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In the summer of 2023, ingestion of Astylus atromaculatus (pollen beetle) was linked to spontaneous fatal disease in grazing cattle and sheep in Argentina and Uruguay. While the disease was experimentally reproduced in sheep and guinea pigs in the 1970's, no experimental reproductions have been attempted in cattle, and controversy exists as to whether this insect is indeed noxious to cattle and at which dose. Here, we demonstrate that A. atromaculatus causes acute fatal disease in Hereford calves at single oral dosages of 2.5, 4.5, 10.0, and 15.0 g of insect/kg body weight. Death or severe disease necessitating euthanasia occurred at 38 to 48 hours postinoculation regardless of the dose, suggesting that the single fatal dosage is likely <2.5 g/kg body weight (this dose representing approximately 850 mL of intact beetles in a 100 kg calf). Clinically, the disease was characterized by acute anorexia, prolonged recumbency, reluctance to move, listlessness/apathy, depression, ruminal hypomotility and tympany, hypothermia, bruxism with frothing at the mouth, and mucoid diarrhea progressing to death. Hematologic and biochemical alterations included hemoconcentration, stress/acute inflammatory leukogram, negative energy balance, and ketosis. The pathological hallmark of this experimental disease is acute necrotizing omaso-reticulo-rumenitis, fibrinohemorrhagic enteritis, and exfoliative colitis with intralesional chitinous insect fragments. While A. atromaculatus might contain a gastrointestinal toxin or pathogen, extensive toxicological testing failed to identify a causative toxin. Other pathomechanisms such as direct physical damage caused by insect fragments on the alimentary tract seem plausible, although further studies are needed to elucidate the pathogenesis of A. atromaculatus -associated disease. [ABSTRACT FROM AUTHOR]

This study investigated two outbreaks of spontaneous poisoning by Baccharis coridifolia (Asteraceae) in early-weaned beef calves in Tacuarembó, Uruguay. A total of 34 affected calves showed signs of salivation, anorexia, apathy, marked dehydration, and diarrhea. Deaths occurred 36–72 h after consumption and mortality varied from 37.5% to 43.3% for outbreak 1 and outbreak 2, respectively. The main pathological findings include diffuse severe necrosis of the prestomachs and lymphoid tissues. Ultrastructurally, epithelial cells of the rumen showed swelling, lysis of the organelles, degradation of intercellular attachments, and degradation of the nuclear chromatin. Using LC-MS with diagnostic fragmentation filtering, 56 macrocyclic trichothecenes including glycosyl and malonyl conjugates were identified. The total concentration of macrocyclic trichothecenes, including conjugates, was estimated to be 1.2 ± 0.1 mg/g plant material. This is the first report of these malonyl–glucose conjugates from Baccharis coridifolia. [ABSTRACT FROM AUTHOR]

Pancreatic eurytrematosis (PE) is an under diagnosed and neglected parasitosis in goats and sheep in the Americas. Clinical and pathological features of PE are not well defined in small ruminants worldwide. Natural cases of PE in small ruminants were detected in the Federal District, Brazil. A survey of necropsy records, including epidemiological and clinicopathological data, in goats and sheep was conducted. Most cases of PE occurred during the rainy season in adult females, with an incidence of 12.9% in goats and 0.8% in sheep. Clinical signs varied from asymptomatic infections to anorexia, lethargy, weakness, marked weight loss and death in some goats. Overall, most cases of PE in goats and sheep were incidental necropsy findings with minor pancreatic lesions. Three goats, however, showed severe chronic pancreatitis, dilation of major pancreatic ducts with numerous trematodes present and marked abdominal fat necrosis. Morphological and molecular characterization of flukes detected Eurytrema coelomaticum. Our findings shed light on the prevalence of E. coelomaticum infections in small ruminants in the region and highlight the possibility of severe and lethal cases in goats. PE must be further investigated in small ruminant populations in relevant livestock production regions of the Americas. [ABSTRACT FROM AUTHOR]

Background: Vascular hamartomas (VH) are rare or simply underdiagnosed injuries in veterinary medicine and represent a non-neoplastic developmental anomaly disorganization and proliferation of endothelial tissue. VH occur in any region of the body, however in the brain present clinical relevance related with the potential for spontaneous bleeding, adjacent tissue compression and convulsive activity. The aim of these report is to describe clinical, pathological and immunohistochemical features of a case of cerebrovascular hamartoma and highlight the diagnosis of these rare brain disorder in dogs. Case: A 10-year-old male dog, a Campeiro Bulldog breed presented convulsions episodes and died before an elective surgical procedure for eyelid nodule removal. Three red nodules were observed in the brain, one between the parietal lobe and the left occipital lobe (in the medium suprasylviam sulcus), the other in the caudal region of the corpus callosum and the third one in the cerebellar cortex. Central nervous system, eyelids and most organs and tissues samples were collected, fixed in 10% formaldehyde and processed for histopathological analysis. Histologically, in the eyelid was detected a sebaceous adenoma. The nervous system samples revealed well-differentiated sizes vascular structures with thin-walled and blood-filled, promoting compression of the brain. Normal neuropile was detected between the vascular structures substantiating cerebral vascular hamartoma diagnosis in the dog. Immunohistochemical assay was conducted with CD31 (monoclonal mouse antibody anti-CD31, Clone JC70A, Dako Corp.) and Von Willebrand factor (monoclonal mouse antibody anti-Von Willebrand factor, Clone F8/86, Dako Corp.) using the biotin-peroxidase-streptavidin method (PolyDetector Plus DAB-HRP, Bio SB) on CNS sections to confirm the vascular origin of the lining cells in the mass. Discussion: Hamartomas are rarely reported in domestic animals and mostly are of vascular origin. VH in nervous tissues can trigger clinical signs related to hemorrhage, brain space occupation, compression and obstructive secondary hydrocephalus. In general, cerebral VH have a slow progression and usually affected animals are asymptomatic. On the other hand, cerebral vascular hamartomas may also cause clinical signs in very young animals about 15 to 16 months old. In humans, clinical presentation of VH may be related with acquired lesions such as trauma, ionizing radiation, and other central nervous system injuries. In the present case, the dog presented convulsion episode only at 10 years old during prechirurgical procedures. The morphological features of the vascular hamartoma we observed in the Campeiro bulldog is classified as capillary teleangiectasia composed by well differentiated capillaries lined with well differentiated endothelial cells interspaced by normal neuronal tissue. Histopathological and immunohistochemical assay are extremely important to differentiate hamartoma from other tumors, since they may be macroscopically similar. The immunolabeling of endotelial cells by anti-CD31 and anti-Von Willebrand factor antibodies in the cerebral VH, highlight the vascular origin of the masses detected. However, it is also important to perform systematic gross examination of the brain in detail to detect even the smallest injuries in asymptomatic animals avoiding underdiagnoses of cerebral VH. [ABSTRACT FROM AUTHOR]

Background: Toxic reactions due bee stings in human, companion animals, food animals and wild animals are sporadically reported. Accidents involving bees have been occurring in urban and rural areas since 1956, when African bees were introduced in Brazil, forming populations of aggressive hybrid Africanized bees. Their sting cause local and systemic reactions, which include dermatologic reactions, anaphylactic reactions and toxic systemic reactions before death. The aim of this article is to describe the clinical and pathological aspects of the toxic systemic reactions of two dogs that suffered a massive bee attack in the Federal District, Brazil. Cases: A 8-year-old female Brazilian mastiff, and one female 6-year-old Belgian shepherd were locked in the kennel when they suffered a massive bee attack. The dogs presented 'apathy, congested mucous membranes, dyspnea, epistaxis, hemoglobinuria, icterus (one of them) and convulsions. Clinical pathology results showed a strong hemolyzed plasma, azotemia, leukocytosis with neutrophilia and monocytosis. Both animals were euthanized due to their critical conditions. At necropsy the dogs showed severe subcutaneous edema in the face, moderate congestion of mucous membranes, hematochezia and hematuria. Both dogs presented kidneys dark brown to blackened colored, urinary bladder replete with dark red fluid, lungs severely congested, intestines with severe mural edema and hyperemia containing bloody fecal matter inside, and the liver of one of the dog moderately icteric. The main histologic findings were the moderate diffuse degeneration of the kidney tubular epithelium with small focal areas of necrosis, countless casts of hemoglobin, granular and hyaline casts inside the renal tubules. The skin affected showed stingers inserted, dissociation of the collagen fibers by edema and multifocal areas of hemorrhage, neutrophils and eosinophils, and the muscular tissue underneath had intense necrosis, with hyalinization and moderate multifocal fragmentation of myocytes. Discussion: Africanized bees are well established in rural areas and can adapt to urban areas and, given their marked aggressiveness, cause accidents with animals and humans. Clinical and hematological changes presented by dogs in the DF are similar to those previously reported in this species, which are usually observed in hemolytic anemias and tissue damage caused by the acute inflammatory response due multiple bee stings. Nephrosis can be considered one of the most important toxic effects, due severe intravascular hemolytic disturbance and rhabdomyolysis, along with acute renal failure caused by the toxin components in the tubules and the toxic-isquemic condition, causing azotemia. Hemolysin proteins such as fosfolipase A and melitina cause rhabdomyolysis, intravascular hemolysis, and hemoglobinemia, which trigger the process of diffuse nephrosis and acute renal failure. The main pathologic changes were observed in the kidneys and skin of the dogs in the DF and were similar to that previously reported in dogs with severe bee stings. The count of inserted bee stingers in the skin and history is considered important to establish a presumptive diagnosis and initiate immediate treatment for the affected animals. The epidemiologic and clinical-pathologic findings presented in these cases are similar to those observed in humans who had suffered systemic toxicity by bee stings and aggravates the general condition of the patient even leading to death. Based on these findings, it was possible to establish the diagnosis of systemic toxic reaction in dogs secondary to poisoning by Africanized bee stings. [ABSTRACT FROM AUTHOR]

Background: Zooantroponoses that affect pets are rare. Microorganisms involved in human tuberculosis has great importance to public health and has potentiality to produce reverse zoonoses. Infection by Mycobacterium tuberculosis is in top of the most important infectious diseases related to public health. In dogs, the infection occurs through prolonged exposure to aerosols and respiratory secretions from humans. Canine tuberculosis is little reported and known in Brazil, this work aims to describe the anatomopathological findings of the first case of canine tuberculosis in a 5-year-old dog in the Federal District and alert to the presence of this disease in this region. Case: The dog had history of close contact with its owner, who has been treated for pulmonary tuberculosis six months before. At necropsy scattered multifocal, firm, white to yellow-gray nodules, varying in size (3 mm to 10 mm) involving lungs, kidneys, heart, liver and spleen was observed. In frontal and occipital cerebral cortex, pale-gray circular lesions were detected with the same characteristics. The histological findings were, multifocal to coalescent granulomas, well organized with a central core of necrosis with foci of mineralization, surrounded by histiocytes, epithelioid macrophage, rare Langhans giant cells, some intact and degenerate plasma cells and neutrophils, and a rim of reactive fibroblasts producing fibrous connective tissue. Histological staining with ZN revealed free acid-fast bacilli and in the cytoplasm of macrophages and granulomas in all affected organs. The PCR allowed identification of DNA was extracted from formalin fixed paraffin embedded (FFPE) tissues using the ReliaPrep™ FFPE gDNA Miniprep System®, according to the manufacturer's instructions (Promega, EUA). The Speed-Oligo Mycobacteria assay was used to identify the presence of M. tuberculosis complex DNA in tissue samples. Discussion: Zooantroponoses should be considered as differential diagnosis of infectious diseases affecting companion animals. Tuberculosis is a prevalent and highly relevant disease that plagues humans and animals. Canine tuberculosis is neglected what become information on the epidemiological and clinical situation scarce and its diagnosis a challenge. The systemic form of M. tuberculosis infection is rare in dogs, it occurs by contact with secretions of actively infected humans or ingested contaminated food with the bacillus. In the present case the dog contracted the infection by direct contact with owner who had tuberculosis and presented acute clinical alterations resulting from the disseminated form of the disease. Transmission of M. tuberculosis from humans to dogs is considered a determinant in the epidemiological chain of infection in companion animals. Histological lesions in natural cases of tuberculosis in dogs and cats differ from typical tuberculoid granulomas found in cattle and humans. In this case of disseminated tuberculosis in the DF scarce Langhans giant cells in the granulomas was obseved, which is a typical manifestation of the disease in the species. The coloration of Ziehl- Neelsen allows evidence of alcohol-acid-resistant bacilli, as seen in the present report. Health actions aiming prevention and control of tuberculosis should include investigation of the disease in companion animals in households where there are records of human tuberculosis. The anatomopathological and molecular findings confirmed the diagnosis of Mycobacterium tuberculosis infection transmitted by the owner, an uncommon disease in companion animals, a challenge to the clinical diagnosis, and previously unknown in the Federal District. [ABSTRACT FROM AUTHOR]

In Brazil, Leucaena leucocephala (Leg. Mimosoideae) poisoning has been described in sheep, goats, and horses. The leaves of this leguminous plant are highly palatable and contain the toxic non-protein amino acid mimosine. Mimosine concentrations associated with Leucaena toxicosis are not readily available in the literature. The present study describes the epidemiological findings, clinical signs, and toxicologic analysis of an outbreak of L. leucocephala poisoning in horses in Araguari, Triângulo Mineiro, Minas Gerais, Brazil. The outbreak affected three of four adult horses of the farm. The animals consumed the leaves spontaneously during the drought period (July to September). The horses exhibited moderate to severe alopecia of the tail and mane. Leaves of the plant were randomly sampled (50 g), dried at ambient temperature, and sent for mimosine analysis. Quantitative analysis by a high-performance liquid chromatography method (HLPC-UV) measured a concentration of 5.5 mg/g of mimosine in the dry plant material. The horses recovered after being removed from the paddocks that contained the toxic plant material. L. leucocephala poisoning should be considered a differential diagnosis for horses presenting alopecia in the state of Minas Gerais, and the toxicologic analysis results can be used for comparisons in future studies. [ABSTRACT FROM AUTHOR]

We described the first case of rhinofacial pythiosis with dissemination in an adult horse in Uruguay. The affected horse presented a partially circumscribed mass measuring 30 x 23 x 9 cm affecting the right side of the face with involvement of cutaneous, subcutaneous, and muscular tissues, the right nasal cavity, and adjacent structures. At postmortem examination, the main lesions were “kunkers” characterized by pyogranulomatous and eosinophilic dermatitis, Splendore-Hoeppli reaction and numerous intralesional hyphae immunolabeling with polyclonal anti-Pythium insidiosum antibody. Similar lesions were observed in the lung and submandibular lymph nodes. The diagnosis was made by the characteristic histological lesions and the strong immunolabelling by anti-P. insidiosum antibody. [ABSTRACT FROM AUTHOR]

The downer cow syndrome (DCS) is characterized by an alert cow showing inability or reluctance to stand for 12 hours or more. This paper reported clinical, laboratory, and pathological findings in a Guzerá heifer with rhabdomyolysis, pigmenturia and acute renal failure following DCS. A 17-month-old Guzerá heifer was transported via a 350-km ride in a truck and showed sternal recumbency and severe difficulty in standing and walking. Neurological examination was unremarkable, and the heifer presented normal response to cranial nerves and spinal cord tests. Rectal palpation revealed a 5-month gravid uterus. No other abnormalities were noted in the pelvis or around the coxofemoral joints. Biochemical abnormalities included extremely high muscular enzyme activities (creatine phosphokinase and aspartate aminotransferase) and high creatinine levels. Urinalysis revealed blackish and cloudy urine, proteinuria, and a positive occult blood test. Spinal cord ultrasonography showed no abnormalities. This report highlighted an uncommon clinical presentation (myoglobinuria) and pathological findings in a heifer with DCS as a consequence of severe compressive muscle damage. Practitioners and producers must be aware of the risk of careless road transportation for long distances of cattle, especially obese cows, avoiding unnecessary suffering and expenses due to DCS. [ABSTRACT FROM AUTHOR]