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Objective To explore the prospect of nonlinear autoregressive neural network in fitting and predicting the incidence tendency of hemorrhagic fever with renal syndrome (HFRS),in the mainland of China.Methods Monthly reported case series of HFRS in China from 2004 to 2013 were used to build both ARIMA and NAR neural network models,in order to predict the monthly incidence of HFRS in China in 2014.Fitness and prediction on the effects of these two models were compared.Results For the Fitting dataset,MAE,RMSE and MAPE of the ARIMA model were 148.058,272.077 and 12.678％ respectively,while the MAE,RMSE and MAPE of NAR neural network appeared as 119.436,186.671 and 11.778％ respectively.For the Predicting dataset,MAE,RMSE and MAPE of the ARIMA model appeared as 189.088,221.133 and 21.296％,while the MAE,RMSE and MAPE of the NAR neural network as 119.733,151.329 and 11.431％ respectively.Conclusion The NAR neural network showed better effects in fitting and predicting the incidence tendency of HFRS than using the traditional ARIMA model,in China.NAR neural network seemed to have strong application value in the prevention and control of HFRS.
RESUMO
Objective To understand the epidemiologic characteristics and pathogenic virus of cases of viral diarrhea in sentinel hospitals in Liaoning Province.Methods From Jan 2009 to Dec 2011,639 stool samples from sentinel hospitals of Liaoning Province were collected.Rotavirus,human calicivirus,astrovirus and adenovirus were detected by polymerase chain reaction and reverse transcriptase-polymerase chain reaction.The data analysis used chi-squanetest and Fisher's exact test.Results Rotavirus,human calicivirus,astrovirus and adenovirus were detected in 15.96 ％,11.25 ％,1.25％ and 0.31％ of the 639 specimens,respectively.G3 was the most prevailing serotype and P[8] was the most common genotype among 101 group A rotavirus isolates.One strain of group C rotavirus was also detected,which was reported for the first time from Liaoning Province.Phylogenetic analysis showed that this group C rotavirus JX407109 in the present study had the closest genetic relationship with the outbreak strain AB648916 from Japan,with nucleotide sequence consistency of 99 ％.Among the 72 samples of human calicivirus,70 samples were norovirus with G Ⅱ/4 being the predominant genotype,and 2 samples were sapovirus.Astrovirus was detected in 8 samples,most of which were genotype 1.Adenovirus was detected in 2 samples,and both were genotype 41.High incidences of viral diarrhea were noted during the months from December to next year February,and children under 5 years of age had high incidence of rotavirus and astrovirus,while the incidence of calicivirus were similar among different age groups.Conclusions The predominant pathogens of viral diarrhea in Liaoning Province are group A rotavirus and calicivirus.Notably,the group C rotavirus in Liaoning Province shares high genetic consistency with the outbreak strain from Japan.