ONE-DAY DETECTION OF ENTEROVIRUSES IN CLINICAL SPECIMENS BY MAGNETIC BEAD EXTRACTION OF VIRAL RNA AND NESTED POLYMERASE CHAIN REACTION

The enteroviruses are a large group of positive strand RNA viruses belonging to the Picornaviridae family, At least 70 serotypes are known to cause infection in humans, including the polioviruses, group A and B coxsackieviruses and the ECHO viruses. Viral replication occurs initially in mucosal tissue of the gastrointestinal tract. Following viraemic spread, secondary replication may occur in various target organs, including cardiac or skeletal muscle, the central nervous system, the skin or mucous membranes. Enterovirus infection is probably mild or asymptomatic in most cases, but may be associated with acute myopericarditis, paralytic poliomyelitis, aseptic meningitis, or, more rarely, encephalitis (reviewed by Melnick 1990). Laboratory diagnosis is necessary to confirm the clinical diagnosis and to distinguish enterovirus-related disease from similar conditions of non-enteroviral aetiology. However this is not always straightforward. Athough enterovirus may be detected by culture in cerebrospinal fluid (CSF), stool or throat swabs, virus is rarely cultured from patients with cardiac or skeletal muscle symptoms, which usually occur as a post-acute manifestation of infection. Furthermore, some enterovirus serotypes grow poorly in cell culture. Serological diagnosis is complicated by the large numbers of serotypes, the difficulty in demonstrating significant rises in antibody titre in many patients, particularly those with post-acute symptoms, and the high prevalence of virus-specific antibody, reflecting past exposure, in the general population.