PRAJAPATI, K. S.DAVE, PURNIMA N.2018-06-142018-06-141989http://krishikosh.egranth.ac.in/handle/1/5810052983Outbreaks of acute form of Marek's disease were studied in five successive flocks (AKP, RBCP, AICRP, CPRS and RRS)of WIfi birds at Poultry Complex of Gujarat Agricultural University, Anand. Study was carried out on pathological and serological aspects of acute MD. Daily mortality due to MD was recorded from 11th week onwards to 45 weeks of age in a l l the five flocks. Maximum mortality of 32.09 per cent was observed in the AKP flock. The mortality was higher in the male birds than the female birds in RBCP flock while the mortality was more in the female birds than the male birds in RRS flock. No significant difference was noticed between the sexes in r e s t of the flocks. Liver was most frequently grossly affected organ in all the five flocks. The gross lesions were of nodular or diffuse type in nature. The microscopto picture was essentially the same in the various visceral organs and tissues with characteristic pleomorphic lymphoid cell proliferation. Nuclear inclusions were clearly evident in the FFE of the skin stained by Page Green stain. Impression smears prepared from nodular growths of ovary revealed characteristic infrequent pyroninophilic lymphoblasts, Serological studies showed 40 to 90 per cent seroprevalence in various flocks while FF showed 100 per cent positive reactions in all the five flocks.enPATHOLOGYA STUDYThesis