Epidemiological And Etiological Characteristics Of Hand, Foot And Mouth Disease In Guilin City Guangxi Province In2010

Background HFMD epidemic occurred in many areas in China2010,especially in Guangxi Province,whose reported morbidity was the highest of other provinces.Each city reported cases in Guangxi Province in2010,one of which is Guilin City whose deaths and case fatality was highest.Ten infant deaths who were suspected caused by EV71were reported in Quanzhou County,Guangxi Province from January to April.Quanzhou County became the hot county in2010. The Health Ministry issued the new technical guidelines of HFMD treatment, prevention and control in April20th2010. At the same time,the old one was canceled.Objective To analyze the epidemiological and etiological characteristics of Hand, Foot and Mouth disease (HFMD) in Quanzhou county,Guilin City Guangxi Province in2010,to find the epidemic rules and characteristics,to discuss the reason of this outbreak for HFMD. Laboratory diagnosis is essential for identification of the etiological agent. To identify the agent associated with this outbreak,33clinical specimens from16HFMD cases collected were presented to the National Lab for Poliomyelitis to make laboratory diagnosis in April.Methods Make use of the Chinese Center for Disease Control and Prevention statutory infectious disease reporting system to collect the national and Guangxi Province Guilin City and Quanzhou County HFMD cases, use of excel2003and MapInfo Professional softwares from the point of view of description of epidemics to analyze the characteristics of HFMD. A total of33specimens collected from16cases, including specimens of stool,throat swab, serum, virus isolation was performed on, using RD and HEp-2. The VP1coding gene of EV71(Enterovirus Type71, EV71) strains from clinical specimens was amplified by reverse transcription-polymerase chain reaction (RT-PCR) and sequenced. The homology and phylogenetic analyses were done between the5isolates and other EV71strains based on the sequence of VP1gene.Results (1) All provinces in China reported HFMD epidemics in2010, the morbidity is133.40/100000, which ranked the first in all kinds of infectious diseases, while Guilin City of Guangxi Province is474.12/100000,and Quanzhou County is651.15/100000.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 gender ratio of1.60:1, while1.36:1of Guilin City and Quanzhou County; Most cases were0-5-year-old children, which accouned for89.11%of the total reported cases, while0-3-year-old chilren accounting for61.28%; In Guilin city, most cases aged0to5and accounted for90.44%of the total number of reported cases, whereas0-3-year-old children accounted for65.22%;In Quanzhou county, most cases aged0to5and accounted for90.94%of the total number of reported cases,2-3years childrens’morbidity was highest.The occupational distribution of the cases is scattered children on top of the list, accounting for the total number of reported cases69.72%, followed by children in preschools, accounting for26.28%, students account ing for3.57%. Guilin city were70.72%,24.62%,4.39%, respectively.Quanzhou county were11.69%,19.76%、2.51%, respectively.(3) A total of63733laboratory confirmed cases were reported, which accounted for3.59%,and52.63%of which were caused by EV71.522laboratory confirmed cases were reported in Guilin city,which accounted for2.19%,70.50%of which were caused by EV71.106laboratory confirmed cases were reported in Quanzhou county,which accounted for2.31%,72.64%of which were caused by EV71and27.36%of which were casused by other EV.(4) According to molecular epidemiological analysis, EV71epidemic during this outbreak had the largest nucleotide sequence identity (99.6%) with C4a subgenogroup and clustered with C4references in phylogenetic tree (85bootstrap), belonged to C4a subgenogroup. Excluding QZ10-5F(EV71)、QZ1O-11F(EV71) and QZ10-16F(EV71), belonged to the same clade,the bootstrap is82,and the bootstrap is100of other two.Nucleotide sequence identity and Amino acid sequence identity between5EV71were98.7%～100%and97.5%～99.9%separately.Conclusion Severe HFMD outbreaks caused by HEV71occured in China in2010, some areas including Guangxi Province and Hunan 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. EV71of subgenotype C4a was the main pathogen for severe and death cases of HFMD in Quanzhou county. Suggestions To lower the case fatality,we should develop the epidemic and etiological surveillance and reporting of HEV71in different areas in China, especially the early diagnosis and treatment of these severe cases. To enhance the research of prevention and control measures for HFMD.Early positive rapid diagnostic techniques and effective antiviral drugs and HEV71vaccine should be developed.