Aspectos clinicopatológicos e laboratoriais do envenenamento experimental por Bothrops moojeni e Bothropoides neuwiedi em ovinos

Abstract

Spontaneous envenoming by snake bite is described as a cause of death in domestic animals. However, there are just few information about the species of snake involved, course, and clinicopathological and laboratory findings. Thus, this work aimed to determine the clinicopathological and laboratory changes induced by Bothrops moojeni and Bothropoides neuwiedi snake venoms in sheep in order to provide additional information regarding snakebites in farm animals, to help establish the diagnosis of this condition. The lyophilized snake venoms were dissolved in 1 mL saline solution and administered in the subcutaneous right face of four sheep, at doses of 0.41 mg/kg and 0.82 mg/kg of the B. moojeni venom for two sheep, and 1.0 mg/kg of the B. neuwiedi venom for two sheep. Only the sheep which received the lowest dose (0.41 mg/kg) survived, but developed very severe clinical signs, similar to the others. First clinical signs were observed about 10 minutes after inoculation in all sheep. The course varied from two and four days. The clinical findings in all sheep were characterized by apathy, marked swelling of the face, of the ventral neck and esternal region, and mild swelling of the proximal portion of the forelimbs, as well as increased bleeding time, tachycardia, pale mucous membranes, and large quantity of undigested blood in the intestinal content. Laboratory exams showed mainly a reduction in serum protein and increased creatine kinase in all sheep. At necropsy, extensive hematomas were observed in the subcutaneous tissue of the areas of swelling. Besides petechiae, bruises and mild to moderate suffusions on the serosas of various organs, and blood mixed with intestinal content in the last portion of the rectum were observed. In addition to hemorrhages the main histopathological alteration was necrosis of skeletal muscle fibers and walls of the blood vessels next to the inoculation area. In this study, the increase of volume observed in the face, neck, esternal region and limbs of the sheep was constituted of blood.