Risk factors for severe hand foot and mouth disease

Background: Hand foot and mouth disease (HFMD) and herpangina are enteroviral infectious diseases caused mainly by Coxsackie virus A (CA) or enterovirus 71 (EV71). From 2000 to 2002, many complicated cases were reported in Japan, therefore a nationwide questionnaire survey was carried out to assess the situation. The subjects were patients with HFMD or herpangina, or other enterovirus infection from 2000 to 2002, who were either hospitalized over 24 h or who died. The response rates were 41.3% in 2000 and 2001 and 31.6% in 2002. The survey period included the year 2000, when HFMD epidemics due to EV71 occurred. To examine risk factors causing complications of enterovirus infection, severe cases of HFMD were focused on. Methods: HFMD cases in 2000 were divided into two groups according to severity: 'more severe' and 'less severe'. 'More severe' was defined as 'fatal, involving sequelae, or involving hospitalization for 7 days or longer'. Statistical analyses were conducted with Epi info version 3.3 and the association between risk factors and severity was estimated. Results: The number of patients with more severe and less severe cases was 96 and 103, respectively. There was no difference in sex, age, having siblings and family history between the two groups. There was a significant association between attending child care center and severe HFMD. Conclusions: It is not clear why attending child care centers was associated with HFMD severity. Further study is needed.