Mouse hepatitis virus: A betacoronavirus model to study the virucidal activity of air disinfection equipment on surface contamination.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has infected millions of people worldwide. SARS-CoV-2 belongs to the Betacoronavirus genus, containing the mouse hepatitis virus (MHV), an extensively studied animal coronavirus. Since MHV and SARS-CoV-2 share the same genus, MHV could offer insights relative to SARS-CoV-2 studies. MHV-3 strain causes hepatitis and cellular injury, making MHV-3 infection one of the best models for this debilitating disease. Surrogate coronaviruses have been used for virus resistance and inactivation studies, and although real-life conditions using SARS-CoV-2 should be encouraged, their use needs to be balanced with safety and costs. MHV can be manipulated under BSL2 laboratory conditions, unlike SARS-CoV-2, making it a model for studying the virucidal effects on coronaviruses. In this study, we used the betacoronavirus MHV-3 as a model to investigate the virucidal activity of an air disinfection equipment named STR Solution®, an air sterilizer with patented technology. MHV-3 was dried on different surfaces and exposed at varying distances from the STR Solution® equipment and at different exposure times. The residual infectivity was evaluated using the endpoint method. There was not a significant reduction (mean p-value = 0.4) of the viral titer under STR Solution® exposition. STR Solution® caused a slight decrease of the infectious particles' titer (> 1 log) only under the following conditions: polypropylene at 3 m, for 1 and 3 h (1.2 log reduction TCID) and Sus domesticus skin at 0.05 m, for 1 h (1.3 log reduction TCID50), and at 3 m for 1 h (1.2 log reduction TCID). These and other studies confirm the usefulness of this model to evaluate virucidal activity.