| ObjectiveTo analyze the epidemiological characteristics and incidence trends of Hand,Foot,and Mouth Disease(HFMD)during 2009-2013 in Lanzhou City,Pingliang City,Wuwei City of Gansu province,and to predict the numbers of HFMD cases in those cities and thus to provide the basic evidence for prevention and control of HFMD.MethodsWith the method of description study for epidemiological disease,epidemiological characteristics of HFMD emergence during 2009-2013 in Lanzhou,Pingliang and Wuwei were described.The incidence cases,morbidity and proportion were used as descriptive indexes.The ARIMA model was established respectively on the basis of weekly cases occurring in Lanzhou City,Pingliang City and Wuwei City during 2009-2012,and accordingly the incurrence cases of 2014 were predicted in the three cities.The root mean square error(RMSE),mean absolute percentage error(MAPE),and mean absolute error(AAE)were used as the fitting goodness indicators.ResultsThe number of HFMD cases reported in Lanzhou City during 2009-2013 was 15495 cases,with the annual incidence rate of 56.84/100,000-122.68/100,000,while the standardized incidence rate is 74.73/100,000-160.57/100,000.The number of HFMD cases reported in Pingliang City during 2009-2013 was 5356 cases,with the annual incidence rate of 20.34/100,000-104.14/100,000,while the standardized incidence rate is 20.23/100,000-112.95/100,000.The number of HFMD cases reported in Wuwei City during 2009-2013 was 5389 cases,with the annual incidence rate of 10.47/100,000-120.35/100,000,while the standardized incidence rate is 11.49/100,000-136.01/100,000.There was a seasonal distribution of HFMD in Lanzhou City,Pingliang City,Wuwei City during 2009-2013.The incidence curve during the five years in Lanzhou city was a two-peak mode,and the second peak was obvious but not prominent.The incidence curve in Wuwei City in 2009 and 2010 was respectively a two-peak mode,while in the other years it was a one-peak mode.The incidence curve in Pingliang City during the five years was a one-peak mode.In Lanzhou,the first peak was during April to July,and the second minor peak was during September to November.During April to July in 2009-2013,the incidences of HFMD accounting for the proportion of the total incidence were 64.60%,66%,63.50%,75.4%,73.30%.In Pingliang City,the peak time was during May to August,and the incidences of hand foot mouth disease during May to August accounting for the proportion of the total incidence were 52.4%,87.10%,66.40%,80.2%,90.80%.The onset time in Wuwei City is not the same,and the incidences of hand foot mouth disease during May to August accounting for the proportion of the total incidence were 65%,26.8%,65.1%,89.6%,47.4%annually.The number of cases of male was higher than female during 2009-2013 in Lanzhou City,Pingliang City,Wuwei City,.Lanzhou male cases accounted for 60.6%-62.5%of all cases,Pingliang 62.3%-67.4%and Wuwei 60.4%-65.5%.The average age of incidence during 2009-2013 in Lanzhou City,Pingliang City,and Wuwei City was respectively 3.56-3.66 years old,2.74-2,87 years,and 3.09-3.22 years old.The proportion of cases of children under 5 years old was respectively 86.6%-89.3%,88.3%-92.1%,87.1%-89.8%in Lanzhou City,Pingliang City,and Wuwei City.The proportion of cases of children under 10 years old was respectively97.5%-97.7%,97.5%-99.5%,97.5%-98.6%in Lanzhou City,Pingliang City,and Wuwei City.During 2009-2013 year in Lanzhou City,Pingliang City and Wuwei City,HFMD cases were mainly in nursery children and scattered children,followed by students,while the three together accounted for the proportion of 99.2%in Lanzhou City,99.8%in Pingliang City,and 99.6%in Wuwei City.With the weekly incidence data of Lanzhou City,Pingliang city and Wuwei city during 2009-2012,through the parameters and model test of goodness of fit,the ARIMA model was determined as following:in Lanzhou City,ARIMA(0,1,2)(0,1,1)52,RMSE=24.092,MAPE=45.600,Normalized BIC=6.674,Ljung-Box Q(18)P=0.650:in Pingliang City,ARIMA(3,1,0)(0,1,0)52,RMSE=9.329,MAPE=110.313,Normalized BIC=4.904,Ljung-Box Q(18)P=0.348;and in Wuwei city,ARIMA(0,1,1)(0,0,1)52,RMSE=18.276,MAPE=126.498,Normalized BIC=5.914,Ljung-Box Q(18)P=0.109.Weekly value and real value during 1-52 weeks in 2013 in Lanzhou City,Pingliang City and Wuwei city were compared,and predict forecast indexes of RMSE and AAE during 1-20 weeks and the 50th week were respectively calculated.In Lanzhou,during 1-20 weeks,RMSE = 8.01,AAE=5.05;in the 50th week,RMSE =9.93,AAE=6.82.In Pingliang,during 1-20 weeks,RMSE = 2.62,AAE=2.08;in the 50th week,RMSE = 6.48,AAE=4.68.In Wuwei,during 1-20 weeks,RMSE = 2.62,AAE=0.47;in the 50th week,RMSE = 2.90,AAE=4.01.Based on the indexes of RMSE and AAE during 1-20 weeks and the 50th week,the differences were minor,indicating the stability of prediction.The incidence cases in Lanzhou City in 2014 were forecasted as 3520 cases;the sequence diagram was predicted to be the two-peak model;and the onset peak time was predicted in the 27th week(June to July)and 45th week(around November).The incidence cases in Pingliang City in 2014 were forecasted as 1042 cases;the sequence diagram was predicted to be the solo-peak model;and the onset peak time was predicted in the 26th week(around June).The incidence cases in Wuwei City in 2014 were forecasted as 640 cases;the sequence diagram was predicted to be abnormal slowly rising trend.ConclusionThe morbidity of HFMD during 2010-2013 in Lanzhou was higher than that in Pingliang and Wuwei;the incidence of male was higher than female.The HFMD incidence showed significant seasonal distribution in the three cities,and peak time was during from April to August.Children under 5 years old was a high risk for HFMD,while the children of 1-3 years old had the highest proportion.Therefore young children should be supervised foremost.Seasonal ARIMA model can reflect the variation and incidence trends of HFMD cases in the three cities,and its prediction effect is stable. |
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