RESUMO
Objective:To analyze and compare VP1 and VP4 genetic characteristics of human enterovirus 71(EV71) isolated from children with severe and mild hand-foot and mouth disease(HFMD).Methods:EV71 strains isolated from severe HFMD patients (6 cases) and mild HFMD patients (6 cases) in Taizhou district, Zhejiang province were included during 2016.Total virus RNA was extracted by Viral RNA Mini Extraction Kit, and reverse transcription polymerase chain reaction(RT-PCR) was used to amplify the sequence of the VP1 and VP4 genes of EV71.And then the sequencing results were compared with those of A, B, C genotype reference EV71 strains from GenBank by nucleotide alignment and amino acid alignment analysis.Results:There were no statistically significant differences in sex and age between the two groups(χ 2=14.51, t=2.82, all P<0.05). The homogeneity between EV71 strains from severe patients and mild patients was 95.8%~99.6% and 99.1%~100.0% for VP1 nucleotide sequences and amino acid sequences, respectively, while 95.0%~99.9% and 99.0%~100.0% for VP4 nucleotide sequences and amino acid sequences, respectively.The twelve EV71 strains isolated from HFMD patients in Taizhou shared the highest identity with EV71-genotype C, especially genotype C4a.In addition, compared with the mild patients, three respective strains from severe HFMD patients showed mutations at the residue 170 in the VP1 protein(V→L), residue 293 in the VP1 protein(A→S) and residue 7 in the VP4 protein(T→A). Conclusion:All EV71 strains isolated from severe and mild HFMD patients in Taizhou district share high homology of nucleotide and amino sequence, and all of them belong to subgenogroup C4a.The mutations in the VP1 and VP4 of EV71 might be related to HFMD disease severity.
RESUMO
Objective @#To estimate the risk threshold of route index（RI）and mosq-ovitrap index（MOI）based on Breteau index（BI）,as supplements for dengue fever risk monitoring in specific habitats. @*Methods @#Two towns and two streets were selected from nine towns（streets）in Jiashan County,and then one village（community）was selected from each of them as a Aedes albopictus monitoring site. The BI,RI and MOI were employed at the same time and area from April to October in the year 2018. Linear regression models were built with RI,MOI and BI to calculate the dengue risk threshold of RI and MOI according to BI. @*Results @#The linear regression model of BI（X）and RI（Y）was Y=0.145+0.662X（P<0.05）,of BI（X）and MOI（Y）was Y=3.423+0.524X（P<0.05）. If BI=5（having risk of transmission of dengue fever）,then RI=3.455（95%CI：1.717-5.198）,MOI=6.043（95%CI：-0.327-12.417）. If BI=10（having risk of outbreak）,then RI=6.765（95%CI：5.018-8.518）,MOI=8.663（95%CI：2.260-15.071）. If BI=20（having risk of epidemic）,then RI=13.385（95%CI：11.326-15.453）,MOI=13.903（95%CI：6.352-21.461）.@*Conclusion @#The dengue fever risk threshold of RI estimated by BI had a narrow 95%CI and could be applied for dengue fever risk assessment,while the risk threshold of MOI had a wide 95%CI and the application value needed further study.