An account of a recent outbreak of Marek's Disease in Kenya

Abstract

Data was collected from a number of flocks following an outbreak of Marek's disease in Thika, Kiambu and Nairobi, in 1997. Clinically, the disease presented as a rapid emaciation and depression followed by death. Weekly point and cumulative mortalities were calculated in two of the flocks. Postmortem examination revealed, initially, an atrophy of the bursa of Fabricious. Later, there were turmours in a proportion of the birds. The tumours were observed in the heart muscle, the liver, intestines, and bursa of fabricious. Later, there were tumours in a proportion of birds. The tumours were observed in heart muscles, the liver, intestines, bursa of Fabricious and the skin. There was swelling, oedema and frequently ulceration of the proventriculus. The spleen was usually spotted and enlarged. Microscopically, lesions consisted of a mixture of both proliferative and necrotic lesions the suspected contributory causative factors were high field infections pressure, failure to vaccinate, vaccination failure and lack of quarantine and other disease control measures. Failure to institute effective control measures against the disease is likely to seriously affect the poultry industry in the country.