GLOBAL RETROSPECTIVE REVIEW OF SEVERE ACUTE RESPIRATORY SYNDROME SARS COV-2 INFECTIONS IN NONDOMESTIC FELIDS: MARCH 2020-FEBRUARY 2021.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in nondomestic felids have been documented in North America, South America, Africa, Europe, and Asia. Between March 2020 and February 2021, at nine institutions across three continents, infection was confirmed in 16 tigers (Panthera tigris), 14 lions (Panthera leo), three snow leopards (Panthera uncia), one cougar (Puma concolor), and one Amur leopard cat (Prionailurus bengalensis euptilurus) ranging from 2 to 21 yr old (average, 10 yr). Infection was suspected in an additional 12 tigers, 4 lions, and 9 cougars. Clinical signs (in order of most to least common) included coughing, ocular and/or nasal discharge, wheezing, sneezing, decreased appetite, lethargy, diarrhea, and vomiting. Most felids recovered uneventfully, but one geriatric tiger with comorbidities developed severe dyspnea and neurologic signs necessitating euthanasia. Clinical signs lasted 1-19 d (average, 8 d); one tiger was asymptomatic. Infection was confirmed by various methods, including antigen tests and/or polymerase chain reaction (PCR) of nasal or oral swabs, tracheal wash, and feces, or virus isolation from feces or tracheal wash. Infection status and resolution were determined by testing nasal swabs from awake animals, fecal PCR, and observation of clinical signs. Shedding of fecal viral RNA was significantly longer than duration of clinical signs. Postinfection seropositivity was confirmed by four institutions including 11 felids (5 lions, 6 tigers). In most instances, asymptomatic or presymptomatic keepers were the presumed or confirmed source of infection, although in some instances the infection source remains uncertain. Almost all infections occurred despite using cloth facemasks and disposable gloves when in proximity to the felids and during food preparation. Although transmission may have occurred during momentary lapses in personal protective equipment compliance, it seems probable that cloth masks are insufficient at preventing transmission of SARS-CoV-2 from humans to nondomestic felids. Surgical or higher grade masks may be warranted when working with nondomestic felids.

INTERVERTEBRAL DISC DISEASE IN THREE LARGE FELIDS (PANTHERA SPP.) TREATED SURGICALLY.

Intervertebral disc disease (IVDD) in captive large felids is a commonly encountered syndrome that is usually treated medically, with surgical cases only sparsely documented in the literature. This case series describes the diagnosis, surgical treatment, and postoperative care of three cases of IVDD in large felids: an 8-yr-old male Bengal tiger (Panthera tigris tigris) with acute paraplegia, a 10-yr-old male tiger of unknown subspecies (Panthera tigris) with progressive tetraparesis, and a 17-yr-old female African lion (Panthera leo) with mild paraparesis. Two cases were diagnosed via magnetic resonance imaging (MRI) and the third was diagnosed with computed tomography myelography. Disc herniations were confirmed during surgery in all cases and via necropsy in two cases. Surgical procedures included a thoracolumbar dorsal hemilaminectomy in one tiger, a cervical hemilaminectomy in the other tiger, and a continuous lumbar dorsal hemilaminectomy in the lion. One tiger was euthanized approximately 1 wk after surgery and the other tiger was euthanized approximately 1 mon after surgery, following a lack of clinical improvement in both cases. The lion, however, improved markedly over several months after surgery before acutely declining secondary to spinal neoplasia. Analysis of these cases suggests that pursuing MRI and surgery as soon as possible after the onset of clinical signs and marking affected disc sites based on imaging to provide landmarks for the surgeon may improve long-term prognosis. Additionally, strict postoperative confinement in an accessible cage is beneficial to facilitate care and prevent overexertion while allowing early movement.

ECHOCARDIOGRAPHIC MEASUREMENTS IN ANESTHETIZED CAPTIVE RED PANDAS (AILURUS FULGENS).

A recent review of mortality in captive red pandas (Ailurus fulgens) listed cardiac pathology as the most common cause of death in the adult age group. The aim of this study was to describe the standard echocardiographic variables in 13 captive, healthy, adult red pandas that underwent an elective health examination. In addition, differences between the two subspecies of red panda, A. f. styani than in A. f. fulgens, and association of these echocardiographic variables with age, sex, and body condition score, were examined. Anesthesia was induced and maintained with isoflurane inhalant anesthetic. All animals underwent a full physical examination and comprehensive echocardiogram including 2D, M-mode, and Doppler modes of ultrasound examination. Mean and SD of the echocardiographic variables are reported. Systolic performance was considered subnormal due to the effect of the anesthetic agent. The echocardiographic variables were similar for the two subspecies and sexes, with the exception of the left atrial dimension (2D), which measured larger (P= 0.03) in A. f. styani than in A. f. fulgens, and left ventricular internal diameter in diastole, which measured larger (P = 0.04) in males than females. Several echocardiographic measurements were correlated with age (P < 0.05), whereas the only measurement that significantly correlated with body condition score was end diastolic volume (P = 0.01). These results provide ranges that can offer guidance for predicting cardiac disease in red panda.

EVALUATION OF AGREEMENT BETWEEN OSCILLOMETRIC AND DIRECT BLOOD PRESSURE MEASUREMENTS IN ANESTHETIZED TIGERS (PANTHERA TIGRIS).

Noninvasive blood pressure measurement is commonly performed with oscillometry; however, this technique provides clinically helpful information only if it is representative of the gold standard. Agreement between direct and oscillometric blood pressure measurements were performed in 14 anesthetized, captive tigers (Panthera tigris). A cuff, placed around the tail base and connected to a multiparameter monitor, was used to measure arterial blood pressure oscillometrically and provided systolic, mean, and diastolic pressures. At the same time, direct blood pressures were obtained from a dorsal pedal arterial catheter, and the oscillometric and direct readings were considered paired data points. Agreement between the two methods was evaluated by Bland-Altman plots. All animals completed the study and provided 196 paired data points. The bias (mm Hg) for systolic, mean, and diastolic arterial pressures was -3.7, -0.8, and -1.6, respectively. Limits of agreement (mm Hg) for systolic, mean, and diastolic arterial pressures were -31 to 24, -29 to 27, and -29 to 26, respectively. Oscillometry provided an acceptable amount of readings within 10 and 20 mm Hg of the gold standard. The oscillometric technique provided reasonable agreement with direct measurements. Therefore, in the conditions used in this study, oscillometric blood pressure measured via the ventral coccygeal artery provided reasonable estimates of invasive blood pressure in anesthetized tigers.

RABIES DIAGNOSIS AND RESPONSE TO VACCINATION IN SOUTHERN TAMANDUA (TAMANDUA TETRADACTYLA).

Rabies has rarely been described in Xenarthra, and rabies vaccine response has not been documented. A southern tamandua (Tamandua tetradactyla) presented with nonspecific clinical signs and was euthanatized. Subsequently, immunohistochemistry and RT-PCR confirmed a rabies diagnosis. Following these tests, a group of eight captive tamanduas were vaccinated with a killed rabies vaccine, and titers were measured at the time of vaccination and 23 d later. One animal had day 0 titers suggestive of previous vaccination or exposure. All animals had detectable neutralizing rabies virus antibody titers after vaccination, but one animal failed to meet the World Organization for Animal Health's definition for adequate vaccination (≥0.5 IU/ml), and two other animals had low antibody titers (0.56 and 0.6 IU/ml). Rabies should be considered as a possible cause of illness in tamanduas, and rabies vaccination may be a useful preventative measure when anthropic interaction through medical care or ambassador roles is occurring.

MELANOCYTIC NEOPLASIA IN PANTHERA SPECIES: CLINICAL PRESENTATIONS, PATHOLOGIC FINDINGS AND RESPONSES TO TREATMENT.

Neoplasia is a common cause of morbidity and mortality in captive nondomestic felids. Seven tigers (Panthera tigris), two African lions (Panthera leo), and two snow leopards (Panthera uncia) were diagnosed with melanocytic neoplasia (10 malignant melanomas, two benign melanocytomas) over a 20-yr period. Animals were 10-19 yr old and 5/7 tigers were phenotypically white. Malignant melanoma tumor location included skin (n = 4), oral mucosa (n = 2), nasal planum (n = 1), iris/uvea (n = 2), and lip margin (n = 1); melanocytomas were found in skin (n = 2). Metastasis to regional lymph nodes was seen at diagnosis in 3/7 melanoma cases. Thoracic radiography (n = 6) and/or computed tomography (n = 2) did not detect pulmonary metastasis at diagnosis but were useful for detection later in the disease course. Median survival time (MST) for all cases ranged from 1 mon - 40 mon. Seven cases with malignant melanoma underwent treatment, which included surgery, radiation therapy, and administration of the canine melanoma vaccine (Oncept®) or a combination of these treatments; MST was 5-40 mon for these cases. While multimodal therapy may provide an improved survival time, the majority of animals with malignant melanoma invariably died from neoplastic disease. Necropsy confirmed metastasis of malignant melanoma in 7/9 animals; sites included lung, liver, lymph node, kidney, mesentery, pleural cavity, heart, stomach, spleen, and adrenal gland. This case series describes the clinical and histologic findings of melanocytic neoplasia in nondomestic felids as well as multimodal treatment strategies incorporating the canine melanoma vaccine.

RETROSPECTIVE REVIEW OF MORBIDITY AND MORTALITY IN A POPULATION OF CAPTIVE BUDGERIGARS (MELOPSITTACUS UNDULATES).

This retrospective study reviews the diseases associated with morbidity and mortality in 221 budgerigars (Melopsittacus undulates) from a captive population from 2013 to 2019. The study aimed to evaluate the health status of a flock of budgerigars typical of today's zoologic collections. Based on previous literature, it was hypothesized that age-related conditions such as neoplasia would be common, whereas metabolic and nutritional disorders would be less common. Neoplasia was widespread among the population, affecting 34% of birds (75/221). Carcinomas made up most neoplastic processes and most commonly affected the renal system (n = 22), followed by the proventriculus (n = 7). Pituitary, adrenal, and hepatocellular carcinomas were less commonly diagnosed. Sarcomas affected the population less often than carcinomas and were found within the coelom (undifferentiated four cases), within the spleen (three cases), within the kidney (two cases), and one subcutaneous soft tissue sarcoma. There were five cases of multicentric lymphoma found most commonly affecting the spleen and liver. Benign neoplasms affected the pituitary most commonly (nine cases), followed by the reproductive system, with seminomas (seven cases) being most common. Macrorhabdus ornithogaster (MO) was found in 56 cases. The majority (38 cases) were found in conjunction with a range of comorbidities, but several birds experienced MO infections alone, and it was thought to have been the cause of death in these birds (22 cases). In contrast to our hypothesis, disease associated with nutritional or metabolic disorders impacted a substantial portion of the population; hepatic lipidosis (26 cases) was the most common along with obesity (26 cases), followed by atherosclerosis, xanthomas, and gout (8, 7, and 4 cases, respectively). Traumatic lesions were noted in 41 cases and were most commonly characterized by head trauma and cerebral hemorrhage. Toxicity was rare; five total cases caused by a single carbon monoxide event were identified.

Blood concentration of symmetric dimethylarginine correlates with kidney damage as assessed with a proposed histologic grading system for chronic kidney disease in tigers (Panthera tigris).

OBJECTIVE: To determine the utility of blood symmetric dimethylarginine (SDMA) concentration measurement as a diagnostic tool for chronic kidney disease (CKD) in tigers (Panthera tigris) by comparing results for SDMA with those for traditional renal biomarkers and investigating correlations between these biomarkers and histopathologic kidney changes in tigers with CKD. SAMPLE: Blood, urine, and kidney samples from 35 tigers with CKD from 2 sanctuaries. PROCEDURES: Blood (serum or plasma) and urine samples were collected antemortem. Necropsy, including gross and histologic assessment, was performed for tigers that died or were euthanized for quality-of-life reasons. Results for CKD biomarkers in blood (BUN, creatinine, phosphorus, and SDMA concentrations) and urine (protein concentration, urine protein-to-creatinine ratio, and urine specific gravity) were evaluated for correlation with histologic kidney damage scored with an objective grading scale defined by percentage of inflammation, fibrosis, and tubular atrophy. RESULTS: Symmetric dimethylarginine had the strongest significant correlation (ρ = 0.667) with histologic kidney damage score, followed by urine specific gravity (ρ = -0.639), blood creatinine concentration (ρ = 0.624), and BUN (ρ = 0.588). No significant correlation with kidney score was identified for blood phosphorus concentration, urine protein concentration, or the urine protein-to-creatinine ratio. CLINICAL RELEVANCE: We recommend SDMA be prioritized as a renal biomarker in tigers, with SDMA results considered in addition to those of other traditional renal biomarkers when assessing kidney function in tigers. Additionally, the grading scale we developed could be replicated across patients and pathologists for more consistent postmortem assessment of CKD in tigers.

DETECTION OF VECTOR-BORNE INFECTIONS IN LIONS AND TIGERS AT TWO ZOOS IN TENNESSEE AND OKLAHOMA, USA.

Protozoal and bacterial vector-borne infections are frequently diagnosed in domestic felids. However, with the exception of Mycoplasma haemofelis and Cytauxzoon felis, their occurrence in managed nondomestic felids housed in the United States is largely unknown. Following a case in February 2020 of fulminant cytauxzoonosis in an African lion (Panthera leo), EDTA-whole blood samples were collected opportunistically from February 2020 through June 2020 from 34 adult tigers (Panthera tigris) and eight adult African lions from the same sanctuary in eastern Tennessee as well as 14 adult tigers from a zoo in southern Oklahoma. Samples were analyzed for Cytauxzoon felis, Bartonella spp., hemotropic Mycoplasma, Rickettsia spp., Anaplasma spp., Ehrlichia spp., Babesia spp., and Hepatozoon spp. DNA by PCR amplification. All animals were asymptomatic at the time of collection. None of the Oklahoma animals were positive for vector-borne organisms, but these pathogens were detected in tigers at the Tennessee facility, including Cytauxzoon felis (11.8%), "Candidatus Mycoplasma haemominutum" (5.9%), and Ehrlichia ewingii (2.9%). During the study period, two animals developed clinical signs of cytauxzoonosis and were assessed for vector-borne infections as part of their diagnostic evaluation. This study documents the presence of tick-borne diseases in managed nondomestic felids in the southeastern United States and underscores that ectoparasite control measures should be practiced to minimize exposure of carnivores in managed care.

METHOD COMPARISON FOR MEASUREMENT OF SYMMETRIC DIMETHYLARGININE IN TIGERS (PANTHERA TIGRIS).

Renal disease is well documented in nondomestic felids and is monitored and diagnosed by serum concentration of blood urea nitrogen, creatinine, and phosphorous. Symmetric dimethylarginine (SDMA) has proven to be an earlier and more sensitive biomarker for the assessment of glomerular filtration rate. Although SDMA is commonly measured in nondomestic felids, information concerning the validity of the assay is lacking. The purpose of the study was to perform a method comparison between high-throughput immunoassay and the reference method, liquid chromatography-tandem mass spectrometry (LC-MS/MS), to quantify SDMA concentrations in tiger blood samples. Concentrations of SDMA were measured for 81 individual tiger samples. The SDMA immunoassay demonstrated excellent correlation to the LC-MS/MS reference method. A Passing and Bablok linear regression analysis had a slope of 1.03 (95% CI, 0.99-1.11), an intercept of 1.64 (95% CI, 0.46-2.34), and a Pearson R= 0.99. The mean bias was 1.53 µg/dl (95% CI, 0.63-2.42 µg/dl), and the limit of agreement was ±7.96 µg/dl. The degree of bias is within established acceptance criteria of 1-3 µg/dl for the immunoassay. Although this study provides good evidence of the utility of the immunoassay to measure SDMA in tiger serum and plasma, further assay validation is recommended.

Magnetic Resonance Imaging in 50 Captive Non-domestic Felids - Technique and Imaging Diagnoses.

Magnetic resonance imaging (MRI) is the recognized gold standard for diagnostic imaging of the central nervous system in human and veterinary patients. Information on the use of this modality and possible imaging abnormalities in captive non-domestic felids is currently limited to individual case reports or small case series. This retrospective study provides information on technique and imaging findings in a cohort of cases undergoing MRI at an academic Veterinary Medical Center. The University of Tennessee College of Veterinary Medicine MRI database was searched for non-domestic felids undergoing MRI of the brain or spine from 2008 to 2021. Medical record data were recorded, and MRI studies were reviewed. Fifty animals met the inclusion criteria. The most common brain diseases were Chiari-like malformation (n = 8) and inflammatory conditions (n = 8). Other abnormalities included pituitary lesions (n = 5), brain atrophy (n = 2), and one each of metabolic and traumatic conditions. Fourteen animals had a normal brain MRI study. The most common spinal abnormality was intervertebral disc disease (n = 7). Other disorders included vertebral dysplasia (n = 2), presumptive ischemic myelopathy (n = 1), subdural ossification causing spinal cord compression (n = 1), and multiple myeloma (n = 1). Spinal cord swelling of undetermined cause was suspected in two animals, and seven patients had a normal MRI study of the spine. MRI is a valuable tool in the diagnostic workup of non-domestic felids with presumptive neurologic disease.

Agreement between oscillometric and direct blood pressure measurements in anesthetized captive chimpanzees (Pan troglodytes).

OBJECTIVE: To evaluate the level of agreement (LOA) between direct and oscillometric blood pressure (BP) measurements and the ability of oscillometric measurements to accurately detect hypotension in anesthetized chimpanzees (Pan troglodytes). ANIMALS: 8 captive, adult chimpanzees. PROCEDURES: During prescheduled annual examinations, each chimpanzee underwent general anesthesia and patient monitoring for their examination, echocardiography for a concurrent study, and measurement of direct BP with the use of tibial artery catheterization and oscillometry with the use of a cuff placed around a brachium and a cuff placed around the second digit of the contralateral forelimb for the present study. Bland-Altman plots were generated to compare results for direct and oscillometric BP measurements. Mean bias and 95% LOAs were calculated for oscillometric measurements of systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP) for each cuff site. Sensitivity and specificity in detecting hypotension were also determined for each cuff site. RESULTS: There were 74 paired direct and brachial oscillometric measurements of each, SAP, MAP, and DAP and 66 paired direct and digit oscillometric measurements of each, SAP, MAP, and DAP. Only brachial oscillometric measurements of MAP had adequate sensitivity (78%) and specificity (95%) to accurately detect hypotension, and this technique also had the least mean bias (0.8 mm Hg; 95% LOA, -29 to 31 mm Hg). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that brachial oscillometric measurement of MAP provided reasonable agreement with tibial arterial direct MAP measurement and performed well in diagnosing hypotension in anesthetized chimpanzees.

A RETROSPECTIVE STUDY OF BRAIN LESIONS IN CAPTIVE NONDOMESTIC FELIDS.

This retrospective study identified and characterized brain lesions in captive nondomestic felids from a large cat sanctuary. Necropsy reports from January 2002 through December 2018 were examined, and gross images and microscopic slides were reviewed from individual cats, where available. In total, 255 cats met the following inclusion criteria: complete necropsy report available, brain examined grossly or microscopically, and age of >1 mon. Of the 255 cats, 49 cats (19%) were determined to have brain lesions. Eleven different felid species, as well as one captive-bred hybrid (liger), were included in the study, with tigers (Panthera tigris) (55%) and lions (Panthera leo) (18%) being the most common species. Lesions were grouped into six etiologic categories: neoplastic (32%), vascular (26%), inflammatory or infectious (20%), congenital (9%), idiopathic (7%), and metabolic (6%). Not included in these categorized lesions were previously undescribed amphophilic globules in the cerebral cortex of many cats with and without other brain lesions; these were in 95% of lion and 93% of tiger brains where the cerebral cortex was available for histologic examination. These globules were not associated with clinical disease. The histopathologic and gross brain changes documented in this study provide insight into specific diseases and pathologic processes that affect the brains of captive large cat populations.

EXOCRINE PANCREATIC INSUFFICIENCY-LIKE SYNDROME IN FOUR CAPTIVE TIGERS (PANTHERA TIGRIS).

Exocrine pancreatic insufficiency (EPI) is a condition characterized by a decreased synthesis and secretion of pancreatic enzymes, which results in weight loss, poor hair coat, and diarrhea. The diagnostic test of choice for EPI in domestic cats is feline serum trypsin-like immunoreactivity (fTLI). This paper details four tigers (Panthera tigris) with clinical signs compatible with EPI. On the basis of domestic cat reference ranges, fTLI assays for all four clinically affected tigers were diagnostic for EPI (median 1.0 µg/L; range 0.5-1.2 µg/L). All four tigers had a rapid clinical response to pancreatic enzyme supplementation. Serum from 10 clinically healthy tigers was submitted for the fTLI assay, for comparative purposes. The healthy tigers' fTLI assays were also within range for a diagnosis of EPI in domestic cats (median 3.1 µg/L; range 1.9-4.5 µg/L); however, clinically affected tigers had significantly lower serum fTLI concentrations than healthy tigers (P = 0.0058). Serum cobalamin was below the detection limit in both the affected and healthy tigers (<150 ng/L). Measuring fTLI appears to be a useful tool in the diagnosis of EPI-like syndrome in tigers. As in other species, EPI-like syndrome in tigers may also be associated with cobalamin deficiency.

ECHOCARDIOGRAPHY AND DIRECT ARTERIAL BLOOD PRESSURE MEASUREMENT IN CAPTIVE CHIMPANZEES (PAN TROGLODYTES) DURING TWO PHASES OF AN ANESTHETIC PROTOCOL.

The effects of α-2 agonists on echocardiographic findings in great apes are not well documented, and knowledge of these effects would expand the understanding of cardiac examinations of chimpanzees under anesthesia with protocols using these drugs. Ten adult chimpanzees (Pan troglodytes), four males and six females, underwent echocardiographic examinations after anesthesia with dexmedetomidine, midazolam, and ketamine (phase 1). Four animals required isoflurane to achieve an adequate plane of anesthesia. Atipamezole was used to antagonize dexmedetomidine, and all remaining animals were placed on isoflurane (phase 2), and then a second echocardiogram was performed. Direct arterial blood pressure was monitored during the anesthetic event. Measurements and recordings were assessed for statistically significant differences between the two phases and sex. There were no significant differences between phases or sex for any two-dimensional echocardiographic measurement of systolic function, although interventricular septum thickness at end systole approached a significant decrease from phase 1 to phase 2 (P = 0.058) when sex was considered a between-subject factor. Left ventricular outflow tract (P = 0.017) and pulmonary artery (P = 0.028) velocities increased after reversal of the dexmedetomidine. Diastolic transmitral flow was consistent with grade 3 diastolic dysfunction (median early to late ventricular filling velocities (E/A) of 2.02, interquartile range [IQR], 1.53-2.13) with a nonsignificant decrease of E velocity and increase in A velocity and decreased E/A after reversal. Trace mitral and tricuspid regurgitation were common findings in the sample population. Arterial blood pressure significantly decreased between phase 1 and phase 2 (P < 0.01). All chimpanzees entered a hypotensive state (mean arterial pressure < 60 mm Hg) during phase 2. Although limited by the small number of chimpanzees, this study showed an increase in afterload, potential diastolic dysfunction, and a decrease in blood pressure after the antagonism of dexmedetomidine. Additional studies to further assess the effects of α-2 agonists in chimpanzees are warranted.

DURATION OF ANTIGEN SHEDDING AND DEVELOPMENT OF ANTIBODY TITERS IN MALAYAN TIGERS (PANTHERA TIGRIS JACKSONI) NATURALLY INFECTED WITH SARS-CoV-2.

Natural infection of three captive Malayan tigers (Panthera tigris jacksoni) with SARS-CoV-2 caused mild to moderate symptoms of lethargy, anorexia, and coughing. Each tiger was longitudinally sampled opportunistically via consciously obtained oral, nasal, and/or fecal samples during and after resolution of clinical signs, until 2 wk of negative results were obtained. Persistent shedding of SARS-CoV-2 genetic material was detected via reverse transcription-polymerase chain reaction in feces up to 29 d after initial onset of clinical signs, but not in nasal or oral samples. Tigers became resistant to behavioral training to obtain nasal samples but tolerated longitudinal oral sampling. Serum was obtained from two tigers, and antibody titers revealed a robust antibody response within 9 d of onset of clinical signs, which was sustained for at least 3 mon. The tigers were infected despite the use of masks and gloves by husbandry personnel. No known cause of the outbreak was identified, despite extensive investigational efforts by the regional health department. No forward cross-species transmission was observed in primates housed in nearby enclosures. The increasing regularity of reports of SARS-CoV-2 infection in nondomestic felids warrants further investigations into shedding and immunity.

CANINE DISTEMPER AND PARVOVIRUS VACCINATION WITH RECOMBITEK C3 IN AFRICAN WILD DOGS (LYCAON PICTUS).

Infectious disease threats are increasingly recognized as a major contributor to mortality in wild populations of African wild dog (Lycaon pictus, AWD). Canine distemper virus (CDV) infection has been implicated as a cause of pack mortality in both captive and wild AWD populations. Ten animals were vaccinated with RecombitekTM C3, a vaccine containing a recombinant CDV, and modified live canine parvovirus (CPV) and adenovirus-2 components, at 8, 12, and 16 wk of age. Half of the pups received the vaccine IM and the other half SC. All ten pups had a positive serological response to CDV after the second vaccination, which decreased or stagnated after the third vaccination. Half of the pups had CDV titers ≥32 at 20 wk of age. Titers to CPV were high in all pups prior to vaccination and dropped precipitously over the course of the vaccine series. At the last sampling period, only 50% of the pups had measurable CPV titers. An initially higher titer was seen for CDV in the IM administration group; however, this was not significant at later time points. Vaccination with Recombitek C3 appears to be safe and effected a sustained serological response to CDV in AWD.

Ophthalmic findings in 10 captive, anesthetized chimpanzees (Pan troglodytes).

OBJECTIVES: To document ophthalmic findings, Schirmer's tear test I (STT), and intraocular pressure (IOP) values for anesthetized chimpanzees (Pan troglodytes). ANIMALS STUDIED: Ten captive chimpanzees from Zoo Knoxville and Chattanooga Zoo. PROCEDURES: Ten chimpanzees were anesthetized for annual physical examinations, blood collection, and ophthalmic examination. Each was anesthetized with intramuscular (IM) injections of dexmedetomidine, midazolam, and ketamine. Ophthalmic findings and STT and IOP values in addition to general health information were recorded for each chimpanzee. Pupillary diameter was measured after topical tropicamide administration. A Shapiro-Wilk test of normality was done for age, weight, STT values, IOP values, and pupil size. RESULTS: Ages ranged from 11 to 42 years. Weight range was 40.9-83.6 kg. The mean STT was 13.4 ± 5.3 mm/min. The mean IOP was 14 ± 4.2 mm Hg. Seven of the 10 chimpanzees were considered geriatric, and each had perilimbal lipid deposits. Sedative-associated miosis was successfully counteracted with a regimen of repeated applications of tropicamide, enabling complete fundic examination. CONCLUSIONS: A complete ophthalmic examination can be done on anesthetized chimpanzees with the protocol used in this study.

Natural Canine Distemper Virus Infection in Linnaeus's 2-Toed Sloths (Choloepus didactylus).

An outbreak of canine distemper virus in a private zoo in eastern Tennessee in July 2016 led to fatal clinical disease in 5 adult, wild-caught Linnaeus's 2-toed sloths (Choloepus didactylus). Clinical signs included hyporexia, lethargy, mucopurulent nasal discharge, and oral and facial ulcers. At necropsy, affected animals had crusts and ulcers on the lips, nose, tongue, and oral cavity. Microscopically, all sloths had widespread, random, hepatic necrosis; lymphoid depletion; and bronchointerstitial pneumonia. The central nervous system did not contain gross or histopathologic lesions in any of the 5 sloths, although immunoreactivity for viral antigen was present within vessel walls. Epithelial cells and histiocytes within numerous organs contained intranuclear and intracytoplasmic inclusions and occasional syncytial cells. Canine distemper virus was confirmed with immunohistochemistry and virus isolation. Viral sequencing identified the novel American-4 strain prevalent in eastern Tennessee wildlife. This is the first pathologic characterization of canine distemper virus infection in sloths (family Choloepodidae, order Pilosa) and emphasizes the significant morbidity and mortality in this species.

TIGER (PANTHERA TIGRIS) AND DOMESTIC CAT (FELIS CATUS) IMMUNE RESPONSES TO CANARYPOX-VECTORED CANINE DISTEMPER VACCINATION.

Two methods for delivering a canarypox-vectored canine distemper vaccine to tigers (Panthera tigris) and domestic cats (Felis catus) were investigated. Eight tigers were divided randomly into two vaccination groups: subcutaneous injection or topical tonsillar application. Each tiger received 2 ml of canine distemper virus (CDV) vaccine (Merial Ferret Distemper Vaccine). Blood was collected from tigers on days 0, 21, 35 or 37, and 112 post-initial vaccination (PIV). Domestic cats were divided randomly into four treatment groups: saline injection (negative controls), low- and high-dose oral, and subcutaneous vaccinates. Blood was collected from domestic cats on days 0, 7, 21, and 28 and 165 or 208 PIV. Sera were tested for CDV antibodies by virus neutralization. All individuals were seronegative at the beginning of the study. One tiger vaccinated subcutaneously developed a titer of 32 by day 35, which reduced to 16 by day 112. Another tiger vaccinated by tonsillar application developed a titer of 8 on day 112. All other tigers remained seronegative. Cats that received saline injection or oral vaccination remained seronegative at each sampling time. Domestic cats vaccinated subcutaneously developed titers ranging from 4 to >128 by day 28, and those re-bled at day 166 had titers of 16 or 64. The disparity in response between domestic cats and tigers may be due to species differences or it may represent a dose-dependent effect. Subcutaneous vaccination with canarypox-vectored Purevax Ferret Distemper® is safe and elicits persistent antibody titers in domestic cats vaccinated parenterally.