The surveillance of the epidemiological and serotype characteristics of hand, foot, mouth disease in Neijiang city, China, 2010-2017: A retrospective study

Abstract

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.

Forecasting hand-foot-and-mouth disease cases using wavelet-based SARIMA–NNAR hybrid model

“…Although the EV71 vaccine has been introduced and the number of cases of EV71 and CA16 have decreased, other enteroviruses have increased gradually [1,4]. The incidence of HFMD remained high [4][5][6]. Active early intervention is important.…”

A neonatal murine model of coxsackievirus A4 infection for evaluation of vaccines and antiviral drugs

“…Prior to 2009, viral pathogens associated with HFMD included enterovirus A71 (EVA71) and CVA16; however, in recent years, other types of enteroviruses (EVs), such as CVA4, CVA6 and CVA10 have increased in prevalence [2–3]. Numerous outbreaks of CVA4 have occurred during recent years in different regions in China, such as Fujian [4], Shandong [5, 6], Sichuan [7], Yunnan [8], and Jiangsu [9]. Other countries, such as Thailand [2, 10], Australia [11] and Italy [12] have also reported CVA4 infections.…”

Association of the IRAK4 rs4251545 genetic polymorphism with severity of enterovirus‐71 infection in Chinese children

“…Third, no genotyping and sequencing analysis of the EV71 virus was carried out in this study, but C4 was the most popular type in this period according to other reports. 28 , 29 , 30 Moreover, the mechanism by which the IRAK4 rs4251545 polymorphism affects the function of IRAK4 in EV71 infection progression should be elucidated.…”