Etiologic spectrum of hand, foot and mouth disease and the genetic characteristics of the Coxsackievirus A10 and A6 in Qingdao in 2014 / 中华实验和临床病毒学杂志

ABSTRACT

Objective@#To investigate the etiology spectrum of hand foot and mouth disease (HFMD) and to analyze the molecular characteristics of Coxsackievirus A10 and A6 in Qingdao in 2014.@*Methods@#Throat swabs of HFMD cases were tested for total enteroviruses (EVs), EV-A71, CV-A16, CV-A10 and CV-A6 by multiplex real time RT-PCR. Other EV serotypes were identified through the sequences of partial VP1 gene. The full-length of VP1 gene of CV-A10 and CV-A6 were amplified and sequenced. The sequences were phylogenetically analyzed using MEGA 5.0 software package.@*Results@#A total of 1727 HFMD patients were detected in 2014 and 11serotypes of enteroviruses were identified. EV-A71(38.0%, 410/1078), CV-A16(28.8%, 311/1078), CV-A10(14.1%, 152/1078)and CV-A6(3.2%, 34/1078)were the most dominant pathogen in 2014 in Qingdao. Proportions of CV-A10 in enterovirus infected children varied dramatically in different ages(χ2=15.19, P=0.001), showing a downtrend with age. Proportion of CV-A10 in inpatients was much higher than that in outpatients(χ2=49.1, P <0.001), while 60% of those inpatients showed nervous system damage symptoms, with pathological reflex or disappearance of physiological reflex. Phylogenetic analysis of complete VP1 sequences showed that all CV-A10 strains identied in this study belonged to genotype C, 71.7% of which located in branch C5; all CV-A6 strains belonged to genotype D while 83.3% of which located in branch D5.@*Conclusions@#EV-A71, CV-A16, CV-A10 and CV-A6 were the prevalent pathogens of HFMD in Qingdao in 2014. CV-A10 was more frequently detected in lower age group with HFMD, which can cause damage to nervous system. Strains of branch C5 in genotype C were the dominant strains of CV-A10 circulated in Qingdao in 2014 while strains of branch D5 in genotype D were the major strains of CV-A6.