Clinical and epidemiologic features of Coxsackievirus A6 infection in children in northern Taiwan between 2004 and 2009

Background: Isolates of Coxsackievirus A6 (Cox A6) is increasing clinically in 2009 in Taiwan but detailed clinical features of Cox A6 infections in children have not been reported. This study is to define clinical manifestations and laboratory findings of Cox A6 infection in children. Methods: From January 2004 to December 2009, a total of 4,664 children with enterovirus infections, based on throat virus culture, were treated in Chang Gung Children's hospital. Two hundred and ninety-six (6.3%) patients positive for Cox A6 infection were included in this study. One hundred and forty-one (47.6%) inpatients were further analyzed for clinical presentations, laboratory findings, and clinical diagnoses. Results: There were two peaks of Cox A6 infection in 2007 and 2009 during the study period, especially during the warm season. The proportion of Cox A6 among total enterovirus isolates was 15.5% in 2007 and up to 22.2% in 2009. The mean age of inpatients was 2.42±0.14 years. The mean hospitalization duration was 4.21±0.11 days. The most common symptoms were fever (100%), oral ulcers (90.8%), and decreased oral intake (89.4%). The mean duration of fever was 2.78±1 days (range, 1-7 days). Seventy-seven (54.6%) patients had fever more than 3 days. The mean leukocyte count was 14,850/mm³, and 63 (45%) patients had leukocytosis (>15,000/mm³). The mean serum C-reactive protein (CRP) level was 44.1±3.3mg/L (normal, <10mg/L) and 62 (44%) had a CRP level >40mg/L. One hundred and eight (76.6%) inpatients were diagnosed as herpangina and 18 (12.8%) hand-foot-mouth disease. Three patients had complications, including aseptic meningitis in one and encephalitis in two. All 141 inpatients recovered uneventfully. Conclusions: Cox A6 is among the major serotypes of enteroviruses in Taiwan and most cases presented as herpangina and hand-foot-mouth disease. Nearly half of the cases may have leukocytosis and elevated CRP levels. Outcomes are usually good.