Epidemiological Characteristics And Risk Factors Of Hand-Foot-Mouth Disease Outbreaks In Xi'an

Background:Hand,Foot and mouth disease(HFMD)is an infectious disease caused by a variety of human enteroviruses,mainly in children before five years old.Its major symptom is the appearance of herpes on hands,feet and mouths.For severely infected children,the symptom is often accompanied by central nervous systems.In this situation,the disease worsens rapidly and could possibly lead to death.Ever since the Ministry of Health counted HFMD as a class C infectious disease for management.HFMD has become the top one notifiable disease in the number of reported cases and shown the tendency of cluster infection in Xi'an from 2009 to 2013.Therefore,the study aims to describe its epidemiological and etiological characteristics,to analyze the risk factors of HFMD outbreak in Xi'an,and to set up a scientific basis for hand,foot and mouth disease prevention.Methods:1.The anal swab specimens of HFMD cases in aggregated epidemic were collected and the pathogen was classified by qPT-PCR.All of 43 kindergartens with HFMD outbreak were as case group.According to the matching conditions of the regional environment,the institution size and the type of organization,the selected kindergarten without cluster infection were taken as the control group at the ratio of 1:2.A questionnaire was designed to obtain the history of demographic characteristics and risk factors,which mainly include basic information of institutions,the hardware configuration,the formulation and implementation of control measures,the ways of disinfection measures and their implementation.2.All data were recorded by Epidata 3.1 and analyzed through SPSS 20.0.Measurement data is examined through chi-square analysis.Multivariate analysis is made by means of Logistic stepwise regression.Statistically significant difference boundary value was set as P<0.05.Results:1.All cases of the 25,257 cases HFMD were reported in Xi'an in 2014.The annual incidence rate was 294.06/10 million.In 2014,there were 43 kindergartens reporting HFMD aggregated epidemics indifferent districts and counties of Xi'an There were 228 HFMD cases reported among 13,703 children.The incidence rate was 1.66%,and no death cases were reported.2.The epidemiological characteristics: In 2014,there were two epidemic peaks in Xi'an.One was from April to July,and other one was from October to November.Aggregated epidemics soared in April,May and June.There was non-clustered epidemic report in January,February,August,and December.All of 14 districts and counties in Xi'an reported HFMD cases,and the number of aggregated epidemics reported in urban areas was the least.The number of reported epidemics in nearby suburbs was higher than that in outer suburbs.All aggregated epidemics occurred in nurseries and kindergartens.The virus strains of clustered epidemic were mainly Cox A16(69.01%),EV71(18.71%),and other enterovirus with the proportion of 12.28%.3.Multi-factor weighted logistic regression analysis showed that forced ventilation(OR=1.771,95%CI: 1.292-2.429),independent toilet and washing room(OR=1.771,95%CI: 1.292-2.429),HFMD prevention and control system(OR=7.500,95%CI:2.650-21.228),the way of hand washing(OR=3.975,95%CI:2.643-5.018)and towel disinfection(OR=2.100,95%CI:1.137-3.878)were influential factors of cluster HFMD epidemic.Conclusions:1.The cluster HFMD epidemic in Xi'an mainly appeared at childcare institutions in the nearby suburbs,often in April to June,and Cox A16 is predominant virus.2.The main risk factors of HFMD epidemic were:(1)there were no forced ventilation,independent toilet and washing room in childcare institution.(2)the rules and regulations of preventing HFMD were not strictly enforced.(3)hand washing way after defecation was not under teachers' supervision.(4)the disinfection of towel was used of ultraviolet ray or disinfectant cabinet.3.In order to control HFMD epidemic,enhancing prevention and health publicity and education for parents and children are essential.Besides HFMD vaccine,strengthening measures to implement,improvement of ventilation,correcting wrong way of hand washing in childcare institutes are also very important.