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@#Hand, foot, and mouth disease (HFMD) is a contagious childhood disease caused by enteroviruses including enterovirus A71 (EV-A71), coxsackievirus A6 (CV-A6) and CV-A16 transmitted via direct and indirect contact. Different types of toy surfaces can affect the stability of viruses. Understanding the stability of enteroviruses on toys provides insightful data for effective disinfection in kindergartens or homes. Porous (ethylene-vinyl acetate mat foam, paper, pinewood, polyester fabric, and squishy polyurethane foam) and non-porous (acrylonitrile butadiene styrene plastic and stainless-steel coin) surfaces were inoculated with EV-A71 at 4, 24, and 35°C, and coxsackieviruses at 24°C. Infectious enteroviruses were recovered and titred in median tissue culture infectious dose assay (TCID50). Atomic force microscopy (AFM) images were taken from surfaces to examine association of surface roughness with virus stability. Overall, infectious enteroviruses were persistent on all non-porous and porous surfaces. Virus persistence was longest at 4°C followed by 24°C and 35°C. EV-A71 half-lives ranged between 6.4-12.8 hours at 4°C, 2.4-6.7 hours at 24°C, and 0.13-2.7 hours at 35°C. At lower virus titres exposed to 24°C, half-lives of enteroviruses ranged from 0.1-1.4 hours. Surface roughness values from AFM suggested smooth surfaces of non-porous surfaces were associated with better virus stability. Temperature, enterovirus concentration, and type of surface affected persistence and stability of enteroviruses. Our findings suggest both porous and non-porous surfaces in kindergartens allow enterovirus persistence and should be frequently disinfected to curb HFMD outbreaks in kindergartens.
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Objective@#To investigate the genetic characteristics of enterovirus A group 71 type (EV-A71) and etiological features of hand, foot and mouth disease (HFMD) in Xining city in 2017.@*Methods@#The pharyngeal swab specimens were collected from HFMD patients, and detected by real-time reverse transcription-polymerase chain reaction (RT-PCR). For EV-A71 positive samples, virus isolation was performed. Then RNA of EV-A71 strains was extracted, and then VP1 coding region was amplified by RT-PCR. The phylogenetic tree was constructed by comparing with other genotypes and sub-genotypes strains of EV-A71.@*Results@#Total 57 strains of EV-A71 were isolated in Xining city in 2017, which all belonged to genotype C4a, and could be divided into two different lineages by phylogenetic analysis. The epidemic strains of EV-A71 in Xining City was closely related to other provinces of China in 2017.@*Conclusions@#C4a was the dominant genotype of EV-A71 in Xining city in 2017, and no other genotype was detected. In addition, EV-A71 isolated from Xining city was co-evolved with EV-A71 in other provinces of China.
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Objectives@#To evaluate the safety of inactivated enterovirus A71(EV-A71) vaccines after large-scale immunization in the community.@*Methods@#We selected EV-A71 susceptible people (healthy children) aged 6-59 months in vaccination clinics from 89 counties in Zhejiang Province between April 2016 and March 2018. All local and systematic adverse actions were collected by 30 min on-site inspection, within 3 days and 4-30 days follow-up. Chi-square test and Fisher′s exact test were used to compare the difference of AEs incidence in various characteristics among two groups.@*Results@#A total of 71 663 doses of vaccines were included for active safety analysis, which included 37 331 doses in boys and 34 332 doses in girls. Among all the doses, children aged 6 to 11 months, 12 to 23 months and 24 to 59 months were received 13 707, 32 639 and 25 317 doses respectively. The incidence of adverse reactions within 30 min, 3 days and 4-30 days were 0.33% (239 doses), 1.58% (1 133 doses) and 0.34% (244 doses) respectively. Adverse reactions within 3 days were 1 372 doses, with a incidence of 1.91%; among all the cases, 539 doses (0.75%) were grade 1, 677 doses (0.94%) were grade 2 and 156 doses (0.22%) were grade 3, no grade-4 adverse reaction was reported. The common local adverse reactions were redness, swelling and pruritus, with the incidence rates were 0.05% (39 doses), 0.02% (16 doses) and 0.02% (12 doses), respectively, while the most common systemic adverse reaction was pyrexia with an incidence of 1.19% (856 doses), followed by diarrhea and anorexia with the incidence rates were 0.15% (104 doses) and 0.13% (90 doses) respectively.@*Conclusion@#Most adverse actions of EV-A71 vaccines were mild and moderate and majority of them were common adverse actions. No new adverse reactions were found in the study.
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Objective@#To detect the single nucleotide polymorphism (SNP) at locus 1 165 of β1-adrenoceptor (β1-AR) and to investigate the association between the SNP and the infection by enterovirus A71(EV-A71).@*Methods@#Polymerase chain reaction (PCR) amplification technique was used to detect the SNP at locus 1 165 of β1-AR between hand, foot and mouth disease (HFMD) and healthy controls by sanger sequencing method .@*Results@#There was a G1165C SNP and three kinds of genotypes (GG, GC, CC) in β1-AR gene in the 77 cases of EV-A71 HFMD patients and 66 cases of healthy controls. For HFMD patients, frequencies of GG, GC and CC genotypes of the G1165C locus were 10%, 47% and 43%, respectively, and alleles frequency of G and C were 34% and 66%, respectively. But in healthy children, GG, GC, CC genotype frequencies were 7%, 41% and 52%, respectively, and G and C allele frequencies were 28% and 72% respectively. Chi-square analysis showed that there were no significant differences in distribution of genotypes (χ2=1.154, df=2, P=0.562) and alleles frequency (χ2=1.091, df=2, P=0.296) between the EV-A71-infected group and the healthy control group. Between mild and severe EV-A71-infected group, there were no significant differences in distribution of genotypes (χ2=3.945, df=2, P=0.139) and alleles frequency (χ2=3.763, df=2, P=0.052).@*Conclusions@#The 1 165 SNP in the coding region of β1-AR was not associated with EV-A71 infection and its severity.
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Objective@#To explore the virulence related risk factors based on the enterovirus A71 (EV-A71) genome.@*Methods@#The pairwise distance of each section of gene between mild and fatal cases was analyzed. The ⅴ domain of 5′UTR from mild and fatal cases in this study were constructed. Amino acid sequences of EV-A71 were analyzed to find the potential virulence regions which were statistically different between fatal and mild cases.@*Results@#The two EV-A71 genome sequences in this study belonged to C4a genotype with the genomic homology of 96.2%-97.5%. The nucleotides in the ⅴ domains of the 5 ′UTR of EV-A71 from mild and fatal cases were the same. Each gene of EV-A71 from 31 mild cases and 30 fatal cases shared high homology. A total of four potential virulence sites (2 A: R68 M、2C: K41R、3 A: T/V47 A and 3C: I158 V) which were significantly different between mild cases and fatal cases were obtained.@*Conclusions@#The four sites in the unstructured protein coding region might be related with the virulence of EV-A71.