Novel Methods in the Investigation, Detection, and Control of Foodborne Viruses

Background & Objectives: Human norovirus is the leading cause of foodborne illness and one of the leading causes of foodborne death globally—inflicting a considerable public health and economic burden. Despite recent advances, multiple hurdles related to noroviruses remain: I.) understanding viral pathogenesis in light of reports that enteric bacteria may assist norovirus infection, II.) rapidly and sensitively concentrating and detecting viruses from foods, and III.) controlling viral transmission with effective disinfectants and edible therapeutics. The goal of our work is to address all three of these challenges with novel approaches.
Methods & Results: The objectives were addressed using a variety of methods. I.) The degree and nature of norovirus-bacteria binding was characterized and candidate ligands identified; including a 35 kDa glycoprotein present in 7 enteric bacteria capable of broadly binding 6 norovirus genotypes. II.) Work to identify and produce bacteria capable of concentrating human norovirus has been completed, with observed capture efficiencies >75%. Application of an isothermal amplification technique, recombinase polymerase amplification, to the detection of epidemic human noroviruses resulted in sensitive, specific detection of virus in <20 minutes with promising tolerance to inhibitors in stool. III.) Development of techniques to understand viral inactivation mechanisms were successfully applied to silver dihydrogen citrate and copper. Nucleic acid aptamers, which show potential as therapeutics, were developed against an under-targeted viral protein necessary for replication. Initial reduction in replication by over 75% was observed.
Conclusions: Multiple challenges related to the I.) investigation, II.) detection, and III.) control of noroviruses were and continue to be addressed with novel techniques. I.) Identifying the bacterial ligand responsible for norovirus binding can reveal information about viral pathogenesis that allows for treatment/prevention. II.) Replacing paramagnetic beads with bacteria allows for cheap, scalable concentration of virus for detection with unprecedented efficiency. Application of true lab-in-a-suitcase technology for sensitive detection of norovirus in <30 minutes can mobilize detection and improve control. III.) Understanding viral inactivation allows for better identification of promising disinfectant formulations. Because most deaths occur from complications related to the severity of norovirus symptoms, inexpensive edible therapeutics capable of reducing viral replication/symptoms would likely reduce death.