Epidemiological and genetic analysis concerning the non-enterovirus 71 and non-coxsackievirus A16 causative agents related to hand, foot and mouth disease in Anyang city, Henan Province, China, from 2011 to 2015.

Enterovirus 71 (EV-A71) and coxsackievirus A16 (CV-A16) are major pathogens of hand, foot, and mouth disease (HFMD) and have been associated with consecutive outbreaks of HFMD in China over the past years. Although several other human enteroviruses (HEVs) have also acted as causative agents of HFMD, published information on their roles in the prevalence of HFMD is limited. This study was conducted to reveal the characteristics of the pathogenic spectrum and molecular epidemiology of the non-EV-71 and -CV-A16 HEVs in Anyang City, which is located in north-central China and has a population of five million. From 2011 to 2015, 2270 samples were collected from HFMD patients (3.89 ± 1.06 years of age), and 1863 HEV-positive samples, including 524 samples with 23 non-EV-71 and non-CV-A16 serotypes, were identified. Based on the nucleotide sequence of the VP1 gene, 6 common non-EV-71 and non-CV-A16 HEVs, including coxsackievirus A2, A6, A10, A14, B2, and B5, were studied to determine their phylogenies and selective pressures. Phylogenetic analyses revealed a high level of genetic divergence and a pattern of lineage replacement over time in Mainland China. Selective pressure analyses showed that purifying selection was predominant in the evolution of the VP1 gene, whereas positive selection acted on individual codons. Overall, non-EV-71 and non-CV-A16 HEVs were important constituents of the pathogenic spectrum of HFMD in Anyang City during 2011-2015. Some of these HEVs with complex and active phylogenies represent a potential threat to public health, suggesting that long-term monitoring of these pathogens should be implemented to prevent HFMD outbreaks.

[Gene Characteristic Analysis for The VP1 Region of Coxsackievirus A6 Associated with HFMD in the Anyang Area of China during 2013].

This study aims to investigate the etiologic spectrum features of hand, foot and mouth disease(HFMD)and the VP1 region of coxsackievirus A6(CV-A6)in the Anyang area of China during 2013.A total of 479 HFMD fecal specimens were identified using real-time RT-PCR. The positive specimens of the different serotypes and the proportion of each serotype were calculated. A total of 10 positive of CV-A6 specimens were amplified and sequenced to obtain the profile of the VP1 region. Based on the data of the VP1 sequences from the Anyang strains and other referenced strains deposited in the NCBI database, the similarities of the nucleotide and amino-acid sequences for the VP1 region, as well as phylogenetic analyses were performed by the BIOEIDT 7.2and MEGA 5.1software packages. The results revealed that 429 positive specimens of enterovirus, including 90 positive specimens of CV-A6 were identified. The CV-A6 specimens accounted for 20.98%of the total positive specimens.CV-A6 had become the second preponderant pathogen of the HFMD in the Anyang area during 2013.It was the first record of an enterovirus serotype of which was neither CV-A16 nor EV-A71,had become one of the primary pathogens associated with HFMD in the region. A great diversity of the nucleotide and amino-acid sequences between 10 Anyang strains and a prototype strain (Gdula) was found. Compared with the Henan strain(HN421),four Anyang sequences with nucleotide and amino-acid sequences exhibited greater diversity than the other six Anyang sequences. The phylogenetic analysis showed that all of 49CV-A6 strains could be clustered into four branches. Branch D could be further clustered into two sub-branches;6 Anyang sequences belonged to sub-branch D1,and the other four belonged to sub-branch D2.