Molecular Diagnosis and Clinical Presentations of Enteroviral Infections in Taipei during the 2008 Epidemic

Background: In 2008, an epidemic of enterovirus EV infection caused hand, foot, and mouth disease HFMD and herpangina in children in Taiwan, and some of them died. To establish an early detection and effective management for children with EV71 infection, sensitive molecular diagnostic methods were applied from May to July 2008. Methods: We used virus isolation, EV71 real-time reverse-transcription polymerase chain reaction RT-PCR, and viral protein 1 VP1 RT-PCR followed by direct sequencing to detect EV71 and the other EVs in the infected outpatient or inpatient children. Clinical presentations of children infected with EV71 and other EVs were compared. Results: From May 2008 to July 2008 , 255 swabs were tested by both PCR diagnostic methods. Based on the viral isolation results, the sensitivities of EV71 real-time RT-PCR and VP1 RT- PCR followed by direct sequencing were 71% and 86%, respectively. Among the 221 children who were enrolled for clinical analysis, 73% 161 of 221 had herpangina, and 27% 60 of 221 had HFMD. Coxsackievirus A2 CA2 was the most prevalent among the identifiable viruses 65%, 104 of 160, followed by EV71 28%, 45 of 160. EV71 was the most commonly detected virus among the HFMD cases 63%, 38 of 60, whereas herpangina was mainly caused by CA2 61%, 98 of 161. Of the CA2 cases, 94% 98 of 104 had herpangina, and the most common manifestation of EV 71 infection was HFMD with or without complications 84%, 38 of 45. Phylogenetic study revealed that the genotype of EV71 cases during this epidemic was of B5 lineage. Conclusion: During the 2008 EV epidemic, most of the HFMD was caused by EV71, whereas herpangina was mainly caused by CA2. Real-time RT-PCR for EV71 is a time- saving and sensitive diagnostic tool