| Background From late-March to mid-April2008,18children death cases with severe pneumonia were reported by Fuyang City, Anhui Province. Clinical specimens from12death cases were detected by RT-PCR on April23in the Chinese Center for Disease Control and Prevention. The results revealed that specimens of5cases were positive for Human Enterovious71(HEV71). HEV71were isolated from both the mild cases and the severe cases specimens, and most of the paients appear manifestations of rash on their hands, feet and mouths, which confirmed that the disease was hand-foot-mouth disease (HFMD) caused by the infection of HEV71. Retrospective case investigation revealed that an outbreak of HFMD occurred in Fuyang City, Anhui Province in2008. At the same time, HFMD epidemic caused by HEV71also occurred in some other provinces in China. A small number of patients died of serious complications. The Health Ministry issued the technical guidelines of HFMD treatment, prevention and control in time. Furthermore, HFMD is timely brought into management of the Class C notifiable infectious diseases.Objective To find HFMD related risk factors and provide prevention and control measures for HFMD after it is incorporated into notifiable infectious diseases, the epidemiology characteristics of HFMD outbreaks in the whole country and in Fuyang City in Anhui Province in2008were analyzed. To know HEV71natural infection stitution, the level of susceptibility and the dynamic changes of the immune in children of Fuyang City in the late prevalence of HFMD, the serum neutralizing antibody of HEV71of healthy children in Fuyang City in2008were detected. To understand HEV71natural infection stitution and the level of immune in the past in China, a retrospective survey about the serum neutralizing antibody level of HEV71of healthy children in some other counties in2005were developed, and the survey results of HEV71Seroepidemiology in2005and2008were compared.Methods Make use of the Chinese Center for Disease Control and Prevention statutory infectious disease reporting system to collect the national and Anhui Province Fuyang City HFMD cases, use of excel2003, SPSS13.0softwares from the point of view of description of epidemics to analyze the characteristics of HFMD. On latte May of2008, during the latter phase of Fuyang City of HFMD epidemic, using random cluster sampling method to choose Yingzhou district and Yingshang County of Fuyang City as survey points.209and2880-5-year-old healthy children were randomly chosen in Yingzhou district and Yingshang County, respectively, a total of497serum specimens were conducted epidemiological survey to determine the children’s serum antibody levels of HEV71. Use children serum specimens that used for measles antibodies detection on September2005, HEV71neutralizing antibodies were detected with3711～6-year-old children’s serum specimens collected from Kuqa County of Xinjiang, Ninglang County of Yunnan, Dianbai County of Guangdong.Results (1) All provinces in China in2008reported HFMD epidemics, the national incidence rate is38.45/100000, which ranked the fourth in all kinds of infectious diseases, while Fuyang City of Anhui Province is112.86/100000. HFMD epidemic was seasonal, the peak incidence occurred from April to July, with peaked in May.(2) The number of HFMD cases of boys was more than HFMD cases of girls, with the ratio of1.75:1, while1.84:1of Fuyang City; Most cases were0-5-year-old children, which accouned for91.25%of the total reported cases, while0-3-year-old chilren accounting for71.81%; In Fuyang city, most cases aged0to5and accounted for93.53%of the total number of reported cases, whereas0-3-year-old children accounted for80.31%. The occupational distribution of the cases is scattered children on top of the list, accounting for the total number of reported cases66%, followed by children in preschools, accounting for28%, students account for5%. Fuyang city were80%,17%,3%, respectively.(3) The HEV71antibody positive rate in Fuyang City in2008for children aged0to5was48.08%, and56.5%for Yingzhou district,42.0%for Yingshang County; While the HEV71antibody positive rate in3Counties of1-5-years-old children in2005was44.2%, and Dianbai, Kuqa, Ninglang counties were43.7%,45.4%,43.4%, respectively; The antobody positive rate in Fuyang City in2008was significantly higher than other three counties in2005of children within the same age group (χ2=5.73, P<0.05).(4) The3Counties in2005for children aged1to5, Fuyang City in2008for children aged0to5, HEV71antibody positive rate growed as ages increase. Three counties in2005have the same trend, which is from0to5years of age increased gradually, to5year old reached the level of about60%; while the two districts and counties of Fuyang City in2008in the0to3 years increased rapidly, and reached the level of60%in the age of3year old. Three counties in2005children between the antibody positive rate makes no difference, Fuyang City in2008positive rate of the two districts has significant statistical difference; Fuyang City0to5-year-old children’s HEV71-positive rate has nothing to do with the child’s gender(5) Fuyang City in2008for children aged0to5positive rate of HEV71multi-factor logistic regression analysis results showed that the antibody positive rate of children related to age, region, but has nothing to do with gender. Age group for the OR value is1.987,95%of the feasible limit is1.649～2.393; Yingzhou area verse Yingshang County for the OR value is1.509,95%of the feasible limit is1.028-2.216.(6)3Counties in2005for1to5-year-old children, Fuyang City in2008for children aged0to5antibody geometric mean titer HEV71level lower in the low age group, and it increased with age.(7) In20053County1to5-year-old children, Fuyang City in2008for children aged0to5the composition of various HEV71antibody titer level are mainly negative, accounting for more than50%. However, high antibody level group (≥1:256), the proportion of Fuyang City in2008was significantly higher than that of the three counties findings in2005.Conclusion Severe HFMD outbreaks caused by HEV71occured in China in2008, some areas including Fuyang city in Anhui Province appear the prevalence of the epidemic; Children under5years old, especially those under3years, are suspectible of HFMD, and these children should be attentioned in prevention and contral of HFMD. Before2005HEV71virus has been circulated and spreat in some areas of China, and there are nature infection in some extent. In0-5-year-old children, HEV71positive rate related to the child’s age and location of the site, the rate of antibody positive children increased with age, for children between different regions of different antibody positive rate. The HEV71antibody positive rate and geometric mean antibody tite of Children in Fuyang City after HFMD outbreak in2008were higher than that of3counties in2005;0-5-year-old children, especially children under the age of3for HFMD are susceptible population.HFMD infection are mainly inapparent infection.Suggestions We should develop the dynamic surveillance of HEV71seroepidemiology in different areas in China, especially in the areas with HFMD outbreak in recent years. So the HEV71stitution of nature infection in different areas can be known, and hige-risk aread and groups can be found in time. Grasp Chinese HFMD incidence and prevalence of law. Early positive rapid diagnostic techniques and effective antiviral drugs and HEV71vaccine should be developed. |
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