| Rabies is a zoonotic infectious disease caused by rabies virus and its mortality rate is nearly 100%when infected.Nowadays,human rabies cases mainly occur in developing countries in Asia and Africaand since 1996 human rabies cases in China have risen continuously until it has become one of the countries experiencing the largest number of cases.Since 2007,although the number of human cases in China has declined overall,some provinces and regions have continued to experience a rise and recently some regions have even seen a re-emergence in number of cases.Thus,rabies prevention and control in China continues to be a matter of great importance.Recently the geographical spread of serious in china,and Incubation period of the rabies is shorter than before.And it become to be a big public health promble in some areas.At present,the epidemic investigations on rabies were developed.In addition,G is the binding site of virus and host cell receptors,determining viral tissue tropism and is related to viral virulence and pathogenicity.Thus,the G protein is a good choice for examining the relationship between different viral isolates.Therefor,the study on G genes sequence played an important role in exploring heredity mutation status of virus and molecular epidemiology.Comparison of main function sites,homology analysis and phylogenesis analysis on G genes were done at the molecular level,and to explore etiology status of rabies and evolution characteristic on P,M genes.To explore the relationship between G gene atatus and high prevalence and epidemic situation in China,and to provide evidence for the development of surveilence and control of rabies.To investigate the origin and the factors affecting the spread of rabies in China,specimens were collected from 2007 to 2011 from provinces with emerging and re-emerging cases and tested for the presence of the rabies virus.Positive specimens were combined with sequences from GenBank to perform comparisons of homology and functional sites,and to carry out phylogenetic analyses.Out of these regions,five provinces had 9 positive specimens from canine and cattle,and 34 canine or human specimens were obtained from previously high-incidence provinces.Complete sequences of G gene were obtained for these samples.Homology of the sequences of these 43 specimens was 87%-100%at the nucleotide level and 93.7%-100%at the amino acid level.These G gene sequences were combined with reference sequence from GenBank and used to construct a phylogenetic tree.The results showed that 43 specimens were all assigned to China clade I and clade II,with all specimens from emerging and re-emerging areas placed within clade I.Specimens isolated from Shanxi and Inner Mongolia in 2011 were distinct from previously-isolated local strains and had closer homology to strains from Hebei,Beijing and Tianjin whereas new isolates from Shanghai were tightly clustered with strains isolated in the 1990s.Finally,Shaanxi isolates were clustered with strains from adjacent Sichuan.Whereas,based on rabies virus evolutionary analysis nationwide,Heibei,Tianjin,Inner Mongolia,Shanxi and Shandong Provinces located on the north of Yellow River formed an independent evolutionary group;Anhui and Henan Province located on the south of Yellow River formed another standalone cycling;virus isolated from Zhejiang,Jiangsu Province and Shanghai City share a more closed genetic relationship;virus separated from Guangdong,Guizhou,Guangxi and Hunan Provinces constructed a conjunct epidemic areas circulatory circle;virus isolated from Zhejiang and Jiangxi.Province also formed a circulatory circle among wildlife.Our results suggest that the rabies cases in emerging and re-emerging areas in China in the last 5 years are a consequence of the epidemic spreading from of neighboring provinces and regions experiencing a serious epidemic of rabies.There are more conjunct circulatory circles and widely crossing spread among endemic provinces and areas.In some provinces,there are even circulatory transmission among wildlife. |
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