Plague Epidemic Trends In West China And Prediction Of F1Antigen Epitopes Of Y.Pestis

Western China which characterized by a vast land and large population is in the core area of buiding and development which be promoted by national strategies. In these area, along with the economic reform and opening up policy, the economy has been developed rapidly. However, wich the changes of environmental and ecological, the population migration, and especially the construction of the Three Gorges, the threatens of infectious disease epidemics and outbreaks are increased.Therefore, describe and analyze of plague epidemic trends in Western region, and the molecular structure of the specific antigen components of Y. pestis will rich the theory of plague epidemiology, and provide scientific data for further reseash. It is important for plague control.Objective:Systematically analyze the literatures of plague epidemic and ecologic characteristic of focuses in western area of china from2000to2008. To describe the plague’s development in recent years. Exploring the immunogenicity effect of F1antigen by bioinformatics techniques.Methods:①.All related literatures,which were evaluated strictly by principle of system qualitative analysis, were searched from the database of PubMed,Science, Direct and Chinese periodical full-text articles, the official network station of WHO,USA,CDC and other arganizations.The epidemic trend, characteristics of geographical landscapes, animal reservoirs and insect vector characters of plague were analyzed systematically.②To learn the animal types、media types and density,we monitored and sampled of the rodents、insects in24plague monitoring stations in the three gorges reservoir area (Chongqing section) from2003to2010.③The gene sequences of Y. pestis collected from rattus flavipectus plague epidemic focus in Yunnan provience has been used as the target. The bioinformatics techniques has been used to analyze the molecular structure of F1antigen epitopes. Results:①.Thirteen original literatures and one review have been used to analyze the epidemic trends.②.Contain the regions of Yunnan, Guizhou and Sichuan, the southwest region has been covered and surrounded by plague foci of five styles. In2000, the plague epidemic reached at the peak, and than declined from the subsequent years, and keeped at a steady condition; In Sichuan, the plague foci had a slightly active tendency. But there was no case be reported. The similar types of focuses in different areas have the homoioplastic characteristics of geographical landscape type and animals species.③. After the impoundment of the three gorges reservoir area(2003-2010), the indoor rat density was1.61%in eight counties of Chongqing reservoir area.Rattus norvegicus (36.15%)、Mus musculus(35.19%) and Anourosorex squamipes(17.71%) were the dominant species.Outdoor density (1.77%) was slightly higher than that of indoor density,Anourosorex squamipes(58.23%)、Rattus norvegicus(15.67%) and Mus musculus(12.01%)、were the dominant species. The total flea index was0.19,and the average flea-carrying rate was5.78%.20194only live rat serum F1antibody of yersinia pestis test results were negative.④.The F1antigen collected from focus of rattus flavipectus and vole have the characteristic of gene homology. The170amino acid sequence have the state of β-sheet (amino acids accounted for40.59%), β-turn (14.71%), the a-helix (11.76%), and random coil (Coil)32.94%.⑤.The analytic results showed that, in the peptide sequences of F1antigen, the best antigenic epitope is sequence of105-132. Increase this fragment (27amino acids) among the peptide sequences, there is no significantly change in the prediction model of secondary and tertiary structure. But the hydrophilicity, flexibility, surface probability and antigenic index have been increased. This inferred that the F1antigen activity could be improved by artificial design.Conclusions:①. In recent years, the plague epidemic situation of southwest region keeped at the steady condition. Some of the focuses had a slightly active tendency. There have the threatens of plague port spreading. The monitoring measures must be increased.②. No plague epidemic situation was found in the three gorges reservoir area of chongqing area,but R.flavipectus and X. cheopis were widely distributed in this region with high density and rat flea infection rate.In recent year,rat density increased,which result in the potential danger of plague in the reservoir.③. For the F1antigen of Y.pestis which collected from rattus flavipectus, The sequence of amino acids105-132is the best antigen epitope and coule be artificially modified furehter.