Room Decontamination Using Ionized Hydrogen Peroxide Fog and Mist Reduces Hatching Rates of Syphacia obvelata Ova

Abstract

This study evaluated the efficacy of ionized hydrogen peroxide (iHP) fog and mist for environmental and surface decontaminationof Syphacia obvelata ova in rodent rooms. Ova were collected by perianal tape impression from S. obvelata infectedmice. In experiment 1, ova were exposed to iHP using a whole-room fogging decontamination system with a 15 min initialfog application cycle in unoccupied rodent rooms. Ova were removed from the fogged environment after a 15 min, 30 min, 90min, or 240 min iHP exposure time. In experiment 2, a second cohort of ova were exposed to iHP using the whole-room foggingdecontamination system. Ova were removed after 3, 4 or 6 continuous fog application cycles with 45 min dwelling timebetween each cycle and 15 h dwelling time for the last time point. In experiment 3, a third set of ova was exposed to an iHPsurface misting unit with 1, 2, or 3 iHP mist applications. A 7 min contact time followed each application. After exposure, ovawere incubated in a hatching medium for 6 h. Control ova were maintained at room temperature without iHP exposure beforeincubation in the hatching medium. After incubation, the number of ova hatched was assessed by microscopic examination.For experiment 1, results ranged from 46% to 57% of exposed ova hatched. For experiment 2, results ranged from 43% to 49%of ova hatched. For experiment 3, 37% to 46% of exposed ova hatched. Conversely, for the control groups above 80% of ovahatched for all 3 experiments. These data suggest that exposure to iHP fog and mist has variable effectiveness in reducingviability of S. obvelata ova at the time points tracked. Further studies are needed to identify iHP exposures that will furtherreduce or eliminate the hatching of rodent pinworm ova.