Accidental and experimental Closantel intoxication in Uruguayan sheep

Rivero, Rodolfo; Matto, Carolina; Soares, Mauro Pereira; Adrien, María de Lourdes

doi:10.1590/s0100-736x2015000700001

Cited by 9 publications

(7 citation statements)

References 12 publications

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“…Neurological clinical signs are predominant in this disease, and blindness is frequently observed. Characteristic histopathological changes are also observed, such as myelin edema in the nervous system and optic nerve (FURLAN et al, 2009;RIVERO et al, 2015). Closantel was not administered to the goats in the studied case.…”

Section: Discussionmentioning

confidence: 92%

Outbreak of salt poisoning in goats in the state of Pará, Brazil

Duarte

Júnior

Bomjardim

et al. 2019

SCA

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The present study reports two outbreaks of salt poisoning in goats on a property in the state of Pará, Brazil. The outbreaks occurred in July and August 2011 when young and adult goats received a mineral mixture after approximately three days of restriction from the supplement. The animals were kept in barns with a high stocking density and had an inadequate supply of water. In the second outbreak, the goats were supplemented too with brewery residue added to 3.3% of the mixture mineral. From a flock of 191 goats, 12 animals (nine crossbreeds, two Anglo-Nubians and one Boer) showed nervous symptomatology, and the morbidity rate was 6.28%. The most frequent clinical signs were head lowering, head tilt, muscle weakness, mydriasis and ataxia. Three goats died, four recovered spontaneously from the first outbreak, and five recovered from the second outbreak over three days after treatment with dexamethasone, thiamine and gradual water supply. The lethality rate was 25%. In two animals, necropsy was performed, and no macro- or microscopic alterations in the nervous system or other organs were observed. These negative pathological findings indicate that the neurological clinical signs were initiated by functional disturbances in the central nervous system. In the brain, a high sodium concentration (3703 and 3675 ppm), compared with the reference values for cattle was detected. Normonatremia was observed in the sick goats, and hypernatremia was observed in the goats from the same lot of affected animals based on blood serum samples obtained before the first outbreak. These results pointed out that the goats were consuming high sodium concentrations. Normal values for the sick animals were assigned after rapid osmotic control via adequate water intake. We conclude that the salt poisoning on the goats occurred due to a high intake of the mineral mixture caused by management errors and associated with water restrictions.

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Section: Discussionmentioning

confidence: 92%

Outbreak of salt poisoning in goats in the state of Pará, Brazil

Duarte

Júnior

Bomjardim

et al. 2019

SCA

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“…The mechanism of closantel poisoning remains poorly understood in sheep; nevertheless, some previous studies suggest that ocular lesions are associated with optic neuropathy following retinal edema [10,11,17]. Edema leads to the degeneration of ganglia cells, reflecting in the toxic effect on neurons.…”

Section: Discussionmentioning

confidence: 99%

“…Edema leads to the degeneration of ganglia cells, reflecting in the toxic effect on neurons. Moreover, axonal lesions in the optic nerve may occur [17,19]. Other mechanisms which may be involved in lesion development include optic nerve compression within the bone structures of the optic canal and the rupture of cells and compacted cell membrane layers, these are associated with retinopathy, myelin edema and white matter vacuolation [11,16].…”

Section: Discussionmentioning

confidence: 99%

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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“…This paper presents Closantel intoxication with its clinical findings and outcome in sheep. Accidental poisoning occurs when a drug get ingested at a rate 2-6 times higher than recommended dose (Rivero et al, 2015).…”

Section: Issn: 2319-7706 Volume 7 Number 10 (2018)mentioning

confidence: 99%