Pulsed-UV light inactivation of Cryptosporidium parvum.
Cryptosporidium parvum is an organism that threatens public health in the water industry. It is critical to develop improved detection methods as well as disinfection methods for protecting against cryptosporidiosis, which is caused by C. parvum. In this study, we investigated the ability of pulsed-light irradiation at 200-900 nm to inactivate C. parvum. Absolute quantitative real-time PCR was performed with cDNA made from total RNA extracted from C. parvum oocysts or HCT-8 cells infected with C. parvum oocysts in vitro. C. parvum oocysts in 100-mL quartz flasks were positioned 20, 30, and 40 cm from the light source, and the duration of irradiation was either 5 or 60 s. The reductions in oocyst viability (4.9 log10) and infectivity (6 log10) were maximal when the C. parvum oocysts were irradiated 20 cm from the pulsed-light source for 60 s, for which the UV dose was 278 mJ/cm2. The minimum dose of pulsed-UV light required for effective reduction in C. parvum infectivity (2 log10) was 15 mJ/cm2, which was achieved by 5 s of irradiation at 30 cm from the light source. This study confirmed that short-duration pulsed-UV light is an effective disinfection measure for C. parvum.
Lee
Soo-Ung
SU
Department of Environmental and Tropical Medicine, Konkuk University School of Medicine, Chungju 380-701, Republic of Korea.
Joung
Migyo
M
Yang
Dong-Jin
DJ
Park
Soon-Ho
SH
Huh
Sun
S
Park
Woo-Yoon
WY
Yu
Jae-Ran
JR
D000818:Animals; D002470:Cell Survival; D016785:Cryptosporidium parvum / Q000528:radiation effects*; D004203:Disinfection / Q000379:methods*; D005260:Female; D051379:Mice; D033661:Oocysts / Q000528:radiation effects; D014466:Ultraviolet Rays