As an alternative to using ultraviolet (UV) lamps, which are made with mercury that is toxic to the environment and human health, UV light-emitting diodes (UV-LEDs) are expected to be effective for inactivating microorganisms in water. Although UV-LEDs have been reported to be effective against bacteria and viruses, the effectiveness of UV-LEDs against Cryptosporidium parasites has not been fully evaluated. As we report here, we have developed an in vivo quantitative inactivation assay for C. parvum oocysts using immunodeficient mice. Using the assay, we evaluated the effectiveness of treatment by UV lamp (254 nm) at approximately 1000 μJ/cm² (for 3 s at a distance of 95 mm) compared to inactivation by commercially available UV-LEDs (with peak wavelengths of 268, 275, 284, and 289 nm). The shed patterns of oocysts after treatment with 284- and 289-nm wavelength UV-LEDs were significantly delayed compared to that after treatment with a UV lamp. These findings provide the first suggestion that UV-LEDs are effective against these parasites, as assessed using commercially available 350-mA UV-LEDs under conditions of fixed exposure distance and time.

作为使用由对环境和人类健康有毒的汞制得的紫外线（UV）灯的替代方法，紫外线发光二极管（UV-LED）有望有效灭活水中的微生物。尽管已经报道了UV-LED对细菌和病毒有效，但是尚未完全评估UV-LED对隐孢子虫寄生虫的有效性。正如我们在这里报告的那样，我们已经开发了使用免疫缺陷小鼠的小球藻卵囊体内定量灭活测定法。使用该测定法，我们评估了在约1000μJ/ cm ^{2的条件下}通过紫外线灯（254 nm）进行治疗的有效性（距离95 mm持续3 s）相比，可通过市售的UV-LED灭活（峰值波长为268、275、284和289 nm）。与用紫外灯处理后相比，用284和289 nm波长的UV-LED处理后的卵囊脱落模式明显延迟。这些发现提供了第一个暗示，即在固定的曝光距离和时间条件下，使用市售的350 mA UV-LED评估，UV-LED对这些寄生虫有效。