Clinical features of echovirus 6 and 9 infections in children

Background: Clinical features of echovirus 6 and 9 infections in children have not been comprehensively evaluated, particularly for sporadic cases. Objective: To describe the clinical features of children with echovirus 6 or 9 infections. Study designs: From 2000 to 2008, 199 children with culture-proven echovirus 6 or 9 infections identified in a university-affiliated hospital were included. Data extracted from 174 inpatients were further analyzed. Results: Age ranged from 4 days to 15 years with a mean of 4.7 years. 123 (62%) were male. The disease spectrums were similar for echovirus 6 (n=100) and 9 (n=74) infections, with aseptic meningitis (49% and 51%, respectively) being the most common syndrome, followed by meningismus, upper respiratory tract infection, pneumonia, and herpangina. All 174 inpatients had fever but the duration of fever was significantly longer in patient with echovirus 9 infection than those with echovirus 6 infections (6.0 days vs. 3.8 days, p<0.001). The rate of leukocytosis (leukocyte count. >15,000/μL) were significantly higher in patients with echovirus 6 infections than those with echovirus 9 infection (p<0.001). One neonate with echovirus 6 infection died from hepatic necrosis with coagulopathy, and one infant with echovirus 6 infection and one child with echovirus 9 infection died from brain involvement. Two children had long-term sequelae of seizure disorder. The remaining 169 children (97%) recovered uneventfully. Conclusion: For children with echovirus 6 or 9 infections requiring hospitalization, aseptic meningitis was the most common manifestation and fatal outcome or long-term sequel, though rare, might occur.