| Peste des Petits Ruminants?PPR?is a highly contagious disease affecting sheep and goats caused by PPRV.In 2007,PPRV spreaded in the Ali area of Tibet.At the end of 2013,the disease was founded again in Xinjiang and quickly spreaded to 22provinces in China,which leaving small ruminants at highly risk.In order to investigate the molecular epidemic characteristics of PPRV strains in China,we sequenced 28strains of PPRV collected in China from 2014 to 2017 by the second-generation sequencing technology.The nucleotide and deduced amino acid sequence of PPRV were analyzed and phylogenetic tree was constructed by using MEGA 6.0 software.Molecular evolution analysis was conducted using the BEAST software package.The genome length of China PPRV strains from 2014 to 2017 is 15954 nt,and the nucleotide homology was 99.7%100%.There are 518 nucleotides difference,representing 138amino acids among sequenced strains,where the most variable gene is the H gene.The evolution rate of PPRV between 2013 and 2017 is 2.69×10-6 nucleotide site per site per day(95%HPD2.29×10-63.04×10-66 nucleotide site/site/day),9.81×10-4 nucleotide site per site per year(95%HPD 8.37×10-41.11×10-33 nucleotide site/site/year).The time to the most recent common ancestor?TMRCA?was July 2013.The PPRV strains between 2013 and 2017 were divided into five evolutionary clades,and three of which were dominant evolutionary clades.No differences were found in temporal and geographical distribution between strains.The number of animal populations infected by PPRV increased rapidly from January 2014 to April 2014,and reached a plateau after August 2014.This study reveals epidemiological characteristics of PPRV virus in China and is valuable for the prevention and control of this disease. |
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