Change trends of pathogen of severe hand, foot and mouth disease in Chaoshan area during 2011 to 2015

Objective To discuss the change trends of pathogen of severe hand, foot and mouth disease(HFMD) in Chaoshan area during 2011 to 2015. Methods All 1 410 throat swabs of cases who were diagnosed as HFMD were collected from children hospitalized in our hospital during May 2011 to August 2015.Enterovirus were detected by nest RT-PCR, and the results of these positive cases diagnosed as severe HFMD were analyzed. Results (1) There were 216 positive cases(67.29%, 216/321) diagnosed as severe HFMD, including 53.70%(116/216)enterovirus 71(EV71), 19.91%(43/216)coxsackievirus A16(CA16), 12.04%(26/216)CA6, 8.80%(19/216)CA10, 3.24%(7/216)CA4, 0.93%(2/216)coxsackievirus B5, 0.46%(1/216)enteric cytopathogenic human orphan virus and 0.93%(2/216)unclassified samples were unclassified to species.(2)Five cases of critical HFMD were all caused by EV71.(3)The EV71 positive samples were given priority to severe cases(51.79%, 116/224)and the non EV71 positive samples were given priority to mild cases(82.08%, 458/558), the difference was statistically significant(χ2=91.68, P<0.001). (4)The change trends of severe HFMD year by year were consistent with the change trends of EV71 composition, and were highly correlated(Rs=0.9, P=0.037). (5) Severe HFMD caused by non EV71 virus gradually increased. Conclusion Severe HFMD in Chaoshan area during 2011 to 2015 were mainly caused by EV71, non EV71 viruses including CA16, CA6, CA10, CA4, coxsackievirus B5, enteric cytopathogenic human orphan virus 6 could also develop to severe HFMD.The composition ratio of severe HFMD increased accordingly in the year of EV71 as the dominant pathogen.The proportion of severe HFMD caused by non EV71 virus gradually increased after 2013 year. Key words: Severe hand, foot and mouth disease; Pathogen; Enterovirus 71; Non enterovirus 71 virus