Doença tremorgênica em ruminantes e equídeos no semiárido da Paraíba

Abstract

Eight outbreaks of a tremorgenic disease are reported in ruminants and equidae in the semiarid region of the Brazilian state of Paraíba. Seven outbreaks occurred from July to December 2007, with highest frequency in September and October. Another outbreak was observed in February 2008. All outbreaks occurred during the dry season. The disease affected horses, mules, cattle and sheep. Clinical signs were staggering, hypermetria, ataxia, widebased stance and alertness. After being removed from pastures the animals recovered in a period of 3-4 days to two weeks, however when returned to the pasture clinical signs reappeared. One affected sheep was euthanized and necropsied. Gross and histologic lesions were not observed. Different grasses including Digitaria bicornis, Enteropogon mollis, Chloris virgata and Chloris barbata were present in the pastures where the disease occurred. In six farms the disease occurred in cultures of Opuntia ficcus-indica invaded by grasses and two in deforested native vegetation invaded by similar grasses. Two horses were fed ad libitum during seven days, mature forage collected in pastures where the disease occurred. One horse showed mild signs of the disease on the fifth day of consumption, but recovered one day later. These results suggest that the disease is associated with the ingestion of some graminae, probably Chloris spp. Previous reports mentioned the occurrence of a similar disease, between 1956 and 1962, in the semiarid region of Pernambuco, in pastures with Chloris orthonothon.