RESUMO
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.
Assuntos
Criptosporidiose/prevenção & controle , Cryptosporidium parvum/efeitos dos fármacos , Desinfetantes/farmacologia , Iodo/farmacologia , Medicina Militar , Purificação da Água/métodos , Água/parasitologia , Animais , Criptosporidiose/parasitologia , Camundongos , Segurança , Comprimidos , Estados Unidos , Água/análiseRESUMO
A synergistic effect between silver and UV radiation has been observed that can appreciably enhance the effectiveness of UV radiation for inactivation of viruses. At a fluence of ca. 40 mJ/cm(2), the synergistic effect between silver and UV was observed at silver concentrations as low as 10 microg/liter (P < 0.0615). At the same fluence, an MS-2 inactivation of ca. 3.5 logs (99.97%) was achieved at a silver concentration of 0.1 mg/liter, a significant improvement (P < 0.0001) over the ca. 1.8-log (98.42%) inactivation of MS-2 at ca. 40 mJ/cm(2) in the absence of silver. Modified Chick-Watson kinetics were used to model the synergistic effect of silver and UV radiation. For an MS-2 inactivation of 4 logs (99.99%), the coefficient of dilution (n) was determined to be 0.31, which suggests that changes in fluence have a greater influence on inactivation than does a proportionate change in silver concentration.