| Background:Hand, foot and mouth disease(HFMD) is a kind of infectious disease caused by a variety of human intestinal virus, infectivity is strong, easy to cause epidemic and outbreak. The incidence of HFMD in China is high. Shanghai found that since 1981, after the first HFMD patients appeared, many provinces(municipalities) appeared the popularity of HFMD even large-scale outbreak. China's ministry of health officially listed HFMD in the People's Republic of China on the prevention and control of infectious diseases specified scope of C class infectious diseases on May 2,2008. During 2010-2015, HFMD incidence is the top of the charts a statutory infectious diseases report six years in a row, deaths in fifth place. From 2014 to 2015, HFMD reports cases in Ningxia is the third and first among statutory infectious reported diseases and the form of HFMD epidemic prevention still ten in Ningxia.Objective1. Analysis on the epidemic characteristics of HFMD from 2014 to 2015 in ningxia, to master the epidemic law of the disease in time, then to provide theoretical basis for scientific and effective prevention and control measures.2. Analysis HFMD pathogen spectrum, combining the epidemiological data, analysis of genetic evolution characteristics of some advantage pathogens, to master its molecular change rule.3. Analysis risk factors for severe cases of HFMD,in order to timely prevention and intervention in the early onset.Method1. Epidemiological studies of HFMD: using the description epidemiology method to statistical analysis of HFMD monitoring data, describe three distribution characteristic of HFMD from 2014 to 2015 in Ningxia;2. Etiology characteristics of HFMD research: For five cities(counties) EV-U which are non EV71 and non Cox A16 feces from 2014 to 2015 in Ningxia, after the virus separation, accounting extraction, rt-pcr and sequence determination and other steps, then analysis of genetic evolution characteristics of the isolates.3. Severe risk factors analysis: To collect information about severe case table, using multiariable Logistic regression analysis method carried out on the severe factors regression analysis.Results1. In 2014-2015, Ningxia reports 15157 cases of HFMD disease, accounted for 19.66% of all the legal infectious diseases, account for 38.93% of the c class infectious diseases, the incidence are 88.17/10 and 88.17/10 respectively, a total of 51 cases of serious illness case, reported incidence of severe 0.71% of all the illness case.2. In 2014-2015, 81.58% HFMD for children under 5 years old that one year of age group and three years of age group are the highest incidence. After 6 years of age, morbidity decrease with increasing age, disease constitute has a statistically significant differences in different age groups(?22014-2015 = 121.47, P < 0.001), the proportion of incidence between men and women with an average of 1.47:1(?22014-2015 = 3.51, P > 0.05), the incidence of scattered children above nursery children, students, and other professional people.3. HFMD has obvious seasonal characteristics in Ningxia, present a master a bimodal distribution, incidence peak for 5 to 7 months, two years peak incidence(cases) of 45.93 per 100,000(3005 cases)and 98.39 per 100,000(6509 cases), 52.1% and 69.33% of the total number of HFMD. Onset time to peak from September to October, and the total incidence(cases) of 20.73 per 100,000(1356 cases)and 14.95 per 100,000(989cases),4. HFMD epidemic covers widely, various cities all have reported cases, Yinchuan incidence is the hightest in Ningxia that up to the incidence of 130.13/10 and 222.70/10 respectively, were 47.75%, 50.77% of the total during 2014-2015. Five cities incidence of HFMD are different in Ningxia, 2014-2015(?22014-2015=239.072, P < 0.001). Two years in various cities in the sequence of Yinchuan>Wuzhong> Shizuishan > Zhongwei>Guyuan, Yinchuan>wuzhong>Guyuan>Zhongwei>Shizuishan.5. In 2014-2015, laboratory diagnosis of 2427 cases of HFMD cases, Cox A16 accounted for 47.75%, EV71 accounted for 22.88%, EV-U accounted for 29.38%. Two years in different pathogens constitute is different(?22014 = 56.16, P < 0.001; ?22015 = 68.532, P < 0.001). Different areas of pathogens is different(?22014 = 104.22, P < 0.001; ?22015 = 100.51, P < 0.001). In 2014-2015 of Ningxia the centers for disease control and prevention was conducted on 640 specimens of EV-U positive virus separation, acquired a total of 188 isolates, the average separation rate is 29.38%.6. After of 188 isolates type identification, found 2014 Cox A10 as the main type among EV-U, accounting for 65.2%, followed by Cox A4(10.64%), Cox A8(6.38%), EV11(4.26%), Cox A14(2.13%) and Cox B5(2.13%). In 2015, Cox A6 as the main type among EV-U, accounting for 39.72%(56/141), followed by Cox A10(4.96%), Cox A2(1.42%) and Cox A4(0.71%).7. In 2014-2015, the two main type of Cox A6, Cox A10 of EV-U's genetic evolution analysis shows: In 2015,56 Cox A6 isolates of Ningxia local area with the genetic distance of Cox A6 prototype strains and abroad genetic is far, genetic relationship is far,but the genetic distance with Fujian, Jiangsu, Shanghai and other places of China isolates' genetic distance is close, close relatives. So popular Cox A6 in Ningxia with national Cox A6 in a popular cycle.Time distribution, Cox A6 of Ningxia local strain distribution in the same year is relatively concentrated, and the homology of the isolates in the same year is higher than the homology during two years(92.8% 100%);Regional distribution, isolates of the same area is relatively concentrated among five cities, nucleotide homology in different parts of the five cities of Ningxia is greater than the overall nucleotide homology.Illustrate Ningxia popular Cox A6 has the characteristics of time distribution and regional characteristics.In 2014-2015, Cox A10 genetic evolution analysis shows: Two years popular Cox A10 belong to type C of Cox A10 virus. Homology results also showed that 38 strains Cox A10 of Ningxia local strain and C represent the nucleotide homology of the highest, 2014 and 2015 strains with C representative nucleotide homology of 89.7%-96.9% and 94.3%-98% respectively. From an evolutionary tree as a whole, from 2014 to 2015 in Ningxia popular Cox A10 genetic distance with foreign popular reference strains, and with the domestic Hebei far better affinity. Time distribution,2013 isolates from 2014 to 2015 strains are clearly in the evolution of the two different branches, explain popular Cox A10 mutate more easily in Ningxia, time popular feature is obvious.8. Severe cases in the majority with one year of age group of scattered children, boys(35 cases) than girls(16 cases). Two years female incidence ratio is 2.19:1. EV71 remains the leading cause of severe cases occur pathogens, multiariable Logistic regression showed that age, and both the interval number between attack and first visit, type of pathogens is leading to a risk factor for severe HFMD occur.Conclusion1. From 2014 to 2015, HFMD epidemic situation is still grim in Ningxia, rendered every 1 to 2 years in great popular characteristic; Mainly occur among scattered children under 5 years old, with one year of age groups and 3 years old the highest incidence of this disease, the incidence of men is more than women; The time distribution displayed bimodal, peaks for 5 to 7 months, sub peak for 9-10 month; Yinchuan is the highest incidence of HFMD in Ningxia.2. Cox A16 for HFMD is the main advantage of pathogens from 2014 to 2015 in Ningxia,the second main advantage pathogenic from EV71 to EV-U, separation of EV-U isolates, in 2014 is given priority to Cox A10, in 2015 is given priority to Cox A6.Two years of popular Cox A6 and Cox A10 are in line with the national trend, but there are differences in the time distribution and regional distribution.3. The most severe cases with one year of age groups, the priority of scattered children is largest, the popularity of overall time distribution and two years at the same time. Age, both the interval number between attack and first visit, type of pathogens is leading to a risk factor for severe HFMD occur.and caused severe EV71 is still the main pathogens. |
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