Clinical and molecular epidemiological characteristics of hand foot and mouth disease caused by Coxsackievirus A6 in Ninghai, Zhejiang, 2018

ObjectiveTo understand the clinical characteristics of hand foot and mouth disease (HFMD) caused by Coxsackievirus A6 (Cox A6) in Ninghai county of Zhejiang province and discuss its prevention and control strategies and measures.

MethodsThe information about HFMD in Ninghai in 2018 were obtained from the National Disease Surveillance Information System, and the stool samples and/or pharynx swabs were collected from the outpatients and inpatients of HFMD in the First Hospital of Ninghai for the detection of enteroviruses and nucleic acid typing by fluorescence RT-PCR. VP1 total length gene amplification, sequencing and phylogenetic analysis of Cox A6 positive samples were further studied by RT-PCR.

ResultsA total of 635 cases were enterovirus nucleic acid positive, the positive rate was 75.42%, among them, 412 were CV-A6 positive (64.88 %) and 223 were non-Cox A6 positive (35.12 %). The clinical manifestations of Cox A6 positive cases and non-Cox A6 positive cases were compared. There were significant differences in age, fever and heat range, distribution of rash, incidence of herpes and large herpes, skin pain and itching, desquamation and pigmentation, as well as nail separation rate in 16 weeks follow-up between Cox A6 positive cases and non-Cox A6 positive cases. Sequence analysis showed that the Cox A6 viruses detected in Ninghai in 2018 belonged to D3 gene subgroups and D3.2 clade.

ConclusionIn 2018, Cox A6 virus D3 gene subgroup spread in Ninghai, the infection cases were clinically characterized by fever and herpes pharyngitis, followed by severe skin mucosa reaction. The rash was distributed more widely in Cox A6 cases than in non-Cox A6 cases. Nail separation was mainly caused by the attack of Cox A6.