Cutaneous Histiocytosis in an Eastern Gray Squirrel (Sciurus carolinensis).

A free-ranging Eastern gray squirrel (Sciurus carolinensis) was presented for ulcerated cutaneous masses at the base of both pinnae in July 2021. Diagnosis of cutaneous histiocytosis was achieved by histologic and immunohistochemical examination of one excised mass and supported by spontaneous resolution of the contralateral mass before the squirrel's release.

Postmortem diagnoses and factors influencing diagnoses in captive white-tailed deer in Wisconsin, 2009-2021.

There have been significant changes to Wisconsin agriculture since ~2010, one of which is the growth of commercial farming of white-tailed deer (WTD; Odocoileus virginianus). These high-density populations may lead to the emergence of previously unrecognized or under-recognized disease trends. I evaluated archived pathology records at the Wisconsin Veterinary Diagnostic Laboratory (WVDL) from 2009-2021 for captive WTD postmortem cases and included records from 277 WTD cases. Diagnoses were found in 81.9% of cases, with an average of 1.3 diagnoses per animal. Submissions with a clinical history of respiratory disease were 7.0 times more likely to have a diagnosis than the average case. Fawns were 1.9 times more likely to have a diagnosis. The most common diagnoses were bronchopneumonia and enteritis and/or enterocolitis (both 16.2% of total diagnoses). The most common isolates from bronchopneumonia cases were Pasteurella multocida, Bibersteinia trehalosi, and Trueperella pyogenes. The pathogens identified most often in enteritis and/or enterocolitis cases were rotavirus, Clostridium perfringens, and Escherichia coli. The most common non-infectious diagnoses were poor nutritional status or inanition, hepatic lipidosis, and selenium and/or vitamin E deficiency. Focusing on testing for pathogens in fawns and in cervid respiratory disease complex submissions may be recommended for laboratories expanding their WTD testing.

Follicular dysplasia and hair loss in white-tailed deer (Odocoileus virginianus).

There have been unpublished reports of a follicular dysplastic syndrome in adult white-tailed deer (Odocoileus virginianus; WTD), known colloquially as "toothpaste hair disease." The current report aims to describe the gross and histologic lesions in skin samples from 2 adult WTDs that presented to the Wisconsin Department of Natural Resources and the Wisconsin Veterinary Diagnostic Laboratory with reports of hair loss in 2018. Both cases were grossly alopecic with sparing of the distal extremities and variably the head and neck. Histologic features included hair follicles and adnexa present in relatively normal numbers, dilated and misshapen follicles, and dysplastic hair bulbs. Hair follicles were empty, contained fragmented and irregular hair shafts, or contained concretions of keratin. Hair bulbs were rarely infiltrated by small lymphocytes, suggestive of alopecia areata as a cause of the gross appearance. This condition does not appear to be directly responsible for WTD mortality but presumably would predispose affected animals to greater environmental exposure. Evaluation of additional affected individuals is warranted to further evaluate for features of alopecia areata.

Histiocytic sarcoma with central nervous system involvement in 6 cats.

Here we characterize 6 cases (4 autopsies and 2 biopsies) of histiocytic sarcoma in the CNS of cats. All affected cats had chronic, progressive clinical signs. Three autopsied cats were euthanized because of a poor prognosis, and one died. The clinical outcome for the biopsy cases remains unknown. Tumors occurred in the brain (4 cases), spinal cord (1 case), and brain and spinal cord (1 case). Neoplasms were restricted to the CNS in 3 cases. Reported gross changes in the 4 autopsy cases consisted of neuroparenchymal swelling with or without tissue pallor or gray discoloration (2 cases) and a yellow or dark-gray mass (2 cases). Histologically, pleomorphic, round-to-elongate neoplastic cells with typical histiocytic morphology effaced the neuroparenchyma and leptomeninges. Multinucleate neoplastic cells were observed in all cases. The mitotic count was 1-24 in 2.37 mm2 (10 FN22 40× fields). Neoplastic cells in all cases had positive immunolabeling for Iba1; immunolabeling was negative for E-cadherin, CD3, CD79, and MUM1, confirming their histiocytic origin.

Clinicopathologic Findings in Chickens (Gallus gallus domesticus) Administered Amikacin Through Intravenous Regional Limb Perfusion.

Regional limb perfusion (RLP) has been used to treat cases of distal limb infections in avian species. Potentially nephrotoxic drugs, such as amikacin, may increase the risk of nephrotoxicity with RLP because of the presence of the renal portal system and direct venous blood flow from the pelvic limbs to the kidneys. In a randomized, blinded, placebo-controlled study, the safety of repeated amikacin administration (20 mg/kg q24h for 3 doses) via RLP was evaluated in healthy female chickens (Gallus gallus domesticus; n = 8 treatment, n = 8 saline control group). Plasma uric acid concentrations were not significantly elevated in treated birds compared with the control group at any time point following RLP. One week following the final RLP, birds were necropsied and the kidneys evaluated grossly and histologically. There was no significant difference in renal pathology scores between treated and control birds or between kidneys ipsilateral to the perfused limb and contralateral kidneys. This study concludes that RLP of amikacin at high doses produced no discernable renal pathology in healthy euhydrated chickens.

North American Arboviruses and White-Tailed Deer (Odocoileus virginianus): Associated Diseases and Role in Transmission.

Background: Arboviral disease is of increasing concern to human and animal health professionals as emerging and re-emerging arboviruses are more frequently recognized. Wildlife species are known to play a role in the transmission and maintenance of arboviruses and infections can result in morbidity and mortality in wildlife hosts. Materials and Methods: In this review, we detail existing evidence of white-tailed deer (Odocoileus virginianus) as an important host to a diverse collection of arboviruses and evaluate the utility of this species as a resource to better understand the epidemiology of related viral diseases. Results: Relevant veterinary and zoonotic viral pathogens endemic to North America include epizootic hemorrhagic disease virus, bluetongue virus, orthobunyaviruses, vesicular stomatitis virus, Eastern equine encephalitis virus, West Nile virus, and Powassan virus. Exotic viral pathogens that may infect white-tailed deer are also identified with an emphasis on zoonotic disease risks. The utility of this species is attributed to the high degree of contact with humans and domestic livestock and evidence of preferential feeding by various insect vectors. Conclusions: There is mounting evidence that white-tailed deer are a useful, widely available source of information regarding arboviral circulation, and that surveillance and monitoring of deer populations would be of value to the understanding of certain viral transmission dynamics, with implications for improving human and domestic animal health.

Postmortem diagnoses in South American camelids and factors influencing diagnostic rate in the Upper Midwest USA, 2009-2019.

South American camelids (SACs) have become increasingly popular as livestock and companion animals in the Midwestern United States. With increased ownership, postmortem evaluations and samples available for diagnostic assessment are being submitted more frequently to veterinary diagnostic laboratories. We searched archived pathology records at the Wisconsin Veterinary Diagnostic Laboratory (WVDL) between 2009-2019 for SAC cases. Postmortem records from 166 alpacas and 27 llamas were included, with an average of 1.42 diagnoses per animal. The overall average diagnostic rate was 79.8%. Abortion and neonatal cases (fetus to 1-wk-old) had the lowest diagnostic rate (33.3%) and was the only group with a diagnostic rate statistically significantly lower than the average. The most common diagnoses were gastrointestinal parasitism and suboptimal nutritional status or inanition; 78% of cases diagnosed with suboptimal nutritional status were also parasitized. The gastrointestinal parasites identified most frequently were Eimeria sp. and strongyles, especially Nematodirus sp. Our findings may aid allocation of diagnostic resources to better serve regional SAC populations and provide a framework for practitioners who send samples to laboratories for analysis. Submission of whole bodies, euthanized animals, fresh tissue, and inclusion of placental tissues in abortion cases are recommended for optimal diagnostic outcome.

Experimental Infection of Domestic Piglets (Sus scrofa) with Rift Valley Fever Virus.

Rift Valley fever phlebovirus (RVFV) is a mosquito-transmitted phlebovirus (Family: Phenuiviridae, Order: Bunyavirales) causing severe neonatal mortality and abortion primarily in domestic ruminants. The susceptibility of young domestic swine to RVFV and this species' role in geographic expansion and establishment of viral endemicity is unclear. Six commercially bred Landrace-cross piglets were inoculated subcutaneously with 105 plaque-forming units of RVFV ZH501 strain and two piglets received a sham inoculum. All animals were monitored for clinical signs, viremia, viral shedding, and antibody response for 14 days. Piglets did not develop evidence of clinical disease, become febrile, or experience decreased weight gain during the study period. A brief lymphopenia followed by progressive lymphocytosis was observed following inoculation in all piglets. Four piglets developed a brief viremia for 2 days post-inoculation and three of these had detectable virus in oronasal secretions three days post-inoculation. Primary inoculated piglets seroconverted and those that developed detectable viremias had the highest titers assessed by serum neutralization (1:64-1:256). Two viremic piglets had a lymphoplasmacytic encephalitis with glial nodules; RVFV was not detected by immunohistochemistry in these sections. While young piglets do not appear to readily develop clinical disease following RVFV infection, results suggest swine could be subclinically infected with RVFV.

The Effect of Maternal Antibodies on Clinical Response to Infection with Epizootic Hemorrhagic Disease Virus in White-Tailed Deer (Odocoileus virginianus) Fawns.

We investigated whether naturally acquired maternal antibodies to epizootic hemorrhagic disease virus serotype 2 (EHDV-2) would protect white-tailed deer (Odocoileus virginianus) fawns against infection and clinical disease following an EHDV-2 challenge. We compared viremia and clinical response in 27-47-d-old, experimentally infected fawns with and without maternally derived antibodies to EHDV-2. Mild to moderate clinical signs were observed in four seronegative (maternal antibody-negative) fawns, which were viremic from 3 to 14 d postinoculation. Individual peak blood virus titers for seronegative fawns ranged from 104.3 to 106.3 median tissue culture infective doses (TCID50)/mL. In contrast, clinical signs were not observed in seropositive (maternal antibody-positive) fawns and a transient low-level viremia (≤102.4 TCID50/mL) occurred in two of six fawns. Our results indicated that the presence of maternally derived EHDV-2 antibodies in fawns prevents or greatly reduces clinical disease and the level and duration of EHDV-2 viremia.

Computed tomographic and ultrasonographic diagnosis with successful excision of a lipoma in a shusui koi (Cyprinus carpio).

CASE DESCRIPTION: A client-owned 12-year-old 10.3-kg (22.7-lb) female shusui koi (Cyprinus carpio) was evaluated because of an ulcerated mass on the left body wall, hyporexia, and decreased activity. CLINICAL FINDINGS: The patient was anesthetized with a solution of eugenol in water for all examinations and procedures. An approximately 7 × 5-cm smooth, raised, ulcerated, and firm mass was present ventral and lateral to the dorsal fin on the left body wall. Whole-body CT images obtained before and after contrast administration revealed an encapsulated, homogeneous, fat-opaque mass within the muscle. The mass was fat echoic with poor vascularity on ultrasonographic examination. Histologic evaluation of an ultrasound-guided needle biopsy specimen was suggestive of a lipoma. TREATMENT AND OUTCOME: The mass was excised, and the fish was placed in water with 0.3% salinity for 3 weeks after surgery. Postoperative antimicrobial administration was not indicated, and additional postoperative analgesic administration was considered impractical. The patient had noticeable improvement in appetite and activity with no indication of discomfort immediately following surgery. Five weeks after surgery, the incision site had healed with minimal scarring, and evaluation of CT images revealed no evidence of mass regrowth or regional osteomyelitis. CLINICAL RELEVANCE: Antemortem evaluation and diagnosis of a lipoma in a teleost with subsequent excision was described. This report highlighted the logistic challenges associated with anesthesia, advanced diagnostic imaging, and surgery in fish and showed that they can be successfully overcome so that high-level medical care can be provided to such patients.

Central nervous system diseases of cattle in Georgia, 2001-2017.

In a review of 159 archived bovine autopsy cases submitted to the Georgia Veterinary Diagnostic Laboratory System from 2001 to 2017, we evaluated histologic lesions and other laboratory test results in cases diagnosed with central nervous system (CNS) disease to determine the most common disorders and the rate of definitive morphologic and etiologic diagnosis within the population. The most common breed was Aberdeen Angus or Angus (31%), and female animals comprised 60% of the overall submissions. Gross anatomic changes were described in 33% of cases that had histologic lesions. Suppurative meningoencephalitis was the most common diagnosis (28% of cases overall) and was frequently associated with bacterial sepsis. Lymphocytic meningoencephalitis without an identified etiology was diagnosed in 17% of cases. Polioencephalomalacia was the most commonly identified noninfectious diagnosis (17%). Hydrocephalus was the most common CNS comorbidity and potential congenital defect. Identification of specific agents was sporadic, and infectious disease testing was largely dependent on fluorescent antibody testing, almost all of which were negative. Our findings indicate the common differential diagnoses for cattle with neurologic signs in the southeastern United States, as well the need for a well-defined, methodical diagnostic approach, including autopsy, histology, and appropriate additional laboratory testing.

EXPERIMENTAL INFECTION OF WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS) WITH BLUETONGUE VIRUS SEROTYPE 3.

Bluetongue virus serotype 3 (BTV-3) has been found in the US since 1999 and was recently identified in white-tailed deer (WTD; Odocoileus virginianus) found dead in Virginia, US and West Virginia, US in 2016. Bluetongue viruses are known to cause pathologic changes in WTD; however, the relative virulence and pathogenicity of BTV-3 in WTD is unknown. In our study, eight WTD fawns, 6-12 wk old, were needle inoculated subcutaneously with a field isolate of BTV-3, with one fawn shaminoculated as a control during July 2017; all were monitored to determine the pathogenicity of BTV-3 in WTD. All inoculated fawns developed viremias that were first detected on postinoculation day (PID), 3 with peak titers on PID 5 by both quantitative reverse-transcription PCR (qRT-PCR) and virus isolation. The sham-inoculated control fawn also became viremic on PID 12, presumably through contact with infected fawns. Mild clinical signs, including periorbital edema and hyperemia, were first seen on PID 5. None of the fawns developed a significant febrile response, clinical pathology changes, or BTV-3 neutralizing antibodies. The cytokines TNF-α, IL-1ß, and IFN-α were not detected by commercial enzyme-linked immunosorbent assays developed for bovids. The absence of severe clinical disease, fibrinogenemia, thrombocytopenia, and leukopenia, along with the lack of seroconversion and a detectable cytokine response during the study period, is atypical when compared to previous experimental BTV serotype infections in WTD but may be related to the young age of these deer, possible attenuation of the BTV-3 strain used, innate resistance or, in some cases to maternally derived antibody to other BTV serotypes.

Embryonal central nervous system tumor in the brain of a goose.

Embryonal central nervous system (CNS) tumor is a rare malignant neoplasm that arises from the neural crest. Herein we describe an embryonal tumor in the brain of an adult male domestic goose ( Anser anser) that was euthanized after a short history of wandering and lethargy. Grossly, a focal, bright-red, soft plaque was present on the ventral aspect of the brain, extending from the optic chiasm to the midbrain, as well as into the dorsal neuroparenchyma. Histologically, the nodule consisted of a poorly demarcated population of neoplastic cells arranged in streams and bundles, and occasionally palisading around small capillaries (pseudorosettes). Neoplastic cells were elongate and had scant, finely granular, eosinophilic cytoplasm, and elongate nuclei with dense chromatin. Mitoses were uncommon. Scattered foci of intratumoral necrosis and microvascular proliferation were present. Neoplastic cells were immunoreactive for doublecortin and neuronal nuclei. Ultrastructurally, neoplastic cells had elongated-to-polyhedral cytoplasm with short processes, scarce intermediate filaments, and small round mitochondria and rough endoplasmic reticulum. The cell membrane had varied numbers of intercellular anchoring-like junctions, and nuclei were round-to-elongate and had marginal aggregates of heterochromatin. Morphologic, immunohistochemical, and ultrastructural findings in our case are consistent with a poorly differentiated embryonal tumor.

Heartland Virus Exposure in White-Tailed Deer in the Southeastern United States, 2001-2015.

Heartland virus (HRTV) is a North American phlebovirus suspected to be transmitted by the lone star tick Amblyomma americanum. White-tailed deer (WTD) have been shown to develop HRTV-neutralizing antibodies following experimental infection. To further define the geographic distribution of HRTV through retrospective sampling of WTD, sera from the WTD herd health serum archive at the Southeastern Cooperative Wildlife Disease Study between 2001 and 2015 were analyzed using serum neutralization. Of 783 serum samples tested, 57 (7.3%) were positive for HRTV-neutralizing antibodies. Deer with moderate to heavy tick burdens were more likely seropositive. Seropositive samples were obtained from deer originating from states with documented human cases of HRTV-associated disease. Seropositive samples were identified from years before the recognition of the first human case in 2009. Overall, this study indicates that WTD in the southeastern United States have been exposed to HRTV as early as 2001 and that the presence of seropositive animals corresponds roughly with reported human HRTV-associated disease.

Experimental Infection of White-Tailed Deer (Odocoileus virginanus) with Heartland Virus.

Heartland virus (HRTV) is a phlebovirus suspected to be transmitted by Amblyomma americanum, commonly known as the lone star tick, and reported to cause illness in humans, which is characterized by thrombocytopenia and leukopenia. Heartland virus-reactive antibodies have been detected in a variety of wildlife species including white-tailed deer (WTD). To better understand the potential role of deer in the epidemiology of HRTV, we experimentally inoculated five WTD fawns with HRTV and monitored for clinical disease, viremia, virus shedding, and seroconversion. None of the animals showed signs of clinical disease, and there was no detectable viremia or virus shedding postinoculation. Two wild-caught fawns entered the study with preexisting antibody titers against HRTV. All animals showed minimal immune responses against HRTV after needle inoculation. In conclusion, this study does not indicate that WTD are a likely reservoir for HRTV in natural settings.

Congenital Ocular Abnormalities in Free-Ranging White-Tailed Deer.

Congenital ocular abnormalities in cervids have been previously reported as individual cases from various regions of the United States and include microphthalmia, anophthalmia, congenital cataracts, dermoids, and colobomata. A common underlying cause for these abnormalities, such as nutritional deficiencies, environmental toxin exposures, or genetic mutations, has not been established. This retrospective study summarized and compared cases of suspected congenital ocular abnormalities in free-ranging white-tailed deer ( Odocoileus virginianus) submitted to the Southeastern Cooperative Wildlife Disease Study (SCWDS) in Athens, Georgia, to the preexisting literature. Of 3645 accessions of white-tailed deer submitted to SCWDS, 15 qualifying case records were found. An additional 15 cases were reported previously in the literature. Conditions described in SCWDS cases included microphthalmia (8/15), congenital cataracts (3/15), anophthalmia (2/15), colobomata (1/15), anterior segment dysgenesis (1/15), ectopic lacrimal gland tissue (1/15), and congenital blindness with corneal opacity (1/15). Most (11/15; 73%) of the SCWDS cases were male fawns with an average age of 4 months at presentation, consistent with previously described cases. Most animals had bilateral abnormalities with few extraocular congenital abnormalities, also consistent with existing reports. Cases were variably tested for various infectious agents at the time of submission; 2 cases were seropositive for bluetongue virus. Spatiotemporal clustering of cases was not evident. This study provided a concise and systematic summary of known existing cases of congenital ocular defects in fawns but did not identify a cause.

Malignant rectal melanoma in 2 dogs.

Two rare cases of malignant rectal melanoma in dogs are described. Tumors were locally invasive and composed of spindle cells arranged in interweaving bundles, sheets, and nests within preexisting fibrovascular stroma. Mitotic count was high. The diagnosis was achieved based on histopathology and immunohistochemistry for PNL2 and melan-A.

Mélanome rectal malin chez 2 chiens. Deux cas rares de mélanome rectal malin chez les chiens sont décrits. Les tumeurs étaient localement envahissantes et composées de cellules fusiformes disposées en faisceaux entrelacés, de feuilles et de nids dans le stroma fibrovasculaire préexistant. Le compte mitotique était élevé. Le diagnostic a été réalisé sur la base de l'histopathologie et de l'immunohistochimie pour le PNL2 et le melan-A.(Traduit par les auteurs).

Atypical cytologic presentation of a histiocytic sarcoma in a Cavalier King Charles Spaniel dog.

A Cavalier King Charles Spaniel dog was presented because of a 10-d history of progressive vomiting, inappetence, and lethargy, with mild neurologic signs. Fine-needle aspirates of splenic nodules seen on ultrasound were suggestive of a carcinoma. On autopsy, a disseminated neoplasm was present in the lung, spleen, and adrenal glands. Additionally, there was a Chiari-like malformation of the skull with corresponding syringomyelia of the cranial spinal cord. Histologically, the neoplasm was comprised of a pleomorphic population of round cells with a high mitotic rate. Cells stained positive for vimentin and CD18 and negative for cytokeratin, chromogranin A, CD3, CD20, MHC II, and CD11d, and hence the tumor was diagnosed as a histiocytic sarcoma. The cytologic presentation in this case is uncommon for this type of tumor, as was the clinical presentation.

Pathologic and molecular characterization of histomoniasis in peafowl ( Pavo cristatus).

Histomonas meleagridis is a flagellate protozoan organism that can cause severe necrotizing typhlitis and hepatitis in gallinaceous birds. Peafowl ( Pavo spp.) have been shown to be susceptible to histomoniasis in experimental settings, but there are few reports of natural histomoniasis in this species. A retrospective study of the archived cases at 2 veterinary diagnostic laboratories in the United States yielded 5 cases of peafowl with gross and histologic findings characteristic of histomoniasis. Lesions included bilateral, transmural fibrinonecrotic typhlitis and multifocal necrotizing hepatitis with associated trophozoites morphologically consistent with H. meleagridis. There was no evidence of Heterakis gallinarum infestation in the studied cases. DNA was extracted from formalin-fixed, paraffin-embedded liver and ceca from all 5 cases and was analyzed using multiple sets of primers with subsequent sequencing and genotyping. Four samples were positive for H. meleagridis, and 1 sample was positive for both H. meleagridis and Tetratrichomonas gallinarum. These results confirm that peafowl develop clinical disease similar to that described previously in other gallinaceous birds infected by H. meleagridis. The role of T. gallinarum remains unknown and further research is necessary to elucidate its role, if any, in the pathogenesis of the observed lesions.

Assessment of the ability of Aedes species mosquitoes to transmit feline Mycoplasma haemofelis and ' Candidatus Mycoplasma haemominutum'.

Objectives The objective of this study was to evaluate wild-caught mosquitoes for evidence of hemotropic Mycoplasma species DNA and to determine whether the feline hemoplasmas, Mycoplasma haemofelis (Mhf) and ' Candidatus Mycoplasma haemominutum' (Mhm), can be transmitted by Aedes aegypti mosquitoes in a laboratory setting. Methods Wild-caught mosquito pools (50 mosquitoes per pool, 84 pools) utilized in routine public health department disease surveillance programs were tested for hemotropic Mycoplasma species DNA using PCR with primers designed to amplify all known hemoplasmas. Additionally, mosquitoes were trapped in the vicinity of known feral cat colonies, pooled (50 mosquitoes per pool) and tested (84 pools). Purpose-bred cats housed in a research facility were infected with Mhf or Mhm and then colonized laboratory A aegypti were fed upon the bacteremic cats. After a 7 day incubation period, mosquitoes previously fed on infected cats were allowed to feed again on naive cats, which were monitored for bacteremia for 10 weeks. Results Mycoplasma wenyonii DNA was confirmed in one wild-caught mosquito pool by DNA sequencing. While 7% of cats tested in feral colonies were hemoplasma positive, none of the mosquitoes trapped near colonies were positive. Hemoplasma DNA was amplified from A aegypti by PCR immediately after the infectious blood meal, but DNA was not detected at 7 and 14 days after feeding. Although evidence for uptake of organisms existed, hemoplasma DNA was not amplified from the experimentally infested cats in the 10 week observation period. Conclusions and relevance While wild-caught mosquitoes contained hemoplasma DNA and laboratory reared A aegypti mosquitoes take up hemoplasmas during the blood meal, there was no evidence of biologic transmission in this model.