Chemical Disinfectants for Inactivation of Human Norovirus Surrogates

Human noroviruses (HNoVs) are considered the leading cause of acute non-bacterial gastroenteritis worldwide. Effective chemical disinfectants to inactivate HNoVs are needed. Since HNoVs cannot be cultivated in the lab, cultivable surrogates, feline calicivirus (FCV-F9) and murine norovirus (MNV-1), are used to determine inactivation using infectivity plaque assays. This study aimed to: 1) determine the ability of benzalkonium chloride (BAC) and potassium peroxymonosulfate (KPMS) to inactivate FCV-F9 and MNV-1 in vitro using suspension and carrier tests under clean and simulated dirty (5% fetal bovine serum) conditions over 1 h at room temperature; 2) determine inactivation of FCV-F9 and MNV-1 in suspension and carrier tests over 1 h at room temperature by sodium metasilicate (SMS). In suspension tests, BAC caused 1.94 and 2.59 log reductions of low and high FCV-F9 titers after 1 h, respectively. MNV-1 at low and high titers was reduced by > 3and 1.47 logs with BAC after 1 h, respectively. KPMS at 5 and 10 mg/mL reduced low titers of both viruses to non-detectable levels within 30 s. High FCV-F9 titers were non-detectable after 2 min with 5 mg/mL and within 30 s with 10 mg/mL of KPMS. KPMS at 5 mg/mL had little effect against high titers of MNV-1, but caused a 4.61 log reduction after 5 min with 10 mg/mL of KPMS. Using clean carrier tests, KPMS at 5 and 10 mg/mL reduced both tested viruses at low titers after 30 s and only high FCV-F9 titers after 10 min to undetectable levels. MNV-1 at high titers were reduced to non-detectable levels after 15 min with 10 mg/mL KPMS. BAC reduced low titers of both viruses to undetectable levels after 1 h using carrier tests with no significant reduction of high titers even after 2 h. The antiviral effect of both chemicals decreased under simulated dirty conditions. Both viruses were reduced within 15 s by 5% and 10% SMS using suspension tests. FCV-F9 and MNV-1 at high titers were reduced to undetectable levels after 2 min and 15 s, respectively with 2% SMS. KPMS and SMS appear suitable for the rapid control of HNoV transmission.