Abstract

A ten year retrospective study (2000-2009) of Marek’s disease (MD) was conducted in the Veterinary Teaching Hospital, Ahmadu Bello University, Zaria. 3,039 different poultry diseases were recorded, MD represents 4.9%. 63% of MD was recorded in birds 10 to 20 weeks old, 9.3% in birds above 30 weeks and 2.0% in birds below ten weeks. MD occurred mainly during the pre-rainy to rainy seasons with a progressive yearly increase. Strong association existed between season and MD (p < 0.05), risk estimate was also relevant (OR-2.4). A clinical analysis of birds affected with MD over the years revealed uneven growth and progressive weight loss as major complaints; ruffled feathers and whitish-yellow diarrhea were the major observable signs. Major gross lesions were severe emaciation, thickened proventriculus and flabby heart with loss of coronary fats. Histopathology revealed focal to diffuse neoplastic lesions in the affected organs. MD mainly affected chickens aged 10 to 20 weeks. The disease is endemic and on the increase in Zaria and its environs. We recommend that an effective MD vaccination technique and schedule be established for this region, purchase of point of lay chickens for production should be discouraged and standard biosecurity measures must be enhanced in hatcheries and farms to prevent primary exposure.

Key words: Marek’s disease, occurrence, diagnosis, Zaria.