The Distribution Of Aedes Albopictus In Guangzhou And Its Association With Meteorological Factors And The Occurrence Of Dengue Fever

ObjectiveTo realize the distribution of Aedes albopictus and its density in Guangzhou and compare the results from different monitoring methods,to study the influence of meteorological factors on density of Aedes albopictus and the relationship between Aedes albopictus and dengue fever.Eventually scientific basis for prevention and control of dengue fever is provided as a result.MethodsThe information about Aedes albopictus surveillance(House Index(HI),Container Index(CI),Breteau Index(BI),Standard Space Index(SSI),Mosquito Ovitrap Index(MOI)and Adult-mosquito Density Index(ADI)),meteorology(air temperature,Cumulative rainfall,atmospheric pressure and relative humidity)and dengue fever cases(native clinical case and confirmed case)of Guangzhou between 2007 and 2016 were collected systematically.Descriptive analysis was utilized to analyze the density of Aedes albopictus and its time and spatial distribution characteristics.The Spatial interpolation was utilized to fill the missing data of density of mosquito vector in the street.Space-time scan statistics was utilized for the analysis of the spatial-temporal distribution characteristics of Aedes albopictus and its density change tendencies.Correlation analysis was utilized for univariate analysis of the relationship between the meteorological factors and density of Aedes albopictus(BI and MOI),and the relationship between density of Aedes albopictus(BI,SSI and MOI)and dengue fever.DLNM(distributed lag nonlinear model)was utilized to study the influence of meteorological factors on density of Aedes albopictus(BI and MOI).Statistical software that used in this study were R(version 3.3.0),SPSS(version 20.0)and Arc GIS(version 10.2).Results1.The total HI,CI and BI were 3.25,5.61 and 4.05 in the residential areas of Guangzhou between 2007 and 2016,respectively.The total CI and SSI were 8.66 and 0.40 in the outside environment of non-residential areas,respectively.The total MOI of Guangzhou was 7.52 and the ADI of Guangzhou was 1.76 from April to October in 2016.2.The HI,CI and BI of the residential areas,SSI of outside environment of non-residential areas and MOI in Guangzhou showed the same change pattern from 2007-2016,which appeared high value in summer and autumn(June to November),and appeared low value in spring and winter(January to May and December).The peak value of these index primarily appeared between July and October,which indicated dengue fever transmission risk for Guangzhou.The ADI of Guangzhou indicated dengue fever transmission risk from June to July in 2016.3.The BI for the Panyu district,Haizhu district,Huadu district,Huangpu district,Liwan district,Nansha district and Zengcheng district and the SSI for the Liwan district and Yuexiu district all indicated low dengue fever transmission risk in dengue fever epidemic period.The MOI for the park and other types of sites indicated dengue fever outbreak risk,and the MOI for the residential areas,hospital,construction site and recycling station indicated low dengue fever transmission risk.4.The results showed strong correlation among BI,SSI and MOI,the correlation coefficient between the two of the three was 0.86 for BI and MOI,0.80 for BI and SSI,0.79 for MOI and SSI,respectively.The amount of months which all indicated dengue fever outbreak risk were 2,4 and 30 from BI,SSI and MOI,respectively.The constituent ratio of the three were 1.7%,3.4% and 25.4%,respectively,which showed statistically significant on difference(c2=64.754,P<0.01).5.The BI of Aedes albopictus showed high spatial-temporal cluster characteristics in Guangzhou,2007-2016,in which appeared I-IV level cluster areas.The I level cluster areas primarily distributed in the street of central and southern Guangzhou,the II-III level cluster areas primarily distributed in the street of central Guangzhou,the IV level cluster areas primarily distributed in the street of northern Guangzhou.The streets of which BI appeared cluster up to 5 years or more primarily distributed in the central and southern Guangzhou.The BI of Changzhou street of Huangpu district appeared cluster for every year.6.The meteorological factors had impact on density of Aedes albopictus,and showed lag effect and cumulative effect.The max lag time of cumulative rainfall,atmospheric pressure and relative humidity were 2 month,1 month and 2 month for BI increasing and air temperature showed no lag effect on BI increasing.The max lag time of atmospheric pressure was 1 month for MOI increasing and other meteorological factors showed no lag effect on MOI increasing.When the air temperature,cumulative rainfall,atmospheric pressure and relative humidity were 30?,880 mm,995h Pa and 87%,respectively,the max relative risks were 1.844(1.479~2.298)and 2.777(1.947~3.961),1.739(1.380~2.192)and 2.077(1.311~3.291),1.655(1.464~1.871)and 2.203(1.802~2.693),1.155(1.050~1.269)and 1.329(1.107 ~ 1.594)for BI and MOI,respectively and the cumulative effect(relative risks)were 2.212(1.803~2.715)and 3.777(2.752~5.183),6.358(2.692~15.145)and 7.237(1.753 ~ 30.178),2.477(1.682 ~ 3.647)and 5.839(3.206 ~ 10.633),1.899(1.392~2.589)and 3.117(1.872~5.191)for BI and MOI,respectively.7.The BI,SSI and MOI of current month and lag 1-4 month were all related to the dengue fever cases and the strong correlation was at the lag 2 month between these index and dengue fever cases.The correlation coefficient were 0.73,0.61 and 0.70 for BI,SSI,MOI,respectively.These index showed no correlation at lag 5 month with dengue fever cases.Conclusions1.The density of Aedes albopictus showed the trend of high value in summer and autumn(June to November)and low value in spring and winter(January to May and December)in Guangzhou,2007-2016.The peak value of density primarily appeared between July and October,which indicated dengue fever transmission risk.2.The density of Aedes albopictus showed spatial-temporal cluster characteristics and the cluster areas primarily in central and southern Guangzhou.3.The meteorological factors had impact on density of Aedes albopictus and showed lag effect.4.The density of Aedes albopictus was related to the occurrence of dengue fever and showed lag correlation.