Do iodine water purification tablets provide an effective barrier against Cryptosporidium parvum?
U.S. Army Iodine Water Purification Tablets were tested to determine their efficacy against Cryptosporidium parvum, a protozoan resistant to chemical disinfection. Purified oocysts in phosphate-buffered water were treated with varying concentrations of iodine or with iodine tablets as per U.S. Army protocol. Neonatal mouse pups were then each inoculated with 10,000 treated oocysts, and 1 week later scored as infected or uninfected. Using this methodology, iodine tablets were found to be inadequate against C. parvum because the Army doctrinal dose of 560 mg min/L, calculated as 16 mg of I2/L and 35 minutes of contact time, showed less than 1 log inactivation. A dose of 29 mg of I2/L at the same contact time was required to achieve a 2 log inactivation.
Butkus
Michael A
MA
Department of Geography and Environmental Engineering, U.S. Military Academy, West Point, NY 10996, USA.
Starke
Jeffrey A
JA
Bowman
Dwight D
DD
Labare
Michael
M
Fogarty
Elizabeth A
EA
Lucio-Forster
Araceli
A
Barbi
Joseph
J
Jenkins
Michael B
MB
Pavlo
Mary
M
D000818:Animals; D003457:Cryptosporidiosis / Q000469:parasitology / Q000517:prevention & control*; D016785:Cryptosporidium parvum / Q000187:drug effects*; D004202:Disinfectants / Q000494:pharmacology*; D007455:Iodine / Q000494:pharmacology*; D051379:Mice; D008887:Military Medicine; D012449:Safety; D013607:Tablets; D014481:United States; D014867:Water / Q000032:analysis / Q000469:parasitology*; D018508:Water Purification / Q000379:methods*
D004202:Disinfectants; D013607:Tablets; D014867:Water; D007455:Iodine