Mortality associated with SARS-CoV-2 in nondomestic felids.

Between September and November 2021, 5 snow leopards (Panthera uncia) and 1 lion (Panthera leo) were naturally infected with severe acute respiratory coronavirus 2 (SARS-CoV-2) and developed progressive respiratory disease that resulted in death. Severe acute respiratory syndrome coronavirus 2 sequencing identified the delta variant in all cases sequenced, which was the predominant human variant at that time. The time between initial clinical signs and death ranged from 3 to 45 days. Gross lesions in all 6 cats included nasal turbinate hyperemia with purulent discharge and marked pulmonary edema. Ulcerative tracheitis and bronchitis were noted in 4 cases. Histologically, there was necrotizing and ulcerative rhinotracheitis and bronchitis with fibrinocellular exudates and fibrinosuppurative to pyogranulomatous bronchopneumonia. The 4 cats that survived longer than 8 days had fungal abscesses. Concurrent bacteria were noted in 4 cases, including those with more acute disease courses. Severe acute respiratory syndrome coronavirus 2 was detected by in situ hybridization using probes against SARS-CoV-2 spike and nucleocapsid genes and by immunohistochemistry. Viral nucleic acid and protein were variably localized to mucosal and glandular epithelial cells, pneumocytes, macrophages, and fibrinocellular debris. Based on established criteria, SARS-CoV-2 was considered a contributing cause of death in all 6 cats. While mild clinical infections are more common, these findings suggest that some SARS-CoV-2 variants may cause more severe disease and that snow leopards may be more severely affected than other felids.

CAMPYLOBACTER HYOINTESTINALIS ISOLATION FROM HOWLER (ALOUATTA CARAYA) AND SPIDER MONKEYS (ATELES FUSCICEPS ROBUSTUS) AT A ZOOLOGIC FACILITY IN CENTRAL ILLINOIS.

Campylobacter hyointestinalis was initially isolated from an asymptomatic black howler monkey (Alouatta caraya) in a routine fecal culture examination. Fecal cultures from other individuals in this group and an adjacently housed black-headed spider monkey (Ateles fusciceps robustus) group recovered C. hyointestinalis from all but one of the individuals sampled (1.1 spider monkeys and 2.1 howler monkeys). Concurrently, one spider monkey presented with acute onset severe rectal prolapse and diarrhea. Whole-genome sequencing results of C. hyointestinalis isolates from all individuals were homologous and closely related to Campylobacter hyointestinalis subsp. hyointestinalis TTU_618, a strain typically associated with environmental samples. In addition, two cytolethal distending toxin (CDT) expressing gene clusters, cdt-I and cdt-II, were identified in all isolates. These results suggest C. hyointestinalis is transmissible to both howler monkeys and spider monkeys, though the origin of infection and whether it is transmissible between these species is undetermined.

Dermatophytosis is uncommon in asymptomatic wild eastern cottontail rabbits in Illinois, Midwestern United States.

OBJECTIVE: To investigate the presence of dermatophytes on the haircoat of wild eastern cottontail rabbits (ECR) (Sylvilagus floridanus) with and without skin lesions. ANIMALS: 2-week-old or older ECR admitted to a Wildlife Medical Clinic (WMC) in central Illinois, Midwest United States, from September 2021 to August 2022. METHODS: ECR were surveyed over a 1-year period to assess the prevalence and seasonality of dermatophytosis. A Wood's lamp exam was performed over the haircoat. Hairs were sampled with a sterile toothbrush and plated on Sabouraud dextrose agar. The plates were photographed twice weekly for 3 weeks, and colonies were identified as contaminants or dermatophytes. RESULTS: 523 ECR were admitted to WMC, 141 ECR met the age inclusion criteria, and 121 samples were plated. ECR presented as a litter were sampled together. None of the sampled ECR presented skin lesions other than acute traumatic wounds. No fluorescence was observed on any ECR during the Wood's lamp examination. Based on culture colony morphology, 115/121 of the samples were identified as contaminants and no growth was observed in 6/121 of plates. Dermatophytes' colonies were not identified on any of the culture plates. CLINICAL RELEVANCE: Dermatophytes are zoonotic fungi and can potentially be carried by wild animals. The fungal infection poses a health concern to humans and domestic pets through direct interaction. Our current results suggest that dermatophytosis may not be prevalent in asymptomatic wild rabbits in the studied areas of the Midwestern United States.

COMPARISON OF HEMATOLOGIC DIFFERENCES WITH LITHIUM HEPARIN AND DIPOTASSIUM ETHYLENEDIAMINETETRAACETIC ACID IN EUROPEAN STARLINGS (STURNUS VULGARIS).

Preservation of blood through use of anticoagulants allows delayed assessment of hematologic health and is commonly employed in veterinary health assessments. The two most common anticoagulants are lithium heparin (LH) and dipotassium ethylenediaminetetraacetic acid (EDTA), and their effects can vary widely between species. The hematologic effects of these anticoagulants on blood from European starlings (Sturnus vulgaris) have not been established, and these birds could serve as models for passerine species both in managed collections and in the wild. Blood was drawn from 45 European starlings and immediately divided into either LH or EDTA microtainers. For each sample, packed cell volume (PCV), total solids (TS), and complete blood counts were performed. There were no significant differences between EDTA and LH anticoagulated blood for PCV, white blood cell count (WBC) slide estimates, WBC determined by Leukopet, absolute heterophils, absolute lymphocytes, absolute monocytes, absolute eosinophils, or absolute basophils. Blood anticoagulated with EDTA had higher total solids than blood mixed with LH. For both anticoagulants, Leukopet-measured total WBC were consistently higher than blood film estimates. There were no subjective morphologic differences for WBC and no hemolysis observed in the samples. Thrombocyte clumping was prominent for LH blood samples and minimal for EDTA samples. These results reveal that LH and EDTA are both suitable anticoagulants for use in European starlings, and EDTA may be superior for diagnostic purposes or for qualitative evaluation of thrombocyte quantity.

THE PHARMACOKINETICS AND PHARMACODYNAMICS OF ORAL PONAZURIL IN THE TREATMENT OF SYSTEMIC ISOSPOROSIS IN PASSERINE BIRDS.

Systemic isosporosis, previously atoxoplasmosis, is a significant cause of mortality in juvenile passerine birds. Recommended treatment regimens are empiric and vary in efficacy. The goal of this study was to determine the pharmacokinetics and pharmacodynamics of ponazuril for treatment of systemic isosporosis. Ponazuril, diluted with water to create an oral suspension (50 mg/ml), was administered (100 mg/kg) to 72 European starlings (Sturnus vulgaris) by a single dose via direct oral gavage (n = 24), a single dose injected into superworm larvae (Zophobas morio; n = 24), or a daily dose mixed with commercial dog food to top-dress feed for 5 d (n = 24). Peak plasma concentrations were 5.84, 2.46, and 9.13 µg/ml for the direct gavage, injected larvae, and top-dressed feed groups, respectively. With repeated dosing, mean plasma concentrations from the top-dressed feed group were maintained between 8.12 to 13.11 µg/ml. Results suggested ponazuril at a dosage of 100 mg/kg administered via direct gavage or top-dressed feed, but not via injected larvae, would exceed the concentrations needed to inhibit merogony of other apicomplexan parasites in cell culture (5 µg/ml). To assess the pharmacodynamics of this dose, seven passerine birds, red-vented bulbuls (Pycnonotus cafer; n = 2), blue-grey tanager (Thraupis episcopus; n = 1), and red-capped cardinals (Paroaria gularis; n = 4), were identified as shedders of systemic Isospora spp. via fecal qPCR. Birds were then treated with ponazuril (100 mg/kg) daily on top-dressed feed for 14 d. Fecal shedding was assessed via qPCR for 6 wk from the initiation of treatment. Treatment was associated with reduction in proportions of fecal shedding during the treatment period and the week following treatment, but shedding resumed in all birds by the end of sampling. Results support that treatment of breeding birds with 100 mg/kg ponazuril could reduce the shedding of active oocysts and decrease risk of clinical infection in susceptible juveniles.

Clinical disease and treatment of Leptospira kirschneri sv Grippotyphosa in a Sumatran tiger (Panthera tigris sumatrae).

CASE DESCRIPTION: A 12-year-old sexually intact male zoo-managed Sumatran tiger (Panthera tigris sumatrae) was evaluated for a 3-day history of vomiting, hyporexia, and lethargy. Radiographs were supportive of gastrointestinal obstruction, and an exploratory laparotomy was performed. CLINICAL FINDINGS: Diffuse tan foci were present on the liver parenchyma, and the tiger became icteric throughout the procedure. Hepatic histopathology and immunohistochemistry resulted in a diagnosis of leptospirosis. Serum microagglutination testing for Leptospira spp antibody titers were positive for L kirschneri serovar Grippotyphosa, rising from 1:400 to 1:3,200 in 2 days. TREATMENT AND OUTCOME: The tiger was treated with antimicrobials, ursodiol, and mirtazapine, and increased biosecurity measures were instituted. Free-ranging wildlife on grounds were trapped, euthanized, and submitted for necropsy to screen for disease vectors. The tiger's urine was intermittently opportunistically collected from the enclosure and remained PCR assay negative for Leptospira spp until being positive once again on day 595. Although the tiger was without clinical signs at that time, antimicrobial therapy and increased biosecurity protocols were instituted a second time until urinary Leptospira shedding was confirmed to have stopped. By 1,071 days after initial presentation, the tiger remained nonclinical, with no additional urinary shedding episodes. CLINICAL RELEVANCE: While domestic and nondomestic free-ranging felids have been reported as subclinical Leptospira spp carriers, this report indicates the clinical importance of leptospirosis when a tiger presents with generalized gastrointestinal signs and icterus. Due to the zoonotic potential, biosecurity measures are necessary. This patient had a clinically successful outcome with antimicrobial therapy and supportive care.

PHARMACOKINETICS OF PRIMAQUINE PHOSPHATE AFTER A SINGLE ORAL ADMINISTRATION TO AFRICAN PENGUINS (SPHENISCUS DEMERSUS).

Primaquine is an 8-aminoquinolone drug commonly used for the chemoprophylaxis and treatment of avian malarial infections in managed penguin populations worldwide. Little is known about its pharmacokinetic properties in avian species. The objective of this study was to describe the disposition of primaquine phosphate after a single oral dose in 15 healthy African penguins (Spheniscus demersus). A single tablet containing 26.3 mg of primaquine phosphate (equivalent to 15 mg primaquine base) was administered orally to each bird in a herring fish. Blood samples were collected prior to drug administration and at predetermined timepoints through 144 hr postadministration. Plasma was analyzed for drug concentration by high-performance liquid chromatography with ultraviolet detection. Mean maximum plasma concentration of primaquine phosphate was 277 ± 96 ng/ml at approximately 3.1 hr following oral administration. The mean disappearance half-life was 3.6 ± 1.6 hr. Plasma concentrations were below detectable limits in all but one penguin by 36 hr. A single oral administration of 26.3 mg of primaquine phosphate in African penguins resulted in a pharmacokinetic profile comparable to those attained in human studies. These results suggest that a dosing interval similar to human regimens may be of potential use in the prevention and treatment of avian malaria in penguins. Additional clinical studies are needed to determine the efficacy and safety of this regimen.

FACTORS AFFECTING ABNORMAL MOLTING IN THE MANAGED AFRICAN PENGUIN (SPHENISCUS DEMERSUS) POPULATION IN NORTH AMERICA.

Abnormal molting, including partial or incomplete molt, arrested molt cycle, or inappropriate frequency of molt, is a primary concern for the managed African penguin (Spheniscus demersus) population and is documented across institutions. To identify factors associated with increased odds of abnormal molts and characterize intervention opportunities, a comprehensive survey evaluating numerous husbandry and medical parameters was created. Survey results represent 45 North American African penguin holding facilities and 736 unique animals. Of these individuals, 135 (18.3%) demonstrated an abnormal molt over the 5-yr study period (2012-2017). Increased odds ratios for abnormal molt included biologic (age, sex, etc.), geographic (elevation, latitude), and husbandry (exhibit design, diet, etc.) variables. The mean age of affected animals was 15.2 yr (1-45 yr, n = 135) compared with 9.92 yr (4 mo-38 yr, n = 601) for unaffected animals. In addition, although statistically insignificant, males were overrepresented in the affected cohort compared with a near even distribution among unaffected animals. Identified factors with increased odds for abnormal molting included advanced age and facilities using freshwater pools. Normally molting penguins were more commonly found with saltwater pool access and natural lighting exposure. Anecdotal medical intervention attempts are discussed, although further research is needed to define their use. Of attempted interventions, subcutaneous 5.4-mg melatonin implants placed in anticipation of environmental molting cues showed the most promise at inducing catastrophic molt, with 14 of 17 (82.3%) of affected individuals molting normally following this treatment. Survey analysis indicated that abnormal molt is a complex, multifactorial process, and modifiable factors that may predispose animals to abnormally molt exist. Addressing these factors in future exhibit design may mitigate the prevalence of this condition. Despite these efforts, it is likely that medical interventions will be required to aid in the treatment of abnormal molting in this species.

COMPARISON OF CIRCULATING IRON, TOTAL IRON BINDING CAPACITY, AND PERCENT TRANSFERRIN SATURATION IN WILD AND CAPTIVE KORI BUSTARDS ( ARDEOTIS KORI).

The kori bustard ( Ardeotis kori) is one of the largest extant flighted birds and is displayed in zoos primarily in North America and Europe. In captivity, kori bustard diets are primarily based on animal proteins, whereas in the wild these birds eat a wide variety of plants, insects, and small vertebrate prey. The purpose of this study was to compare circulating iron, total iron binding capacity, and percent transferrin saturation levels in apparently healthy wild and captive kori bustards. Adult captive kori bustards had slightly higher percent transferrin saturation levels than juvenile captive birds, although this finding was not statistically significant. This information can be referenced as a guide for the assessment of nutrition and health in captive birds.

CLINICAL EFFECT OF HEMOPARASITE INFECTIONS IN SNOWY OWLS ( BUBO SCANDIACUS).

Vector-borne hemoparasites are commonly found in avian species. Plasmodium spp., the causative agent of avian malaria, are intraerythrocytic parasites that can cause signs ranging from subclinical infection to severe acute disease. In raptor species, most hemoparasites are associated with subclinical infection and are generally not treated when seen on blood evaluation. This case series reviews five cases of hemoparasite infection in snowy owls ( Bubo scandiacus). These animals were infected with a variety of hemoparasites, including Plasmodium, Haemoproteus, and Leukocytozoon spp. Death of one of these birds due to hemoparasite burden led to a change in the monitoring for and treatment of subclinical hemoparasitic infections in this species. Three subsequently infected snowy owls have been treated with primaquine and chloroquine. The birds that were treated survived infection, and parasite burdens in peripheral blood diminished. Postulated reasons for increased morbidity and mortality associated with hemoparasitic infections in captive snowy owls, as opposed to other raptor species, include stress, concurrent disease, novel pathogen exposure, and elevated environmental temperatures.

CALCINOSIS CIRCUMSCRIPTA IN A COHORT OF RELATED JUVENILE AFRICAN LIONS (PANTHERA LEO).

Three juvenile, genetically related African lions (Panthera leo) were evaluated for discrete dome-shaped subcutaneous masses present over the proximal lateral metatarsal-tarsal area. The lesions measured 3-8 cm in diameter, were fluctuant to firm, nonulcerated, and attached to underlying structures. On radiographic evaluation, the lesions were characterized by well-circumscribed punctate mineralizations in the soft tissue surrounded by soft tissue swelling without evidence of adjacent bony involvement. On cut surface, the lesions were made of numerous loculi containing 2-5-mm round-to-ovoid, white-to-gray, firm structures interspersed with fibrous tissue and pockets of serosanguinous fluid. Hematology, serum biochemistry, serum thyroid screening (including total thyroxine, total triiodothyronine, free thyroxine, and free triiodothyronine), and serum vitamin D panels (including parathyroid hormone, ionized calcium, and 25-hydroxyvitamin D) were unremarkable. Histopathologic evaluation of the lesions was consistent with calcinosis circumscripta with fibroplasia, chronic inflammation, and seroma formation. An additional two genetically related lions were considered suspect for calcinosis circumscripta based on presentation, exam findings, and similarity to the confirmed cases. All masses self-regressed and were not associated with additional clinical signs other than initial lameness in two cases.

ACUTE PHASE PROTEINS AS A MARKER OF RESPIRATORY INFLAMMATION IN PRZEWALSKI'S HORSE (EQUUS FERUS PRZEWALSKII).

Acute phase proteins are sensitive markers of inflammation, which are highly conserved across taxa. Although the utility of these proteins are becoming well defined in human and domestic animal medical fields, their role in nondomestic species remains unclear. In this communication, a 20-yr-old Przewalski's horse was presented for unresolving aspiration pneumonia, which cultured a unique Actinomyces-like bacteria. Despite waxing and waning clinical signs and minimal changes on baseline hematologic analysis, protein electrophoresis, serum amyloid A, and surfactant protein D serum concentrations showed changes that more accurately reflected the clinical severity of this case.

PHARMACOKINETICS OF A SINGLE DOSE OF METRONIDAZOLE AFTER RECTAL ADMINISTRATION IN CAPTIVE ASIAN ELEPHANTS (ELEPHAS MAXIMUS).

Metronidazole is a nitroimidazole antibacterial and antiprotozoal drug with bacteriocidal activity against a broad range of anaerobic bacteria. It is a recognized treatment for elephants diagnosed with anaerobic bacterial infection or protozoal disease or exhibiting signs of colonic impaction, diarrhea, and colic. This study evaluated the pharmacokinetics of rectally administered metronidazole (15 mg/kg) in five adult female Asian elephants (Elephas maximus). Serum samples were collected from each animal for 96 hr after rectal administration of metronidazole. Serum concentrations of metronidazole and its primary metabolite, hydroxymetronidazole, were measured via ultraperformance liquid chromatography. Data were analyzed via a noncompartmental pharmacokinetic approach. Results indicated that serum levels of metronidazole were quantifiable at the 0.25 hr time point and absent in all elephants by the 96 hr time point. The serum peak concentration (mean ± SD, 13.15 ± 2.59 µg/ml) and area under the curve from time 0 to infinity (mean ± SD, 108.79 ± 24.77 hr × µg/ml) were higher than that reported in domestic horses after similar usage. Concurrently, the time of maximum serum concentration (mean ± SD, 1.2 ± 0.45 hr) and terminal elimination half-life (harmonic mean ± pseudo-SD, 7.85 ± 0.93 hr) were longer when compared to equine reports. Rectal administration of metronidazole was well tolerated and rapidly absorbed in all study elephants. Based on the findings in this study, metronidazole administered at a single dose of 15 mg/kg per rectum in the Asian elephant is likely to result in serum concentrations above 4 µg/ml for 8 hr and above 2 µg/ml for 24 hr after treatment is administered. Dosing recommendations should reflect the mean inhibitory concentration of metronidazole for each pathogen.

CEREBELLAR AND MESENCEPHALON NEOPLASIA IN A NILE HIPOPPOTAMUS (HIPPOPOTAMUS AMPHIBIOUS).

A 52-yr-old female Nile hippopotamus ( Hippopotamus amphibious ) was presented for acute onset anorexia, depression, lethargy, instability, and weakness in the pelvic limbs. Clinical signs were rapidly progressive, despite empiric therapy with anti-inflammatory medications, resulting in the death of the animal. Gross necropsy evaluation revealed two tan, firm masses in the cerebellum and mesencephalon and a single mass in the right cranial adrenal gland. All three masses had a similar histologic morphology, and immunohistochemical investigation confirmed the general diagnosis of an adenocarcinoma, but the exact cell of origin remains unclear. In addition, there was evidence of neuroendocrine differentiation in the adrenal gland and not in the brain. These findings suggest either two distinct neoplastic populations or a metastasizing adenocarcinoma with focal endocrine differentiation. In dogs, anal sac and clitoral adenocarcinomas have been reported to undergo focal endocrine differentiation, and both can cause widespread metastasis while the primary lesion can be small. A small neoplasm of these glands may have been missed on gross examination.

Metronomic Chemotherapy for Myxosarcoma Treatment in a Kori Bustard (Ardeotis kori).

A 22-year-old, wild-caught male kori bustard (Ardeotis kori) developed a large, slow-growing subcutaneous mass over the keel. The mass was surgically debulked and histopathologically described as a myxosarcoma. Surgical dehiscence and concurrent local tumor regrowth, with no evidence of metastasis, occurred over the subsequent 3 months, necessitating 2 additional surgical procedures to close the wound. At 19 weeks after the initial procedure, a second debulking surgical procedure was performed, at which time carboplatin-impregnated matrix beads were placed in the lesion. Moderate local tumor regrowth was clinically appreciable 4 weeks after surgery, at which time an oral metronomic chemotherapeutic protocol consisting of daily cyclophosphamide (10 mg/m(2)) and meloxicam (0.1 mg/kg) was initiated. Four months later, the tumor was no longer palpable. While oral therapy was discontinued during the breeding season, mass regrowth was observed, and the mass was surgically debulked before reinitiating oral chemotherapy. Treatment was extended for over 1 year with no hematologic evaluation or serum biochemical abnormalities, and the bird otherwise remained clinically healthy. To our knowledge, this is the first report of a myxosarcoma in a bustard species and the first report of successful clinical application of metronomic chemotherapy in an avian species.