通过检测活性氧降解酶和清除剂在紫外线照射下对微小隐孢子虫卵囊活力的保护作用，进行了微小隐孢子虫灭活实验。通过两种重要的染色程序:DAPI/PI和SYTO（R）9染色来测量存活率。将酶/清除剂添加到PBS或天然水中的卵囊悬浮液中，并在20℃下在黑暗中或连续暴露于紫外线照射下培养24和48小时。紫外线强度（365 nm）调整为3.5 mW/cm2。羟基自由基清除剂硫脲（100 mM）表现出最大的保护作用，这表明羟基自由基是通过紫外线照射在PBS和天然水中产生的，它们对卵囊的活力产生影响。 分解过氧化氢的过氧化氢酶（800 U/mL）对卵囊活力也有显著的保护作用。超氧化物歧化酶（900 U/mL）能将超氧阴离子分解为过氧化氢，但没有明显的保护作用，表明过氧化氢参与了光毒性。在密歇根湖样品中，超氧化物歧化酶和过氧化氢酶的组合表现出比PBS更大的光保护效果，这表明当受到紫外线照射时，密歇根湖超氧阴离子和/或过氧化氢的生成不如PBS中的显著。这项研究表明，某些活性氧物种，尤其是羟基自由基和过氧化氢，与失活有关（照片）- 当这些寄生虫暴露在紫外线照射下时观察到的微小隐孢子虫卵囊的毒性）。

Cryptosporidium parvum inactivation experiments were performed by testing the protective effect of reactive oxygen species-degrading enzymes and scavengers on Cryptosporidium parvum oocyst viability in the presence of ultraviolet irradiation. Viability was measured by using two vital staining procedures: DAPI/PI and SYTO(R)9 staining. Enzymes/scavengers were added to the oocyst suspensions in PBS or natural water and incubated for 24 and 48 hours at 20 degrees C either in the dark or with continuous exposure to ultraviolet irradiation. The ultraviolet light intensity (365 nm) was adjusted to 3.5 mW/cm2. Thiourea (100 mM), a hydroxyl radical scavenger, exhibited the most protective effect, suggesting that hydroxyl radicals were generated by ultraviolet irradiation in both PBS and natural water and that they exerted an effect on oocyst viability. Catalase (800 U/mL), which breaks down hydrogen peroxide, also exhibited a significant protective effect on oocyst viability. Superoxide dismutase (900 U/mL), which breaks down superoxide anions to hydrogen peroxide, had no significant protective effect, suggesting that hydrogen peroxide was involved in photo-toxicity. The combination of superoxide dismutase and catalase exhibited a greater photo-protective effect in Lake Michigan samples than in PBS, indicating that the production of superoxide anions and/or hydrogen peroxide was less significant in Lake Michigan than in PBS, when subjected to ultraviolet irradiation. This study shows that certain reactive oxygen species, especially hydroxyl radicals and hydrogen peroxide, were associated with the inactivation (photo-toxicity) of Cryptosporidium parvum oocysts observed when these parasites were exposed to ultraviolet irradiation.