Closantel toxicosis of sheep and goats in Fars province

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Closantel is a halogenated salicylanilide with anthehelmintic activity in cattle and small ruminants. This drug binds strongly to plasma proteins in the blood, especially albumin and acts on parasites by interfering with synthesis of adenosine triphosphate (ATP) by cellular oxidative phosphorylation. Metabolic degeneration of this drug mainly occurs in the liver and 80 percent is eliminated in faces and 0.5 percent in urine. Closantel is extensively used for annually deworming programs by farmers especially in sheep and goat flocks in Fars province and accidental poisoning may occur. Four reports of sheep and goat toxicosis with closantel in Fars province were described. One episode occurred in Lar region; a farmer used closantel for his small herd, five times higher than the recommended dose. Eleven, six month to two year-old goats were poisoned. One of them died and the remaining had clinical signs of depression, salivation, blindness, inappetance and ataxia one day after medication. The second episode was occurred after common deworming program in a large herd in Eghlid region. Out of 332 sheep in different ages, twelve, three to six month-old lambs were showed clinical signs of toxicosis including blindness, mydriasis, opisthotonus, nystagmus and wide stance. The third episode observed in three adult Najdi goats that were treated by closantel in two times higher than the recommended dose. Two days after medication, all goats were blind, ataxic and hyperesthetic. The last episode occurred in a small flock of sheep and goat treated by closantel in 1.5 times higher than the recommended dose. Two goats and one sheep showed blindness. These reports describe the iatrogenic poisoning of sheep and goat with closantel and present the clinical finding associated with this toxicosis. The importance of history taking in clinical diagnosis of the toxicosis in these reports is confirmed.