This study reports poisoning in sheep wich have received two applications of closantel in therapeutic dosage (7.5mg/kg) within a preestablished 28-day period for effectiveness formulation. A high percentage of efficiency was observed after the first and second treatment, but around 72 hours after the second administration of closantel (D30), three sheep have showed mild apathy, anorexia, diarrhea, bilateral blindness, and dilated pupils without reaction. These three animals, were observed in the following 250 days, and the bilateral blindness remained. Numerous reports of animals poisoned by closantel emphasize that overdose and/or nutritional status of the animals are key factors to occur poisoning due closantel administration. However, in this experiment the signs of poisoning (mild apathy, anorexia, diarrhea and ophthalmic disturbance), observed in the three clinically healthy sheep, occurred when they received two applications of closantel (7.5mg/kg), in a interval of 28 days, highlighting the fact of obtaining a cumulative residual effect of closantel in the animal organism, caused by two consecutive applications, may also be a predisposing factor for sheep to demonstrate irreversible signs of intoxication.
Closantel; efficacy; poisoning; sheep; retina
