Purpose: To compare characteristics of five HuNoV surrogate viruses including FCV, MNV, porcine enteric calicivirus (PEC), Tulane virus (TuV) and aichivirus (AiV).
Methods: Viruses dried on stainless steel disks for 90 min were exposed to 200 and 1000 ppm sodium hypochlorite for 5 min at RT. Viruses were diluted in acid (pH 2, 3) and alkaline (pH 9, 10) conditions for 30 min at 37°C. Sensitivity to heat (56°C, 63°C) was evaluated by dilution in PBS and sensitivity to alcohols by dilution in indicated alcohols. Effects of High Hydrostatic Pressure (HHP) was evaluated at 100-800MPa for 1min at 4oC. Remaining infectious virus was assayed by plaque assay; PEC by an antigen end-point assay.
Results: FCV, Aichi, Tulane and MNV were reduced by 4, 0.5 and 0.1 log, respectively, after exposure to 1000 ppm chlorine. MNV, TuV, AiV and PEC were reduced less than 0.5 log by pH 2 and 3 treatment; FCV,5.5 and 3.5 log FCV at pH 2 and 3; All viruses were reduced 0.5 log or less at pH 9; only AiV was not inactivated at pH 10. PEC was most susceptible to alcohols followed by MNV; FCV was reduced by 2 log with 70% ethanol for 5 minutes. After 5 minutes at 56°C, MNV, TuV and AiV were reduced by 4 log, but 10 min was required for FCV. HHP reduced MNV, FCV and TuV by at least 4 log at 400 MPa, but AiV was resistant to 800MPa.
Significance: This is the first study to uniformly compare the characteristics of several established and new HuNoV surrogate viruses.