Intoxicação por Poiretia punctata em ruminantes e megasôfago de provável origem tóxica em ruminantes.

Abstract

In Brazil there are 131 species and 79 genera of toxic plants and this number increases permanently. In the Northeastern region, plant poisonings are very important because there is a extended dry season and many farmers raise sheep, goats and cattle in native or cultivated pastures in extensive or semi-extensive systems. Outbreaks can occur in several situations that depend on access to the plant site, palatability, social facilitation, hunger, ingestion period and toxic doses, among others. The negative impact caused by plant poisoning in livestock justifies the development in the last decades a lot of research to characterize the epidemiology of these intoxications and to develop technologies for their control and prophylaxis. This dissertation consists of two original articles: the first submitted to Toxicon, describes the poisoning Poiretia punctata in sheep and cattle in the state of Sergipe. P. punctata is a legume, popularly known as " pela bucho ", described by producers as responsible for poisonings and deaths of cattle and sheep in the state of Sergipe. Nine properties were visited to collect clinical and epidemiological data, between 2010 and 2012. Usually the animals were found dead or have died after a clinical course of up to 18 hours. The clinical signs were observed when the staggering gait and sudden falls, often followed by death. The disease has been reproduced experimentally in two sheep receiving 40 g/kg body weight and showed apathy, staggering gait and loss of balance, ataxia, increased support base and head down, engorgement of jugular falls mandibular trismus, opisthotonos, nystagmus progressing to sternal recumbency lateral recumbency and paddling. The clinical course of the animals died after 3 and 8 hours, respectively. Two animals that received 20g/kg of body weight, showed apath, anorexia and remained lying down looking to the side recovering later. No gross or histological lesions of significance were found. It is concluded that P. punctata is a toxic plant that causes death in sheep and cattle in the state of Sergipe. The second article reports submitted to Rural Science collective cases of megaesophagus in sheep, goats and cattle in the state of Paraíba. Megaesophagus is a rare disease in ruminants characterized by regurgitation of rumen contents. This paper describes two outbreaks of megaesophagus in sheep and goats cattle. On a farm in the municipality of Ibiara 18 cases of megaesophagus in cattle occurred, with 12 deaths, in a herd of 200 animals. In another farm two cases in sheep and in goats, a herd of 50 goats and 40 sheep, all breeding males occurred. All animals showed regurgitation of rumen contents and weight loss, but the evolution of the disease was different, while goats and sheep showed a chronic form, an increase of several months, the cattle have an acute form, an increase of 3-8 days. In necropsy all animals showed megaesophagus. Histological examination showed segmental muscle necrosis in the esophagus and skeletal muscles. Epidemiological data and pathology suggested that the disease could have been caused by some toxic plant, but not known plants have been found to cause segmental muscle necrosis in areas where the disease occurred.