Survival of a Norovirus surrogate on surfaces in synthetic gastric fluid

Norovirus (NoV) can survive in buffer at a range of pH values. However, when variations to pH are combined with the enzymatic conditions typical in gastric fluid, NoV survival is less predictable. Added to this, the material on which expelled vomitus fluid lands e.g. safety vinyl or carpet, might also affect the level of NoV survival in the environment.

This study assessed survival of the NoV surrogate Feline calicivirus (FCV) after application onto four material types in the presence of synthetic gastric fluid of varying pH values.

Synthetic gastric fluid of varying pH values (1.5, 2.5, 3.5 and 4.5) containing FCV (1×10⁶ PFU/100 μL of gastric fluid) was seeded (100 μL) onto four material types: Formica, safety vinyl, cotton sheet and carpet tiles (2 cm × 2 cm) and left for 0, 30 and 60 minutes before recovering and identifying any viable viruses via plaque assay.

FCV survived in synthetic gastric fluid at pH values as low as 2.5 and in some cases as low as 1.5 for at least 30 min when associated with certain materials. Greater average numbers of viable virus were recovered from the more absorbent materials of cotton (1900 PFU/sample) and carpet (1600 PFU/sample) compared with Formica (360 PFU/sample) and safety vinyl (380 PFU/sample).

This study showed that FCV can survive in synthetic gastric fluids of low pH values for significant time periods especially on absorbent materials. This emphasises the importance of ensuring effective cleaning and decontamination procedures, particularly of soft furnishings and laundry, for infection prevention and control of NoV outbreaks.