Department of Virology, National Institute of Hygiene and Epidemiology, No. 1 Yersin, Hanoi, Vietnam.
Hokkaido University, Sapporo, Japan.
Arch Virol. 2020 Apr;165(4):823-834. doi: 10.1007/s00705-020-04536-3. Epub 2020 Feb 1.
While conducting sentinel surveillance of hand, foot, and mouth disease (HFMD) in Vietnam, we found a sudden increase in the prevalence of coxsackievirus A10 (CV-A10) in 2016 and CV-A2 and CV-A4 in 2017, the emergence of which has been reported recently to be associated with various clinical manifestations in other countries. However, there have been only a limited number of molecular studies on those serotypes, with none being conducted in Vietnam. Therefore, we sequenced the entire VP1 genes of CV-A10, CV-A4, and CV-A2 strains associated with HFMD in Vietnam between 2012 and 2017. Phylogenetic analysis revealed a trend of endemic circulation of Vietnamese CV-A10, CV-A4, and CV-A2 strains and the emergence of thus-far undescribed HFMD-causing lineages of CV-A4 and CV-A2. The Vietnamese CV-A10 strains belonged to a genotype comprising isolates from patients with HFMD from several other countries; however, most of the Vietnamese strains were grouped into a local lineage. Recently, emerging CV-A4 strains in Vietnam were grouped into a unique lineage within a genotype comprising strains isolated from patients with acute flaccid paralysis from various countries. New substitutions were detected in the putative BC and HI loops in the Vietnamese CV-A4 strains. Except for one strain, Vietnamese CV-A2 isolates were grouped into a unique lineage of a genotype that includes strains from various countries that are associated with other clinical manifestations. Enhanced surveillance is required to monitor their spread and to specify their roles as etiological agents of HFMD or "HFMD-like" diseases, especially for CV-A4 and CV-A2. Further studies including whole-genome sequencing should be conducted to fully understand the evolutionary changes occurring in these newly emerging strains.
在越南进行手足口病（HFMD）哨点监测时，我们发现 2016 年柯萨奇病毒 A10（CV-A10）和 2017 年 CV-A2 和 CV-A4 的发病率突然增加，最近有报道称这些病毒与其他国家的各种临床表现有关。然而，关于这些血清型的分子研究数量有限，越南尚未进行此类研究。因此，我们对 2012 年至 2017 年期间与越南 HFMD 相关的 CV-A10、CV-A4 和 CV-A2 病毒株的整个 VP1 基因进行了测序。系统进化分析显示，越南 CV-A10、CV-A4 和 CV-A2 病毒株呈地方性流行，并且出现了迄今尚未描述的引起 HFMD 的 CV-A4 和 CV-A2 病毒株。越南 CV-A10 病毒株属于一种基因型，包括来自其他国家 HFMD 患者的分离株；然而，大多数越南分离株被分为一个地方性谱系。最近，越南出现的新兴 CV-A4 病毒株被分为一个独特的谱系，该谱系包括来自不同国家的急性弛缓性麻痹患者的分离株。在越南的 CV-A4 病毒株中检测到在假定的 BC 和 HI 环中有新的取代。除了一个分离株外，越南 CV-A2 分离株被分为一个独特的谱系，该谱系包括与其他临床表现相关的来自不同国家的分离株。需要加强监测，以监测其传播，并确定其作为 HFMD 或“HFMD 样”疾病的病因的作用，特别是对于 CV-A4 和 CV-A2。应进行包括全基因组测序在内的进一步研究，以充分了解这些新出现的病毒株中发生的进化变化。
