Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA, USA.
Zoonoses Public Health. 2010 Feb;57(1):74-81. doi: 10.1111/j.1863-2378.2009.01280.x. Epub 2009 Sep 10.
Toxoplasma gondii, a ubiquitous parasitic protozoan, is emerging as an aquatic biological pollutant. Infections can result from drinking water contaminated with environmentally resistant oocysts. However, recommendations regarding water treatment for oocyst inactivation have not been established. In this study, the physical method of radiofrequency (RF) power was evaluated for its ability to inactivate T. gondii oocysts in water. Oocysts were exposed to various RF energy levels to induce 50, 55, 60, 70 and 80 degrees C temperatures maintained for 1 min. Post-treatment oocyst viability was determined by mouse bioassay with serology, immunohistochemistry and in vitro parasite isolation to confirm T. gondii infections in mice. None of the mice inoculated with oocysts treated with RF-induced temperatures of > or =60 degrees C in an initial experiment became infected; however, there was incomplete oocyst activation in subsequent experiments conducted under similar conditions. These results indicate that T. gondii oocysts may not always be inactivated when exposed to a minimum of 60 degrees C for 1 min. The impact of factors such as water heating time, cooling time and the volume of water treated must be considered when evaluating the efficacy of RF power for oocyst inactivation.
刚地弓形虫，一种普遍存在的寄生原生动物，正在成为一种水生生物污染物。饮用被环境抗性卵囊污染的水会导致感染。然而，尚未制定针对卵囊灭活的水疗建议。在这项研究中，评估了射频（RF）功率的物理方法，以确定其在水中灭活弓形虫卵囊的能力。将卵囊暴露于不同的 RF 能量水平下，以诱导 50、55、60、70 和 80°C 的温度保持 1 分钟。通过血清学、免疫组织化学和体外寄生虫分离来确定小鼠生物测定后卵囊的存活能力，以确认小鼠中的弓形虫感染。在初始实验中，用 RF 诱导的温度 >或=60°C 处理的卵囊接种的所有小鼠均未感染；然而，在类似条件下进行的后续实验中，卵囊的激活不完全。这些结果表明，当暴露于至少 60°C 1 分钟时，弓形虫卵囊可能并不总是被灭活。在评估 RF 功率对卵囊灭活的效果时，必须考虑水加热时间、冷却时间和处理水量等因素的影响。
