including culture and PCR on a bronchoalveolar lavage, on feces, or on postmortem tissues. This case series highlights the usefulness of a control group when interpreting unvalidated test results for detection of MTBC, the value of training big cats for conscious blood sampling, and the practical implications of placing the comparative intradermal TB test in the eyelids, when dealing with a species that requires a general anesthetic for most hands-on interventions.

THE MANAGEMENT OF AN ORAL ANAPLASTIC SARCOMA IN A PYGMY HIPPOPOTAMUS (CHOEROPSIS LIBERIENSIS) USING INTRALESIONAL CHEMOTHERAPY.

An adult female captive pygmy hippopotamus (Choeropsis liberiensis) was diagnosed with an oral anaplastic sarcoma. The tumor was surgically debulked and intralesional chemotherapy with mitomycin C (0.4 mg/cm3 of tumor) and cisplatin (1 mg/cm3 of tumor) was administered. Chemotherapeutic treatment proved difficult due to the risks of repeated anesthetics and unknown drug efficacies. Marked proliferation of the mass was observed during estrus, and chemotherapy was repeated as an experimental treatment to slow tumor progression in order for the animal to remain in the species breeding program. Tumor proliferation was detected during the first trimester of pregnancy; however, in the lactation period, the mass became quiescent. No adverse reactions to chemotherapeutic drugs were observed and the animal continues to be monitored for tumor progression. This is the first report of an anaplastic sarcoma and of chemotherapy use in a pygmy hippopotamus and it highlights logistical considerations for treating neoplasia in this species.

Fatal echinococcosis in three lemurs in the United Kingdom--A case series.

Tapeworms of the genus Echinococcus reside in the small intestine of a number of carnivorous species, predominantly canids. In enzootic areas, hydatidosis caused by taeniid metacestodes can present a significant problem in accidental intermediate hosts, including humans. Whereas the United Kingdom is currently considered free of Echinococcus multilocularis, Echinococcus granulosus sensu stricto (s.s.) and Echinococcus equinus are endemic in the UK and have been reported in a variety of captive mammals. The presentation of echinoccocosis in non-human primates widely parallels disease in humans, and public health concerns are related to the four genera, E. granulosus, E. multilocularis, Echinococcus vogeli and Echinococcus oligarthrus. In contrast, sporadic outbreaks and individual hydatid disease cases in non-human primates have been associated with several Echinococcus and Taenia species. Here we describe three fatal cases of cystic echinococcosis in two captive ring-tailed lemurs (Lemur catta) and one captive red-ruffed lemur (Varecia variegata rubra) and provide molecular tapeworm characterisation. To the best of the authors' knowledge, this includes the first report of Echinococcus ortleppi in a UK born ring-tailed lemur and provides the first in depth case reports of echinococcosis due to E. equinus in UK born ring-tailed and red ruffed lemurs with detailed clinical and pathological findings. The cestode life cycle and implications for zoo collections are discussed.

Unilateral eyelid lesion and ophthalmologic findings in an aardvark (Orycteropus afer): case report and literature review.

OBJECTIVE: To summarize the medical knowledge surrounding aardvarks to date, to describe the ophthalmic examination of a specimen with a chronic history of an upper eyelid lesion, of an assumed blind left eye, and to detail the anesthesia procedure performed. PROCEDURE: A 23-year-old aardvark was examined under general anesthesia and multiple ocular abnormalities were detected in the left eye (globe deviation, corneal opacities, iridodonesis, and aphakia). A thickening of the palpebral conjunctiva affecting the medial upper eyelid with erosion of the normal eyelid margin anatomy was identified. The adnexal lesion was resected by a wedge resection and histopathology was performed. Suture breakdown 3 days postoperatively required a second surgery, where buried sutures were used. The surgical techniques and postoperative care are discussed. RESULTS: The histopathology revealed mucosal hyperplasia and moderate neutrophilic and lymphoplasmacytic blepharitis. No causal organisms were identified. Following initial wound dehiscence and a modified surgical technique, the upper eyelid healed without complication and retained complete function. CONCLUSIONS: The eyelid lesion involved a benign inflammatory and hyperplastic pathology of unknown etiology. Adjusting routine ophthalmic surgical techniques to wildlife and zoo animals can be challenging and complicated. It is important to understand the nature of the animals being managed, their circadian cycle, and habitat, to adjust and individualize the surgical approach, instrumentation, suture material, and perioperative treatment.

Debilitating clinical disease in a wild-born captive western lowland gorilla (Gorilla gorilla gorilla) co-infected with varicella zoster virus (VZV) and simian T-lymphotropic virus (STLV).

A wild-born, 34-yr-old female western lowland gorilla (Gorilla gorilla gorilla) was transferred between zoologic collections in the United Kingdom. Adjustment to its new environment was difficult and a series of health problems ensued. Progressive severe illness of multiple etiologies, and a failure to respond to multiple therapies, led to its euthanasia 5 mo later. Disease processes included severe thoracic and axillary cutaneous ulceration of T2-3 dermatome distribution, gastroenteritis, ulcerative stomatitis, emaciation, hind limb weakness or paresis, and decubitus ulcers of the ankles and elbows. Ante- and postmortem infectious disease screening revealed that this animal was not infected with Mycobacterium tuberculosis, simian varicella virus (SVV), simian immunodeficiency virus (SIV), or hepatitis B virus; but was infected with varicella-zoster virus (VZV) and simian T-lymphotropic virus (STLV). It is hypothesized that recrudescence of VZV and other disease processes described were associated with chronic STLV infection and the end of a characteristically long incubation period.

Peri-anaesthetic and anaesthetic-related mortality risks in great apes (Hominidae) in zoological collections in the UK and Ireland.

OBJECTIVE: To estimate the risk of death and identify the major risk factors for peri-anaesthetic mortality in great apes (Hominidae) that underwent anaesthesia in zoological collections in the UK and Ireland between 1 January 1990 and 30 June 2005. STUDY DESIGN: confidential, retrospective cohort study. ANIMAL POPULATION: The study population comprised all great apes from 16 zoological collections in the UK and Ireland that were anaesthetised during that period. METHODS: All available anaesthetic records were collected. Outcome at 7 days post-anaesthesia was recorded as alive, dead or euthanased. The risk of peri-anaesthetic mortality was calculated. Multivariable analysis of potential risk factors was performed. RESULTS: A total of 1182 anaesthetic records were collected and analysed. Sixteen peri-anaesthetic deaths occurred, resulting in a peri-anaesthetic mortality risk of 1.35%. Twenty percent of deaths (3/15) occurred during maintenance and 80% (12/15) occurred post-anaesthetic but within 7 days. A subjective assessment suggests at least five anaesthetic-related deaths occurred; in other words an anaesthetic-related mortality risk of 0.42% (5/1182) or above. In the multivariable analysis, health status and age were significantly associated with peri-anaesthetic mortality. Animals assessed as 'sick' pre-anaesthetic were associated with a 26-fold (95% CI 5.55-122.32) increased risk of death compared with animals with a good health status. Animals aged over 30 years were associated with a 30-fold (95% CI 3.44-261.85) increased risk of death, compared with adults aged between 10 and 30 years. CONCLUSIONS AND CLINICAL RELEVANCE: This study has shown that great ape anaesthesia appears to carry a high risk of mortality. Sick and aged patients are at an increased risk of death and particular care should be exercised during their anaesthesia. Standardisation and completeness of anaesthetic records across zoological collections would assist greatly in further studies.