Outbreak of hand, foot and mouth disease/herpangina associated with coxsackievirus A6 and A10 infections in 2010, France: a large citywide, prospective observational study

Hand, foot and mouth disease (HFMD) and herpangina (HA) are frequently caused by several distinct serotypes belonging to the human enterovirus A species (HEVA). Enterovirus 71 is considered as a significant public health threat because of rare but fatal neurological complications. A sentinel surveillance system involving paediatricians from Clermont-Ferrand (France) was set up to determine the clinical and epidemiological characteristics of HFMD/HA associated with enterovirus infections. A standardized report form was used to collect demographic and clinical data. Throat or buccal specimens were obtained prospectively and tested for the presence of enteroviruses. The frequency of HEVA serotypes was determined by genotyping. Phylogenetic relationships were analysed to identify potential new virus variants. From 1 April to 31 December 2010, a total of 222 children were enrolled. The predominant clinical presentation was HA (63.8%) and this was frequently associated with clinical signs of HFMD (48%). An enterovirus infection was diagnosed in 143 (64.4%) patients and serotype identification was achieved in 141/143 (98.6%). The predominant serotypes were coxsackievirus A10 (39.9%) and A6 (28%), followed by coxsackievirus A16 (17.5%) and enterovirus 71 (6.3%). Fever was observed in 115 (80.4%) children. No patient had neurological complications. Coxsackievirus A10 and A6 strains involved in the outbreak were consistently genetically related with those detected earlier in Finland and constituted distinct European lineages. Although several enterovirus serotypes have been involved in HFMD/HA cases, the outbreak described in this population survey was caused by coxsackievirus A6 and coxsackievirus A10, the third dual outbreak in Europe in the last 3 years.