Epidemiological Characteristics And Death Risk Factors Of Hand, Foot And Mouth Disease In Shandong Province,2007-2011

[Background]Hand, foot and mouth disease (HFMD) is an acute viral infection disease that caused by enterovirus. China has a high incidence rate of HFMD. Since the first case was reported in Shanghai in1981, more than ten provinces have proved the exist of HFMD cases followed. So far, HFMD has spread to all of the province in China. Recent years, some regions of China emerged HFMD pandemic, especially in Guangdong, Anhui, Shandong, Henan, Jiangsu. The HFMD cases and death cases increased year by year. In2010, the mainland China reported a total of1,773,500HFMD cases, increased53.71%compared with the1,153,800of2009; the number of death cases is904, increased155.37%compared with the year2009. HFMD dose have pose a serious hazard to the health of children and adolescents, the prevention and control of HFMD is of great urgency.[Objectives]1. To analyze the epidemical features, clinical characteristics, temporal distribution features of HFMD in Shandong province from2007to2011, so as to provide a scientific basis for the prevention and control of the HFMD.2. To analyze the etiological constitution of HFMD in Shandong province.3. To build a data base of VP1complete gene of EV71isolated in Shandong province, and analyzes the gene evolution characteristics of EV71.4. To build a data base of VP1complete gene of CoxA16isolated in Shandong province, and analyzes the gene evolution characteristics of CoxA16.5. To analyze the clinical characteristics and death risk factors of HFMD death cases. [Methods]1. Descriptive research:In the study, the HFMD cases data of Shandong province between2007and2011will be collect from China Disease Prevention and Control information system, and then the incidence rate, age-related constituent ratio, gender-related constituent ratio, etiological constituent of HFMD in Shandong province will be analyze. We will describe the three intervals distribution of HFMD in Shandong province by using the principle of descriptive epidemiology. The clinical characteristics of death cases will be analyze according to the result of HFMD case survey.2. Etiological characteristics research:The stool and throat swabs specimens of HFMD cases that submitted by city CDC will be selected randomly, then through the procedure that viral culture, extraction of Nucleic Acid, RT-PCR, sequence determination and analysis, and then analyze the gene evolution characteristics of EV71and CoxA16.3. The death risk factors analyze:We choose the HFMD death cases as the case group, and select the HFMD severe cases as the control group, then the1:3matched case-control study method will be used to analyze the death risk factors of HFMD. Condition Logistic regression analyze was used in the study, and SAS9.1software was used to execute the Statistics.[Results]1. In the year between2007and2011, the annual number of cases of HFMD in Shandong province is38267,32434,138227,141744,95796. The annual cumulative incidence rate of HFMD are4.09per10000,3.46per10000,14.76per10000,15.13per10000,10.01per10000.2. Children under5years old is the major group who suffering from HFMD. In the year between2007and2011, the annual constituent ratios of cases under5years old are88.57%,91.28%,91.89%,91.21%,89.00%. The severe cases concentrated in children under3years old. During the year2009to2011, the annual constituent ratios of severe cases under3years old in all the severe cases are84.08%,77.94%,73.01%. The male cases is more than female, the annual sex ratio between male and female during the year2007to2011are between1.66and1.80. The peak period of incidence of HFMD in Shandong province is between May and August, during the year2007to2011, the annual constituent ratios of cases turn up between May and August are81.38%,77.73%,64.10%, 74.72%,73.60%.3. EV71and CoxA16is the major pathogens of HFMD in Shandong Province. During the year2008to2011, the annual constituent ratios of cases caused by EV71in all laboratory confirmed cases are60.53%,67.02%,34.69%,50.57%, meanwhile, the annual constituent ratios of cases caused by CoxA16in all laboratory confirmed cases are27.63%,3.64%,37.08%,29.78%.4. The67EV71strains isolated in Shandong province during the year2007to2011are all C4a subtype. The nucleotide homology analysis showed62.1%～63.4%nucleotide identities between EV71strains isolated in2011and CoxA16prototype strain,80.5%～82.9%nucleotide identities between EV71strains isolated in2011and EV71prototype strain,83.0%～85.4%nucleotide identities between EV71strains isolated in2011and EV71B subtype representative strain,85.6%～88.5%nucleotide identities between EV71strains isolated in2011and EV71C1subtype representative strain,87.4%～90.3%nucleotide identities between EV71strains isolated in2011and EV71C2subtype representative strain,86.7%～88.7%nucleotide identities between EV71strains isolated in2011and EV71C3subtype representative strain,93.3%～96.6%nucleotide identities between EV71strains isolated in2011and EV71C4a subtype representative strain,90.1%～93.1%nucleotide identities between EV71strains isolated in2011and EV71C4b subtype representative strain.5. The38CoxA16strains isolated in Shandong province during the year2007to2011are all B1subtype. The nucleotide homology analysis showed75.1%～77.3%nucleotide identities between CoxA16strains isolated in2011and CoxA16prototype strain,89.0%～90.0%nucleotide identities between CoxA16strains isolated in2011and CoxA16B2subtype representative strain,90.9%～95.3%nucleotide identities between CoxA16strains isolated in2011and CoxA16strains isolated in2007.6. The average course of fatal cases was82.40±5.39hours, and the mean maximum temperature was39.08±0.15℃. The death risk factor contains cough (OR=16.16, P=0.0398), cervical resistance(OR=189.50, P=0.0072), vomiting (OR=16.16, P=0.0398);older age (OR=8.04, P=0.0131) is a protective factor. [Conclusions]1. Shandong province has a high incidence rate and constituent ratio of severe case of HFMD. HFMD is harmful to the people’s health, we should strengthen the prevention and control of HFMD.2. Children under5years old is the high-risk population for HFMD, and children under3years old is the high-risk group of severe case and death case. We should strengthen the clinical monitoring of patients under3years old, so as to prevent severe case and death case.3. May to August is a high-risk period of HFMD in Shandong province, the health sectors should strengthen the health education of children and adolescents in that time. Meanwhile, health sectors should strengthen the disinfection of places where children congregate, such as nursery, primary school, and prevent the outbreak of HFMD.4. EV71is the most important advantaged pathogen of HFMD in Shandong Province, and EV71infection is the risk factor of severe case.5. EV71and CoxA16are both in the process of gene mutation and the virus variation is fast. we should strengthen the monitoring of EV71and CoxA16, so as to prevent the epidemic of new strains.6. Cough, cervical resistance, vomiting is the death risk factor of HFMD, and older age is a protective factor. The clinical care and monitoring of younger patients with cough, cervical resistance, cold of extremities and vomiting should be strengthened.