Evaluation of sprayed hypochlorous acid solutions for their virucidal activity against avian influenza virus through <i>in vitro</i> experiments

Abstract

Hypochlorous acid (HOCl) solutions were evaluated for their virucidal ability against a low pathogenic avian influenza virus (AIV), H7N1. HOCl solutions containing 50, 100 and 200 ppm chlorine (pH 6) or their sprayed solutions (harvested in dishes placed at 1 or 30 cm distance between the spray nozzle and dish) were mixed with the virus with or without organic materials (5% fetal bovine serum: FBS). Under plain diluent conditions (without FBS), harvested solutions of HOCl after spraying could decrease the AIV titer by more than 1,000 times, to an undetectable level (< 2.5 log10TCID50/ml) within 5 sec, with the exception of the 50 ppm solution harvested after spraying at the distance of 30 cm. Under the dirty conditions (in the presence of 5% FBS), they lost their virucidal activity. When HOCl solutions were sprayed directly on the virus on rayon sheets for 10 sec, the solutions of 100 and 200 ppm could inactivate AIV immediately after spraying, while 50 ppm solution required at least 3 min of contact time. In the indirect spray form, after 10 sec of spraying, the lids of the dishes were opened to expose the virus on rayon sheets to HOCl. In this form, the 200 ppm solution inactivated AIV within 10 min of contact, while 50 and 100 ppm could not inactivate it. These data suggest that HOCl can be used in spray form to inactivate AIV at the farm level.

Stability of Weakly Acidic Hypochlorous Acid Solution with Microbicidal Activity

“…Indeed, there are many emerging pathogenic bacteria and viruses such as norovirus, influenza virus, coronavirus, etc. surrounding us Song et al, 2015, Hakim et al, 2015, Ishihara et al, 2015 In the past, millions have lost their lives due to the presence of pathogenic microorganisms in the daily environment. Of especial concern is the need to protect vulnerable children in local communities of African and south and east Asian countries where infectious diseases are endemic.…”

Inactivation of bacteria on surfaces by sprayed slightly acidic hypochlorous acid water: <i>in vitro</i> experiments

“…In the above equation, tpc is bacterial titer from an untreated sample in log 10 CFU/m l , whereas ta is the titer of recovered bacteria from treated samples. The inactivation rate was acceptable when the RF was greater than or equal to 3 [ 13 , 27 , 42 , 43 ].…”

“…It has a high capacity for killing pathogens by irreversibly denaturing the critical components of cells, such as nucleic acids (DNA/RNA), mitochondria, enzymes and surface proteins [ 48 ]. Previously, we have reported that SAHW has a virucidal efficacy toward avian influenza virus (AIV) on surfaces [ 13 ] and Newcastle disease virus (NDV) in the air, along with confirmed safety for chicks [ 14 ]. In the present study, we evaluated sprayed SAHW for its efficacy in inactivating Salmonella Infantis and E .…”

Comparison of Various Disinfectants on Bactericidal Activity Under Organic Matter Contaminated Environments

“…HClO solution at around pH 6, which is prepared by the addition of NaClO and HCl to sterile water or saline, has been demonstrated to have excellent in vitro bactericidal properties at lower concentrations 50 200 ppm than NaClO for gram positive bacteria such as S. aureus, B. cereus, and B. subtilis, as well as gram negative bacteria such as P. aeruginosa Hakim et al, 2015;Ono et al, 2012;Hao et al, 2013;Sakarya et al, 2014 . However, HClO readily reacts with various NH 2 or CHO-containing organic e.g., protein, amino acid, and carbohydrate and inorganic compounds, and it leads to the rapid consumption of HClO under organic matter contaminated environments Ishihara et al, 2017, Sato et al, 2018 .…”