Pathological and molecular diagnosis of Marek's disease in Kamrupa chickens

Abstract

Marek's disease (MD) is an economically important lymphoproliferative disease of poultry caused by Gallid alphaherpesvirus 2. The present study investigated a suspected outbreak of MD in a flock of 12-week-old Kamrupa dual-purpose chickens through gross pathology, histopathology and molecular confirmation. Ten birds were subjected to postmortem examination. Gross lesions included emaciation with prominent keel bones, atrophied breast muscles, hepatomegaly with diffuse white nodular lesions, marked splenomegaly, pale nodular kidneys, thymic atrophy and haemorrhagic lesions in the proventriculus and gizzard. Histopathological examination revealed diffuse proliferation of pleomorphic lymphoid cells in the liver and spleen with loss of normal tissue architecture, while kidneys and proventriculus showed lymphomatous and lymphoproliferative lesions. For molecular confirmation, DNA extracted from representative tissues was subjected to PCR targeting the Meq gene. Amplification of the expected 400 bp product confirmed the presence of Marek's disease virus (MDV). Based on characteristic gross and microscopic lesions along with PCR confirmation, the outbreak was diagnosed as MD.