Initial fast reaction of bromine on reovirus in turbulent flowing water

Abstract

An apparatus is described for precise observation of the kinetics of the initial fast reaction of bromine with reovirus in turbulent flowing water. When quantitative electron microscopy shows that virus suspensions are essentially all single particles, the loss of infectivity follows first-order kinetics, the plaque titer falling at the rate of 3 log,,, units/s at pH 7, 2 C, and at a 3-AM bromine concentration. Virus suspensions containing small aggregates (2 to 10/clump) exhibit a constantly decreasing disinfection rate with bromine. At a survival level of 10-3 for single virions, the aggregated preparations have lost only 99% of their plaque titer and 10-4 is reached only after 4 s of exposure. The disinfection rate does not appear to be a simple function of the size and frequency of aggregates in the virus suspension even when the aggregates contain no foreign material. Unpurified virus preparations (crude freeze-thaw lysates of infected cells) are shown, by zonal centrifugation, to contain 50% to over 90% of the infectivity in large, fast sedimenting aggregates. Such aggregates would strongly influence the bromine resistance of virus in polluted water.

Polyhexamethylene biguanide exposure leads to viral aggregation

“…Viral aggregate size >300 nm was observed following exposure to VANTOCIL TM TG or COSMOCIL TM at a concentration of 800 ppm (Figs 2 and 3). Based on the evidence from other studies (Sharp et al 1975(Sharp et al , 1976Jensen et al 1980;Young and Sharp 1985;Espinosa et al 2008) and our data demonstrating the formation of aggregates following exposure to PHMB, it would be tempting to associate the lack of activity of the biguanide to the formation of aggregates with the understanding that viral particles inside the clump are protected from the deleterious effect of the biguanide.…”

“…Such inactivation kinetic is usually explained from either the depletion of the active biocide or the presence of 'resistant' organisms. The formation of viral aggregates has been shown to lead to the survival of viral particles following biocide exposure (Sharp et al 1975(Sharp et al , 1976Espinosa et al 2008), notably with chlorine (Jensen et al 1980;Young and Sharp 1985). The propensity of particles to aggregates depends upon surface properties and notably hydrophobicity (Persson and Gekas 1994).…”

Effect of ionic environment on the inactivation of poliovirus in water by chlorine

“…Preparation of apparatus and chlorine solutions was the same as described in previous work (5). In some of the experiments, it was necessary to observe the effect on the virus of chlorine exposures for times as short as 1 s, and many data points were taken within 15 s after contact so the continuous flow apparatus (14) was used for all the inactivation experiments. Briefly, 20 liters of buffered, chlorine demand-free water was adjusted to the temperature and chlorine concentration required for the experiment.…”

“…The buffer utilized in the maintenance of the desired pH value was prepared by mixing crystalline KH2PO4 (Fisher Scientific Co., catalog no. P-382, primary standard grade) and Na2CO3 (Fisher S-281, alkalimetric standard) together in 20 liters of deionized glass distilled water in a Pyrex glass bottle (the large vessel described in [14]). The final molarities of each reagent are given in Table 1.…”

Development of Poliovirus Having Increased Resistance to Chlorine Inactivation

“…Several recent studies have examined the influence of the physical state of poliovirus and reovirus on the kinetics of inactivation (5,12,13). It was clearly demonstrated in these studies that aggregated virus was substantially more resistant to disinfection than suspensions of single particles.…”