Iodine is frequently employed for backcountry water disinfection. However, the dynamics of the disinfection process have not been adequately studied, particularly with regard to the most resistant organism, Giardia lamblia. Using Giardia muris as a model for the human pathogen, we measured the iodine inactivation of cysts over a range of water temperatures and iodine concentrations. These data indicate that manufacturers’ recommendations for backcountry water disinfection with iodine are inadequate to insure complete inactivation of Giardia cysts. New recommendations for water disinfection with iodine are made.
CraunG.F.Waterborne Disease in the United States. Boca Raton, FL: CRC Press, 1986
2.
BackerH.D.Field water disinfection. In: AuerbachP.S.GeehrE.C. eds. Management of Wilderness and Environmental Emergencies. 2nd ed.St. Louis: C. V. Mosby Company, 1989, 805–827
3.
BurkheadG.VogtR.L.Epidemiologic surveillance for endemic Giardia lamblia infection in Vermont. Am J Epidemiol1989; 129, 762–768
4.
MonzingoD.L.StevensD.R.Giardia contamination of surface waters: a survey of three selected backcountry streams in Rocky Mountain National Park. Water Resources Rep. No. 86–2. Fort Collins, CO: National Park Service, 1986
5.
BlackA.P.KinmanR.N.ThomasW.C.et al.Use of Iodine for Disinfection. JA WWA1965; 57, 1401–1421
6.
ChangS.L.The use of active iodine as a water disinfectant. J Am Pharm Assoc1958; 47, 417–423
7.
JarrollE.L.BinghamA.K.MeyerE.A.Inability of an iodination method to destroy completely Giardia cysts in cold water. West J Med1980; 132, 567–569
8.
JarrollE.L.BinghamA.K.MeyerE.A.Giardia cyst destruction: effectiveness of six small-quantity water disinfection methods. Am J Tropical Med Hyg1980; 29, 8–11
9.
SchaeferF.W.RiceE.W.HoffJ.C.Factors promoting in vitro excystation of Giardia muris cysts. Trans Royal Soc Trop Med Hyg1984; 78, 795–800
10.
OngerthJ.E.JohnsonR.L.MacdonaldS.C.FrostF.StibbsH.H.Backcountry water treatment to prevent giardiasis. Am J Public Health1989; 79, 1633–1637
11.
SchaubS.A.Report of Task Force on Guide, Standard and Protocol for Testing Microbiological Water Purifiers. Environmental Protection Agency1986April
12.
RiceE.W.HoffJ.C.SchaeferF.W.Inactivation of Giardia cysts by chlorine. Appl Environ Microbiol1982; 43, 250–251
13.
SchaeferF.W.A review of methods that are used to determine Giardia cyst viability. In: WallisP.M.HammondB.R. eds. Advances in Giardia Research, Calgary: University of Calgary Press, 1988, 249–254
14.
HoffJ.C.RiceE.W.SchaeferF.W.Comparison of animal infectivity and excystation as measures of Giardia muris cyst inactivation by chlorine. Appl Environ Microbiol1985; 50, 1115–1117
15.
DeRegnierD.P.ColeL.SchuppD.G.ErlandsenS.L.Viability of Giardia cysts suspended in lake, river, and tap water. Appl Environ Microbiol1989; 55, 1223–1229
