Retrospective Comparison of the Anesthetic Effects of Tiletamine-Zolazepam with Dexmedetomidine and Ketamine with Dexmedetomidine in Captive Formosan Serow (Capricornis swinhoei).

Formosan serows are endemic to the mountainous regions of Taiwan. This crossover study aimed to assess and compare the anesthetic induction and recovery using either dexmedetomidine-tiletamine-zolazepam (DZ) or dexmedetomidine-ketamine (DK) by intramuscular injection from a blow-dart in a zoo environment. Ten anesthetic procedures were performed with five adult Formosan serows. Each participant was anesthetized with both combinations at least once with a minimal 12-month washout. The average dosages were 22.6 ± 8.3 µg/kg and 35.8 ± 2.5 µg/kg for dexmedetomidine and 185.6 ± 123.6 and 357.8 ± 25.2 µg/kg for atipamezole for the DZ and DK groups, respectively. The doses of tiletamine-zolazepam and ketamine were 2.1 ± 0.25 mg/kg and 3.6 ± 0.3 mg/kg, respectively, in the DZ and DK groups. All participants were induced within 10 min (median: 8 min for both groups), except one serow in the DK group with an induction time of 22 min. Serows in the DZ group had a lower respiratory rate (p = 0.016) and lower rectal temperature (p = 0.008) than those in the DK group. The quality of recovery was poor for DZ because of paddling, prolonged recovery, and ataxia after antagonism of dexmedetomidine with atipamezole. The induction of anesthesia with dexmedetomidine-tiletamine-zolazepam was uneventful and rapid. However, recovery from this combination was not smooth.

Investigation of Toxoplasma infection in zoo animals using multispecies ELISA and GRA7 nested PCR.

BACKGROUND: Toxoplasma is an obligate intracellular protozoan that causes an important zoonotic disease with a worldwide distribution. Felids are the definitive hosts of this parasite, while virtually all warm-blooded animals, including birds, serve as intermediate hosts. Four ring-tailed lemurs (Lemur catta) in the Taipei Zoo died of acute Toxoplasma infection in June 2019. Since then, Toxoplasma has occasionally been identified in this Zoo during necropsy of dead animals and PCR of animal blood samples. Therefore, a general survey of Toxoplasma infection in animals in the Zoo seems to be needed. METHODS AND RESULTS: An indirect multispecies ELISA was used for the first time to screen for Toxoplasma infection in 326 serum samples collected from 75 species of animals. The infection rate of Toxoplasma was 27% (88/326). A commercial latex agglutination (LAT) assay was used to re-examine the samples with doubtful and uncertain ELISA results (151 samples from 42 species). The infection rate increased to 36.2% (118/326), and the indirect multispecies ELISA appeared to be applicable to 31 of 75 species animals included in this study. Nested PCR assays targeting the dense granule protein 7 (GRA7) gene and B1 gene were also used to detect Toxoplasma in DNA samples extracted from 10 liver or blood specimens from 8 animals. GRA7 gene fragments were amplified from 8 samples from 7 animals, while B1 gene fragments were amplified from only 4 samples from 4 animals. From the B1 nested PCR and the sequence data of GRA7 fragments amplified from infectious specimens, the animals in the Zoo were speculated to have been infected by at least three different Toxoplasma variants. CONCLUSIONS: According to the serological investigation, we speculated that over one-third (36.2%) of animals in Taipei Zoo presented the infection of Toxoplasma, and the indirect multispecies ELISA we used can be applied to detect Toxoplasma infection in 31 animal species included in this study. Sequence analysis revealed that at least three Toxoplasma variants were infecting the animals of Taipei Zoo.

Molecular and serological detection of Toxoplasma gondii infection in mammals in the Taipei Zoo.

Toxoplasmosis caused by Toxoplasma gondii affects both conservation and public health efforts. In the Taipei Zoo, toxoplasmosis was diagnosed in ring-tailed lemurs and a meerkat in 2019 while a freeze-thaw meat strategy had been applied to carnivores before the event. To investigate the possible risk factors associated with T. gondii infection in the Taipei Zoo, 179 veterinary visiting mammals from 2019-2021 and six stray cats were included to detect anti-T. gondii IgG and IgM in their serum via ELISA, and T. gondii in their faeces and blood via PCR. Although the overall T. gondii IgG seroprevalence was 33.5% and PCR positivity was 16.2% in the zoo mammals, the correlation between T. gondii PCR and systemic IgG results was low. An omnivorous diet (adjusted OR = 0.4; 95% CI: 0.2-1.0), a herbivorous diet (adjusted OR = 3.2; 95% CI: 1.1-9.6), and animals in the Conservation Area where stray cats appeared (adjusted OR = 18.3; 95% CI: 3.9-85.9) were independent risk factors for T. gondii infection. The low T. gondii-specific IgM positivity (0.6%) suggests that most animals did not have acute T. gondii infection. In conclusion, our findings indirectly support that feeding frozen meat to carnivores, cleaning fresh food, and restricting access to stray cats to prevent faecal contaminants could prevent animals from T. gondii exposure.

Malignant Perivascular Epithelioid Cell Tumour in a Savannah Monitor (Varanus exanthematicus).

A 9-year-old male captive savannah monitor (Varanus exanthematicus) with a history of general debility was submitted for necropsy. Grossly, there were multiple white masses in the colon, mesorchium and tracheal adventitia. Histologically, the lesions were composed of epithelioid to spindloid neoplastic cells arranged in sheets to interlacing and interwoven bundles, and separated by abundant myxoid material or extensive stromal hyalinization and fibrosis with occasional chondroid metaplasia. Perivascular infiltration of epithelioid neoplastic cells was occasionally seen. Neoplastic cells were immunopositive for alpha-smooth muscle actin, melan-A and S100. The unique histological features and concurrent myogenic and melanocytic immunophenotypes suggest a malignant perivascular epithelioid cell tumour. To our knowledge, this is the first report of perivascular epithelioid cell tumours in a non-human species.

Retroperitoneal extraosseous peripheral primitive neuroectodermal tumor in a Formosan serow: case report and literature review.

A 10-y-old female captive Formosan serow (Capricornis swinhoei) was inactive and was azotemic. An autopsy was performed following her death, and multiple irregularly shaped, white-to-gray masses of 0.5-2 cm diameter were noted on both ureters, the left adrenal gland, urinary bladder, and uterus. Microscopically, organs were effaced by a poorly demarcated, highly infiltrative neoplasm, composed of neoplastic round cells arranged in islands, sheets, or nests with occasional rosette formation. The neoplastic cells were small: ≤2 red blood cell (≤ 15 µm) diameter. The neoplastic cells were positive for CD56, CK, FLI-1, and NSE, but negative for desmin, GFAP, melan A, NF, PAX-8, S100, synaptophysin, and vimentin. Therefore, the diagnosis of retroperitoneal extraosseous peripheral primitive neuroectodermal tumor (pPNET) was made. pPNET with FLI-1 expression has not been reported previously in animals, to our knowledge.

Comparison of xylazine-ketamine and dexmedetomidine-ketamine anesthesia in captive Formosan serows (Capricornis swinhoei).

The Formosan serow (Capricornis swinhoei) is a rare endemic species found in Taiwan. Few studies, including studies on anesthetic protocols, have been conducted on this species. This study evaluates the anesthetic effectiveness of intramuscular xylazine-ketamine and dexmedetomidine-ketamine on captive Formosan serows. Fifty-seven anesthetic events were performed on 22 adults using a combination of xylazine (2.6 ± 0.5 mg/kg) and ketamine (3.7 ± 1.0 mg/kg). Forty-eight anesthetic events were performed on 29 adults using a combination of dexmedetomidine (33.9 ± 4.3 µg/kg) and ketamine (3.4 ± 0.4 mg/kg). Xylazine-ketamine anesthesia was antagonized with tolazoline (3.3 ± 0.8 mg/kg). Dexmedetomidine-ketamine anesthesia was antagonized with atipamezole (272.8 ± 78.2 µg/kg). Both drug combinations showed smooth anesthetic and recovery processes without statistical differences in respiratory rate, heart rate, rectal temperature and hemoglobin oxygen saturation. Dexmedetomidine-ketamine reversed by atipamezole showed a significantly shorter recovery time (1.8 ± 2.3 min) than xylazine-ketamine reversed by tolazoline (4.5 ± 1.7 min) (P < 0.05). Both anesthetic protocols indicated safe and reliable immobilization whereas atipamezole provided better reversal.

Meningothelial meningioma in a Malayan sun bear (Helarctos malayanus).

A 24-year-old, spayed female Malayan sun bear (Helarctos malayanus) in the Taipei Zoo (Taipei, Taiwan) showed clinical signs of slowly progressive anorexia, dullness, compulsive pacing, and circling. The animal subsequently developed acute severe stupor and persistent recumbency. Postcontrast study of computed tomography revealed a spheroid, extra-axial mass with strong but heterogeneous hyperattenuation in the left temporal lobe of the cerebrum. At necropsy, a solitary, well-circumscribed intracranial mass measuring 3 cm × 2.5 cm × 2 cm was attached to the left pyriform lobe with compression of the adjacent neuroparenchyma. Cytological examination obtained from the mass revealed large clumps and sheets of cohesive polyhedral cells with round nuclei, wispy cytoplasm, and indistinct cell borders. Microscopically, the mass was composed of densely packed round to polygonal cells arranged in lobules and small nests. Psammoma bodies, xanthomatous change, and cholesterol deposition were also noted. Immunohistochemical staining of the tumor was positive for vimentin, pancytokeratin, cytokeratin (CK)34BE12, neuron-specific enolase, and epithelial membrane antigen, but negative for glial fibrillary acidic protein and S100 protein. The cytological, histological, and immunohistochemical features were compatible with a meningothelial meningioma.