Inactivation of Poliovirus with Some Chlorine Compounds Chloramine Formation in Virus Suspension and Its Effect on the Inactivation Rate.

Abstract

The inactivation rates of poliovirus (Lsc, 2ab strain) suspended in cell maintenance medium (MEM) and in phosphate buffer salt solution (PBS) with sodium hypochlorite (NaOCl), dichloro-, and trichloro-isocyanurates (2Cl-ICA, and 3Cl-ICA) and monochloramine (NH2Cl), 0.1-2.0 mg/l as available chlorine, were compared in the same conditions at pH 7 and 20°C. The formation of combined available chlorine (CA-Cl) with the virus suspension and the efficacy of the formed CA-Cl on the virus were studied. The amount of CA-Cl formed in the MEM suspension was greater than that in the PBS suspension and the virus was inactivated rapidly with free available chlorine (FA-Cl). In the PBS suspension containing 0.4 mg/l of chlorine, only a part of the chlorine convert to CA-Cl and more than 99% of the virus was inactivated in 3 min. In the MEM suspension containing the same concentration of chlorine, all of the chlorine was converted to CA-Cl and the inactivation of virus was not observed in 5 min. In 2.0 mg/l of chlorine with MEM suspension, about a half of FA-Cl remained and 99% of the virus was inactivated in 1 min. In 0.4 mg/l of NH2Cl, only 20% of the virus was inactivated in 5 min. The differences of CA-Cl formed in the virus suspension will give a significant variation in virus inactivation. There were no difference in CA-Cl formation in the virus suspension and the inactivation rate of the virus between hypochlorite and chloroisocyanurates.