PESQUISA VETERINÁRIA BRASILEIRA

Abstract in English:

ABSTRACT.- Kindlovits L.M., Miranda F.J.B., Damasceno-Sá J.C., Da Matta R.A. & Almosny N.R.P. 2017. [Morphological and ultrastructural aspects of Crotalus durissus terrificus blood cells.] Aspectos morfológicos e ultraestruturais de células sanguíneas de Crotalus durissus terrificus. Pesquisa Veterinária Brasileira 37(2):183-194. Departamento de Patologia Clínica Veterinária, Faculdade de Veterinária, Universidade Federal Fluminense, Rua Vital Brazil Filho 64, Niterói, RJ 24230-360, Brazil. E-mail: almosny@gmail.com Hematological evaluation, important for the diagnostic by the small domestic animal clinician, has become common in wildlife clinic, and for handling and study of the physiology of various species. Given the increased demand for drug production of pharmaceutical importance, the breeding of venomous snakes has become common and is already recognized as production. Knowledge of the management and clinics of snakes is still insufficient and their mortality is high. Although some hematological studies have already been conducted in the rattlesnake (Crotalus durissus), the analyzed data are still insufficient, especially with respect to the characterization of blood cells, and few electron microscopy studies have been performed on snakes. In order to characterize morphologically blood cells with light and ultrastructural microscopy, blood samples from 52 individuals of subspecies of Crotalus durissus terrificus were collected to perform blood smears and ultrastructural evaluation. It was concluded that hematologic Giemsa staining allows morphological evaluation and differentiation of the blood cells as well as of snake hemoparasites. The ultrastructural evaluation will highlight the cell organelles and differentiation between cells, including leukocyte types; although still further studies are needed to elucidate the hypothesis of eosinophils in the species studied as also is necessary a better characterization of azurophilic beads to confirm a possible difference between the typical monocyte and the azurophilic.

• Electronic microscopy hematology blood cells leukocytes snake diagnóstico hematologia células sanguíneas leucócitos microscopia eletrônica serpente

Abstract in Portuguese:

RESUMO.- Kindlovits L.M., Miranda F.J.B., Damasceno-Sá J.C., Da Matta R.A. & Almosny N.R.P. 2017. [Morphological and ultrastructural aspects of Crotalus durissus terrificus blood cells.] Aspectos morfológicos e ultraestruturais de células sanguíneas de Crotalus durissus terrificus. Pesquisa Veterinária Brasileira 37(2):183-194. Departamento de Patologia Clínica Veterinária, Faculdade de Veterinária, Universidade Federal Fluminense, Rua Vital Brazil Filho 64, Niterói, RJ 24230-360, Brazil. E-mail: almosny@gmail.com A avaliação hematológica, de importância comprovada como um meio auxiliar de diagnóstico ao clínico de pequenos animais domésticos, vem se tornando comum em animais selvagens não apenas para a clínica, mas para a avaliação do manejo e como estudo auxiliar para a fisiologia das várias espécies. Tendo em vista o aumento da demanda para a produção de várias drogas de importância farmacêutica, a criação de serpentes peçonhentas vem se tornando comum a ponto destes animais já serem reconhecidos como sendo de produção. O conhecimento do manejo e da clínica destes animais ainda é escasso e a mortalidade é elevada nos criatórios, tornando urgente a ampliação destes. Embora alguns estudos hematológicos já tenham sido realizados em cascavéis (Crotalus durissus) os dados analisados ainda são insipientes, notadamente em relação à caracterização das células do sangue e poucos estudos em microscopia eletrônica foram realizados em serpentes. Com o objetivo de caracterizar as células sanguíneas morfologicamente, sob microscopia óptica e ultraestrutural, foram coletadas amostras de sangue de 52 de indivíduos da subespécie Crotalus durissus terrificus para a realização de esfregaços sanguíneos e avaliação ultraestrutural. Concluiu-se que a coloração hematológica de Giemsa permite a avaliação morfológica e a diferenciação das células sanguíneas em serpentes assim como a visualização de hemoparasitos. A avaliação ultraestrutural permite evidenciar as organelas celulares e a diferenciação entre as células, inclusive entre os tipos leucocitários, porém ainda são necessários outros estudos para que seja elucidada a hipótese da existência dos eosinófilos na espécie estudada assim como é necessária melhor caracterização dos grânulos dos azurófilos para que se confirme uma possível diferença entre os monócitos típicos e os azurófilos.

Abstract in English:

ABSTRACT.- Tokarnia C.H., Brito M.F., Barbosa J.D. & Döbereiner J. 2014. [Clinical and pathological pictures of snakebite poisoning by Crotalus durissus terrificus and Bothrops spp. in livestock.]Quadros clínico-patológicos do envenenamento ofídico por Crotalus durissus terrificus e Bothrops spp. em animais de produção. Pesquisa Veterinária Brasileira 34(4):301-312. Departamento de Nutrição Animal e Pastagem, Instituto de Zootecnia, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ 23890-000, Brazil. E-mail: tokarnia@ufrrj.br A review was performed about the clinical and pathological pictures caused by the venoms of Crotalus durissus terrificus and Bothrops spp. in cattle, buffaloes, horses, sheep and swine. The data were compiled from experiments in livestock species found in the literature, from experimentation accomplished by our research group, and from communicated natural cases of snakebite poisoning. The most important data were placed on two Tables, the analysis of which revealed some interesting aspects: (1) in our experiments the venom of Crotalus durissus terrificus caused in horses severe edema at the site of subcutaneous injection, to the contrary as observed in all other experimental animal species, an aspect not recorded in the literature; (2) in our experiments the venom of Bothrops species in cattle, sheep and horses, injected subcutaneously, did not cause edema as generally reported in the literature, but caused severe subcutaneous hemorrhages at the injection site. In the non fatal cases the blood was reabsorbed in a few days without leaving sequelae; exception was the reaction to the venom of Bothrops jararacussu, which caused edema in the experimental sheep, and severe tumefaction resulting in fistulous elimination of serous liquid in the experimental horses. The aim of this study was to contribute for the diagnostic of snakebite accidents in livestock.

• Snake venom poisoning Crotalus durissus terrificus Bothrops spp. envenenamento ofídico

Abstract in Portuguese:

RESUMO.- Tokarnia C.H., Brito M.F., Barbosa J.D. & Döbereiner J. 2014. [Clinical and pathological pictures of snakebite poisoning by Crotalus durissus terrificus and Bothrops spp. in livestock.]Quadros clínico-patológicos do envenenamento ofídico por Crotalus durissus terrificus e Bothrops spp. em animais de produção. Pesquisa Veterinária Brasileira 34(4):301-312. Departamento de Nutrição Animal e Pastagem, Instituto de Zootecnia, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ 23890-000, Brazil. E-mail: tokarnia@ufrrj.br Foi realizada uma revisão dos quadros clínico-patológicos causados pelos venenos de Crotalus durissus terrificus e Bothrops spp. em bovinos, búfalos, ovinos equinos e suínos. Foram compilados os dados obtidos pela experimentação em animais de produção encontrados na literatura e os obtidos através de experimentação realizada por nossa equipe. Também foram revisados os casos naturais de envenenamento ofídico comunicados. Em dois Quadros foram lançados os mais importantes dados dessas revisões, que revelou diversos aspectos interessantes: 1) em nossos experimentos, o veneno de Crotalus durissus terrificus, quando injetado por via subcutânea em cavalos, causou um edema acentuado no local da aplicação, ao contrário do que tem sido observado em todas as outras espécies animais, aspecto não relatado na literatura; 2) em nossos experimentos, o veneno de diversas espécies de Bothrops, quando injetado por via subcutânea em bovinos, ovinos e equinos, não causou edema como em geral é relatado na literatura, e sim hemorragias subcutâneas acentuadas no local da aplicação. Nos casos não fatais este sangue era reabsorvido em poucos dias sem deixar sequelas. Exceção foi a reação ao veneno de Bothrops jararacussu, que causou edema nos ovinos experimentais, e tumefação acentuada que resultou em fístula com eliminação de líquido seroso nos equinos experimentais. O objetivo do presente estudo visa contribuir para o aperfeiçoamento do diagnóstico de acidentes ofídicos em animais de produção.

Abstract in English:

ABSTRACT.- Barbosa J.D., Sousa M.G.S., Tokarnia C.H., Brito M.F., Belo Reis A.S., Bomjardim H.A., Lopes C.T.A. & Oliveira C.M.C. 2011. [Comparison between the clinical and pathological picture in the experimental poisoning by crotalic venom.] Quadro clínico-patológico do envenenamento crotálico experimental em bubalinos comparado com o de bovinos. Pesquisa Veterinária Brasileira 31(11):967-973. Central de Diagnóstico Veterinário, Universidade Federal do Pará, Rua Maximino Porpino da Silva 1000, Pirapora, Castanhal, PA 68743-080, Brazil. E-mail: diomedes@ufpa.br The objective of the study was to verify the sensibility of buffaloes to the poison of Crotalus durissus terrificus and to study the clinical-pathological picture in buffaloes in comparison with the one in cattle. The subcutaneous inoculation of the liofilized poison of the snake, diluted in 1ml of physiologic solution, was done in the area of the humerus-radio-ulnar joint of three buffaloes at doses of 0.015, 0.03 and 0.066mg/kg, and of two cattle at doses of 0.03 and 0.066mg/kg. The buffalo that received the 0.03mg/kg dose presented severe clinical signs but recovered six days later. The bovine that received the same dose, died after a clinical course of 22h56min. The 0.066mg/kg dose caused death of the bovine as also the buffalo, with a clinical course of 4h23min and 8h12min, respectively. The buffalo that received the 0.015mg/kg dose recovered, after a course of 48 hours. The buffalo that died, showed clinical signs from 3h58min on, and the buffaloes that showed symptoms from 17h25min and 24h00min after inoculation of the venom, but recovered. In the two cattle that died (with doses of 0.03 and 0.066mg/kg), the first clinical signs occurred 6h10min and 6h31min after the inoculation of the venom. The inoculation produced in the buffaloes and cattle nervous symptoms of flaccid paralysis. The main signs observed in the buffaloes as well as the cattle, were slight volume increase at the site of inoculation, respiration difficulties characterized by predominantly abdominal breathing, apathy, sialorreia, difficulty to get up when stimulated, evolution to sternal decubitus followed by lateral decubitus with peddling movements of the legs, and decrease of the reflexes related to the cranial nerves. The buffaloes showed also augmentation of the sustentation base, dragging of the hooves of the hind legs, slow and staggering gait, difficulty in apprehension of the food, The cattle showed additionally paralysis of the eyeballs, revealed through non-exhibition of the sclera during head rotation in latero-caudal direction. Laboratory exams revealed in the cattle and the buffaloes leucocytosis by neutrofilia, and in the biochemistry series, increase in the levels of alanine aminotransferase, aspartato aminotransferase, creatinaquinase and lactic dehydrogenase. There was no alteration in the urinalysis nor in the activation time of protrombine and in the time of partially activated tromboplastin. Necropsy only evidenced slight edema corresponding to the inoculation site in one bovine. Histopathological examination revealed picnosis of the epitelial cell nuclei of some kidney tubules in the cortex (in the buffalo and in one bovine) and slight vacuolation of hepatocites (in one bovine).

• Crotalic poisoning Crotalus durissus terrificus snakebite accident nvenenamento crotálico acidente ofídico

Abstract in Portuguese:

RESUMO.- Barbosa J.D., Sousa M.G.S., Tokarnia C.H., Brito M.F., Belo Reis A.S., Bomjardim H.A., Lopes C.T.A. & Oliveira C.M.C. 2011. [Comparison between the clinical and pathological picture in the experimental poisoning by crotalic venom.] Quadro clínico-patológico do envenenamento crotálico experimental em bubalinos comparado com o de bovinos. Pesquisa Veterinária Brasileira 31(11):967-973. Central de Diagnóstico Veterinário, Universidade Federal do Pará, Rua Maximino Porpino da Silva 1000, Pirapora, Castanhal, PA 68743-080, Brazil. E-mail: diomedes@ufpa.br O estudo teve por objetivo verificar a sensibilidade dos bubalinos à peçonha de Crotalus durissus terrificus, estudar o quadro clínico-patológico e laboratorial nessa espécie e estabelecer comparações com o verificado em bovinos. A inoculação do veneno liofilizado de Crotalus durissus terrificus, diluído em 1ml de solução fisiológica, foi feita na região da articulação úmero-rádio-ulnar, por via subcutânea, em três bubalinos (doses de 0,015; 0,03; e 0,066mg/kg) e em dois bovinos (doses de 0,03 e 0,066mg/kg). O bubalino que recebeu a dose de 0,03mg/kg apresentou sinais clínicos graves recuperou-se seis dias após, e o bovino que recebeu a mesma dose morreu com evolução de 22h56min. A dose de 0,066mg/kg causou a morte tanto do bovino quanto do bubalino, com evolução clínica de 4h23min e 8h12min, respectivamente. O bubalino que recebeu a dose de 0,015mg/kg, recuperou-se com evolução de 48 horas. Os sinais clínicos tiveram início dentro de 3h58min no bubalino que morreu, e nos bubalinos que adoeceram mas se recuperaram, dentro de 17h25min e 24h00min após a inoculação do veneno. Nos dois bovinos que morreram (com doses de 0,03 e 0,066mg/kg), os primeiros sinais clínicos foram observados 6h10min e 6h31min após a inoculação do veneno. A inoculação do veneno produziu nos búfalos e bovinos um quadro nervoso de paralisia flácida. Os principais sinais observados tanto nos búfalos quanto nos bovinos, foram discreto aumento de volume no local da inoculação, dificuldade respiratória caracterizada por respiração predominantemente abdominal, apatia, sialorreia, dificuldade para se levantar quando estimulados, evolução para decúbito esternal permanente, seguido de decúbito lateral e movimentos de pedalagem, e diminuição dos reflexos relacionados aos pares de nervos cranianos. Nos bubalinos adicionalmente foi observado aumento da base de sustentação, arrastar das pinças dos membros posteriores, marcha lenta e cambaleante, dificuldade na apreensão dos alimentos; nos bovinos ainda foram observados paralisia do globo ocular, revelada através da não exposição da esclera durante a rotação da cabeça na direção latero-caudal. Tanto nos bovinos quanto nos bubalinos, verificou-se no leucograma, leucocitose por neutrofilia, e na bioquímica sérica, aumento nos níveis de alanina aminotransferase, aspartato aminotransferase, creatinaquinase e dehidrogenase láctica. Não houve alterações na urinálise, nem no tempo de ativação da protrombina e nem no tempo de tromboplastina parcial ativada. À necropsia evidenciou-se apenas discreto edema correspondente ao local da inoculação em um bovino. Os achados histopatológicos observados foram picnose nos núcleos de células epiteliais de alguns túbulos uriníferos no córtex renal (em um búfalo e um bovino) e fígado com leve vacuolização de hepatócitos (em um bovino).

Abstract in English:

ABSTRACT.- Ferreira Junior R.S., Siqueira A.K., Campagner M.V., Salerno T., Soares T.C.S., Lucheis S.B., Paes A.C. & Barraviera B. 2009. Comparison of wildlife and captivity rattlesnakes (Crotalus durissus terrificus) microbiota. [Comparação da microbiota de cascavéis (Crotalus durissus terrificus) de vida-livre e cativeiro.]Pesquisa Veterinária Brasileira 29(12):999-1003. Centro de Estudos de Venenos e Animais Peçonhentos, Universidade Estadual Paulista, Fazenda Experimental Lageado, Rua José Barbosa de Barros 1780, Botucatu, SP 18610-307, Brazil. E-mail: rseabra@cevap.org.br The study evaluated and compared the aerobic microbiota from the oral cavity, cloaca and venom of Crotalus durissus terrificus snakes, recently caught from the wild and kept under quarantine (WQ), individual captivity (IC) and collective captivity (CC). Antimicrobial drug effectiveness on isolated agents also was assayed. From group I, II and III were isolated, respectively, 29 (63.04%), 38 (90.48%) and 21 (42.86%) microorganisms from the cloaca; 15 (32.61%), 3 (7.14%) and 25 (51.02%) microorganisms from the oral cavity; and, 2 (4.35%), 1 (2.38%) and 3 (6.12%) microorganisms from venom. The most frequent bacteria were Pseudomonas aeruginosa, Proteus vulgaris and Morganella morganii, with sensitivity to amikacin, gentamicin, norfloxacin, sulfazotrin and tobramycin. Snakes kept in semi-open captivity exhibited the fewest microorganisms in oral cavities, perhaps due to the environment in captivity, with different temperature gradients, running water, absence of daily handling, circulating air, possibility of moving around, daily cleaning, and sunlight access.

• Cascavel Crotalus durissus terrificus

Abstract in Portuguese:

RESUMO.- Ferreira Junior R.S., Siqueira A.K., Campagner M.V., Salerno T., Soares T.C.S., Lucheis S.B., Paes A.C. & Barraviera B. 2009. Comparison of wildlife and captivity rattlesnakes (Crotalus durissus terrificus) microbiota. Pesquisa Veterinária Brasileira 29(12):999-1003. Centro de Estudos de Venenos e Animais Peçonhentos, Universidade Estadual Paulista, Fazenda Experimental Lageado, Rua José Barbosa de Barros 1780, Botucatu, SP 18610-307, Brazil. E-mail: rseabra@cevap.org.br Este estudo avaliou e comparou a microflora aeróbica da cavidade oral, cloaca e veneno de serpentes Crotalus durissus terrificus recém-capturadas da natureza e mantidas sob quarentena (WQ), mantidas em cativeiro coletivo (CC) e em cativeiro individual (IC). A eficácia de drogas antimicrobianas de agentes isolados foi também avaliada. Foram isolados microorganismos dos grupos I, II e III respectivamente: 29 (63.04%), 38 (90.48%) e 21 (42.86%) da cloaca; 15 (32.61%), 3 (7.14%) e 25 (51.02%) da cavidade oral, e finalmente 2 (4.35%), 1 (2.38%) e 3 (6.12%) do veneno. As bactérias mais frequentes foram Pseudomonas aeruginosa, Proteus vulgaris e Morganella morganii, com sensibilidade para amikacina, gentamicina, norfloxacina, sulfazotrina e tobramicina. Serpentes mantidas no cativeiro semi-aberto mostraram menor número de agentes infecciosos em cavidade oral, talvez devido ao ambiente de cativeiro com diferentes gradientes de temperatura, água corrente, ausência de manejo diário, ampla circulação de ar, possibilidade de movimentação pelos animais, limpeza diária e acesso ao Sol.

Abstract in English:

ABSTRACT.- Fonteque J.H., Kohayagawa A., Takahira R.K., Bianchi E.H., Cherubini A.L., Piccinin A., Bruder E.M. & Ramos P.R.R. 2009. [Serum protein electrophoresis profile of the rattlesnake Crotalus durissus terrificus kept in captivity.] Perfil eletroforético das proteínas séricas de serpentes Crotalus durissus terrificus (cascavel) criadas em cativeiro. Pesquisa Veterinária Brasileira 29(6):457-460. Departamento de Medicina Veterinária, Hospital de Clínica Veterinária, Centro de Ciências Agroveterinárias, Universidade do Estado de Santa Catarina, Av. Luiz de Camões 2090, Lages, SC 88520-000, Brazil. E-mail: fonteque@cav.udesc.br The poisonous snakes of the genera Crotalus and Bothrops have been kept in captivity with the purpose of extracting poison for the production of immunobiological. Knowledge of the physiology of these animals and serum proteins concentration changes are important for early identification of major diseases which lead to states of hypoproteinemia and hyperproteinemia. The objective was to determine the concentration of total protein and serum protein electrophoresis profile of Crotalus durissus terrificus (rattlesnake) in captivity. Blood samples were taken from the ventral coccygeal vein of 21 adult and healthy snakes divided into groups: Group 1 with 12 males, weighing in average 588.89±193.55g, and Group 2 with nine females, weighing in average 708.33±194.04g. The total serum concentration of protein was determined by the method of refractometry and agarose gel electrophoresis. The total protein values in the serum for females was 4.82±0.72, for males 4.51±0.50 and males and females 4.64±0.61, identified by four fractions (g/dL): albumin, a, b and g-globulin. Additionally the albumin/globulin ratio was calculated. The female snakes showed higher values for the variables, albumin and the albumin/globulin (AG) differed significantly (P<0.05) from the group of male snakes, but there was no clinical significance.

• Protein fractions albumin alpha beta and gamma-globulin sex agarose gel

Abstract in Portuguese:

ABSTRACT.- Fonteque J.H., Kohayagawa A., Takahira R.K., Bianchi E.H., Cherubini A.L., Piccinin A., Bruder E.M. & Ramos P.R.R. 2009. [Serum protein electrophoresis profile of the rattlesnake Crotalus durissus terrificus kept in captivity.] Perfil eletroforético das proteínas séricas de serpentes Crotalus durissus terrificus (cascavel) criadas em cativeiro. Pesquisa Veterinária Brasileira 29(6):457-460. Departamento de Medicina Veterinária, Hospital de Clínica Veterinária, Centro de Ciências Agroveterinárias, Universidade do Estado de Santa Catarina, Av. Luiz de Camões 2090, Lages, SC 88520-000, Brazil. E-mail: fonteque@cav.udesc.br The poisonous snakes of the genera Crotalus and Bothrops have been kept in captivity with the purpose of extracting poison for the production of immunobiological. Knowledge of the physiology of these animals and serum proteins concentration changes are important for early identification of major diseases which lead to states of hypoproteinemia and hyperproteinemia. The objective was to determine the concentration of total protein and serum protein electrophoresis profile of Crotalus durissus terrificus (rattlesnake) in captivity. Blood samples were taken from the ventral coccygeal vein of 21 adult and healthy snakes divided into groups: Group 1 with 12 males, weighing in average 588.89±193.55g, and Group 2 with nine females, weighing in average 708.33±194.04g. The total serum concentration of protein was determined by the method of refractometry and agarose gel electrophoresis. The total protein values in the serum for females was 4.82±0.72, for males 4.51±0.50 and males and females 4.64±0.61, identified by four fractions (g/dL): albumin, a, b and g-globulin. Additionally the albumin/globulin ratio was calculated. The female snakes showed higher values for the variables, albumin and the albumin/globulin (AG) differed significantly (P<0.05) from the group of male snakes, but there was no clinical significance.

Abstract in English:

ABSTRACT.- Graça F.A.S., Peixoto P.V., Coelho C.D., Caldas S.A. & Tokarnia C.H. 2008. [Clinical and pathological aspects of experimental Crotalus poisoning in cattle.] Aspectos clinicos e patológicos do envenenamento crotálico experimental em bovinos. Pesquisa Veterinária Brasileira 28(6):261-270. Projeto Sanidade Animal Embrapa/UFRRJ, Seropédica, RJ 23890-000, Brazil. E-mail: flaviograca@uol.com.br Crotalus poisoning was experimentally reproduced by subcutaneous inoculation of Crotalus durissus terrificus (South American rattlesnake) venom into 10 clinically healthy mixed bred 12 to 36-month-old cattle, weighing 125 to 449 kg. Two animals were used as controls. The animal that received a dose of 0.03mg/kg body weight died 7h40min after inoculation. A 0.015mg/kg dose provoked death in 4 out of 7 young oxen. Two animals given 0.0075mg/kg became slightly sick and recovered. Onset of symptoms occurred from 1h30min to 13h45min after inoculation. The clinical course varied from 5h25min to 45h for animals that died, and from 33h15min to 17 days for animals that recovered. The main nervous signs observed were diminished response to external stimuli, hypotonic reflexes, dragging of the hooves, apathy, difficulties in moving around obstacles, ocular globe paralysis, lateral and sternal decubitus, and tongue paralysis. Adipsia and sometimes petechiae in the conjunctival and vaginal mucosa were observed. A slight to moderate increase in bleeding time was noted in 6 animals, and a moderate increase in partial thromboplastin time was found in 7 others. Moderate leukocytosis with neutrophilia, relative lymphopenia, eosinopenia, and monocytosis was found. There was a significant increase in creatine kinase serum levels of a ten-fold order. No significant alterations were revealed by urinalysis. Necropsy revealed minimal edema at the inoculation site, few petechiae and equimoses in the epicardium, omentum, biliary vesicle and bladder mucosa of some animals. Histopathological examination revealed necrosis (hyalinization) of groups or isolated myocytes in different muscles examined, both near and far from the inoculation site, in all animals. The diagnosis of Crotalus poisoning and its differentiation from diseases causing paralysis and muscular necrosis in cattle in Brazil are discussed.

• Poisoning Crotalus durissus terrificus cattle snake bite

Abstract in Portuguese:

ABSTRACT.- Graça F.A.S., Peixoto P.V., Coelho C.D., Caldas S.A. & Tokarnia C.H. 2008. [Clinical and pathological aspects of experimental Crotalus poisoning in cattle.] Aspectos clinicos e patológicos do envenenamento crotálico experimental em bovinos. Pesquisa Veterinária Brasileira 28(6):261-270. Projeto Sanidade Animal Embrapa/UFRRJ, Seropédica, RJ 23890-000, Brazil. E-mail: flaviograca@uol.com.br Crotalus poisoning was experimentally reproduced by subcutaneous inoculation of Crotalus durissus terrificus (South American rattlesnake) venom into 10 clinically healthy mixed bred 12 to 36-month-old cattle, weighing 125 to 449 kg. Two animals were used as controls. The animal that received a dose of 0.03mg/kg body weight died 7h40min after inoculation. A 0.015mg/kg dose provoked death in 4 out of 7 young oxen. Two animals given 0.0075mg/kg became slightly sick and recovered. Onset of symptoms occurred from 1h30min to 13h45min after inoculation. The clinical course varied from 5h25min to 45h for animals that died, and from 33h15min to 17 days for animals that recovered. The main nervous signs observed were diminished response to external stimuli, hypotonic reflexes, dragging of the hooves, apathy, difficulties in moving around obstacles, ocular globe paralysis, lateral and sternal decubitus, and tongue paralysis. Adipsia and sometimes petechiae in the conjunctival and vaginal mucosa were observed. A slight to moderate increase in bleeding time was noted in 6 animals, and a moderate increase in partial thromboplastin time was found in 7 others. Moderate leukocytosis with neutrophilia, relative lymphopenia, eosinopenia, and monocytosis was found. There was a significant increase in creatine kinase serum levels of a ten-fold order. No significant alterations were revealed by urinalysis. Necropsy revealed minimal edema at the inoculation site, few petechiae and equimoses in the epicardium, omentum, biliary vesicle and bladder mucosa of some animals. Histopathological examination revealed necrosis (hyalinization) of groups or isolated myocytes in different muscles examined, both near and far from the inoculation site, in all animals. The diagnosis of Crotalus poisoning and its differentiation from diseases causing paralysis and muscular necrosis in cattle in Brazil are discussed.