Detection and isolation of Duck Plague virus from field outbreaks in Assam, India

Abstract

Duck plague is an acute, contagious and lethal disease of ducks caused by an enveloped DNA virus, belonging to Anatid Herpes Virus 1 under genus Mardivirus, subfamily Alphaherpesvirinae, family Herpesviridae. The disease is characterized by sudden death, high mortality, hemorrhages and necrosis in the internal organs. Duck farming plays an important role in the livelihood of the farmers of Assam. Duck Plague being the major killer disease among duck population of Assam, posing a threat to the growth of duck farming in the state. The present report investigates various outbreaks of Duck plague in Assam, detection and isolation of the virus. A total of 29 outbreaks suspected for Duck Plague were attended in different districts of Assam and 380 numbers of samples comprising of both clinical (n=107) as well as post mortem (n=273) were collected. Presence of DPV in samples was detected by Sandwich-ELISA (S-ELISA) and amplification of UL 44.5 as well as DNA polymerase gene of DPV by PCR. Out of 380 samples collected from 29 outbreaks, 213 (56.05%) and 299 (78.68%) samples were found positive for presence of DPV by S-ELISA and PCR, respectively. Pooled positive samples from various outbreaks were processed for isolation of duck plague virus in DEF primary cell culture. DPV field strain produced CPE comprising of rounding of cells, formation of syncytia, marked cytoplasmic granulations and intracellular vacuoles.