title: Determining UV inactivation of Toxoplasma gondii oocysts by using cell culture and a mouse bioassay.
abstract: The effect of UV exposure on Toxoplasma gondii oocysts has not been completely defined for use in water disinfection. This study evaluated UV-irradiated oocysts by three assays: a SCID mouse bioassay, an in vitro T. gondii oocyst plaque (TOP) assay, and a quantitative reverse transcriptase real-time PCR (RT-qPCR) assay. The results from the animal bioassay show that 1- and 3-log(10) inactivation is achieved with 4 mJ/cm(2) UV and 10 mJ/cm(2) low-pressure UV, respectively. TOP assay results, but not RT-qPCR results, correlate well with bioassay results. In conclusion, a 3-log(10) inactivation of T. gondii oocysts is achieved by 10-mJ/cm(2) low-pressure UV, and the in vitro TOP assay is a promising alternative to the mouse bioassay.
authors.affiliation: National Exposure Research Laboratory, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268, USA.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Ware
authors.forename: Swinburne A J
authors.initials: SA
authors.lastname: Augustine
authors.forename: David O
authors.initials: DO
authors.lastname: Erisman
authors.forename: Mary Jean
authors.initials: MJ
authors.lastname: See
authors.forename: Larry
authors.initials: L
authors.lastname: Wymer
authors.forename: Samuel L
authors.initials: SL
authors.lastname: Hayes
authors.forename: J P
authors.initials: JP
authors.lastname: Dubey
authors.forename: Eric N
authors.initials: EN
authors.lastname: Villegas
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods; D018929:Cell Culture Techniques / Q000379:methods; D051379:Mice; D050296:Microbial Viability / Q000528:radiation effects*; D033661:Oocysts / Q000528:radiation effects*; D010274:Parasitology / Q000379:methods*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014122:Toxoplasma / Q000528:radiation effects*; D014124:Toxoplasmosis, Animal / Q000469:parasitology; D018508:Water Purification / Q000379:methods