ARS | Publication request: Effects of ozone and UV radiation treatments on the infectivity of Toxoplasma gondii oocysts

Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 3, 2007
Publication Date: May 1, 2008
Citation: Dumetre, A., Lebras, C., Baffet, M., Meneceur, P., Dubey, J.P., Derouin, F., Duguet, J., Joyeux, M., Moulin, L. 2008. Effects of ozone and UV radiation treatments on the infectivity of Toxoplasma gondii oocysts. Veterinary Parasitology. 153:209-213.

Interpretive Summary: Toxoplasma gondii is a single-celled parasite of all warm-blooded hosts worldwide. It causes mental retardation and loss of vision in children, and abortion in livestock. Cats are the main reservoir of T. gondii because they are the only hosts that can excrete the resistant stage (oocyst) of the parasite in the feces. Humans become infected by eating undercooked meat from infected animals and food and water contaminated with oocysts.Toxoplasmosis causes mortality in many species of animals in the zoos, especially primates. Scientists at the Beltsville Agricultural Research Center and scientists from France report experiments with disinfection of water with Uv and ozone treatments. The results will be of interest to biologists, parasitologists, and veterinarians.

Technical Abstract: Clinical toxoplasmosis in humans has been epidemiologically-linked to the consumption of drinking water contaminated by Toxoplasma gondii oocysts. We evaluated killing of T. gondii oocysts after ultraviolet (UV) or ozone treatments by bioassay in mice and/or cell culture. A 4-log inactivation of the oocyst/sporozoite infectivity was obtained for UV fluences >20 mJ/cm². In contrast, oocysts were not inactivated by ozone with an exposure (Ct) up to 9.4 mg.min.l-1 in water at 20 °C. In conclusion, UV treatment can be an effective disinfection method to inactivate T. gondii oocysts in drinking water.