Immunomagnetic capture rt-PCR for detection of norovirus from foods implicated in a foodborne outbreak.

In February 2001, an outbreak of acute gastroenteritis due to Norovirus (NV) occurred among employees of 11 companies in Aichi Prefecture. The illness was strongly associated with eating a delivered box-lunch. The use of magnetic beads coated with the antibody to the baculovirus-expressed recombinant capsid proteins of the Chiba virus (rCV) facilitated capture of NV from the food items implicated in the outbreak. Following immunomagnetic capture, NV bound to the beads was detected by reverse transcriptionpolymerase chain reaction (RT-PCR). Of the nine food items tested, two were positive for a genogroup 1 NV. Sequence analysis of RT-PCR products indicated that the nucleotide sequences of NV strains from foods were almost identical to those of NV strains detected in stool samples of ill patients. As the immunocapture RTPCR method is simple and easy to perform, this technique should be useful for the detection of NV from outbreak-implicated foods.