Hepatogenous photosensitization in ruminants and horses caused by the ingestion of Chamaecrista serpens in Brazil.

This study aimed to describe the first reports of outbreaks of hepatogenous photosensitization in cattle, sheep, and horses caused by spontaneous ingestion of Chamaecrista serpens, as well as to reproduce poisoning in sheep experimentally. Eleven photodermatitis outbreaks of unknown cause occurred in cattle, sheep and horses on nine farms in the semiarid region of Bahia, northeastern Brazil, between July 2017 and July 2020. Cutaneous lesions of photosensitization initiated until one week after the animals were introduced in paddocks invaded by the plant at the beginning of the rainy season. The photosensitive skin lesions were progressive and consisted of hyperemia, edema, ulcerative-crusted lesions with necrosis, especially in non-pigmented skin areas. The lesions in young animals were more severe. The animals avoided the sun and exhibited hyporexia, weight loss, restlessness, irritability, and severe itching. An experimental study was made using seven sheep, and resulted in photodermatitis, similar to that observed in the natural poisoning, seven days after the beginning of plant ingestion. Two sheep were reserved for the control group. Serum biochemistry changes indicated liver injury caused by the plant. Skin biopsies and liver biopsy guided by ultrasound were performed. The one sheep that had more pronounced skin lesions was euthanized and necropsied. At the necropsy, the liver was enlarged, diffusely pale, and firm, with an evident lobular pattern and an empty gallbladder. Histopathology revealed similar skin and liver lesions in samples from biopsies and the necropsy. There was a marked disorganization of the cords of hepatocytes associated with degenerative necrotic changes on the liver. The cutaneous injuries included orthokeratotic hyperkeratosis, hypergranulosis, acanthosis, and extensive areas of epidermic necrosis and ulceration. Three sheep were protected from sunlight and the lesions regressed within 45 days after the plant's consumption ceased. In conclusion, C. serpens causes hepatogenous photosensitization in ruminants and horses, and should be included in the list of differential diagnoses in cases of photosensitive dermatitis.

Aspectos epidemiológicos, clínicos e anatomopatológicos da infecção por Gurltia paralysans em gatos / Epidemiological, clinical and pathological aspects of Gurltia paralysans infection in cats

Nos últimos 20 anos, uma doença neurológica desconhecida acometeu populações de gatos da Região da Campanha do RS e tornou-se um desafio diagnóstico para os veterinários locais. Os gatos afetados desenvolviam inicialmente paralisia da cauda, seguida de paraparesia progressiva nos membros pélvicos, alteração da marcha, posição plantígrada e ataxia proprioceptiva. Após longos períodos de evolução clínica (12-24 meses), quando se tornavam marcadamente paraparéticos e começavam a apresentar escaras de decúbito, eram sacrificados pelos proprietários. Na necropsia, demonstravam graus variados de atrofia dos músculos pélvicos e algum grau de avermelhamento das meninges entre T10 e L7, devido à presença de miríades de pequenos vasos sanguíneos, uma típica lesão varicosa, semelhante a um hamartoma vascular. Histologicamente, tais lesões consistiam de distensão do espaço subaracnóideo por vasos sanguíneos dilatados e tortuosos, repletos de sangue e, ocasionalmente, de trombos, que ocluíam parcial ou totalmente seus lúmens. Essas varizes venulares eram aleatoriamente circundadas por infiltrado inflamatório granulomatoso ou linfocítico com pequenos focos de eosinófilos maduros. No lúmen das vênulas varicosas havia secções transversais e longitudinais de parasitos. Com base na morfologia desses parasitos, em sua localização anatômica (vasos sanguíneos meníngeos) e na espécie afetada (gato), o nematódeo foi identificado como Gurltia paralysans. O objetivo desse trabalho é apresentar em detalhes os aspectos epidemiológicos, clínicos e anatomopatológicos dessa intrigante mielopatia de gatos e estabelecer definitivamente seu diagnóstico definitivo: paraplegia crural parasitária felina, uma doença descoberta no Chile, na década de 1930, e agora, pela primeira vez, descrita no Brasil.

In the last 20 years, an unknown neurological disease affected cat populations in the Western Border Region of the State of Rio Grande do Sul, Brazil. The onset of the disease was characterized by tail paralysis, followed by progressive paraparesis in the pelvic limbs, difficulty in ambulation and proprioceptive ataxia. After long prolonged clinical courses (12-24 months), when then affected cats became severely paraparetic and start to develop pressure sores do to decubitus, they were destroyed by the owners. At necropsy there were variable degrees of skeletal muscle atrophy of the pelvic muscles and some degree of reddening of the meninges at the level of T10-L7, due to the presence of a myriad of small blood vessels, as a typical varicose lesion that resembled a vascular hamartoma. Histologically, such lesions consisted of distension of the subarachnoid space due to a collection of dilated, blood-filled, tortuous blood vessels the lumina of which were occasionally partially or completely occluded by thrombi. Those varices were randomly surrounded by a lymphocytic or granulomatous inflammatory infiltrate with small foci of mature eosinophils. In the lumina of these varicose venules cross and longitudinal sections of nematode parasites could be observed. Based on the morphology of these parasites, in their anatomical localization (meningeal blood vessels) and in the species (cat) affected the nematode was identified as Gurltia paralysans. This paper describes detailed aspects of the epidemiology, clinical disease and pathology of this intriguing feline myelopathy and the definitive diagnosis of the condition: Feline crural parasitic paraplegia, a disease first described in Chile in the 1930's and now, for the first time, in Brazil.

Experimental poisoning by Baccharis megapotamica var. weirii in buffalo / Intoxicação experimental por Baccharis megapotamica var. weirii em búfalos

Five male 6-8 month-old Murrah buffalo calves were orally dosed with the fresh aerial parts of Baccharis megapotamica var. weirii at doses of 1, 3, 4, 5 and 10g/kg body weight (bw) (~1-10mg macrocyclic trichothecenes/kg/bw). The B. megapotamica used for the experiment was harvested on a farm where a recent spontaneous outbreak of poisoning caused by such plant had occurred. Clinical signs appeared 4-20 hours and 4 buffaloes died 18-49 hours after the ingestion of the plant. Clinical signs were apathy, anorexia, and watery diarrhea, fever, colic, drooling, muscle tremors, restlessness, laborious breathing and ruminal atony, and dehydration. The most consistent gross findings were restricted to the gastrointestinal (GI) tract consisted of varying degrees of edema and reddening of the mucosa of the forestomach. Histopathological findings consisted of varying degrees of necrosis of the epithelial lining of the forestomach and of lymphocytes within lymphoid organs and aggregates. Fibrin thrombi were consistently found in sub-mucosal vessels of the forestomach and in the lumen of hepatic sinusoids. It is suggested that dehydration, septicemia and disseminated intravascular coagulation participate in the pathogenesis of the intoxication and play a role as a cause of death. A subsample of B. megapotamica var. weirii was frozen-dried and ground and analyzed using UHPLC (Ultra High Performance Liquid Chromatography) with high resolution Time of Flight mass spectrometry and tandem mass spectrometry, it was shown that the plant material contained at least 51 different macrocyclic trichothecenes at a total level of 1.1-1.2mg/g. About 15-20% of the total trichothecenes contents was found to be monosaccharide conjugates, with two thirds of these being glucose conjugates and one third constituted by six aldopentose conjugates (probably xylose), which has never been reported in the literature.

As partes aéreas verdes de Baccharis megapotamica var. weirii foram administradas oralmente a cinco búfalos da raça Murrah de 6-8 meses de idade nas doses de 1, 3, 4, 5 e 10g/kg de peso corporal (pc) (~1-10mg de tricotecenos macrocíclicos/kg/pc). A planta usada no experimento foi colhida numa fazenda onde um surto recente de intoxicação espontânea por essa planta havia ocorrido. Nos búfalos deste experimento, os sinais clínicos apareceram 4-20 horas e 4 búfalos morreram 18-49 horas após a ingestão da planta. Os sinais clínicos consistiram de apatia, anorexia, diarreia aquosa, febre, cólica, salivação, tremores musculares, inquietação, respiração laboriosa, atonia ruminal e desidratação. Os achados macroscópicos mais consistentes estavam restritos ao trato gastrointestinal (GI) e consistiram de graus variados de edema e avermelhamento da mucosa dos pré-estômagos. Os achados histopatológicos consistiam de vários graus de necrose do epitélio de revestimento dos pré-estômagos e de linfócitos em agregados e órgãos linfoides. Trombos de fibrina foram consistentemente encontrados nos vasos da submucosa dos pré-estômagos e na luz dos sinusoides hepáticos. É sugerido que desidratação, septicemia e coagulação intravascular disseminada participem da patogênese da intoxicação e sejam fatores responsáveis pela morte dos animais afetados pela intoxicação. Uma subamostra de B. megapotamica var. weirii foi congelada a seco, moída e analisada usando UHPLC (Cromatografia Líquida de Ultra Alta Performance) com espectrometria de tempo-de-vôo de alta resolução e espectrometria de massa em tandem. Foi demonstrado que o material de planta analisado continha pelo menos 51 tricotecenos macrocíclicos diferentes num nível total de 1,1-1,2mg/g. Cerca de 15-20% do conteúdo total de tricotecenos eram conjugados de monossacarídeos, sendo dois terços desses, conjugados de glicose e um terço constituídos por seis conjugados de aldopentose (provavelmente xilose), o que nunca tinha sido antes relatado na literatura.

Baccharis megapotamica var. weirii poisoning in water buffalo (Bubalus bubalis).

An outbreak of an acute disease in buffalo (Bubalus bubalis) caused by the ingestion of Baccharis megapotamica var. weirii occurred in the southern region of Brazil. Ten out of 50 buffalo died 24-48 hr after being introduced into a pasture containing abundant amounts of the plant. Factors influencing the ingestion of the plant and consequent toxicosis included hunger, stress caused by shipment, and unfamiliarity with the plant. Clinical signs included serous ocular discharge, incoordination, mild bloat, and muscle trembling. One buffalo was necropsied. Gross findings included dehydration, abundant liquid in the rumen, reddening of the mucosa of forestomachs, abomasum, and intestine, and edema of the wall of the rumen. The main histologic lesions were superficial to full thickness degeneration and necrosis of the stratified epithelium lining the forestomachs, necrosis of the intestinal mucosa, and widespread lymphoid necrosis. A calf (Bos taurus) was fed a single dose of 5 g/kg/body weight of B. megapotamica var. weirii harvested from the same site where the buffalo died. Twenty hours after the administration of the plant this calf died with clinical signs and lesions similar to those observed in the naturally poisoned buffalo.

Surto de ceratoconjuntivite infecciosa bovina e hemoncose causando mortalidade em bezerros / Outbreak of infectious bovine keratoconjunctivitis and haemonchosis causing moratality in calves

É descrito um surto de ceratoconjuntivite infecciosa bovina (CIB) e hemoncose intercorrente afetando um grupo de 116 bezerros de 1-2 anos de idade na região central do Rio Grande do Sul. Vinte bezerros foram afetados e nove morreram. Os sinais clínicos incluíam perda de peso, marcada palidez da mucosa oral, lacrimejamento, opacidade focal da córnea e avermelhamento da conjuntiva. Sinais mais avançados incluíam lacrimejamento copioso, opacidade da córnea, ceratocone, ceratomalacia e cegueira. O diagnóstico de CIB foi baseado nos achados epidemiológicos e clínico-patológicos e confirmado pela cultura de uma cepa hemolítica de Moraxella bovis dos olhos de dois terneiros afetados. O alto coeficiente de letalidade (45 por cento) neste surto foi atribuído a grave hemoncose intercorrente.

An outbreak of infectious bovine keratoconjunctivitis (IBK) with concomitant haemonchosis is described affecting a group of 116 yearling calves in southern Brazil. Twenty calves were affected and nine died. Clinical signs included wasting, marked oral mucosal pallor, serous ocular discharge, focal central corneal opacity, and reddening of the conjunctiva. More advanced stages displayed copious serous ocular discharge, corneal opacity, keratoconus, keratomalacia, and blindness. The diagnosis of IBK was based on the epidemiological, clinical, and pathological findings and confirmed by bacteriologic culture of a hemolytic strain of Moraxella bovis from the eye globe of two affected calves. The high lethality rate (45 percent) in this outbreak was caused by concomitant and severe haemonchosis.

Abordagem diagnóstica das principais doenças do sistema nervoso de ruminantes e equinos no Brasil / Diagnostic approaches for the main neurological diseases of ruminants and horses in Brazil

O objetivo deste trabalho é descrever os principais aspectos epidemiológicos e clínico-patológicos das principais doenças do sistema nervoso de ruminantes e equinos diagnosticadas no Laboratório de Patologia Veterinária (LPV) da Universidade Federal de Santa Maria (UFSM) para servir como base para veterinários de campo ou que trabalham em laboratórios de diagnóstico. Esses dados foram buscados em trabalhos publicados pela equipe do LPV-UFSM ou retirados dos arquivos do laboratório. As principais doenças do sistema nervoso diagnosticadas em bovinos foram a raiva, a encefalopatia hepática decorrente de insuficiência hepática por ingestão de Senecio spp., a meningoencefalite por herpesvírus bovino, a babesiose cerebral, a intoxicação por Solanum fastigiatum, a febre catarral maligna e a polioencefalomalacia. Em ovinos foram diagnosticadas a cenurose, a meningoencefalite por Listeria monocytogenes, o tétano, os abscessos encefálicos ou vertebrais e a raiva. Meningoencefalite por L. monocytogenes foi a única doença do sistema nervoso descrita em caprinos. Equinos foram afetados pela leucoencefalomalacia, tripanossomíase e tétano.

The epidemiological, clinical, and pathological hallmarks of neurological diseases of ruminants and horses diagnosed in the Laboratory of Veterinary Pathology (LVP) of the Universidade Federal de Santa Maria (UFSM) are herein described. This paper is intended to work as a compiled database for practitioners or veterinarians working in diagnostic laboratories. Data was gathered from papers published by the LVP-UFSM faculty and staff or retrieved from the laboratory archives. The most important neurological diseases of cattle included rabies, hepatic encephalopathy due to ingestion of Senecio spp., meningoencephalitis by bovine herpesvirus, cerebral babesiosis, poisoning by Solanum fastigiatum, malignant catarrhal fever, and polioencephalomalacia. Sheep were affected mostly by coenurosis, meningoencephalitis by Listeria monocytogenes, tetanus, encephalic or vertebral abscesses, and rabies. Goats were affected by meningoencephalitis by L. monocytogenes. Leukoencephalomalacia, trypanosomiasis by Trypanosoma evansi, and tetanus were important neurological diseases of horses.

Intoxicação por organofosforado em bovinos no Rio Grande do Sul / Poisoning by organophosphate in cattle in southern Brazil

An outbreak of organophosphate (ORF) poisoning in cattle occurred in the central-midwestern region of Rio Grande do Sul, Brazil. The water available for 49 cattle was contaminated with ORF and carbamate (CM). Twenty cows died after a clinical course that lasted for few hours. The classical clinical signs of over stimulation of the parasympathetic nervous system were observed, including motor incoordination, aggressiveness, drooling, muscle tremors and, on occasion, diarrhea. Significant morphological changes were not observed at necropsy or at histopathological examination. ORF e CM were detected by thin layer chromatography in tissue samples of two affected cattle and in a sample from the water consumed by the affected cattle. Additionally, two other water samples accessed by the affected cattle were positive for ORF. A quantitative analysis carried out by gas chromatography in the abomasum contents of an affected cow revealed 0.93µg/g of mancozebe (CM) and 0.07µg/g of phorate (ORF).

Descreve-se um surto de intoxicação por organofosforado (ORF) em bovinos na mesorregião centro ocidental do Rio Grande do Sul. A água fornecida a 49 bovinos foi contaminada com ORF e carbamato (CM). Vinte bovinos morreram após quadro clínico de poucas horas. Foram observados os clássicos sinais clínicos de hiperestimulação do sistema parassimpático incluindo incoordenação motora, agressividade, sialorreia, tremores musculares e, em alguns casos, diarreia. Na necropsia e histopatologia não foram observadas alterações morfológicas significativas. ORF e CM foram detectados por cromatografia em camada delgada em amostras de tecido de dois bovinos afetados. Adicionalmente, uma amostra da água consumida pelos bovinos foi positiva para ORF e CM e outras duas foram positivas para ORF. Uma análise quantitativa realizada por cromatografia gasosa no conteúdo do abomaso de um bovino afetado, revelou 0,93µg/g de mancozebe (CM) e 0,07 µg/g de forato (ORF).

Estudo retrospectivo de 1647 tumores mamários em cães / Retrospective study of 1647 mammary gland tumors in dogs

Tumores mamários são comuns em cães, e constituem o neoplasma mais frequente em cadelas. Este estudo tem como objetivos principais estabelecer a prevalência dos tumores mamários, e dos diferentes tipos histológicos (neoplásicos e não-neoplásicos), diagnosticados em cães no Laboratório de Patologia Veterinária da Universidade Federal de Santa Maria (LPV-UFSM). Foram avaliados 1.304 protocolos de exames histopatológicos recebidos em 1990-2008 e 132 protocolos de necropsias realizadas em 2000-2008. Deles foram obtidos a raça, o sexo e a idade dos cães, a localização do tumor na cadeia mamária, o diagnóstico morfológico e a ocorrência de metástases. Nos protocolos de exame histopatológico, foram diagnosticados 1.495 tumores, considerando que alguns cães tinham mais de um tipo de tumor, sendo 1.465 neoplásicos e 30 não-neoplásicos. Dos neoplásicos, 390 (26,6 por cento) eram benignos e 1.075 (73,3 por cento) eram malignos, estabelecendo-se uma relação benigno: maligno de 1:2,75. Das 1.125 necropsias de cães realizadas em 2000-2008, 132 (11,6 por cento) protocolos tinham descrições de tumor de mama, perfazendo 152 diagnósticos morfológicos, dos quais 150 eram neoplásicos e dois eram não-neoplásicos. Carcinoma simples foi o tipo histológico mais prevalente tanto em biópsias como em necropsias. Nas necropsias, foram observadas metástases para linfonodos em 39 casos (29,5 por cento) e para órgãos distantes em 64 casos (53,3 por cento).

Mammary gland tumors are common in dogs and are the most common type of neoplasm of female dogs. The main purposes of this study were to establish the prevalence of the mammary gland tumors, as well as of its different histologic types (neoplastic and non-neoplastic), diagnosed in the Laboratório de Patologia Veterinária of the Universidade Federal de Santa Maria. There were 1,304 biopsy reports of mammary gland tumors during 1990-2008 and 132 necropsy reports of dogs with mammary tumors in 2000-2008. Data about breed, gender, and age of dogs, tumor localization, morphologic diagnosis, and metastasis occurrence were analyzed. In the biopsy cases, 1,495 tumors were diagnosed, considering the presence of more than one type of tumor in some of the dogs. From those, 1,465 were neoplastic and 30 were non-neoplastic. Within the neoplasms, 390 (26.6 percent) were benign and 1,075 (73.3 percent) were malignant. The benign/malignant ratio was 1:2.75. During the years 2000-2008, 1,125 necropsies of dogs were performed, 132 (11.64 percent) of which with mammary gland tumors. There were 152 morphologic diagnoses, being 150 of neoplastic and two of non-neoplastic lesions. Simple carcinoma was the most prevalent histologic type, both among biopsy and necropsy cases. On necropsy cases, metastases to lymph nodes and distant organs were seen in 39 (29.5 percent) and 64 (53,3 percent) cases, respectively.

Doenças de ovinos da região Central do Rio Grande do Sul: 361 casos / Diseases of sheep from central Rio Grande do Sul State, Brazil: 361 cases

Foram pesquisados os arquivos do Laboratório de Patologia Veterinária (LPV) da Universidade Federal de Santa Maria (UFSM) e revisados os diagnósticos de doenças de ovinos realizados entre 1990 e 2007. No período estudado foram realizados 19.476 exames de animais domésticos. Desses, 6.816 (34,9 por cento) correspondiam a necropsias e 12.660 (65,1 por cento) a exames histopatológicos realizados em materiais enviados por veterinários de campo. Materiais provenientes de experimentos em ovinos foram excluídos deste estudo, sendo obtidas 354 (5,1 por cento) necropsias e 163 (1,2 por cento) exames histopatológicos de ovinos. O diagnóstico foi conclusivo em 265 (74,8 por cento) casos de necropsias e em 96 (59 por cento) casos dos exames histopatológicos, somando 361 casos conclusivos. Esses casos foram divididos em grupos conforme a etiologia: 150 casos (41,6 por cento) de intoxicações e toxiinfecções; 142 casos (39,3 por cento) de doenças infecciosas e parasitárias; 31 casos (8,6 por cento) de doenças metabólicas e nutricionais; 13 casos (3,6 por cento) de neoplasmas e lesões tumoriformes; sete casos (1,9 por cento) de distúrbios causados por agentes físicos; seis casos (1,7 por cento) de distúrbios iatrogênicos; e quatro casos (1,1 por cento) de distúrbios do desenvolvimento. Oito casos (2,2 por cento) foram classificados em outros distúrbios por não se enquadrarem em nenhum dos outros grupos. Hemoncose e intoxicação por Nierembergia veitchii foram as doenças mais importantes para ovinos nesses 18 anos.

An 18-year (1990-2007) database search in the files of the Laboratory of Veterinary Pathology (LPV) of the Universidade Federal de Santa Maria (UFSM), Rio Grande do Sul state, Brazil was carried out. In this period, 19,476 exams in domestic animals were done. Out of these exams, 6,816 (34.9 percent) were necropsies and 12,660 (65.1 percent) were performed in mailed samples from practitioners. Experimental cases were excluded from this study and corresponded to 54 necropsies and 15 histopathologic exams. After the exclusion 354 (5.1 percent) necropsies and 163 (1.2 percent) histopathologic exams were found in sheep. Out of these, 265 (74.8 percent) cases were conclusive in the group of necropsies and 96 (59 percent) were conclusive in the group of the histopathologic exams. The resulting 361 conclusive cases were grouped according to the etiology: 150 (41.6 percent) cases of poisoning or toxi-infections; 142 (39.3 percent) cases of infectious and parasitary diseases; 31 (8.6 percent) of metabolic and nutritional diseases; 13 (3.6 percent) cases of neoplasms and neoplasm-like lesions; 7 (1.9 percent) cases of diseases caused by physical agents; 6 (1.7 percent) cases of iatrogenic conditions; and 4 (1.1 percent) of developmental diseases. Eight cases did not fit in any of the above categories and were grouped under the denomination of other conditions. Hemonchosis and poisoning by Nierembergia veitchii were the most prevalent diseases in sheep during the 18 years of this study.

Enterite granulomatosa associada a larvas de ciatostomíneos em eqüinos no Rio Grande do Sul / Granulomatous enteritis associated with larval cyathostomiasis in horses in Rio Grande do Sul, Brazil

São descritos cinco casos de enterite granulomatosa associada a larvas de ciatostomíneos em eqüinos provenientes de três propriedades rurais do Rio Grande do Sul. Os casos ocorreram entre janeiro de 1999 e dezembro de 2007. A evolução clínica nos dois casos cujo seguimento clínico foi acompanhado foi de 10 e 14 dias. Os sinais clínicos apresentados por três eqüinos foram semelhantes e consistiam de diarréia (3/3), emagrecimento (2/3), pirexia (1/3), taquicardia (1/3) e taquipnéia (1/3). Os achados macroscópicos incluíram espessamento da parede do cólon maior e ceco por edema e ocorrência de numerosos pontos marrom-escuros com 1-4mm, levemente salientes, disseminados pela mucosa. A incisão desses pontos revelou pequenas larvas de nematódeos marrom-avermelhadas de 1-2mm. Numerosos parasitas, compatíveis morfologicamente com pequenos estrôngilos, foram observados na luz intestinal ou aderidos à mucosa do cólon maior e ceco. Histologicamente, na mucosa e submucosa do cólon maior e ceco, foram observados múltiplos granulomas constituídos por moderado ou acentuado infiltrado inflamatório, composto por macrófagos, macrófagos epitelióides e eosinófilos circundados por linfócitos e plasmócitos. No centro desses granulomas, observaram-se cortes transversais de parasitas com morfologia compatível com ciatostomíneos. Adicionalmente, havia edema e infiltrado inflamatório linfo-histioplasmocitário e eosinofílico, leve ou moderado na submucosa e mucosa do cólon maior e ceco; necrose e proliferação linfo-histiocítária em folículos linfóides na submucosa e hiperplasia de células caliciformes na mucosa. O diagnóstico de enterite granulomatosa associada a ciatostomíneos foi realizado com base nos achados epidemiológicos, clínicos e macroscópicos e confirmado pela histologia.

Five cases of granulomatous enteritis associated with cyathostomes are described in horses from three farms in Rio Grande do Sul, Brazil. The cases occurred from January 1999 to December 2007. The clinical course in two cases in which clinical follow-up was available was 10-14 days. Clinical signs presented by two horses were similar and included diarrhea (3/3), weight loss (2/3), pyrexia (1/3), tachycardia (1/3), and tachypnea (1/3). Gross changes consisted of thickening of the wall of large colon and cecum by edema and the occurrence of numerous 1-4mm, dark-tan, slightly raised multifocal pinpoints disseminated throughout the mucosa. Up on the incision of these pinpoints, brown-reddish, small (1-2mm) nematode larvae emerged. Large numbers of parasites with morphology compatible with small strongyles were observed in the lumina of large colon and cecum or adhered to the mucosae of these organs. Histologically, multiple granulomas were seen in the mucosa and submucosa of large colon and cecum. These granulomas consisted of moderate to severe inflammatory infiltrate of macrophages, epithelioid macrophages, and eosinophils surrounded by fewer lymphocytes and plasma cells. In the center of these granulomas, transversal cut sections of parasites with morphology compatible with cyathostomes larvae were observed. Additionally, there was edema and moderate to marked lymphohistioplasmacytic and eosinophilic inflammatory infiltrate throughout the mucosa and submucosa of the large colon and cecum; necrosis and lymphohistiocytic proliferation in the submucosal lymphoid follicles, with hyperplasia of goblet cells in the epithelial lining of these organs were also observed. The diagnosis of granulomatous enteritis associated with larval cyathostomiasis was made based on epidemiological, clinical, and gross findings which were confirmed by histopathology.