Coxsackievirus B4 in southern Taiwan: molecular epidemiology.

Background: Enterovirus outbreaks caused by Coxsackievirus B4 (CB4) in Taiwan in 2004 and 2008.

Objective: To retrospectively analyze the molecular epidemiology and pathogenicity of CB4 in Taiwan.

Study Design: This study analyzed twenty-three CB4 strains isolated in Taiwan during 1993-2004. Sequence variations data were obtained using 420 bp of VP4/VP2 region and 331 bp of 3' VP1 region. Phylogenetic dendrograms were constructed with other CB4 sequences in Genebank. The clinical manifestations of CB4 infection were examined by retrospectively reviewing medical records of infected patients.

Results: Three CB4 genotypes were identified: genotypes II, IVb and VIII. Genotype VIII, a new and geographically distinct cluster, has been isolated in South Korea, China and Taiwan. This genotype was isolated in twelve of twenty-three CB4 patients treated in Taiwan during 1997-2004. Eight of twenty-three strains belonging to genotype II, now the major genotype worldwide, were first identified in Taiwan in 2000. Three isolates (identified 1993-1994) analyzed in this study belonged to genotype IVb. In this retrospective follow-up study of sixteen patients with CB4 infection, the median patient age at the time of infection diagnosis was 4-year-old (range, 18 days to 10-year-old), and male-female ratio was 1:1. None of the sixteen patients suffered IDDM or myocarditis after their B4 infection episodes; four had Attention Deficit Hyperactivity Disorder (ADHD) and/or tic disorders (TDs) at follow-up.

Conclusions: Genotypes II and VIII of CB4 have co-circulated in Taiwan since 2000. Controlled studies are needed to evaluate a possible association between ADHD and TDs with CB4 infection.