Immunoglobulin M capture immunoassay in investigation of coxsackievirus B5 and B6 outbreaks in South Australia

An immunoglobulin M (IgM) capture enzyme immunoassay was used to detect major overlapping outbreaks of disease in South Australia caused by coxsackieviruses B5 (CBV-5) and B6 (CBV-6). CBV-5-specific IgM was detected in patients presenting in spring 1992 with acute febrile illnesses, rash, severe acute respiratory disease, meningitis, myocarditis and/or pericarditis, while tests for other viruses were negative. CBV-5 was isolated from an early case. In December 1992 it was noted that CBV-6 had replaced CBV-5 as the major cause of disease. The CBV-6 epidemic continued until April 1993. Serum samples from 495 patients (276 inpatients) were submitted for testing. CBV-6 infection was associated with lower respiratory tract infection and persistent cough. This study demonstrated success of the IgM enzyme immunoassay and the need for diagnostic virology laboratories to look for CBV-6 infection in addition to the other five CBVs.