In vitro cytotoxicity and virucidal efficacy of potassium hydrogen peroxymonosulfate compared to quaternary ammonium compound under various concentrations, exposure times and temperatures against African swine fever virus

Abstract

Background and Aim: The selection and proper application of disinfectants are crucial to the prevention of many diseases, so disinfectants must be evaluated before being used for the prevention of African swine fever (ASF). Three disinfectant products belonging to the group of potassium hydrogen peroxymonosulfates, product A and product B, and a quaternary ammonium compound called product C, were examined in vitro for host cell cytotoxicity and the efficacy of ASF virus inactivation. The study parameters included various concentrations, exposure times, temperatures, and degrees of cytotoxicity. Materials and Methods: Three disinfectant products were evaluated for cytotoxicity using primary porcine alveolar macrophage (PAM) cells at dilutions from 1:200 to 1:51,200. Disinfectants in concentrations of 1:200, 1:400, and 1:800 were prepared, the pH and the virucidal activity were tested. An equal volume of each dilution was mixed with the ASF virus and incubated at room temperature (20°C) or on ice (4°C) for 1 min, 5 min, or 30 min. Hemadsorption (HAD) or rosette formation was observed using an inverted microscope for 5 days after inoculation, and the virus titer was calculated as HAD50/mL. Each treatment and virus control were tested in triplicate, and the titers were reported as means and standard deviations. The reduction factor was used to measure inactivation. Results: Products A, B, and C at 1:400, 1:800, and 1:25,600 of dilution, respectively, did not show significant cytotoxic effects on PAM cells. Products A and B could inactivate ASF virus at 1:200 dilution within 5 min after exposure at 4°C. However, at 20°C, the exposure time had to be extended to 30 min to inactivate the virus. Product C could inactivate the virus at 1:400 dilution within 5 min under both temperature conditions, whereas at 1:800 dilution, the exposure time had to be extended to 30 min to completely inactivate the virus at 20°C. Conclusion: All disinfectants could inactivate ASF virus in various concentrations, under appropriate exposure times and reaction temperatures, and there was no evidence of host cell cytotoxicity. For the control of ASF in pig farms, the appropriate concentration, ambient temperature, and contact time of these disinfectants should be taken into account.

Disinfectants against African Swine Fever: An Updated Review

“…The QAC-based product was effective at +4 °C following 1 min and at +20 °C following 30 min of contact time at a dilution of 1:200. A recent study by Taesuji and collaborators [ 50 ] has similarities to the work of Sovijit et al [ 43 ] regarding the ASFV strain used and the choice of didecyldimethylammonium chloride that belongs to QACs. Unlike the work of Sovijit et al, in this suspension test, five commercially available disinfectants were tested.…”

“…Only one study of the ASFV by Gabbert et al [ 39 ] adopted this method with slight modifications using carbonated concrete coupons as porous surfaces instead of the stainless steel disks indicated as the reference non-porous surface according to the OECD guidelines [ 31 ]. Other studies investigated the virucidal activity of disinfectants against the ASFV without adopting any international standards [ 40 , 41 , 42 , 43 , 44 ]. These studies tested the virucidal activity resembling the UNI EN 14675:2015 standard by putting the disinfectant in the liquid form and the cell-cultured ASFV strain in contact.…”

“…Regarding the efficacy of the commercially available product Virkon against the ASFV, one study is available [ 39 ]. Several other studies are available on the same active compound contained in the commercial product Virkon [ 34 , 43 , 45 ]. Gabbert et al [ 39 ] tested the efficacy of Virkon on porous concrete surfaces according to the OECD guidelines ( Figure 3 ) [ 31 ].…”

“…The commercial product tested was efficacious in yielding a four log 10 reduction on all tested surfaces. Sovijit et al [ 43 ] tested two commercial products, based on potassium hydrogen peroxymonosulfate (PHP) (H 2 SO 5 ) against the ASFV strain VNUA-ASFV-L01/HN/04/19. All products were tested at the dilutions of 1:200, 1:400 and 1:800 for three contact times: 1, 5 and 30 min at two temperatures: +4 °C and +20 °C.…”

“…The QAC compound was effective at a dilution of 1:3200 with effective concentrations of 0.003%. More recently, Sovijit et al [ 43 ] tested one commercial product based on QAC compounds at three dilutions 1:200, 1:400 and 1:800 for 3 contact times: 1, 5 and 30 min at two temperatures: +4 °C and +20 °C. The QAC-based product was effective at +4 °C following 1 min and at +20 °C following 30 min of contact time at a dilution of 1:200.…”