Recurrent Incidence of Marek's Disease in Native Breed Chickens

The present paper is a report on outbreak of visceral (acute) form of Marek's disease (MD) in 12 week-old non-descriptive chickens reared for meat purpose on two occasions in two different focks. Economic losses due to visceral form of MD caused by very virulent MD virus are very huge due to mortality despite preventive vaccination carried out at hatch. Chickens of native breeds are believed to be resistant for various diseases including MD. Desi chicken fock comprising 2000 birds which was not vaccinated showed sudden mortality upto four to fve birds a day after 12 weeks of age on both occasions. Gross and histopathological lesions were suggestive of MD and nucleic acid of serotype 1 of MD virus was identifed by PCR. It can be concluded that resistance expressed by native breeds of chicken to various diseases could be compromised even if they are properly housed. It is recommended to administer bivalent vaccination at hatch together with biosecurity at farm for prevention of MD in desi chickens. Such occurrences also underline the need of adoption of ‘all-in-all-out’ system of management for effective disease prevention in desi chickens.