Development of a novel carbohydrate-based method for the detection of norovirus from ready-to-eat foods

Norovirus is an enteric pathogen transmitted via the fecal-oral route. It is a leading cause of outbreaks and sporadic cases of gastroenteritis worldwide. Outbreaks of norovirus are often linked to contaminated food or water. Ready-to-eat foods are particularly prone to contamination, since they often require handling during preparation and are not usually heated before serving. Norovirus capsids have been shown to interact specifically with histo-blood group antigens (HBGAs). HBGAs are carbohydrates present on the surface of red blood cells, on mucosal epithelial cells and in bodily fluids. The work in this thesis used the interaction between norovirus and HBGAs to develop a method to detect norovirus in food samples. Magnetic beads were coated with multiple types of HBGA [A, B, H(type 2) and H(type 3)]. These beads were added to a 250 mL volume sample and concentrated using either the Pathatrix(TM) or iCropTheBug. Both systems were able to concentrate the beads from a 250 mL sample to 140 muL, using the magnetic properties of the beads. The RNA was then extracted from the sample and the presence of norovirus was determined using realtime Reverse Transcription-PCR. This method was successful at detecting norovirus from artificially-spiked and naturally-contaminated food samples. It was also able to detect multiple strains from norovirus genogroup I and II within the infectious dose range (10-100 particles). These results demonstrate that carbohydrate-conjugated beads can be successfully used to detect norovirus contamination of food products. This method can provide rapid and effective food testing for use in the investigation of suspected norovirus outbreaks