title: Biological and molecular characterization of classical swine fever challenge virus from India.
abstract: OBJECTIVE
  The aim of this study was biological and molecular characterization of classical swine fever (CSF) challenge virus from India.
  
  
  METHODS
  CSF challenge virus maintained at Division of Biological standardization was experimentally infected to two seronegative piglets. The biological characterization was done by clinical sign and symptoms along with postmortem findings. For molecular characterization 5'-nontranslated region, E2 and NS5B regions were amplified by reverse transcription polymerase chain reaction and sequenced. The sequences were compared with that of reference strains and the local field isolates to establish a phylogenetic relation.
  
  
  RESULTS
  The virus produced symptoms of acute disease in the piglets with typical post-mortem lesions. Phylogenetic analysis of the three regions showed that the current Indian CSF Challenge virus is having maximum similarity with the BresciaX strain (USA) and Madhya Pradesh isolate (India) and is belonging to subgroup 1.2 under Group 1.
  
  
  CONCLUSIONS
  Based on biological and molecular characterization of CSF challenge virus from India is described as a highly virulent virus belonging to subgroup 1.2 under Group 1 along with some field isolates from India and Brescia strain.
authors.affiliation: Division of Biological Standardization, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
authors.forename: Parveen
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Division of Biological Standardization, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
authors.forename: Vikramaditya
authors.initials: V
authors.lastname: Upmanyu
authors.affiliation: Division of Biological Standardization, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
authors.forename: Pronab
authors.initials: P
authors.lastname: Dhar
keywords: Challenge virus; Classical Swine fever; biological characterization; molecular characterization; phylogeny