Capacity Assessment And Community Intervention Study On Dengue Control In Guangdong,China

BackgroundDengue fever(DF)is the most prevalent mosquito-borne viral disease in humans,and has spread rapidly within and across countries over the past few decades.It is also an emerging neglected tropical disease(NTD)with geographical distribution in South China.The increasing number of reports of DF outbreaks in various parts of South China is likely attributable to the increase in trade and human movement through China from the Southeast Asian region where DF is firmly endemic.In addition,Guangzhou and other cities in South China are growing economically,leading to continuous expansion of city size and population density.Instead of merely importing DF,South China could become an epicenter of DF transmission to other parts of China,and possibly the rest of the world,if proper preventive measures are not taken.Integrated Vector Management(IVM)strategy,which is recommended by WHO,is an integrated disease management approach that incorporates all components of disease control,including vector control,prevention,treatment,and reducing human vulnerability.However,fundamental factors contributing to DF transmission need to be identified,e.g.who are vulnerable to DF transmission in South China?How vulnerable populations of China respond to DF outbreaks?Whatpreventive measures are taken?And whether the measures are effective to protect residents from DF?Objective1)To analyze the association between risk factors and DF transmission in Guangzhou,and identify vulnerable population,interrupting human-vector contact through Integrated vector management(IVM).2)To find out prevention and control measures in communities,in order to provide proposal for response and adaptation strategies of dengue fever.3)To assess effectiveness of the sustainable community control plan and strategy to control Aedes,the vector of dengue,compared with a routine strategy.Methodology1)We conducted a case-control study of the initial stage of the 2014 DF outbreak in Guangzhou,China to assess risk factors for DF infection.Cases were randomly sampled from the National Notifiable Infectious Disease Reporting Information System(NNIDRIS).Controls were healthy individuals recruited from 17 DF infected communities through cluster sampling.A structured questionnaire on demographics,knowledge,practices,and living environment was administered to participants(165 cases;492 controls).Univariate analysis,multivariate logistic regression models and artificial neural network(ANN)analysis model was used to identify characteristics of vulnerable populations.2)From April to June 2014,stakeholder analysis was conducted through personal interviews and focus groups in Futian,Luo huo,Liwan,Yuexiu,Haizhu,and Baiyun districts of Guangzhou and Shenzheng.There were 95 participants which from general publics,patients,staffs from the CDC,hospital,municipal management department(Patriotic Health Campaign Committe),disinfection station,and neighborhood committee.3)A total of 434 householders from 8 communities in Guangzhou City were enrolled by random cluster sampling.Knowledge and behavior information on dengue fever was obtained via face-to-face interviews and self-designed questionnaires.SPSS 20.0 and AMOS 21.0 were employed to conduct statistical descriptions and construct a structural equation model based on information,motivation,behavior(IMB)theory.4)A baseline household survey was conducted in July 2014,while entomological and sociological surveys were carried out simultaneously in Guangzhou,China.Eight pilot communities were randomly selected for intervention and 9 communities as a control group.In intervention group,stakeholders analysis was conducted through personal interviews and focus groups.Neighborhood committee,volunteers of residents,property services personnel and schools were mobilized to participant intervention team.Top-down&bottom-up community sustainable vector management approaches and preparedness were designed as intervention guidelines.Innovated ecosystem-based Aedes traps and mobile phone Apps distribution coupled with traditional Patriotic Hygienic Campaign(PHC)approach,i.e.larval source reduction measures,Communication for Behavioural Impact(COMBI)program,routine surveillance and risk reduction were conducted.Follow-up surveys were conducted at intervals,with the final survey after 13 months in 2 groups.Compare mosquito vector density with Breteau Index(BI)and dengue incidence after or along with control work vs.before.Data was entered and analyzed by Microsoft Excel 2013 and SPSS20.0.Principal Findings1)Dengue fever risk factors and vulnerable populationsBy using the back-propagation(BP)of the ANN model during early outbreak,11 factors out of 16 factors were screened,and the top three factors ranked by the importance value were mainly related to lifestyle and DF knowledge,i.e.Using air-conditioner(IV=0.175,NIV=100.0%),Cleaning water and trash in their dwellings(IV=0.153,NIV=87.3%),Awareness of DF(IV=0.149,NIV=85.4%).According the results of Logistic regression,awareness of dengue(OR=0.08,95%CI=0.04-0.17),removing trash and stagnant water from around the residence(OR=0.02,95%CI=0.00-0.17),and using mosquito repellent oils(OR=0.36,95%CI=0.16-0.81)were protective factors.Living in an old flat or shed(OR=2.38,95%CI=1.18-4.79)was a risk factor.2)Community adaptation measures and adaptation capacityOutbreak sites always with high population density were surrounded with vector breeding and habitat.The top-down approach was used in communities.There were knowledge gaps between prevention institution and patients.Community dengue prevention mainly depends on the neighborhood committee and fewer residents participated.Indoor vector surveillance results were inaccurate and curbed in process.Case finding and response early was affected by charge system and cognitive level of prevention staff.There was little effect of insecticide using communities.3)Information and the means to acquire informations related DFThere were 83.4%respondents have heard about dengue fever,however,merely 56.9%of respondents have a clear recognition that "Dengue fever is a vector-borne disease" and behavior formation rate of preventing mosquito is 55.8%.Only 41.1%(44)respondents aged<35 have a correct understanding on "Dengue fever is a mosquito borne disease",and 45.8%behavior formation rate of preventing mosquito,both of which are the lowest knowledge and behavior score compared with other age groups(?2=8.04,P=0.04).The ways people like to accept knowledge related dengue fever are TV(60.3%),newspaper(22.8%),posters(22.1%),community education(18.4%),network media(16.1%).Residents under 35 years old are more willing to acquire knowledge of dengue fever by network than other age groups.4)Behavioral intervention model and structural equation modeling of dengue feverThe results of the structural equation model indicated that the total and indirect effects of knowledge related dengue fever on prevention behavior were 0.69 and 0.14,respectively.The structural equation model was tested and fitted the data well(CMIN/df=1.796,P=0.005,RMSEA=0.043,NFI=0.94,IFI=0.97,TLI=0.93,CFI=0.97).5)Assessment of community interventionIn the 8 matched communities,knowledge score changed before and after intervention was significantly different(from 6.38±1.70 to 7.09±2.02,P<0.01),and the difference value show significant statistically(t=2.637,P=0.034).Community intervention trial results showed that the preventive practice rate rose from 55.8%to 78.6%(?2=51.627;P=0.000),and the control group rose from 59.2%to 71.1%(?2=15.369;P=0.000).Action score changed before and after intervention was significantly different(t=-2.774,P=0.028).Average value of Breteau Index(BI)changed before and after intervention was significantly different(t=2.576,P=0.037).Conclusions1)People live in old flats or sheds,with low knowledge score of DF transmission,and reluctant to clear trash/water around the residence are more vulnerable to DF infection..The public health education and intervention should be encouraged to help population establish a healthy lifestyle such as keep sanitary environment and prevent mosquito bite by using the air conditioner or screening doors and windows.2)Lasting integrated response strategies should be established in high risk areas concluding epidemic surveillance,alerts,mobilize residents participate in community Integrated Vector Management,and conduct disinsection during emergency response.3)Community based Aedes management strategies combined Top-down&bottom-up approaches can reduce Aedes-borne diseases effectively.RecommendationsI.Vulnerable population should be focused on community DF preventionPopulation living in old flats or sheds,without the air conditioner,needs to be protected well.The public health education and intervention should encourage them to establish healthy lifestyle such as keep sanitary environment and prevent mosquito bite by clearing trash/water around the residence,using the air conditioner or screening doors and windows with low cost.II.Precise knowledge and effective measures should be appropriately translated to public.Strengthening the public's capacity for adaptive measures and awareness.Aedes albopictus is the main vector for dengue transmission in Guangzhou,and has a strong preference for human feeding and biting in the daytime.Using mosquito coils and bed nets was not protective factors for DF transmission in Guangzhou.Thus,neighborhood residence should prevent for Aedes albopictus in daytime.Using mosquito repellent oils and other preventive measures was associated with decreased risk of DF infection.Accurately information in recognizing and understanding DF vectors through newly net mass media,should be included in the outbreak response.?.Sustainable community adaptation plan and intervention strategy to control Aedes,the vector of dengue,should be established in a high risk area.Assessment tools for community adaptative capacity could be approaching in dengue prevention.Early epidemic surveillance,alerts,mobilize residents participate in community Integrated Vector Management,and conduct disinsection during emergency response.Communication for Behavioural Impact(COMBI)Program,routine surveillance and risk reduction should be conducted through teamwork and purchase service of PCO.IV.Community participant intervention model should be taken into DF prevention.Adaptive strategies will be initiated by multisectional team.Community stakeholders and selected volunteers will be mobilized to build intervention team.Top-down&bottom-up community sustainable vector management approaches and preparedness were designed as an intervention guideline.Innovated ecosystem-based Aedes traps and mobile phone Apps distribution coupled with traditional Patriotic Hygienic Campaign(PHC)approach,i.e.larval source reduction measures.Community participation action could improve residents' self-efficacy and boost the formation of prevention behaviors.