Inactivation of hepatitis A virus and indicator organisms in water by free chlorine residuals

Abstract

Hepatitis A virus (HAV) and selected indicator organisms were mixed together in chlorine-demand-free buffers at pH 6, 8, or 10 and exposed to free chlorine residuals, and the survival kinetics of individual organisms were compared. HAV was enumerated by a most-probable-number dilution assay, using PLC/PRF/5 liver cells for propagation of the virus and radioimmunoassay for its detection. At all pH levels, HAV was more sensitive than Mycobacteriumfortuitum, coliphage Vl (representing a type of phage common in some sewage-polluted waters), and poliovirus type 2. Under certain conditions, HAV was more resistant than Escherichia coli, Streptococcus faecalis, coliphage MS2, and reovirus type 3. It was always more resistant than SA-11 rotavirus. Evidence is presented that conditions generally specified for the chlorine disinfection of drinking-water supplies will also successfully inactivate HAV and that HAV inactivation by free chlorine residuals can reliably be monitored by practical indicator systems consisting of appropriate combinations of suitable indicators such as coliform and acid-fast bacteria, coliphages, the standard plate count, and fecal streptococci.

Analysis of 10 years of virus monitoring data from Los Angeles County treatment plants meeting California wastewater reclamation criteria

“…Hepatitis A virus (HAV) has been reported to be somewhat more resistant to chlorine than other viruses based on infectivity studies done in monkeys (Peterson et al, 1983). Grabow et al (1983) however, found HAV less resistant to free chlorine than poliovirus 2 and concluded that standard drinking water dis- infection practices would successfully inactivate HAV. This finding would also appear to substantiate the indicator value of enteric viruses.…”

Irrigation Water as a Potential Preharvest Source of Bacterial Contamination of Vegetables

“…Horman et al 2004 found that together with E. coli and fecal coliform, Clostridium perfrigens could be used as indicator of water safety. Also, combination of suitable indicators such as coliform and acid-fast bacteria, coliphages, the standard plate count and fecal streptococci, has been recommended for adequate monitoring (Grabow et al 1983). In fact, Harwood et al 2005 believed that public health cannot be adequately protected through simple monitoring schemes based on the use of E. coli alone but suggested that additional parameters should be used as indicators.…”

Hepatitis viruses and emerging viruses

“…Notably, the active ethanol component of many commercial hand disinfectants has a very limited ability to reduce infectious hepatitis A virus titre from contaminated hands or surfaces (Mbithi et al, 1990;Bidawid et al, 2000a). The most effective disinfectants are 2 % glutaraldehyde and 10 % sodium hypochlorite (5000 ppm free chlorine) (Grabow et al, 1983;Mbithi et al, 1990;Abad et al, 1997a;Jean et al, 2003). Care must always be taken to follow appropriate time/concentration combinations for effective disinfection.…”

“…Effective surface decontamination can also be used to interrupt hepatitis A virus transmission in food service settings, but as described in Section 25.3.1, not all commercial disinfectants are effective against the hepatitis A virus (Mbithi et al, 1990;Abad et al, 1997a;Bidawid et al, 2000a;van Engelenburg et al, 2002;Jean et al, 2003;Bigliardi and Sansebastiano, 2006;Terpstra et al, 2007). For effective disinfectants, such as sodium hypochlorite, concentration and contact time must be followed precisely to effectively inactivate the virus on a contaminated surface (Grabow et al, 1983;Mbithi et al, 1990;Abad et al, 1997a;Jean et al, 2003).…”