Hand, foot and mouth disease (HFMD) is a major public health concern in China. Since its first large outbreak in 2008, the dominant HFMD pathogens are constantly changing. In this study, Fu et al. performed meta-analyses on cohorts which have molecular epidemiological and enterovirus sequence data available in the public databases. They found that a rapid increase of other enteroviruses in accompany with a sharp decrease of EVA71 prevalence in China from 2008 to 2016, and four genotypes EVA71_C4, CVA16_B1, CVA6_D and CVA10_C contributed to over 90% of all HFMD cases in China. This study presents a comprehensive overview of the recent national epidemiology and evolutionary history of the major enteroviruses that cause HFMD in China. See page 21–33 for details.
The relationship between the severity of dengue infection and allergy is still obscure. We conducted an electronic search across 12 databases for relevant articles reporting allergic symptoms, dengue infection, and dengue classification. These studies were categorized according to dengue severity and allergy symptoms, and a meta-analysis was performed by pooling the studies in each category. Among the included 57 articles, pruritus was the most common allergic sign followed by non-specified allergy and asthma (28.6%, 13%, and 6.5%, respectively). Despite the reported significant association of dengue with pruritus and total IgE level (P < 0.05), in comparison with non-dengue cases and healthy controls, there was no association between the different severe dengue group with pruritus, skin allergy, food allergy or asthma. However, removing the largest study revealed a significant association between asthma with dengue hemorrhagic fever (DHF) rather than dengue fever (DF). In comparison with DF, DHF was associated with IgE positivity. Furthermore, specific-IgE level was higher in secondary DF rather than primary DF. There was a possible association between allergy symptoms and dengue severity progression. Further studies are needed to clarify this association.
Enterovirus 71 (EV-A71) is a human pathogen that does not naturally infect rodent cells. However, virus strains that productively infect rodent cells could be produced by serial passage in a rodent cell line. The resulting viruses are useful tools to identify molecular determinants of adaptation to a new host species. We adapted an EV-A71 clinical isolate (EV71:BS) in Chinese hamster ovary (CHO-K1) cells and sequenced the genome of the resulting virus. We explored the contribution of viral capsid mutations that may have contributed to the CHO-adapted phenotype by introducing the mutations surrounding the receptor-binding canyon region into the genome of EV71:BS by reverse genetics tools. We subsequently assessed whether the resulting mutant viruses productively infected CHO-K1 cells. Contrary to previous reports in the literature, our findings demonstrate that a single amino acid substitution in capsid VP2149 K→I is not sufficient for the resulting mutant virus to infect CHO-K1 cells. Moreover, a mutant virus harbouring other capsid mutations we evaluated (VP1 K98→E, E145→A, and L169→F) also did not infect CHO-K1 cells. These findings strongly suggest that cooperation of various adaptive mutations in the capsid is necessary to enable successful EV-A71 infection of a different host species.
本研究从一例来自巴基斯坦的发热患者体内分离到了一株新的基孔肯亚病毒,命名为SZ-SMGC-1。该毒株与中国分离的毒株同源性在92.9% to 99.9%之间,与2016年巴基斯坦分离的毒株同源性最高。与大多数(23/26, 88.5%)中国分离株类似,该毒株属于ECSA(East Central South African)谱系,同时这23株ECSA谱系的病毒都处于印度洋和中非进化分支上(Indian Ocean and Central African clades)。值得注意的是,SZ-SMGC-1毒株包含两个能够增强其在伊蚊中的传染性的突变,包括E1蛋白D284E和E2蛋白I211T突变。细胞实验结果显示,该毒株感染Vero细胞后有明显的细胞病变出现,但是在C6/36细胞中却没有。尽管在这两种细胞系中病毒复制的最高滴度水平相当,但是该毒株在C6/36细胞中的复制速度显著高于Vero细胞。中国南方地区广泛分布着基孔肯雅病毒的传播媒介,以及中国地区毒株的遗传变异特征高。中国地区基孔肯雅病毒传播媒介的广泛分布、人群没有针对基孔肯雅病毒的预存免疫,提示我们再这些地区该病毒有再度出现的风险。因此,我们必须严密监测基孔肯雅病毒,特别是那些来自疫区的旅行人员。