Acute fatal fascioliasis in sheep in Kinangop district, Nyandarua District of Kenya.

摘要

An outbreak of acute fascioliasis in sheep occurred on 3 farms in the Kinangop division of Nyandarua District, Kenya, during August-October 1992 with mortality rates of 5, 23.3 and 55%, respectively. Clinical aspects included anaemia, weakness and loss of appetite and some animals also had laboured breathing. All sheep that died had ascites and enlarged and congested livers with numerous haemorrhagic areas beneath the capsule. There was hydrothorax in 90% of the cases, and 50% showed peritonitis with fibrin deposits on the liver capsules. Cut sections of the liver showed numerous openings which exuded a dark-red fluid and immature Fasciola parasites. Histologically, hepatic lesions consisted of sections of parasites, extensive haemorrhage, necrosis of hepatocytes and proliferation of bile ducts. There were fibrin deposits and infiltration by eosinophils, neutrophils, lymphocytes and macrophages. In cases with laboured breathing, the lungs were pale grossly, and histologically, there was atelectasis and thickening of the interalveolar walls with oedema, fibrin deposits and lymphocytic infiltration. Stilesia hepatica (in the liver) and Haemonchus contortus (in the abomasum) were found in low numbers in a few cases. On 2 farms, nitroxinil at 10 mg/kg reduced mortality and faecal egg counts for liver flukes to zero within 7 and 21-42 days, respectively. Oxyclozanide or albendazole at 15 and 5 mg/kg, respectively, had no significant effect on mortality but reduced faecal egg counts considerably on the third farm.