Virus Transfer at the Skin-Liquid Interface

Understanding virus transfer between liquid and skin is necessary to estimate transmission during water related activities. Here, we modeled virus transfer from liquid-to-skin and skin-to-liquid. We performed human subject studies using three bacteriophages as pathogenic virus surrogates: nonenveloped MS2 and Q beta and enveloped Phi 6. Our study shows that transfer from liquid-to-skin is describable by a single model based on (1) virus concentration and (2) volume of liquid remaining on skin. Contact times (0.1-30 min)) and virus species had little-to-no influence on virus transfer. Likewise, liquid conditions (pH 6-9, ionic strength 10-550 mM) had no influence on transfer as shown for MS2. The model: accounts for both, virus adsorbed onto the skin, and virus in the liquid retained on skin. In comparison, virus transfer from skin-to-liquid was influenced by the wetness of the skin and by liquid type (water, saliva). 90 +/- 19% of the virus inoculated on the skin are transferred to the water when the skin remains wet compared to 30 +/- 17% when the skin is dry. The transfer from skin-to-liquid was 41% higher when the recipient liquid was water as compared with saliva. This study quantifies virus transfer between liquid and skin and guides risk assessments of water-related activities.