The Etiological Features And Molecular Typing Of Hand Foot And Mouth Disease In Changchun Area

HFMD is a common acute infectious disease caused by a variety kinds ofenterovirus, which mostly occurs in children under10years of age. Infants under theage of4get the highest incidence. The clinical symptom of most cases is mild, just forrash or herpes of hand, foot, mouth, buttocks and other parts. There will be a fewcases appearing central nervous system complications. Hand, foot, and mouth diseasewas classified as Class C infectious disease by our country On May2,2008. There isno particularly effective antiviral drugs, vaccines and treatments for HFMD at present.So vigorously carring out basic research about etiology of HFMD is necessary. It willplay an important role in clarifing the viral infection mechanism, the development ofvaccines and disease controlling.In collaboration with the Centers for Disease Control and Prevention, werecollected50specimens (pharyngeal swab and herpes fluid) about suspected cases ofhand, foot and mouth disease in2012-2013. Virus isolation and identification ofclinical specimens: RD cell was used for virus isolation and culturing. Specimens canoccur typical cytopathic effect (CPE) after vaccination as gradually rounded, smallerin size, increased in cytoplasmic granules, refraction enhancement and finally fallfrom the sidewall. Positive samples extracted viral RNA. Enterovirus universal primerRT-PCR results showed that42specimens appeared specific single band which theproportion was84%. HEV71-specific primers and CVA16-specific primers RT-PCRresults showed that there were14HEV71(ratio of77.78%),2CVA16(ratio of11.11%), two other kind of enteroviruses (ratio of11.11%) in all specimens in2012and there were12HEV71(ratio of50.00%),11CVA16(ratio of45.83%), one otherkind of enteroviruses (ratio of4.16%) in all specimens in2013. The results ofSequencing and phylogenetic analysis showed that HEV71belongs to C4asubtype,and CVA16belongs to B2bsubtypes in Changchun area. We analyzed statistically theetiology composition, time of onset, age and sex composition for hand, foot, and mouth disease between2012and2013. The results showed that there was asignificant difference about the etiology composition (χ2=5.983, P <0.05), and timeof onset (χ2=10.536, P <0.05) for HFMD between2012and2013. However, therewas no difference about the age (χ2=0.571, P>0.05) and sex (χ2=0.667, P>0.05)composition for hand, foot, and mouth disease between2012and2013.This study successfully isolated42strains of enterovirus from clinical HFMDpatients in Changchun area. The main pathogens of HFMD is HEV71and CVA16.After Statistical analysis we know that the etiology composition and time of onset forHFMD changed between2012and2013. While gender composition and agedistribution did not changed for HFMD between2012and2013.