title: Pock forming ability of fowl pox virus isolated from layer chicken and its adaptation in chicken embryo fibroblast cell culture.
abstract: OBJECTIVE
  The objective of the present study was to examine pock forming ability of field strain and vaccine strain of fowl pox virus (FPV) in chorioallantoic membrane (CAM) of embryonated chicken eggs and its adaptation in chicken embryo fibroblast (CEF) cell culture.
  
  
  METHODS
  Dry scabs were collected from 25 affected birds in glycerin-saline and preserved at 4°C until processed. Virus was isolated in 10-day-old embryonated chicken eggs by dropped CAM method. The identity of the virus is confirmed by clinical findings of affected birds, pock morphology and histopathology of infected CAM. In addition one field isolate and vaccine strain of FPV was adapted to CEF cell culture. CEF cell culture was prepared from 9-day-old embryonated chicken eggs.
  
  
  RESULTS
  Clinical symptoms observed in affected birds include pox lesion on comb, wattle, eyelids and legs, no internal lesions were observed. All field isolates produced similar findings in CAM. Pocks produced by field isolates ranged from 3 mm to 5 mm at the third passage while initial passages edematous thickening and necrosis of CAM was observed. Pocks formed by lyophilized strain were ranges from 0.5 mm to 2.5 mm in diameter scattered all over the membrane at the first passage. Intra-cytoplasmic inclusion bodies are found on histopathology of CAM. At third passage level, the CEF inoculated with FPV showed characteristic cytopathic effect (CPE) included aggregation of cells, syncytia and plaque formation.
  
  
  CONCLUSIONS
  FPV field isolates and vaccine strain produced distinct pock lesions on CAMs. Infected CAM showed intracytoplasmic inclusion bodies. The CEF inoculated with FPV field isolate as well as a vaccine strain showed characteristic CPE at third passage level.
authors.affiliation: Department of Veterinary Microbiology, College of Veterinary Science and Animal Husbandry, Anjora Durg, Chhattisgarh, India.
authors.forename: Varsha Rani
authors.initials: VR
authors.lastname: Gilhare
authors.affiliation: Department of Veterinary Microbiology, College of Veterinary Science and Animal Husbandry, Anjora Durg, Chhattisgarh, India.
authors.forename: S D
authors.initials: SD
authors.lastname: Hirpurkar
authors.affiliation: Department of Veterinary Microbiology, College of Veterinary Science and Animal Husbandry, Anjora Durg, Chhattisgarh, India.
authors.forename: Ashish
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Department of Animal Nutrition, College of Veterinary Science and Animal Husbandry, Anjora Durg, Chhattisgarh, India.
authors.forename: Surendra Kumar
authors.initials: SK
authors.lastname: Naik
authors.affiliation: Department of Animal Nutrition, College of Veterinary Science and Animal Husbandry, Anjora Durg, Chhattisgarh, India.
authors.forename: Tarini
authors.initials: T
authors.lastname: Sahu
keywords: chicken embryo fibroblast cell culture; chorioallantoic membrane; embryonated egg; fowl pox virus