| BackgroundSince the 1990s, many countries in the Asia-Pacific region have experienced the epidemic of hand, foot, and mouth disease, including Malaysia, Taiwan (China), and China. The epidemic in Malaysia induced 29 deaths from April to June of 1997.78 deaths were reported during the epidemic in Taiwan which was happened in 1998. Early in the 2008, a large epidemic took place in Fuyang city, which is belonged to Anhui province of China, and 23 children died. The pathogen of these large epidemics above was all EV71. Recently, hand, foot, and mouth disease especially EV71-related epidemic has become an important public health problem.Objective:The study aims to describe the epidemiologic, etiologic, and seroepidemiological features of hand, foot, and mouth disease in Shanghai, find the focus of the disease, and finally make the feasible control and prevention strategy which can be piloted in the future.Methods:1. Surveillance data Surveillance data coming from the hand-foot-mouth surveillance system in shanghai have been analyzed with the methods of descriptive epidemiology. Cases reported to the surveillance system from 2005 to 2012, including severe cases, outbreaks and etiologic data from 2009 to 2012, are all analyzed, as well as the seroepidemiological data from 2010 to 2012.2. Data analysis Descriptive epidemiology methods are used to analyze the distribution of hand, foot, and mouth disease in shanghai. All of the data are disposed and analyzed by Excel 2010 and SPSS 19.0.Results:1. Epidemiologic features The incidence of hand, foot, and mouth disease in Shanghai increased year by year. During the period from 2002 to 2006, the incidence was very low, and the annual incidence rate was 5.0-20.0/100,000. In 2007, the incidence rate rose up to 58.1/100,000. Since 2008, the annual incidence rate was maintained above 100.0/100,000, and the highest was 208.0/100,000 in 2012. Severe cases and deaths were reported every year from 2008 to 2012, and the total number was 1229, taking 1% of all the hand, foot, and mouth disease cases. Only 23 deaths were reported to the surveillance system, and the mortality was as low as 0.13/1000.A seasonal peak was seen in summer from May to June; meanwhile a small peak was also found in winter from November to December. The summer peak was much higher than winter peak during 2005-2012, except 2011. The case reports and outbreaks both had two peaks, and showed the similar trend, but severe cases of hand, foot, and mouth disease only have a summer peak. All the districts in shanghai had experienced the epidemic of hand, foot, and mouth disease, and those suburbs with more migrants have a higher incidence, including Minhang, Songjiang, Qingpu, Jiading, and Fengxian. 1116 of all the 1229 severe cases occurred in the suburbs, and over 100 cases were reported in Minhang, Jiading, Songjiang, Pudong, Fengxian, and Qingpu, with the number of 274,198,154,137,128,120, respectively. Only 113 severe cases occurred in urban districts, and the ratio of urban area to suburb is 1:10.Children under 5-year-old were the main group of hand, foot, and mouth disease, but most severe cases were 1 to 3 years old. The number of male cases was much higher than female and the sex ratio (male:female) was 1.6:1; sex ratio for the severe cases was 1.8:1. As much as 4507 outbreaks were happened in child care centers and kindergartens, which took 84.3% of all the outbreaks. The median cases of all the outbreaks were 3 (smallest to most:2-44).64.6% of the outbreaks had 2 to 4 cases, and 27.9% had 5 to 9 cases, while only 7.4% had 10 or even more cases. The median duration of all outbreaks is 5 days (shortest to longest:1-45).73.5% of these outbreaks can be controlled in 7 days, while 94.1% in 14 days.2. Etiologic features EV71 and CoxA16 were the main pathogens of hand, foot, and mouth disease in shanghai, while EV71 was the most critical virus for severe cases. Etiologic surveillance results showed that, Dynamic changes in the proportion of Enterovirus, which can induce hand, foot, and mouth diseases, were occurred every year. CoxA16 was the main pathogen in 2009, with the proportion of 55.2%, but EV71 was only 31.5%. During 2010, EV71 rose up to 43.8%, but CoxA16 declined to 39.8%. In 2011, the proportion of EV71 was even higher than that in 2010, which took 53.9% of all the positive cases. In the first half of 2012, the proportion of EV71 declined to 31.7%, and CoxA16 rose to 43.3%, but in the second half, the proportion of EV71 and CoxA16 went down below 30%. Otherwise, enterovirus except EV71 and CoxA16 had a higher proportion, and became the first pathogen of hand, foot, and mouth disease. The time trends of etiologic surveillance and the lab tests in the outbreaks showed the similar distribution. Lab detection results showed that 92.0% of severe cases were EV71 infection.3. Seroepidemiologic features The neutralizing antibody of EV71 surveillance showed that, the positive rate was 17.3% in the early stage of the epidemic and rose up to 26.2% in the later stage in 2010. Positive rates in 2011 were 33.4% in the early-stage and 34.2% in the later, while 21.9% and 31.6% in 2012. The neutralizing antibody of CoxA16 surveillance showed that, the positive rate was 12.4% in the early stage of the epidemic and rose to 31.6% in the later stage in 2010. Positive rates in 2011 were 33.7% in the early stage and 36.8% in the later, while 22.8% and 29.3% in 2012. Positive rate in the later stage of epidemic was higher than that in the early stage, which was seen of EV71 and CoxA16, significantly in 2010 and 2012. Although there was a little increase of positive rate in 2011 too, analysis results showed there’re no statistical differences.The positive rates of EV71 and CoxA16 neutralizing antibody varied in different age groups, and the rate in 1-4 years old group was the lowest. The positive rate of both EV71 and CoxA16 neutralizing increased with age, but slightly went down for people older than 60 years. The positive rate of male was lower than female, but there were no statistical differences except in 2012, when the positive rate of EV71 neutralizing antibody was 18.2% for male and 25.7% for female in the early stage, as well as the positive rate of CoxA16 neutralizing antibody was 25.5% for male and 33.8% for female in the later stage.Conclusion:1. Hand, foot, and mouth disease is a common infectious disease with high morbidity and low mortality. There is an epidemic in all districts in shanghai, especially those with large amount of migrants. Recently, the migrant population has become an important factor of Hand, Foot, and Mouth Disease prevention and control. In the future, it is necessary to explore new prevention and management modes of Hand, foot, and mouth disease in the context of urbanization.2. Children under 5-year-old are more vulnerable for hand, foot, and mouth disease. Children aged 1 year old are the main group of severe cases, and with the increase of age, the number of severe cases declines. As a result, we should pay more attention to the early detection of severe case and the outbreaks in kindergartens and child care centers.3. There are epidemics of EV71, CoxA16 and other enterovirus in shanghai, and the proportions of different viruses are changing dynamically, but EV71 infection is the main causation of severe cases. Currently, we should enhance the surveillance for hand, foot, and mouth disease, especially EV71, as there are no specific therapeutic drugs and vaccines now. The persistent surveillance can not only provide evidence for analysing the epidemic features and risk assessment, but also give the fundamental data for application of EV71 vaccines in the future.Prevention and control strategy:1. Focus on the early detection of severe case and outbreaks.2. Improve the basic health service system for migrant children gradually.3. Enhance the participating of community and the ability of primary health workers.4. Make targeted health education strategies.5. Strengthen the cooperation and risk communication among different departments and agencies. |
PDF Full Text Request