Immunoglobulin M antibody test to detect genogroup II Norwalk-like virus infection

Sera obtained from adult volunteers inoculated with genogroup II Norwalk-li ke viruses (NLVs), Hawaii virus, and Snow Mountain virus and from patients involved in outbreaks of gastroenteritis were tested for genogroup II NLV M exico virus-specific immunoglobulin M (IgM) by use of a monoclonal antibody , recombinant Mexico virus antigen (rMXV)-based IgM capture enzyme-linked i mmunosorbent assay (ELISA). Sera from genogroup I Norwalk virus (NV)-inocul ated volunteers and from patients involved in a genogroup I NLV outbreak we re also tested. In sera from those infected with genogroup I NV or NLVs in volunteer and outbreak studies, only 3 of 25 were rMXV IgM positive; in con trast, 24 of 25 were IgM positive for recombinant NV (rNV). In sera from th ose infected with genogroup II NLVs in volunteer and outbreak studies, 28 o f 47 were rMXV IgM positive and none were IgM positive for rNV, showing the specificity of each IgM test for its respective genogroup. In an outbreak of gastroenteritis not characterized as being of viral etiology but suspect ed to be due to NV, 7 of 13 persons had IgM responses to rMXV, whereas none had IgM responses to rNV, thus establishing the diagnosis as genogroup II NLV infection. The rMXV-based IgM capture ELISA developed is specific for t he diagnosis of genogroup II NLV infections.