Alterações oftálmicas associadas à intoxicação experimental por closantel em caprinos

Ecco, Roselene; Barros, Claudio S.L.; Graça, Dominguita Lühers

doi:10.1590/s0102-09352008000100007

Cited by 8 publications

(5 citation statements)

References 14 publications

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“…According to the literature, blindness is the primary clinical sign presented in animals intoxicated by Closantel as observed in the outbreak presented here, followed in some cases by ataxia and the death of some animals (Gill et al 1999, Barlow et al 2002, Van der Lugt & Venter 2007, Ecco et al 2008, Furlan et al 2009). In this accidental case, there were no deaths in the affected sheep probably because of the acute intoxication, consistent with findings by other authors (Borges et al 1999, Gill et al 1999, Furlan et al 2009); this could be related to the dose utilized.…”

Section: Ultrastructural Studymentioning

confidence: 56%

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Accidental and experimental Closantel intoxication in Uruguayan sheep

et al. 2015

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An outbreak of Closantel intoxication in sheep in Uruguay is described. The outbreak occurred in a group of 1300 weaning lambs treated orally with a 10% solution of Closantel. One hundred forty eight lambs showed clinical signs of intoxication and 14 died. The clinical signs included mydriasis, nystagmus, and negative pupillary reflex, bilateral blindness, bump into objects, and lateral movement of the head. No macroscopic lesions were observed. The histological lesions of the retina were cytoplasmic vacuolization in ganglion cells and in cells of the inner and outer nuclear layers with different degrees of atrophy. Vacuolization and axonal degeneration were observed in the optic nerve, with multifocal areas of fibrosis and infiltration by lymphocytes and Gitter cells. To reproduce the intoxication, four sheep were given two, four and 10 times the therapeutic dose of Closantel (0.1g/kg of BW). Only the animals receiving 10 times the recommended dose showed clinical signs. The histological examination of the lesions in experimental sheep showed similar results to those described in the accidental outbreak, except for the absence of optic nerve fibrosis and inflammation, characterizing an acute phase. Axonal myelin sheaths loss, fibroblasts and collagen fibers were observed in the ultrastructural study of the optic nerve of accidental intoxicated animals. The optic nerve of experimentally intoxicated animals had vacuoles that separated the myelin sheaths of axons. To prevent outbreaks it is suggested to weigh the animals before Closantel administration to avoid errors in dose calculation.

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Section: Ultrastructural Studymentioning

confidence: 56%

“…This drug is toxic to many species, including dogs (McEntee et al 1995), sheep and goats (Gill et al 1999, Barlow et al 2002, Van der Lugt & Venter 2007, Ecco et al 2008. A combination of Closantel and albendazole was also reported to be toxic for sheep and goats (Obwolo et al 1989).…”

Section: Introductionmentioning

confidence: 99%

Accidental and experimental Closantel intoxication in Uruguayan sheep

et al. 2015

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“…Experimento posterior a esse surto detalhou as alterações oftálmicas associadas à intoxicação experimental por closantel em caprinos (Ecco et al 2008). Outro surto com aspectos epidemiológicos e clínico-patológicos semelhantes foi descrito em Santa Catarina (Furlan et al 2009).…”

Section: Discussionunclassified

Doenças de caprinos diagnosticadas na região Central no Rio Grande do Sul: 114 casos

et al. 2013

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Foi realizado um estudo retrospectivo dos arquivos do LPV-UFSM e examinados os laudos de necropsias de caprinos realizadas num período de 48 anos (1964 a 2011). Foram analisados 114 laudos de necropsias de caprinos. Deste total, 95 (83,33%) tinham diagnóstico conclusivo e 19 (19,66%) tinham diagnóstico inconclusivo. Dos 95 casos conclusivos, as doenças infecciosas e parasitárias foram as mais prevalentes, seguidas em ordem decrescente de prevalência, pelas doenças metabólicas e nutricionais, intoxicações e toxi-infecções e alterações do desenvolvimento. Outras alterações de diferentes naturezas e etiologias que não se enquadravam nos grupos de doenças acima afetaram cerca de 10% dos caprinos examinados. A hemoncose foi a principal causa de morte de caprinos na área de abrangência do LPV-UFSM. Eimeriose e listeriose também foram causas importantes de morte. Dentre as doenças metabólicas e nutricionais, urolitíase, osteoporose, toxemia da prenhez, desnutrição e doença dos músculos brancos foram as mais prevalentes. Principalmente as doenças infecciosas e parasitárias e as metabólicas e nutricionais ocorreram muitas vezes na forma de surtos, acarretando maiores perdas econômicas associadas.

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“…Plant intoxications should be included as a differential diagnosis in the present case [20]. Retinal degeneration and atrophy, without optic nerve alterations, have been reported in cases of Pteridium arachnoideum (bracken fern) poisoning; however, this pathological presentation has never been recorded in Brazil [7,12,21]. In the present study, no plants associated with such condition were observed in the grazing area where sheep were kept.…”

Section: Discussionmentioning

confidence: 45%

Accidental Closantel Poisoning in Sheep in the State of Rio Grande do Sul - Brazil

Pohl

Lorenzett

Cecco

et al. 2020

Acta Scientiae. Vet.

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Background: Verminosis is one of the major health problems in sheep flocks, and is one of the main causes of death in sheep worldwide. Closantel is an antiparasitic drug commonly used in sheep; however, its safety margin is narrow, and this drug may induce intoxication in animals submitted to high doses. Lesions occur mainly in the eyes, and are characterized by edema and compression of the optic nerve, retinopathy, and severe degeneration of ganglia cells. Clinical signs are pupil dilation, which often lead to permanent blindness. This work aims to report an outbreak of sheep mortality due to closantel intoxication, associated with inadequate anthelmintic administration practices.Case: An on-site visit was conducted to a sheep farm, located in the municipality of Osório, Rio Grande do Sul (RS), in which high mortality was reported. The flock consisted of approximately 300 Texel sheep, managed in an extensive grazing system. Lambs and adult animals were affected. According to the information provided by the farm owner, many animals presented clinical signs of haemonchosis, and a closantel dose of 20 mg / lamb was administered in all sheep, regardless of body weight. Lambs weighted on average 13 kg. After closantel administration, several sheep presented neurologic signs and died. At the clinical examination, sheep presented pallor of ocular mucous membranes, as well as submandibular edema. Also, 20 lambs showed signs of blindness, disorientation and bumping into objects, as well as hypothermia and lack of response to the menace reflex. Three 30 to 45-day-old male lambs that died spontaneously were submitted for necropsy. Grossly, only mild ascites was noted. Histopathological examination of the retina showed degeneration and fragmentation of photoreceptor layer as well as depletion of the inner nuclear layer, associated with pyknosis and karyorrhexis. There was also a reduction in the number of ganglia cells in the ganglion cell layer and atrophy and vacuolization in the outer plexiform layer. In the optic nerve, multifocal mild to moderate vacuolization was observed. Diffuse perineural and perivascular edema were observed in the brain, predominantly in the grey matter. In the encephalon of one of the lambs, multifocal vacuolization was observed, which was also evidenced at the junction of the white and gray matter of the telencephalon, and in the white matter of the cerebellum. In the trigeminal ganglia, moderate multifocal vacuolization was noted in the perikaryon of neurons. Furthermore, the spinal cord had moderate multifocal vacuolization at the junction of white and gray matter.Discussion: The diagnosis of closantel intoxication in sheep was based on the clinical history and histopathological findings. The association of these data is crucial to suspect and confirm the diagnosis of this type of intoxication. Closantel is an anthelmintic drug widely used in sheep, and in correct doses may be very effective, but when used in doses higher than recommended may lead to irreversible lesions. The optical damage is derived from edema which leads to degeneration of ganglia cells and injury to the optic nerve. Another proposed mechanism is related to optic nerve compression causing rupture and edema of retinal structures. Lesions tend to be dose related, and poisoning usually occurs when treating groups of animals based on the weight of the heaviest animal. Clinical signs of blindness and pupil dilatation are usually seen. There is no effective treatment for reversion of this condition; therefore, prevention based on correct calculation of anthelmintic dose is pivotal. The epidemiological examination, clinical signs and anatomopathological examination were extremely important to make the final diagnosis of this intoxication.

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Alterações oftálmicas associadas à intoxicação experimental por closantel em caprinos

Cited by 8 publications

References 14 publications

Accidental and experimental Closantel intoxication in Uruguayan sheep

Accidental and experimental Closantel intoxication in Uruguayan sheep

Doenças de caprinos diagnosticadas na região Central no Rio Grande do Sul: 114 casos

Accidental Closantel Poisoning in Sheep in the State of Rio Grande do Sul - Brazil

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