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Coxsackievirus A10 (CV-A10) associated with Hand, foot, and mouth disease (HFMD) cases emerged increasingly in recent years. In this study, the samples from nation-wide HFMD surveillance, including 27 out of 31 provinces in China were investigated, and the continuous and extensive virological surveillance, covered 13 years, were conducted to provide a comprehensive molecular characterization analysis of CV-A10. 855 CV-A10 viruses (33 severe cases included), were isolated from HFMD children patients during 2009 to 2016 in China. 164 representative sequences from these viruses, together with 117 CV-A10 sequences downloaded from GenBank based on entire VP1 were recruited in this study. Two new genotypes (F and G) and two sub-genotypes (C1 and C2) were identified. Among 264 Chinese sequences, 9 of them were genotype B, 8 of them were C1, and the other (247) were C2, the predominant sub-genotype in China since 2012. Chinese C2 viruses showed obvious temporal characteristics and can be divided into 3 clusters (cluster 1~3). Cluster 3 viruses was circulating extensively during 2014 and 2016 with more severe cases. It is very necessary and important to continuously conduct the extensive virological surveillance for CV-A10, and further evolutionary studies will provide more evidence on its evolution and virulence.

an outbreak caused by type 2 circulating vaccine-derived poliovirus (cVDPV) occurred in Aba County, Sichuan, China. During the outbreak, four type 2 VDPVs (>0.6% nucleotide divergence in the VP1 region relative to the Sabin 2 strain) were isolated from 3 patients with acute flaccid paralysis (AFP) and one close contact. In addition, a type 2 pre-VDPV (0.3% to 0.5% divergence from Sabin 2) that was genetically related to these type 2 VDPVs was isolated from another AFP patient. These 4 patients were all unimmunized children 0.7 to 1.1 years old. Nucleotide sequencing revealed that the 4 VDPV isolates differed from Sabin 2 by 0.7% to 1.2% in nucleotides in the VP1 region and shared 5 nucleotide substitutions with the pre-VDPV. All 5 isolates were closely related, and all were S2/S3/S2/S3 recombinants sharing common recombination crossover sites. Although the two major determinants of attenuation and temperature sensitivity phenotype of Sabin 2 (A 481 in the 5= untranslated region and Ile 143 in the VP1 protein) had reverted in all 5 isolates, one VDPV (strain CHN16017) still retained the temperature sensitivity phenotype. Phylogenetic analysis of the third coding position of the complete P1 coding region suggested that the cVDPVs circulated locally for about 7 months following the initiating oral poliovirus vaccine (OPV) dose. Our findings reinforce the point that cVDPVs can emerge and spread in isolated communities with immunity gaps and highlight the emergence risks of type 2 cVDPVs accompanying the trivalent OPV used. To solve this issue, it is recommended that type 2 OPV be removed from the trivalent OPV or that inactivated polio vaccine (IPV) be used instead.

To date, eight hepatitis B virus (HBV) genotypes, A–H, have been designated, and two additional genotypes, I and J, have also been proposed. A serological survey targeting children in difficult‐to‐reach vaccination areas was carried out in remote counties of Sichuan Province, China. HBV genotypes and serotypes were also determined from HBsAg‐positive serum samples by direct sequencing. Phylogenetic analysis showed two strains isolated from the Yi ethnic children clustered with the proposed genotype I. The pairwise genome genetic distance was 7.5% between genotypes I and C, and ranged from 8.4% to 15.2% between genotype I and other genotypes, except genotype C. Grouping Scan analyses of the two strains revealed apparent recombination events between an unknown genotype and genotype C. Two out of four HBV strains isolated from the Yi ethnic children were confirmed to be genotype I, suggesting widespread circulation and common infection with genotype I HBV in the local Yi population. High prevalence of HBsAg and low hepatitis B vaccination coverage indicated that additional efforts are needed to control HBV infection in those areas. J. Med. Virol. 84:866–870, 2012. © 2012 Wiley Periodicals, Inc.

Hand, foot, and mouth disease (HFMD) is well recognized as one of the major threats to children’s health globally. The increasing complexity of the etiology of HFMD still challenges disease control in China. There is little surveillance of the molecular epidemiological characteristics of the enteroviruses (EVs) that cause HFMD in Neijiang city or the Sichuan Basin area in Southwest China. In this study, demographic and epidemiological information for 14,928 probable HFMD cases was extracted and analyzed to describe the epidemic features of HFMD in Neijiang city from Jan 2010 to Dec 2017. The swab samples of select probable HFMD cases from 2012 to 2017 were tested by reverse transcription (RT) real-time PCR to identify the serotype distribution of EVs, and 110 randomly selected RT-real-time PCR positive samples were then amplified and analyzed for the VP1 or VP4 regions of EVs to further analyze the phylogenetic characteristics of the circulating strains in this area. The eight-year average annual incidence was 49.82 per 100,000 in Neijiang. The incidence rates varied between 19.51 and 70.73 per 100,000, demonstrating peaks of incidence in even-number years (2012, 2014 and 2016). The median age of the probable cases was 27 months and the interquartile range (25 th to 75 th percentile) of ages for the probable HFMD cases was between 14 and 42 months. The male-to-female ratio of the probable HFMD cases was 1.47:1, and scattered children were the major population classification (81.7%). Two epidemic peaks were observed: one major peak between April and July and the other lesser peak between October and December. Of 6513 probable cases tested with RT-real-time PCR, 4015 (61.6%) were positive for enterovirus with the serotype distribution as follows: EV71+, 30.1% (n = 1210); CV-A16+, 28.7% (n = 1154) and a sole pan-enterovirus+, 41.1% (n = 1651). A total of 91 cases (82.7%, 91/110) were successfully amplified and underwent phylogenetic analysis: all EV71+ cases were C4a serotype (n = 23/30); all CV-A16+ cases were B2b serotype (n = 24/30); of 42 sole pan-enterovirus+ samples, 20 were CV-A6, 14 were CV-A10 and the rest within this group were CV-A4 (n = 4), CV-A8 (n = 2), CV-A9 (n = 1) and CV-B3 (n = 1). Our findings provide important evidence that aids the improvement of strategies for vaccination against HFMD and comprehensive disease control in China.