| [Objectives]1. Study both epidemic situation and epidemiological distribution of hand-foot-mouth disease (HFMD) in Hunan province, timely knowing about the prevelence pattern of HFMD in the province, so as to provide basises for formulating control and prevention strategies.2. Monitor the HFMD pathogen characteristics in Hunan province, analyze the characteristics of HFMD gene evolution, explore pathogen changes of HFMD in Hunan.3. Analyze risk factors of fatal HFMD cases in Hunan province, providing a scientific basis for effectively curbing incidence of severe HFMD cases especially the fatal ones.[Methods]1. The epidemiological characteristics of hand-foot-mouth disease. Collecting the epidemic data from2008to2012in Hunan province through China Information System for Disease Control and Prevention, apply descriptive epidemiology to describe three distribution(namely time,region and population distribution) in Hunan Province at incidence of HFMD epidemic situation and the epidemic severity.2. Pathogenic characteristics of HFMD. Each HFMD network laboratory data within the province were collected among2009-2012, of which species came from HFMD designated hospital. Separation of virus, nucleic acid extraction, RT-PCR/Real time RT-PCR, and other experimental procedures were taken to analyze pathogen distribution of HFMD. Using MegAlign packaged in the DNAStar software to conduct nucleotide sequence homology of EV71strains of HFMD, and taking MeGa software(NJ method)to construct phylogenetic tree, so as to analyze the characteristics of gene evolution at molecular level. 3. Study on risk factors of HFMD. HFMD fatal cases surveyed among2011-2012in Hunan province were taken as case group,based on gender, living area as matching factors, severe cases were1:1matched as control group during the same period, using the risk respectively according to the single factor and multiple factor Cox regression were analyzed of suspicious variables,including basic information, treatment after disease, previous disease history, clinical symptoms, pathogen,so as to explore the risk factors for death of the HFMD severe cases.[Results]1. A total of465939HFMD cases were reported from2008to2012in Hunan province, accounting for72.36%among C Class infectious diseases, while as31.73%among all the legal infectious disease. The annual incidence rate was42.66per100thousand population,54.31per100thousand population,175.14per100thousand population,155.97per100thousand population,287.32per100thousand population respectively.5401severe cases(including death cases) were reported,of which the severe occurrence rate among the total cases was1.16%.287fatal cases were reported, of which the fatality rate was0.06%, with severe fatality rate at5.31%. A larger-scale epidemic appeared every other year period cycles,when the epidemic of2010and2012were both more severe.2. Seasonal distribution was clear for HFMD in Hunan province, when epidemic period began from April to July. Double peaks distribution were also obvious annually, and the main peak was from May to June, when number of cases proportion to the annual total incidence were62.74%in2008,43.13%in2009,44.84%in2010,41.17%in2011,42.52%in2012. The secondary peak was from mid-October to mid-November. Compared with the same period in2008and2009, the case report increased significantly since2010, and showed an earlier, higher, and longer epidemic characteristics.3. The incidence of HFMD was concentrated in the both central and north of Hunan province, where Changsha, Loudi, Yiyang, Yueyang, Changde. were the more incidence region,whileas Changsha, Loudi, Yiyang, Xiangtan, Yueyang were the higher rate ones. The incidence rate of county areas was higher than that of rural areas. Severe cases was concentrated in Loudi, Shaoyang, Huaihua, Changde, Chenzhou and Yongzhou, while the fatal cases concentrated in Loudi, Shaoyang, Yongzhou, Hengyang.4. Children under3years old was the main HFMD group,accounting for some85%of total cases. The incidence rate was the highest in the age group of1-2years old,and the severe occurrence rate was higher under2years. Severe incidence decreased with the patient age incresed above2years, showing a linear trend:2010(χ2=163.20,P=0.000),2011(χ2=13.77,P=0.000),2012(χ=147.60, P=0.000). The incidence sex ratio of male to female was1.78:1, and the annual incidence of male was higher than female (χ2=5.19, P=0.023in2008; x2=10.18, P=0.001in2009; x2=20.86, P=0.000in2010;χ2=20.68, P=0. OOOin2011; χ2=34.48, P=0.000in2012). The incidence of male was also higher than female in each age group less than5. Scattered children was as the main suffering group, accounting for82.88%in total cases, and had shown an increasing accounting trend since2009.5. Among HFMD confirmed cases from to2009-2012, pathogen EV71accounted for49.80%, CoxA16accounted for20.08%, and other enterovirus, was30.13%. EV71infection positive ratio were both higher in2010and2012, with53.79%and58.35%respectively, and became the main causative pathogen agents of the mild cases,with the positive ratio separately at47.16%and51.25%. Both severe and fatal HFMD cases were mainly caused by EV71infection, which appeared more in2010and2012,when EV71infection accounted for71.40%and74.19%respectively in severe cases, and accounted for90.28%and98.31%respectively in fatal cases.6. Internal nucleotide homology range was96.2-100%of HFMD EV71strain in Hunan province, and showed a higher similarity to type C4strains, in which the nucleotide homology to EV71C4a was the highest at95.4%-97.2%, followed by EV71C4b ranging from92.0to93.5%. As to genetic evolution, EV71Hunan isolated and C4a subtype belong to the same clade. EV71strain in2010was closer with Anhui strain EV71(549/Anhui/08), Yunnan strain (Kunming29/08), Guangdong strain (JF519713/GD/2010), Sichuan strain (AB679738/SC/2010) in2012. EV71strain in2012was closer with Shanghai strain, Jiangsu strain (JF918578/SH/2010)(GU353083/LYG/2009), Hubei strain (EV71/XY18/2011, JQ906805).7. Multivariate Cox regression showed that first-diagnosed in the country (individual) level clinic (OR=3.098, P=0.029), the education degree of HFMD patient take-carer was primary school (OR=10.050, P=0.001), the education degree of take-carer was junior high school (OR=4.512, P=0.007), vomiting (OR=2.853, P=0.028)were all risk factors of HFMD fatal cases,while first-diagnosed as HFMD(OR=0.141, OR=0.002), using antipyretic drugs of Buprofen (P=0.279, OR=0.011) were protective factors.[Conclusions]1. The annual incidence rate was from42.66per100thousand population to287.32per100thousand population respectively. The fatality rate was from0.03%to0.11%. The fatality rate of severe cases was from3.13%to19.10%. The overall epidemic situation of HFMD was severe in Hunan province, and showed a more intensity, longer duration, broader distribution epidemic characteristics. A larger-scale epidemic appeared every other year period cycles.Double peaks distribution were also obvious annually for HFMD in Hunan province,, and the main peak was from May to June, The secondary peak was from mid-October to mid-November.Both Mid-Hunan and the north in Hunan was the main prevalent area of HFMD. Loudi, Shaoyang, Yongzhou, Chenzhou, Huaihua were higher incidence areas both for severe and fatal cases.Children under3was the main HFMD group,within which the incidence rate of1-2years age group was the highest,as well as the severe occurrence rate was higher under2years.2. EV71and CoxA16were the main pathogens of HFMD in Hunan Province, and the epidemic year based on EV71was the main pathogen in epidemic year. EV71was the main pathogen both of severe and fatal HFMD cases. EV71strains isolated were C4a genotype in Hunan province.3.First-diagnosed in the country (individual) level clinic,the education degree of HFMD patient take-carer was primary school,the education degree of take-carer was junior high school, vomitingwere risk factors of HFMD fatal cases,while first-diagnosed as HFMD, using antipyretic drugs of Buprofen were protective factors. |
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