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Summary: Background: Trema micrantha is a tree widely distributed throughout the Americas. The tree produces highly palatable leaves that have been associated with natural poisoning in goats, sheep and horses, in which hepatic necrosis and hepatic encephalopathy have been observed. Objectives: This study describes malacia and haemorrhage in the central nervous system (CNS) due to T. micrantha consumption, with minimal to absent hepatic lesions. Study design: Retrospective case series. Methods: A total of 14 horses with a history of neurological signs and spontaneous consumption of T. micrantha leaves were submitted to necropsy and multiple samples were collected for histopathology. Details of clinical history and signs of the horses were obtained through inquiries to the owners and attending veterinarians. Results: All the 14 horses had neurological signs of ataxia, severe sialorrhoea, involuntary running movements, sternal and lateral recumbency, and death after a clinical course that lasted from 24 h to 9 days. For a few days prior to onset of clinical signs, all horses had spontaneously consumed, potentially toxic doses of T. micrantha leaves. All 14 brains had diffuse yellowish discoloration affecting the rhombencephalon, mesencephalon, diencephalon, telencephalon and corpus striatum. In all cases, the most severe lesions were observed in the pons. Spinal cord lesions were observed affecting the lumbar intumescence, which was swollen with darken and depressed areas at the dorsal and ventral horns, and at the sacral level, which on cut surface displayed a friable and yellowish grey matter. The lesions observed grossly in brain and spinal cord consisted microscopically of severe vasculitis and liquefactive necrosis of white and grey matter of the brainstem, cerebellum and spinal cord. Main limitations: This is a small retrospective series relying on clinical observations reported by owners and attending veterinarians. The mechanism of action of the plant toxin in the CNS is still unidentified. Conclusion: T. micrantha poisoning in horses causes predominantly a neurological disease, with minimal to absent hepatic lesions. [ABSTRACT FROM AUTHOR]

Equine endometrosis is a degenerative and predominantly fibrotic condition resulting from progressive and irreversible multifactorial causes that influence the endometrium of mare. Tissue remodeling in the equine endometrium occurs as part of the pathogenesis of endometrosis, a process characterized by a shift in extracellular matrix (ECM) components. The relationship between matrix metalloproteinases and their specific inhibitors is crucial for the remodeling process. Collagen play a significant role in maintaining a healthy uterus and may promote fibrotic processes. The aim of this study was to quantify endometrial collagen deposition using picrosirius 25 red (PSR) staining, and to evaluate gene expression of collagen type 2 (COL-2) and 3 (COL-3), matrix metalloproteinases 1 (MMP-1) and 2 (MMP-2), their tissue inhibitor (TIMP-2), and tumor necrosis factor (TNF-α) in the endometrium of mares with different grades of fibrosis. The samples (n = 34) were classified into three categories based on the frequency and distribution of fibrosis-related changes in the endometrium: Category I (healthy endometrium, n = 12), Category II (moderate fibrosis, n = 12), and Category III (severe fibrosis, n = 10). Collagen quantification demonstrate a substantial proportional increase (P < 0.0001) in collagen deposition across Category I (11.72 ± 1.39 %), Category II (17.76 ± 1.29 %), and Category III (24.15 ± 1.87 %). In transcript evaluations, higher COL-2 expression was found in Category II than in mares classified as Category I or III. MMP-1 showed increased transcript expression in Category II compared to Category III endometrial samples. Higher expression of MMP-2 was detected in Category III than in Category I and II. TIMP-2 showed lower mRNA expression in Category III vs Category I and II. However, TNF-α gene expression was higher in Category II than in Categories I and III. This study demonstrates that endometrial evaluation using PSR can play an important role in routine analyses for the detection and objective quantification of collagen in endometrial tissues. Additionally, this study demonstrated through gene expression analysis that MMP-1 may be linked to physiological endometrial remodeling. In contrast, MMP-2 could be associated with fibrogenesis in the endometrium, which is regulated by the inhibitor TIMP-2. Furthermore, COL-2 and TNF-α could be considered as biological markers involved in the progression endometrosis in mares. As such, the results of this study may contribute to the development of future antifibrotic therapies that aim to delay or even reverse the pathological remodeling of the extracellular matrix in the uterus, in addition to optimizing the diagnosis and prognosis of endometrial fibrosis in mares., Competing Interests: Declaration of competing interest None of the authors have any conflicts of interest to declare., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Viral neurologic diseases are common in cattle, although most non-suppurative meningoencephalitis (NSM) remains etiologically unknown. We compared the epidemiological, clinical, and pathological data among 79 cases of rabies, 12 cases of NSM of unknown etiology (NSM-UE), and 8 cases of herpetic meningoencephalitis previously diagnosed in cattle in Southern Brazil. Neurological clinical signs were similar among rabies and NSM-UE and different in cattle with herpetic meningoencephalitis. Only two herpetic meningoencephalitis cases had gross lesions in the central nervous system, characterized by malacia and hemorrhage. Histologically, all three groups had mild to severe multifocal infiltrates of lymphocytes, plasma cells, and macrophages/microglial cells in the Virchow-Robin space, neuropil, and leptomeninges, and gliosis. Other findings included malacia and eosinophilic intracytoplasmic inclusion in rabies, and malacia and intranuclear amphophilic inclusion in herpetic meningoencephalitis. By immunohistochemistry, the predominant inflammatory cells in all cases were T lymphocytes, followed by macrophages/microglial cells, B lymphocytes, and astrocytes. The T lymphocyte count showed statistically significant differences between the diseases. Our results revealed few differences between the groups. Although the etiological agent involved has not been identified in cases of NSM-UE, the characteristics observed in this study showed similarity with viral diseases., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

A case of polyparasitism in an 8-year-old female cat from Southern Brazil is reported. Among the described clinical signs, both gurltiosis and lagochilascariasis are of rare occurrence, being categorized as neglected diseases. The diagnosis of feline crural parasitic paraplegia was established through clinical signs, necropsy lesion observations, and the presence of Gurltia paralysans in histological sections of the spinal cord. Lagochilascaris minor was diagnosed with an ulcerated wound in the cervical region and further confirmed by coprology. In addition, other gastrointestinal parasites (i.e., Trichuris spp., Diphyllobothriidae, Toxocara cati, Ancylostoma spp., Cystoisospora spp., and Entamoeba spp.) were diagnosed through fecal examination and Sarcocystis felis by molecular analysis of muscle cysts. Aelurostrongylus abstrusus was detected in histological sections of lung parenchyma and confirmed by molecular analyses. The multiple parasitism detected in this case represents a unique report in terms of the number of parasites in the same individual, indicating the risk represented by stray cats as spreaders of zoonotic agents., Competing Interests: Declarations. Ethical approval: Not applicable. Consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Feline infectious peritonitis (FIP) is one of the most important infectious diseases and a significant cause of death in cats. While the pathology of FIP has been well documented, there is little information on the hepatic lesions. The aim of this study was to characterize the macroscopic, microscopic and immunohistochemical patterns of the liver lesions in cats with FIP. A retrospective study was conducted on 131 cats with FIP, of which 59 had histological inflammatory lesions in the liver and were immunopositive for feline coronavirus. Four major gross patterns were defined: perihepatitis (21/59); nodular with perihepatitis (18/59); nodular multifocal (13/59); and diffuse (7/59). Four histological patterns were observed: (1) random pyogranulomas; (2) random multifocal to coalescent caseous necrosis surrounded by pyogranulomatous inflammatory infiltrate, fibrin and cellular debris; (3) perihepatitis; and (4) random multifocal to coalescent caseous necrosis surrounded by neutrophils, macrophages, lymphocytes and plasma cells. Most cats had more than one histological pattern. FIP virus antigen was detected in macrophages in the pyogranulomas and around the necrotic areas. The diagnosis of FIP remains challenging, especially in cats without effusion. The liver can be considered a suitable site for biopsy when feasible., Competing Interests: Declaration of competing interests The authors declared no conflicts of interest in relation to the research, authorship or publication of this article., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Although tick infestation is a significant health problem in livestock, there are limited studies on the dermatopathological aspects of natural tick infestation in cattle. This study aimed to describe the gross and histologic aspects of cutaneous lesions caused by tick infestation in cattle. Thirteen cases were selected based on necropsy data from a 10-year retrospective study. Predispositions were observed in beef cattle ( P = .049) and the Angus breed ( P = .012), and lesions occurred mainly in the fall ( P = .007). Gross lesions included hypotrichosis (13/13; 100%), scales (12/13; 92%), alopecia (11/13; 85%), ulcers (7/13; 54%), crusts (7/13; 54%), and erosions (2/13; 15%). These gross lesions were mainly located in the thorax (12/13; 92%), head (11/13; 85%), abdomen (10/13; 77%), neck (9/13; 69%), limbs (9/13; 69%), and perineum (9/13; 69%). Histologically, all cases had ticks adhered to the epidermis with erosions (13/13; 100%), ulcers (11/13; 85%), orthokeratotic hyperkeratosis (13/13; 100%), irregular acanthosis (13/13; 100%), intraepidermal pustules (13/13; 100%), crusts (10/13; 77%), and ballooning degeneration (4/13; 31%). In the dermis, just below the tick insertion site, there was coagulation necrosis, fibrin deposition, and inflammatory infiltrate composed of mixed cells (neutrophils, lymphocytes, plasma cells, macrophages, and few eosinophils) (9/13; 69%), neutrophils (3/13; 23%), or eosinophils (1/13; 8%). This study reinforces the different patterns of cutaneous lesions caused by tick infestation in cattle, which should be considered as a potential cause of dermatitis in this species., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Neoplasms in wild felids are more frequently observed in captive animals, of which clinicopathological features of pulmonary tumors are not commonly described. This study aimed to describe the clinical and pathological aspects of a case of diffuse pulmonary acinar adenocarcinoma in a 23-year-old, captive lioness with clinical history of dyspnea, progressive weight loss and inappetence. At necropsy, the lungs were mildly pale, moderately firm, and the pleural surface was diffusely irregular with multifocal to coalescent, grey to white areas. No masses or superficial nodules were detected, but, on the cut surface, there were numerous, spherical, firm, white to yellow areas up to 0.5 cm in diameter affecting all pulmonary lobes. Histologically, in the lungs, there were extensive, non-delineated areas of neoplastic proliferation of columnar, ciliated epithelial cells arranged in irregular tubuloacinar structures. Immunohistochemical analysis revealed immunolabeling of neoplastic cells for pan-cytokeratin and thyroid transcription factor-1. Napsin-A exhibited only scarce and scattered immunolabeling in the neoplastic cells. The gross, histologic and immunohistochemical findings confirmed the final diagnosis of primary diffuse pulmonary adenocarcinoma., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Primary pulmonary neoplasms in cattle are rare. There are few studies on the pathological findings of these neoplasms in this species. This study aimed to describe the histological and immunohistochemical findings of primary and metastatic pulmonary carcinomas in cattle. We conducted a retrospective study of 19 cases of epithelial neoplasms with pulmonary involvement. Histologically, most of the neoplasms were classified as primary pulmonary neoplasms, including different adenocarcinoma subtypes (4/19, 21%) and adenosquamous carcinomas (3/19, 16%), followed by squamous cell carcinoma (6/19, 32%), metastatic uterine adenocarcinoma (4/19, 21%), metastatic hepatocellular carcinoma (1/19, 5%), and metastatic cholangiocarcinoma (1/19, 5%). By immunohistochemistry, all neoplasms were positive for pancytokeratin, and 4/19 (21%) were positive for vimentin. Primary pulmonary neoplasms had immunoreactivity for thyroid transcription factor-1 (6/7), while only 2 of these cases were positive for napsin A. All cases with squamous differentiation (9/9) had immunoreactivity for cytokeratin (CK) 5/6, while only 7 of these cases were positive for p40. CK20, CK7, and CK8/18 showed varied immunoreactivity in the primary and metastatic pulmonary carcinomas but were important markers to confirm the diagnosis of primary mucinous adenocarcinoma and metastatic cholangiocarcinoma. HepPar-1 was only positive in the metastatic hepatocellular carcinoma. The limited number of cases of metastatic uterine adenocarcinomas in this study precluded identification of a specific immunophenotype for this tumor. Immunohistochemistry proved to be an important tool to confirm the proper classification of these neoplasms., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Monensin poisoning is uncommon and has been rarely reported in birds. This work aimed to described clinical-pathological aspects of an outbreak of monensin poisoning in captive and free-ranging birds. Thirty-seven of 600 captive birds fed a diet containing 893.19 mg/kg of monensin died within 10 days (mortality 6.17%). There was no ionophore antibiotics on the feed label supplied to captive birds, which established an error in feed production. Necropsies were performed on twelve animals: Muscovy duck (Cairina moschata) (2/12), greater rhea (Rhea americana) (2/12), black-necked swan (Cygnus melancoryphus) (2/12), garganey (Anas querquedula) (1/12), ostrich (Struthio camelus) (1/12), and common pigeon (Columbus livia) (4/12). These four common pigeons were free-ranging birds and died after eating the same contaminated feed. Birds were mainly found dead, however in animals which clinical signs were observed (Columba livia, Rhea americana, Cairina moschata, Anas querquedula, and Struthio camelus), they included incoordination, inability to stand, and intense prostration, that ranged from 24 to 72 h until death. Grossly, five birds had focally extensive pale firm areas in the myocardium and two had in the skeletal muscles, one being concomitant lesions. Histologically, muscle necrosis and degeneration were observed in striated musculature (skeletal and/or heart) in all birds analyzed. Monensin poisoning outbreaks can affect free-ranging birds that are fed on external feeders, as well as captive birds, due to an error in the feed formulation., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Heavy metal poisoning poses a challenge in diagnostic practices and environmental safety. This study describes the epidemiological, clinical, and pathological aspects of a chromium (Cr) poisoning outbreak in growing/finishing pigs housed in pens with bedding of pine wood shavings containing Cr. A visit to the affected farm was conducted. Epidemiological data were collected, and necropsy and histopathological examinations and heavy metal quantifications were performed. Up to 30% of the animals from the affected pens displayed clinical signs 48 h after housing, characterized by apathy, rigid gait, distended abdomen, pain to abdominal palpation, fever, vomiting, and skin cyanosis. The lethality rate reached 76.6%. Main postmortem findings consisted of ulcerative gastritis with perforation of the glandular stomach in all necropsied swine. Heavy metal analysis revealed a higher concentration of Cr in the bedding of the affected pens, along with elevated levels of Cr in the livers of the affected swine. Given that Cr is a known cause of poisoning in humans (with acute oral exposure resulting in corrosive lesions in the gastrointestinal tract), this study marks the first diagnosis of acute oral natural Cr poisoning in animals. This diagnosis was established through the association of epidemiological, pathological, and heavy metal quantification data.

Background: Simplexvirus humanalpha1 (HuAHV-1) are common anthropozoonosis reported in marmosets but rare in howler monkeys (Alouatta sp.)., Methods: Necropsy of two brown-howler monkeys (A. caraya) and one red-howler monkey (A. guariba clamitans) from different zoo collections were performed. Fragments of all organs were examined through microscopy. Samples were submitted to IHC for Simplexvirus humanalpha 2 (HuAHV-2) [sin. Herpesvirus simplex type 2] and PCR., Results: Grossly, only the A. guariba showed liver lesions characterized by multifocal, pinpoint white areas corresponding microscopically as random necrotizing herpetic hepatitis and ulcerative glossitis. Both A. caraya showed necrotizing meningoencephalitis with Cowdry A-type body inclusions within neurons and astrocytes. Immunolabeling for HuAHV-1/2 was observed in the tongue, liver, and brain. HuAHV-1 was confirmed in all samples by PCR, Sanger sequencing, and phylogenetic analyses., Conclusion: Necrotizing meningoencephalitis was appreciated in 2/3 of animals, and it is associated with neurologic signs. Along with ulcerative glossitis, a hallmark lesion in marmosets, it was present in one animal. Regarding herpetic hepatitis, it is not frequent in monkeys and occurs mainly in immunocompromised animals. HuAHV-1 infection was confirmed corroborating with a human source. This is the second report on captive black-howler monkeys and the first gross, histologic, immunohistochemical, and molecular description of herpetic hepatitis and ulcerative glossitis in red-howler monkeys (A. guariba)., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Branchial cysts are a congenital anomaly in humans and other animal species. In this study, twenty commercially bred slaughtered pigs ranging from 120 to 150 days of age, sourced from different farms and lots, were found to have cysts in the oropharyngeal region at meat inspection despite the absence of clinical signs. Two cysts were selected for histopathological examination. The first cyst was surrounded by fibrous connective tissue and lined by a simple single cell layer of epithelium. The second cyst comprised a squamous pseudostratified to simple stratified epithelium, accompanied by a mild inflammatory infiltrate. This cyst was also surrounded by fibrous connective tissue and glands. The pathological diagnosis of branchial cysts in slaughtered pigs was established on the basis of their anatomical location and gross and microscopic findings., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Meningioangiomatosis (MA) is a rare proliferative meningovascular disorder that affects mainly the cerebral cortex, brainstem and spinal cord of humans and animals and can coexist with other proliferative disorders. A 7.5-year-old male Brazilian Campeiro Bulldog died after a convulsive crisis and cardiorespiratory arrest. At necropsy, a firm, white mass involving the piriform and right occipital lobes was seen. Histologically, the mass consisted of two morphologically distinct entities that collided: a congenital malformation characterized by a proliferation of meningothelial cells around blood vessels, within the perivascular spaces; and a neoplasm composed of two cell populations with astrocytic and oligodendrocytic differentiation. Meningothelial cells and neoplastic glial cells immunolabelled for vimentin. This first reported case of encephalic MA with a high-grade undefined glioma in a dog was confirmed through clinical signs, pathological and immunohistochemical findings., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Among vector-borne helminths, filarioids of the genus Dipetalonema (Spirurida: Onchocercidae) localize in several tissues and body cavities of several animal species, causing mild to moderate lesions. The pathological findings associated with Dipetalonema spp. infection in Neotropical monkeys from southern Brazil are herein described, along with a fatal case due to filarial polyserositis and entrapment of an intestinal segment. At necropsy, nematodes were observed in abdominal and thoracic cavities, or in the pericardium of 37 (31.3%) out of the 118 individuals examined (i.e., 35 Alouatta guariba clamitans and two Sapajus nigritus). In addition, at histology, 27.0% of positive animals presented microfilarie (inside blood vessels of lung, spleen, liver, and brain) and 8.1% presented adult nematodes in the heart, lung, and liver. In two cases, cross-sections of filarioids were associated with areas of epicardial thickening with intense fibrosis and pyogranulomatous inflammation in the brain, heart, liver, lungs, or spleen. The DNA fragment was amplify using the cox1 gene, sequenced and analyzed to identify the nematode species collected; presence of Wolbachia was assessed in the filarioids using the 16S rRNA gene. At BLAST analysis of the cox1 gene, 10 sequences showed 91.7% nucleotide identity with Dipetalonema gracile, and two with D. gracile (98.5%) and Dipetalonema graciliformis (98.3%). Phylogenetic analyses clustered sequences of the cox1 obtained in this study in two clades corresponding with the host species. Wolbachia sp. endosymbiont was detected in four samples. Data herein reported provide a description of pathological lesions associated with the infection by Dipetalonema spp., suggesting that they may cause disease in Neotropical monkeys. In addition, a better understanding of diversity and biology of Dipetalonema spp. in South America is needed to assess the impact they may cause in native non-human primates from Brazil., (© 2023. The Author(s).)

This study aims to report a spontaneous and experimental intoxication in cattle by Melanthera latifolia (Asteraceae) for the first time, and to describe its epidemiological, clinical, and pathological findings. An outbreak of acute toxic hepatopathy in cattle occurred from December of 2021 to January of 2022 in a beef cattle farm from Rio Grande do Sul state, Southern Brazil, and resulted in 94 deaths from a herd of 430 animals. At necropsy, lesions consisted of enhanced lobular pattern of the liver, transmural gallbladder edema, and hemorrhages on the surface of multiple organs. The main microscopic lesion was marked hepatocellular necrosis in the centrilobular region associated with hemorrhage and infiltration of neutrophils. During the outbreak, multiple specimens of M. latifolia were noted in the paddocks where affected cattle were grazing and many showed signs of consumption. No other known acute hepatotoxic plants were found. Two 12-month-old steers were experimentally intoxicated with a single oral dose of the fresh plant (flowers, leaves, and less fibrous stalks). One bovine ingested a dose of 10 g/kg and was euthanized after 48 h, and the other ingested 15 g/kg and was euthanized 17 h later. Clinical signs, macroscopic, and microscopic lesions in both animals were similar to those observed in the spontaneous cases. Thus, this study demonstrates that M. latifolia was the cause of the outbreak of acute toxic hepatopathy with significant mortality in cattle. M. latifolia nor any plant of the genus Melantherahad ever been reported as toxic., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Songbirds are currently the most prevalent animals in illegal trafficking in Brazil and other countries, so they are often confiscated, and this poses legal, ethical, and conservation challenges. Returning them to nature requires complex and expensive management, a topic that is sparingly addressed in the literature. Here, we described the processes and costs associated with an attempt to rehabilitate and release confiscated songbirds into the wild. A total of 1,721 songbirds of several species were quarantined, rehabilitated, and released, primarily on two farms located within their typical geographical distribution. Health assessments were performed on samples from 370 birds. Serology revealed no antibodies against Newcastle disease, and Salmonella spp. cultures were negative. Real-time polymerase chain reactions detected M . gallisepticum in samples from seven birds. Atoxoplasma spp. and Acuaria spp. infections, sepsis, and trauma were the top causes of bird death. About 6% of the released birds were recaptured, within an average period of 249 days after release, and at a mean distance of 2,397 meters from the release sites. The majority of these birds were found with free-living mates within or close to fragments of transitional ecoregions with native or cultivated grasslands, and native groves/forests, and shrublands. However, eucalyptus plantations with rich understory regeneration provided a suitable environment for the released forest species to settle, since they were recaptured during the defense of these sites. Over half of the recaptured birds presented behavioral profiles with both dominant and tame traits. Birds with dominant traits are more likely to settle in habitats and face the live decoys during fieldwork, whereas birds with tame characteristics tend to accept close contact with humans. Ultramarine grosbeak ( Cyanoloxia brissonii ), the least common species among those released, at the release sites showed an almost 2-fold recapture rate in the shortest mean distances from the release sites. This suggests less territory competition, perhaps a major factor of bird re-establishment here. The total per-bird cost was USD 57. Our findings suggested suitable survival and re-establishment of confiscated songbirds in the wild, when managed as we describe., Competing Interests: FC was employed by the company CMPC Celulose Riograndense Ltda. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Cruz, Driemeier, Sonne, Pavarini, Panziera, Funkler, Böelter, Homem, Soares, Tres, Silva, Correa, Caporal, Marques, Soares, Wagner, Nisa-Castro-Neto and Andretta.)

The aim of this study was to characterize the pathological and immunohistochemical aspects of pancreatic carcinoma in cats, through a retrospective study. From January 2010 to December 2021, 1,908 cat necropsies were performed, in which 20 cases of exocrine pancreatic neoplasia were diagnosed (1.04%). Affected cats were mature adults and seniors, except for one 1-year-old cat. In 11 cases the neoplasm was a soft, focal nodule on the left (8/11) or right (3/11) lobe. In nine cases there were multifocal nodules throughout the pancreatic parenchyma. The size of the single masses ranged from 2 to 12 cm, and the multifocal masses from 0.5 to 2 cm. The most frequent tumour type was acinar carcinoma (11/20), followed by ductal carcinoma (8/20), undifferentiated carcinoma (1/20) and carcinosarcoma (1/20). On immunohistochemical evaluation, all the neoplasms were remarkably reactive to pancytokeratin antibody. The ductal carcinomas were strongly reactive for cytokeratins 7 and 20, which proved to be a good marker for pancreatic ductal carcinoma in cats. The main form of metastasis was abdominal carcinomatosis, with a marked invasion of blood and lymphatic vessels by neoplastic cells. Our findings reinforce the fact that pancreatic carcinoma should be rated highly in the differential diagnosis in mature adult and senior cats with abdominal masses, ascites and/or jaundice., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

This report describes 2 events of degenerative myelopathy in 4- to 27-day-old piglets, with mortality rates reaching 40%. Sows were fed rations containing low levels of pantothenic acid. Piglets presented with severe depression, weakness, ataxia, and paresis, which were more pronounced in the pelvic limbs. No significant gross lesions were observed. Histologically, there were degeneration and necrosis of neurons in the spinal cord, primarily in the thoracic nucleus in the thoracic and lumbar segments, and motor neurons in nucleus IX of the ventral horn in the cervical and lumbar intumescence. Minimal-to-moderate axonal and myelin degeneration was observed in the dorsal funiculus of the spinal cord and in the dorsal and ventral nerve roots. Immunohistochemistry demonstrated depletion of acetylcholine neurotransmitters in motor neurons and accumulation of neurofilaments in the perikaryon of neurons in the thoracic nucleus and motor neurons. Ultrastructurally, the thoracic nucleus neurons and motor neurons showed dissolution of Nissl granulation. The topographical distribution of the lesions indicates damage to the second-order neurons of the spinocerebellar tract, first-order axon cuneocerebellar tract, and dorsal column-medial lemniscus pathway as the cause of the conscious and unconscious proprioceptive deficit, and damage to the alpha motor neuron as the cause of the motor deficit. Clinical signs reversed and no new cases occurred after pantothenic acid levels were corrected in the ration, and piglets received parenteral administration of pantothenic acid. This study highlights the important and practical use of detailed neuropathological analysis to refine differential diagnosis.

Generalized and fatal felid alphaherpesvirus-1 (FeHV-1) natural infection with liver involvement is rarely reported in cats, and the occurrence of herpesvirus viraemia with internal organ histologic lesions in adult cats is unknown. A 1.5-year-old cat, female, mixed breed, positive for feline leukaemia virus (FeLV) presented in a veterinary teaching hospital with sneezing, nasal discharge, anorexia, and diarrhoea after two weeks, evolving to inspiratory dyspnoea. Complete blood count and serum biochemistry analysis showed marked leukopenia and thrombocytopenia. After clinical worsening and lack of treatment response, the cat was euthanized. Pathological findings included hepatic necrosis, fibrinonecrotic tracheitis, and bronchointerstitial pneumonia. Marked amounts of coccobacillary bacteria were observed covering the necrotic tracheal and bronchial mucosa, at the cytoplasm of alveolar macrophages, and free in alveoli lumen, mimicking a primary bacterial tracheitis and pneumonia. Both lung and tracheal bacteria exhibited marked immunolabeling in anti-Escherichia coli immunohistochemistry. In addition, rare epithelial cells of bronchi contained round, eosinophilic, intranuclear viral inclusion bodies (4-7 µm) that marginate the chromatin, characteristic of FeHV-1 infection. Strong multifocal anti-FeHV-1 immunolabeling was observed in necrotic epithelial cells of the liver, trachea, and lungs. Generalized herpesvirus infection with the occurrence of acute hepatic necrosis and severe respiratory illness is a potential differential diagnosis in FeLV-positive cats with respiratory signs. The immunodepression in these cats probably favours a FeHV-1 viraemia in addition to the development of opportunistic bacterial infections, such as Escherichia coli, and it is associated with a poor outcome., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Septicaemia is the main pathological manifestation of Salmonella infection in chinchillas (Chinchilla lanigera), although information on its pathology is limited. We now describe the gross, histological and immunohistochemical features of Salmonella enterica subspecies enterica serotype Typhimurium (S. Typhimurium) infection in ranched chinchillas. Eighty-five adult pregnant chinchillas had anorexia, prostration, weight loss, hyperthermia and abortion. Necropsy of 13 animals revealed splenomegaly, hepatomegaly, mesenteric lymphadenomegaly, prominent Peyer's patches, pulmonary oedema, white pinpoint lesions in multiple organs and petechiae in the urinary bladder. In all cases, histological lesions were consistent with septicaemia, characterized by acute necrotizing hepatitis, splenitis, lymphadenitis, cystitis, pneumonia, enterocolitis, gastritis and/or nephritis. Immunohistochemistry for Salmonella spp on seven cases revealed intralesional immunolabelling in all affected organs. Salmonella sp was isolated from liver, spleen, intestinal contents and blood of 10 chinchillas. Isolates of four animals were identified as S. Typhimurium., Competing Interests: Conflict of Interest Statement The authors declared no conflicts of interest with respect to the research, authorship or publication of this manuscript., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Pyometra is a life-threatening infectious disease that frequently affects bitches and queens. Although histopathological patterns of pyometra have been extensively explored, the microbiological aspects, such as bacteria pathogenicity, have not been correlated to microscopy endometrial lesions so far. In this study, these two pathological aspects of pyometra were analysed and correlated. Uterus fragments and intrauterine content samples were collected from pets diagnosed with pyometra (30) and submitted to histopathology analysis and bacterial culture, respectively. The degree of endometrial histopathological lesions in pyometra cases were classified as mild, moderate and severe. Thirty different bacteria isolates were identified from intrauterine content culture. Escherichia coli ( E. coli ) was pure isolated in 57.7% and highly related to severe endometrial lesions. Immunohistochemistry assay revealed the adhesion and invasion of this bacteria agent to the injured endometrium. Virulence aspects of these E. coli strains were explored, demonstrating biofilm formation ability and a set of virulence genes in most isolates. These results support the adaptive genetic and phenotypic advantages of E. coli for uterus infection, and justify the high frequency of this agent involved in pyometra cases.

Fatal hypothermia represents a diagnostic challenge in veterinary pathology. Wischnewski spots (WS) and black oesophagus (BO) have been described in human cases of fatal hypothermia but rarely in animals. We now describe WS and BO in suspected fatal hypothermia in a free-ranging brown howler monkey (Alouatta guariba clamitans) and a pet rabbit (Oryctolagus cuniculus). Both animals had dark spots resembling WS on the gastric mucosa and the monkey also had BO with haematin deposition. In both cases, stress factors and relatively cold environmental conditions were present prior to death., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

We describe a case of penile tuberculosis in a bull. The prepuce was thickened, firm and pale with multifocal to coalescent caseous nodules, and the inguinal and mesenteric lymph nodes were moderately enlarged. Lesions in the prepuce, penis and lymph nodes were characterized by multifocal to coalescent areas of caseous necrosis and marked granulomatous inflammation. Acid-fast bacilli were seen within necrotic foci and Langhans giant cells. Mycobacteriumtuberculosis var. bovis was identified in inguinal lymph nodes by the polymerase chain reaction technique and by bacterial isolation. Although rare, tuberculosis should be considered in the differential diagnosis of granulomatous lesions in the genital tract of bulls., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

A retrospective study compiling cases of feline lymphoma diagnosed during 12 years (2004-2016) in Southern Brazil was performed. A total of 125 cases of lymphoma diagnosed in cats were reviewed, and information including age, breed, sex and tumour topography were collected. FeLV and FIV immunohistochemical tests were performed, as well as immunophenotyping of lymphomas. The alimentary form represented the most common presentation (42/125), followed by mediastinal lymphoma (35/125). Out of 125 cases, 79 presented positive retroviral immunostaining in tumour tissue (52 FeLV alone, 14 FIV alone and 13 presented FIV and FeLV co-infections), 66/125 of the cases were of T-cell origin and 59/125 of the cases were of B-cell origin. The median age of cats with T-cell lymphoma was 120 months (10-240 months), and 60 months (6-204 months) for cats with B-cell lymphoma. The most frequent alimentary tumour presentation was the enteropathy-associated T-cell lymphoma (type 1), and the major type of mediastinal tumour observed was diffuse large B-cell lymphoma. Considering only mediastinal and alimentary lymphomas (n = 77), the prevalence of mediastinal lymphoma in FeLV-positive cats was 2.21 times higher than the prevalence of this type of tumour in FeLV-negative cats (P = .036). Mediastinal lymphoma was more frequently observed in younger cats, and the prevalence of mediastinal tumours in these animals was 3.06 times higher than the prevalence of this tumour form in old cats (P = .0125). The present study indicates that retroviral infections still play an important role in the development of feline lymphomas in southern Brazil., (© 2019 John Wiley & Sons Ltd.)

Teat papillomatosis is caused by different bovine papillomavirus (BPV) types and is especially important for dairy cows, because it results in severe damage to the health and structure of the mammary gland. This work describes the molecular and pathological aspects of teat papillomatosis in dairy cows in southern Brazil. Samples of teat papillomas were collect from 73 slaughtered dairy cows. Fragments of the lesions were collected in individual pools per animal and subjected to PCR using the FAP primer pair and sequencing of the amplification products. Teats with the remaining lesions were fixed in 10% neutral buffered formalin, routinely processed for histopathology, and stained with hematoxylin and eosin (H&E). Papillomatous lesions were characterized by three macroscopic patterns, namely exophytic (5 [6.9%]), flat (29 [39.7%]), and mixed (39 [53.4%]). Histologically, all samples were identified as squamous papillomas. Partial sequencing of the L1 gene resulted in the detection of 8 classical BPV types (BPVs 4, 6, 7, 8, 9, 10, 11, and 12) in 27 samples, 6 previously reported putative BPV types in 17 samples, and 10 putative new BPV types in 15 samples. Four sequences could not be classified, and 10 were negative in the PCR. There was no correlation between the gross pattern and the BPV type identified, and all the samples were characterized by squamous papillomas under histological examination. However, 24 different BPV types were identified, demonstrating high genetic diversity among BPVs associated with teat papillomatosis in dairy cows in southern Brazil.

In this study, we described the morphological features and unusual presentations of hydatidosis, fasciolosis, and eosinophilic myositis caused by Sarcocystis species diagnosed at the slaughterhouse lines. Twenty-seven samples of atypical parasitic lesions from distinct cattle were evaluated, of which 12 corresponded to hydatidosis, 11 to fasciolosis, and 4 to eosinophilic sarcocystosis. Hydatid cysts were observed mainly in the heart, with all cases involving the left ventricle. Fasciolosis lesions involved mainly the lungs, and were characterized by a focal nodular elevated area involving the edges of the lobes. Intralesional trematodes were observed in three cases. Sarcocystosis lesions were observed in four cases, and lesions were primarily located in the skeletal and cardiac muscles. Grossly, they presented as focal or focally extensive streaks, patches, or numerous nodules that were greenish to mildly yellowish. Histologically, all the cases had intralesional ruptured cysts of Sarcocystis that were associated with severe eosinophilic myositis and myocarditis. Parasitic lesions in atypical locations and/or with aberrant responses should be promptly identified because it may mistakenly diagnosed as other potentially zoonotic diseases, such as cysticercosis and tuberculosis.

Mastitis may be caused by a wide range of microorganisms able to induce distinct lesions in mammary tissues. This study aims to characterize the gross and microscopic features of mastitis in dairy cows and to correlate them with the pathogens involved. The udders of slaughtered dairy cows were inspected and milk samples from each mammary quarter or fragments of the parenchyma were sent for microbiological analysis, and tissue collected for histopathological evaluation. A total of 148 cows and 592 mammary quarters were collected. From these, 432 quarters (73%) had mastitis and in 160 (27%), no changes were observed. Mastitis was classified into seven patterns based on the histopathological findings, of which mixed, lymphoplasmacytic, and suppurative mastitides were the most prevalent with 35.9% (155/432), 27.1% (117/432), and 14.3% (62/432) of the cases, respectively. These patterns were associated with the same set of pathogens: Streptococcus spp., coagulase-negative Staphylococcus (CNS), Staphylococcus aureus, Streptococcus agalactiae, Streptococcus uberis, and Corynebacterium bovis. The pyogranulomatous pattern represented 7.2% (31/432) of the cases with distinct distribution based on the agent involved, mostly S. aureus and Nocardia sp. Abscedative mastitis accounted for 6.0% (26/432) of the cases; it was characterized by multiple abscesses in the parenchyma and was mainly caused by Trueperella pyogenes. Necrosuppurative mastitis represented 5.8% (25/432) of the cases which were characterized by severe parenchyma necrosis and were caused by bacteria such as CNS and Escherichia coli. The granulomatous pattern represented 3.7% (16/432) of the cases and was occasionally associated with Mycobacterium sp.

Diseases related to the alimentary system are the main cause of death in horses. This retrospective study aimed to describe the pathological findings of fatal parasite-induced enteritis and typhlocolitis caused by cyathostominae, Eimeria leuckarti, Balantidium coli, and Strongyloides westeri in horses. The records of parasite-induced intestinal lesions in horses necropsied in Southern Brazil between 2005 and 2017 were reviewed. Ten horses had fatal parasitic enteritis and/or typhlocolitis, and the main causes were: cyathostominae typhlocolitis (6/10), E. leuckarti enteritis (1/10), S. westeri enteritis (1/10), B. coli colitis related to cyathostominae (1/10), and infection by multiple agents (1/10). Cyathostominae typhlocolitis showed marked mucosal thickening, with multifocal elevated nodules containing tangled filiform parasites. Microscopic examination revealed that the mucosa and submucosa had encysted parasitic structures surrounded by eosinophilic and granulomatous inflammation. E. leuckarti enteritis was microscopically characterized by macrogamonts, microgamonts, and oocysts inside the host cells. S. westeri enteritis showed microscopic atrophy of the villi with numerous mucosal encysted parasitic structures. B. coli typhlocolitis showed severe diffuse mucosal reddening, with microscopic superficial mucosal necrosis associated with multiple protozoan trophozoites. Fatal parasite-induced enteritis and typhlocolitis are important causes of death in horses in Southern Brazil.

Toxoplasmosis is a disease with a worldwide distribution that affects a wide variety of animal species, though with rare descriptions in chickens. We describe the clinical, epidemiological, pathological, and molecular aspects of a toxoplasmosis outbreak in domestic chickens and guinea fowl in southern Brazil. The flock was composed of 47 domestic chickens and 29 guinea fowl. Of these, 22 birds showed clinical signs of lethargy, anorexia, and neurological signs over a clinical course of 24-72 h, and 15 died. Epidemiological data were obtained through fieldwork performed at the chicken farm and necropsies of six birds. Gross lesions were absent at necropsy, and histopathological findings included inflammatory infiltrate of macrophages, lymphocytes, and plasma cells and necrosis in several tissues associated with intralesional Toxoplasma gondii. Immunohistochemistry for T. gondii was positive. Additionally, restriction fragment length polymorphism (RFLP) analysis with 11 markers (SAG1, SAG2 (5'3'SAG2 and alt. SAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, Apico, and CS3) and microsatellite (MS) analysis with 15 markers (TUB2, W35, TgMA, B18, B17, M33, IV.1, XI.1, N60, N82, AA, N61, N83, M48, and M102) were performed. PCR-RFLP revealed T. gondii genotype ToxoDB-PCR-RFLP #280, and MS analysis also showed a unique genotype. This is the first description of this genotype in chickens and adds to the evidence suggesting considerable genotypic diversity of T. gondii in Brazil.

Background: Trema micrantha is a tree widely distributed throughout the Americas. The tree produces highly palatable leaves that have been associated with natural poisoning in goats, sheep and horses, in which hepatic necrosis and hepatic encephalopathy have been observed., Objectives: This study describes malacia and haemorrhage in the central nervous system (CNS) due to T. micrantha consumption, with minimal to absent hepatic lesions., Study Design: Retrospective case series., Methods: A total of 14 horses with a history of neurological signs and spontaneous consumption of T. micrantha leaves were submitted to necropsy and multiple samples were collected for histopathology. Details of clinical history and signs of the horses were obtained through inquiries to the owners and attending veterinarians., Results: All the 14 horses had neurological signs of ataxia, severe sialorrhoea, involuntary running movements, sternal and lateral recumbency, and death after a clinical course that lasted from 24 h to 9 days. For a few days prior to onset of clinical signs, all horses had spontaneously consumed, potentially toxic doses of T. micrantha leaves. All 14 brains had diffuse yellowish discoloration affecting the rhombencephalon, mesencephalon, diencephalon, telencephalon and corpus striatum. In all cases, the most severe lesions were observed in the pons. Spinal cord lesions were observed affecting the lumbar intumescence, which was swollen with darken and depressed areas at the dorsal and ventral horns, and at the sacral level, which on cut surface displayed a friable and yellowish grey matter. The lesions observed grossly in brain and spinal cord consisted microscopically of severe vasculitis and liquefactive necrosis of white and grey matter of the brainstem, cerebellum and spinal cord., Main Limitations: This is a small retrospective series relying on clinical observations reported by owners and attending veterinarians. The mechanism of action of the plant toxin in the CNS is still unidentified., Conclusion: T. micrantha poisoning in horses causes predominantly a neurological disease, with minimal to absent hepatic lesions., (© 2017 EVJ Ltd.)