author(s)
P Ponnusamy, T Lurthu Reetha, BSM Ronald, B Puvarajan and R Manickam

abstract
The present investigation was performed to find out the etiological agent in duck mortality in migratory flock by conventional and molecular methods. Around 150 ducks aged 10 months were maintained in Neivasal village, Orathanadu taluk, Thanjavur district. Sudden mortality with the history of dullness, depression and mucous discharge from the mouth were observed in the flock during the month of March 2017. On postmortem examination, necrotic foci in liver and hemorrhages in heart were found. Liver, heart and bone marrow samples from 5 dead birds were collected aseptically for bacteriological isolation and identification. Microscopic examination of colonies on sheep blood agar revealed gram negative, non-motile and non-spore forming coccobacilli or rod. Biochemically, the isolate was found to be positive for catalase, oxidase and indole. Further, Polymerase Chain Reaction (PCR) using Pasteurella multocida specific primers derived from KMT1 gene was employed and the isolate was confirmed as Pasteurella multocida by PCR. All 15 samples were found to be positive for Pasteurella multocida by conventional and molecular tests. Later, the isolate was subjected to sequence analysis and characterized as Pasteurella multocida. It is concluded that the disease outbreak in migratory ducks was diagnosed as Pasteurella multocida by conventional and molecular methods and phylogenetically closely related to duck isolates of Kerala.