Intact and decorticated single-celled Ascaris suum eggs were exposed to UV radiation from low-pressure, germicidal lamps at fluences (doses) ranging from 0 to 8,000 J/m2 for intact eggs and from 0 to 500 J/m2 for decorticated eggs. With a UV fluence of 500 J/m2, 0.44- ± 0.20-log inactivation (mean ± 95% confidence interval) (63.7%) of intact eggs was observed, while a fluence of 4,000 J/m2 resulted in 2.23- ± 0.49-log inactivation (99.4%). (The maximum quantifiable inactivation was 2.5 log units.) Thus, according to the methods used here, Ascaris eggs are the most UV-resistant water-related pathogen identified to date. For the range of fluences recommended for disinfecting drinking water and wastewater (200 to 2,000 J/m2), from 0- to 1.5-log inactivation can be expected, although at typical fluences (less than 1,000 J/m2), the inactivation may be less than 1 log. When the eggs were decorticated (the outer egg shell layers were removed with sodium hypochlorite, leaving only the lipoprotein ascaroside layer) before exposure to UV, 1.80- ± 0.32-log reduction (98.4%) was achieved with a fluence of 500 J/m2, suggesting that the outer eggshell layers protected A. suum eggs from inactivation by UV radiation. This protection may have been due to UV absorption by proteins in the outer layers of the 3- to 4-μm-thick eggshell. Stirring alone (without UV exposure) also inactivated some of the Ascaris eggs (∼20% after 75 min), which complicated determination of the inactivation caused by UV radiation alone.
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机译:将完整和去皮的单细胞A虫Suum卵暴露于低压杀菌灯的紫外线辐射下(完整剂量为0到8,000 J / m 2 sup>的通量(剂量),以及0到500的通量) J / m 2 sup>用于去壳鸡蛋。 UV通量为500 J / m 2 sup>时,观察到完整鸡蛋的失活率为0.44-±0.20-log(平均±95%置信区间)(63.7%),而通量为4,000 J / m。 m 2 sup>导致2.23-±0.49-log失活(99.4%)。 (最大的定量灭活为2.5 log单位。)因此,根据此处使用的方法,A虫卵是迄今为止鉴定出的最抗紫外线的与水相关的病原体。对于推荐用于饮用水和废水消毒的注量范围(200至2,000 J / m 2 sup>),可以预期从0到1.5 log的失活,尽管典型的注量(小于1,000 J)。 / m 2 sup>),则停用次数可能少于1个日志。当将蛋去皮(用次氯酸钠除去蛋壳外层,仅留下脂蛋白a糖苷层),然后再暴露于紫外线下,通量为500 J / m时可减少1.80-±0.32-log(98.4%) 2 sup>,表明蛋壳的外层保护了A. suum鸡蛋免受紫外线辐射的灭活。这种保护作用可能是由于3到4微米厚的蛋壳外层中的蛋白质吸收了紫外线。单独搅拌(不暴露于紫外线)也会使一些the虫卵失活(75分钟后约20%),这使确定仅由紫外线辐射引起的失活变得复杂。
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