Evaluation of the efficacy of selected commercial disinfectants in inactivating Giardia muris cysts.
Fourteen commercially available disinfectants were evaluated for their efficacy in inactivating purified Giardia muris cysts in vitro. Each disinfectant was evaluated at the dilution(s) recommended by the manufacturer for use as a general-purpose disinfectant in a kennel(-like) environment and at lower concentrations. Assays were performed within two temperature ranges chosen to approximate the limits of range of temperatures at which disinfectants might be used (that is, 4°C to 10°C and 20°C to 25°C). Shortest contact time needed to produce complete inactivation of giardial cysts was determined for each dilution within each temperature range. The quaternary ammonium-containing disinfectants inactivated G. muris cysts more rapidly and at lower concentrations than did other categories of disinfectants. These disinfectants retained their effectiveness at low temperatures. Relative costs of these compounds compared favourably with costs of other disinfectants.