| Objective To understand the epidemiological characteristics of hand foot and mouth disease(HFMD)in Inner Mongolia from 2016 to 2017,clarify the relationship between the incidence of HFMD and climatic factors,and master the pathogen composition of HFMD and the molecular epidemiological characteristics of CV-A6.Methods Epidemiological data of the above were studied by descriptive epidemiological methods.Epidemic characteristics of HFMD in different regions,different time and different population were analyzed.Spearman rank correlation was used to analyze the relationship with climatic factors and HFMD.Method of Real-time PCR was used to identify nucleic acid for pathogenic specimen of HFMD,positive samples were isolated.Real-time PCR and RT-PCR were used to identify types of viruses.Representative strains identified as CV-A6 were amplified and sequenced by VP1 gene primers.Results 1.From 2016 to 2017,there were 29450 cases of HFMD reported in Inner Mongolia,and 2 cases of cumulative death.The incidence rate was 55.69/100,000 and 61.37/100,000.The main affected population was children aged 0-6 years,accounting for 90.30%.The male-female ratio was 1.35:1.The highest number of reported cases were Hohhot(2842 cases)and Ordos(3093 cases).The lowest number of reported cases was Alashan League.The highest incidence was Ordos City,with the incidence of 123.32/100,000 and 150.49/100,000 respectively.The lowest incidence was Ulanchab City.There were two epidemic peaks,that was from June to August and from October to December,and the highest peak of HFMD occurred from June to August.The correlation between the incidence of HFMD and the temperature,relative humidity and precipitation was statistical significantly positive,the correlation between the incidence of HFMD and the pressure and wind speed was statistical significantly negative.As for sunshine hours,the correlation between it and the incidence of HFMD was not statistically significant.2.The total number of confirmed cases detected by PCR in Inner Mongolia was 3877 cases.In 2016,the main pathogen was CV-A16.In 2017,the main pathogen was EV71.HFMD in Inner Mongolia showed EV71 and CV-A16 alternating infections from 2016 to 2017.955 strains of virus were isolated.The number of EV71,CV-A16 and other enteroviruses was 453,347 and 155.Laboratory eventually identified 97 other enteroviruses strains,included 9 strains of CV-A6,and CV-A10,CV-A4,CV-B4,CV-B5,Echo6 and Echo30.3.The gene evolution analysis showed that the 9 CV-A6 virus isolates isolated from Inner Mongolia from 2016 to 2017 belonged to the D3 subtype,which was the same as the nucleotide and amino acid of the 2015 Shandong reference strain(DY033/SD/CHN/2015-D3).The highest source is 99.96%~99.97%,99.91%~99.94%.This indicates that there are multiple transmission chains in the popular CV-A6 in Inner Mongolia,and they are co-evolving with other provinces in China.Conclusion 1.From 2016 to 2017,the majority of HFMD patients in Inner Mongolia were children aged 0-6,including more boys than girls,and mostly the kindergartens' children and children in divorce.Ordos,Hohhot and other economically developed and relatively densely populated areas were the main disease-causing areas.There were two epidemic peaks,that was from June to August and from October to December,and the highest peak of HFMD occurred from June to August.The correlation between the incidence of HFMD and the temperature,relative humidity,precipitation,pressure and wind speed was statistically significant.2.From 2016 to 2017,HFMD in Inner Mongolia showed the phenomenon of alternating infection of EV71 and CV-A16,and the laboratory identified a variety of other enteroviruses,mostly CV-A10,CV-A6.3.From 2016 to 2017,9 CV-A6 virus representative strains in Inner Mongolia belonged to the D3 subtype,and there were multiple transmission chains.The relationship with the reference strain in Shandong in 2015 was the closest,indicating that the popular of CV-A6 in Inner Mongolia is co-evolving with other provinces in China. |
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