Epidemiological characteristics of hand, foot and mouth disease among people aged 6 and over in Beijing, 2011-2020 / 中华流行病学杂志

Objective: To analyze the epidemiological characteristics of hand, foot and mouth disease (HFMD) among people ≥6 years old in Beijing from 2011 to 2020. Methods: The incidence data of HFMD cases from 2011 to 2020 were collected from the National Notifiable Infectious Disease Reporting System of China Information for Disease Control and Prevention and the etiological surveillance of HFMD in 29 sentinel hospitals from 16 districts of Beijing. Descriptive epidemiological methods were used to analyze the distributions, pathogen constituents, and changes of HFMD cases in Beijing people ≥6 years old. Results: From 2011 to 2020, a total of 38 183 cases of HFMD were reported among people ≥6 years old in Beijing, of which 46 (0.12%) cases were severe. The average annual reported incidence was 19.04/100 000. The ratio of males to females were 1.37∶1(22 064∶16 119). The proportion of HFMD in people ≥6 years old increased from 7.56%(2 606/34 488) in 2011 to 24.54% (546/2 225) in 2020. The average incidence of HFMD was higher in Shunyi district, Yanqing district, and Tongzhou district than in other districts in Beijing. The positive rate of enterovirus in sentinel surveillance was 66.78% (1 976/2 959), the proportion of enterovirus group A 71 (EV-A71) was 45.29% (101/223) in 2014, no EV-A71 positive was detected in 2020, and the proportion of Coxsackievirus A 6 (CV-A6) increased from 15.11% (34/225) in 2016 to 81.08% (60/74) in 2020. Conclusions: From 2011 to 2020, the proportion of cases with HFMD in people ≥6 years old in Beijing increased yearly, and the proportion of EV-A71 positive patients decreased basically. Since 2016, CV-A6 has gradually become the dominant pathogen. More attention should be paid to the epidemic situation and dynamic pathogen changes of hand foot mouth disease in people ≥6 years old.

Study on the Fast Testing Strategy for identifying the wild poliovirus Ⅰ / 中华流行病学杂志

Objective To explore the Fast Testing Sstrategy (FTS) for wild poliovirus Ⅰ (WP1).Methods Epidemiological investigations were carried out on 671 students from WP1 epidemic areas in China.A set of real time RT-PCR assays,including panenterovirus testings (PE) assay,poliovirus serotypings(PS) assay and the assay distinguishing wild strain from vaccine strain of poliovirus Ⅰ (DWV) were introduced into the screening program for WPV1 to replace the conventional RT-PCR,recommended by the China National Polio Laboratory (GNPL).Additionally,sensitivities of all the assays were assessed by poliovirus type Ⅰ to Ⅲ (Sabin stain) and the isolated WPV I.Results ( 1 ) 33 non-poliovirus enterovirus (NPEV) cases were detected,with 16 polio vaccinerelated cases including 5 polio Ⅰ,1 polio Ⅱ,3 polio Ⅲ,1 polio Ⅰ +Ⅱ,4 polio Ⅰ + Ⅲ and 2 polio Ⅰ + Ⅱ + Ⅲ.Three WPV 1 cases were also detected in this study and confirmed by GNPL.(2) For polio virus vaccine strain,sensitivities of the set of real time RT-PCR assays ranged from 1 to 100 times than that of the in-housc RT-PCR assay.The sensitivities of PE and PS assays for the detection of polio Ⅱ were 100 times than that of the RT-PCR assay and the sensitivity of DWV assay used for the detection of polio Ⅰ were 10 times than that of the RT-PCR assay.For WPV1,the sensitivity of three real time RT-PCR was 10 times higher than that of the RT-PCR assay.Conclusion The novel FTS for WPV I suggested by this study would include PE,PS and DWV.It not only could greatly shorten the testing time but also more sensitive than the RT-PCR and suited for emergency detection for WPV1.

Study on the etiology of hand-foot-mouth disease outbreaks in Beijing in 2007 / 中华流行病学杂志

Objective To identify the etiology of 8 human hand-foot-mouth disease(HFMD)outbreaks in Beijing,during May to July 2007.Methods Reverse transcription-polymerase chain reaction(RT-PCR) method was used to directly type the specimens including fluid from the herpes and throat swabs from the HFMD patients.Using RD cell lines,the collected stool specimens were cultured followed by typing.Partial VP1 region of selected EV positive specimens and cultures were sequenced and both nucleic acid sequence and predicted amino acid sequence were analyzed.Results The two HFMD outhreaks in Daxing region in Beijing in 2007 were caused by enterovirus 71 type(EV71),and the others were caused by Coxsackie virus A16(Cox A16).Two EV71 strains caused epidemics in Daxing region in 2007 belonged to C4 subgenotype but on different branches in VP1 gene phylogenefic tree.The differences on nucleic acid sequence and amino acid sequence were 3.7% and 0.8% between the two EV71 stains.respectively.The Cox A16 strain in Shunyi region and the other strains were on different branches in phylogenetic tree,and the difference on nucleic acid and amino acid sequence were 3.7% and 0% respectively between the two Cox A16 shams.Conclusion The HFMD outbreaks occurred in Beijing in 2007 were caused mainly by EV71 and Cox A16, and there were two individual epidemic virus strains.Cox A16 seemed to spread more widely than EV71 in Beiiing,2007.

Genetic characteristics of enterovirus 71 isolated in Beijing,2006-2008 / 中华流行病学杂志

Objective To sequence and analyze the VP1 region of isolated enterovirus from different sources in Beijing,2006-2008.Methods 9 EV71 were selected from the isolates identified through the specimen of human hand foot mouth disease (HFMD),acute flaccid paralysis (AFP) and healthy children in Beijing,2006-2008.Reverse transcription-polymerase chain reaction (RT-PCR) method was used to amplify and sequence the whole VP1 gene of enterovirus.Phylogenetic tree was constructed,with the means of nucleotide homology and distance between/within groups analyzed.Results The 9 selected strains were clustered with C4 subgenotype reference strains in Phylogenetic tree and showed high nucleotide acid identity (92.1%-93.9% ) in nucleotide homology analysis,and had higher homology than C1,C2,C3 subgenotype reference strains (88.8%-89.5%,89.4%-90.0% and 88.4%-89.3%,respectively).High homologous (95.9%-100.0%) was noticed between the isolated stains from three different sources,but low homologous (93.3 %-93.9%,92.1%-92.9%,respectively) showed between the isolated stains and C4 reference strains isolated in 1998.There appeared larger variations between groups in C4 subgenotype when analyzing the distance between groups means,especially between the reference strains and isolated strains (D=0.052-0.071).Conclusion The EV71 isolated in Beijing,from 2006 to 2008 also appeared to be C4 subgenotype and there was no significant difference found in the whole sequence ofVP1 gene of the strains isolated from different regions,sources,or under different diseases occurred in the same period.There were more nucleotide variations and more chances for the presence of new subgenotype,suggesting that it is necessary to strengthen the surveillance program on EV71 isolates.