Background:In order to achieve the goal of malaria elimination,the Chinese government launched the National Malaria Elimination Programme in 2010.However,as a result of increasing cross-border population movements,the...Background:In order to achieve the goal of malaria elimination,the Chinese government launched the National Malaria Elimination Programme in 2010.However,as a result of increasing cross-border population movements,the risk of imported malaria cases still exists at the border areas of China,resulting in a potential threat of local transmission.The focus of this paper is to assess the Plasmodium vivax incidences in Tengchong,Yunnan Province,at the border areas of China and Myanmar.Methods:Time series of P.vivax incidences in Tengchong from 2006 to 2010 are collected from the web-based China Information System for Disease Control and Prevention,which are further separated into time series of imported and local cases.First,the seasonal and trend decomposition are performed on time series of imported cases using Loess method.Then,the impact of climatic factors on the local transmission of P.vivax is assessed using both linear regression models(LRM)and generalized additive models(GAM).Specifically,the notion of vectorial capacity(VCAP)is used to estimate the transmission potential of P.vivax at different locations,which is calculated based on temperature and rainfall collected from China Meteorological Administration.Results:Comparing with Ruili County,the seasonal pattern of imported cases in Tengchong is different:Tengchong has only one peak,while Ruili has two peaks during each year.This may be due to the different cross-border behaviors of peoples in two locations.The vectorial capacity together with the imported cases and the average humidity,can well explain the local incidences of P.vivax through both LRM and GAM methods.Moreover,the maximum daily temperature is verified to be more suitable to calculate VCAP than the minimal and average temperature in Tengchong County.Conclusion:To achieve malaria elimination in China,the assessment results in this paper will provide further guidance in active surveillance and control of malaria at the border areas of China and Myanmar.展开更多
Background:In China since the first human infection of avian influenza A(H7N9)virus was identified in 2013,it has caused serious public health concerns due to its wide spread and high mortality rate.Evidence shows tha...Background:In China since the first human infection of avian influenza A(H7N9)virus was identified in 2013,it has caused serious public health concerns due to its wide spread and high mortality rate.Evidence shows that bird migration plays an essential role in global spread of avian influenza viruses.Accordingly,in this paper,we aim to identify key bird species and geographical hotspots that are relevant to the transmission of avian influenza A(H7N9)virus in China.Methods:We first conducted phylogenetic analysis on 626 viral sequences of avian influenza A(H7N9)virus isolated in chicken,which were collected from the Global Initiative on Sharing All Influenza Data(GISAID),to reveal geographical spread and molecular evolution of the virus in China.Then,we adopted the cross correlation function(CCF)to explore the relationship between the identified influenza A(H7N9)cases and the spatiotemporal distribution of migratory birds.Here,the spatiotemporal distribution of bird species was generated based on bird observation data collected from China Bird Reports,which consists of 157272 observation records about 1145 bird species.Finally,we employed a kernel density estimator to identify geographical hotspots of bird habitat/stopover that are relevant to the influenza A(H7N9)infections.Results:Phylogenetic analysis reveals the evolutionary and geographical patterns of influenza A(H7N9)infections,where cases in the same or nearby municipality/provinces are clustered together with small evolutionary differences.Moreover,three epidemic waves in chicken along the East Asian-Australasian flyway in China are distinguished from the phylogenetic tree.The CCF analysis identifies possible migratory bird species that are relevant to the influenza A(H7N9)infections in Shanghai,Jiangsu,Zhejiang,Fujian,Jiangxi,and Guangdong in China,where the six municipality/provinces account for 91.2%of the total number of isolated H7N9 cases in chicken in GISAID.Based on the spatial distribution of identified bird species,geographical hotspots are further estimated and illustrated within these typical municipality/provinces.Conclusions:In this paper,we have identified key bird species and geographical hotspots that are relevant to the spread of influenza A(H7N9)virus.The results and findings could provide sentinel signal and evidence for active surveillance,as well as strategic control of influenza A(H7N9)transmission in China.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.81402760,81573261,81502858,81273192)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20161563)+2 种基金the Hong Kong Research Grants Council(RGC/HKBU12202415)the Research Foundation of Education Bureau of Zhejiang Province,China(Grant No.Y201222907)The funders had no role in study design,data collection and analysis,decision to publish,or preparation of the manuscript.
文摘Background:In order to achieve the goal of malaria elimination,the Chinese government launched the National Malaria Elimination Programme in 2010.However,as a result of increasing cross-border population movements,the risk of imported malaria cases still exists at the border areas of China,resulting in a potential threat of local transmission.The focus of this paper is to assess the Plasmodium vivax incidences in Tengchong,Yunnan Province,at the border areas of China and Myanmar.Methods:Time series of P.vivax incidences in Tengchong from 2006 to 2010 are collected from the web-based China Information System for Disease Control and Prevention,which are further separated into time series of imported and local cases.First,the seasonal and trend decomposition are performed on time series of imported cases using Loess method.Then,the impact of climatic factors on the local transmission of P.vivax is assessed using both linear regression models(LRM)and generalized additive models(GAM).Specifically,the notion of vectorial capacity(VCAP)is used to estimate the transmission potential of P.vivax at different locations,which is calculated based on temperature and rainfall collected from China Meteorological Administration.Results:Comparing with Ruili County,the seasonal pattern of imported cases in Tengchong is different:Tengchong has only one peak,while Ruili has two peaks during each year.This may be due to the different cross-border behaviors of peoples in two locations.The vectorial capacity together with the imported cases and the average humidity,can well explain the local incidences of P.vivax through both LRM and GAM methods.Moreover,the maximum daily temperature is verified to be more suitable to calculate VCAP than the minimal and average temperature in Tengchong County.Conclusion:To achieve malaria elimination in China,the assessment results in this paper will provide further guidance in active surveillance and control of malaria at the border areas of China and Myanmar.
基金This work was supported by the Hong Kong Research Grants Council(RGC/HKBU12202415)the National Natural Science Foundation of China(Grant Nos.81402760,81573261)+2 种基金the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20161563)Computational work was partially supported by Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(Grant No.U1501501)The funders had no role in study design,data collection and analysis,decision to publish,or preparation of the manuscript。
文摘Background:In China since the first human infection of avian influenza A(H7N9)virus was identified in 2013,it has caused serious public health concerns due to its wide spread and high mortality rate.Evidence shows that bird migration plays an essential role in global spread of avian influenza viruses.Accordingly,in this paper,we aim to identify key bird species and geographical hotspots that are relevant to the transmission of avian influenza A(H7N9)virus in China.Methods:We first conducted phylogenetic analysis on 626 viral sequences of avian influenza A(H7N9)virus isolated in chicken,which were collected from the Global Initiative on Sharing All Influenza Data(GISAID),to reveal geographical spread and molecular evolution of the virus in China.Then,we adopted the cross correlation function(CCF)to explore the relationship between the identified influenza A(H7N9)cases and the spatiotemporal distribution of migratory birds.Here,the spatiotemporal distribution of bird species was generated based on bird observation data collected from China Bird Reports,which consists of 157272 observation records about 1145 bird species.Finally,we employed a kernel density estimator to identify geographical hotspots of bird habitat/stopover that are relevant to the influenza A(H7N9)infections.Results:Phylogenetic analysis reveals the evolutionary and geographical patterns of influenza A(H7N9)infections,where cases in the same or nearby municipality/provinces are clustered together with small evolutionary differences.Moreover,three epidemic waves in chicken along the East Asian-Australasian flyway in China are distinguished from the phylogenetic tree.The CCF analysis identifies possible migratory bird species that are relevant to the influenza A(H7N9)infections in Shanghai,Jiangsu,Zhejiang,Fujian,Jiangxi,and Guangdong in China,where the six municipality/provinces account for 91.2%of the total number of isolated H7N9 cases in chicken in GISAID.Based on the spatial distribution of identified bird species,geographical hotspots are further estimated and illustrated within these typical municipality/provinces.Conclusions:In this paper,we have identified key bird species and geographical hotspots that are relevant to the spread of influenza A(H7N9)virus.The results and findings could provide sentinel signal and evidence for active surveillance,as well as strategic control of influenza A(H7N9)transmission in China.
