Early and rapid detection of enterovirus 71 infection by an IgM-capture ELISA

Enterovirus 71 infection is more likely to induce severe complications and mortality than other enteroviruses. Laboratory diagnosis of enterovirus 71 in Taiwan still relies mainly on conventional virus isolation techniques that often require 5-10 days to obtain a result, thus hindering seriously the subsequent treatment and disease control measures. This study was to find a better alternative by developing a rapid enterovirus 71 detecting procedure, which can afford an earlier diagnosis and a more rapid outcome. In this study, an enterovirus 71-IgM-capture enzyme-linked immunosorbent assay (ELISA) was designed and tested with a total of 336 serum specimens collected from 236 cases of reported enterovirus infection with complications. Using virus isolation and neutralization test as standards, the sensitivity and specificity of the new protocol were 97.7 and 93.3%, respectively. Most of the IgM positive serum specimens were collected within 7 days after the onset of symptoms, while it appeared detectable up to 94 days after the onset of symptoms. Apart from being highly sensitive, rapid and low in cost, the new IgM-capture ELISA is sufficiently accurate to provide also reliable results for early detection of the virus. With this protocol, enterovirus 71 infections can be detected within 4h.