Mast cell tumors are uncommon in horses and typically have a benign clinical course, but there are occasional reports of more aggressive behavior. The objective of this study was to review histologic features and KIT expression patterns of 72 previously diagnosed equine cutaneous mast cell tumors to determine if either is associated with clinical outcomes. Biopsy specimens were reviewed using histologic criteria derived from grading schemes, and KIT antibody expression patterns used in canine tumors and surveys were sent to referring veterinarians for follow-up clinical data. Arabians were overrepresented relative to the reference population. Most tumors were well differentiated with low mitotic rates (96%), and aberrant KIT staining patterns, as described in dogs, were uncommonly identified (12%). Associated clinical disease was uncommon and no tumors exhibited malignant behavior. Overall, KIT staining pattern and histologic features were not associated with poor clinical outcome or abnormal tumor behavior.

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.Note: Supplemental tables appear at www.ajtmh.org.

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.

The use of natural language data for animal population surveillance represents a valuable opportunity to gather information about potential disease outbreaks, emerging zoonotic diseases, or bioterrorism threats. In this study, we evaluate machine learning methods for conducting syndromic surveillance using free-text veterinary necropsy reports. We train a system to detect if a necropsy report from the Wisconsin Veterinary Diagnostic Laboratory contains evidence of gastrointestinal, respiratory, or urinary pathology. We evaluate the performance of several machine learning algorithms including deep learning with a long shortterm memory network. Although no single algorithm was superior, random forest using feature vectors of TF-IDF statistics ranked among the top-performing models with F1 scores of 0.923 (gastrointestinal), 0.960 (respiratory), and 0.888 (urinary). This model was applied to over 33,000 necropsy reports and was used to describe temporal and spatial features of diseases within a 14-year period, exposing epidemiological trends and detecting a potential focus of gastrointestinal disease from a single submitting producer in the fall of 2016.

Ticks, sera and ethylenediaminetetraacetic acid (EDTA) blood were collected from dogs evaluated at the Amakom Veterinary Clinic in Kumasi, Ghana. Sera were evaluated for Dirofilaria immitis antigen and antibodies against Borrelia burgdorferi, Anaplasma phagocytophilum and Ehrlichia canis. Conventional polymerase chain reaction assays designed to amplify the deoxyribonucleic acid (DNA) of Ehrlichia spp. or Anaplasma spp. or Neorickettsia spp. or Wolbachia spp., Babesia spp., Rickettsia spp., Hepatozoon spp., Bartonella spp. and the haemoplasmas were performed on DNA extracted from EDTA blood and all positive amplicons were sequenced. This small survey shows that the following vector-borne pathogens are present in urban Ghanian dogs: Ehrlichia canis, Hepatozoon canis,Dirofilaria immitis and Anaplasma platys. Bartonella henselae was isolated from ticks but not from the dogs.

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.

Heartland virus (HRTV) is a phlebovirus suspected to be transmitted by , 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.

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.