Spontaneous poisoning by larvae of Perreyia flavipes in cattle from the State of Santa Catarina, Brazil

摘要

> size="2" face="Verdana, Arial, Helvetica, sans-serif">This article describes an outbreak of Perreyia flavipes poisoning in August of 2006 in a cattle herd of 280 animals in Sombrio, Santa Catarina, southern Brazil. Seventeen bovines between 1 and 2 years old from one herd of 77 mixed breed cattle died. The herd was kept in a paddock of 90 hectares (P1) for 30 days. After de first two deaths occurred, the herd was transferred to a second paddock (P2), and 15 more animals died in the next 5 days. Samples from 6 of these animals were analyzed. During the necropsy, hemorrhage was seen in the subcutaneous tissue, abomasal mucosa, and subepicardial area. The animals presented ascites and edema of the abomasal folds, duodenum, pancreas, and gallbladder. The liver was yellowish, had subcapsular petechial hemorrhages, and accentuated lobular pattern. P. flavipes larval body fragments and heads were found in the rumen content of three of the animals. In the histological examination the liver showed hepatocellular tumefaction, diffuse coagulative necrosis of centrilobular and midzone hepatocytes, hemorrhage and centrilobular congestion. Lymphoid depletion and diffuse necrosis of germinative centers of lymphoid follicles in mesenteric lymph nodes, Peyer’s patches and spleen were also observed. The diagnosis of intoxication by P. flavipes larvae in this outbreak was based on the epidemiological data, necropsy, and histological findings. The confirmation of P. flavipes larvae as cause of the outbreak was done by the observation of intact larvae and remnants in the ruminal content of the necropsied bovines and by the presence of a great number of larvae clusters in the paddock 1 (P1).