Lagapa J T, Konno K, Oku Y, Nonaka N, Kamiya M
Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
Parasitol Res. 2001 Aug;87(8):593-7. doi: 10.1007/s004360100391.
The expanding distribution of alveolar echinococcosis in Hokkaido, Japan necessitates a search for control measures, particularly for killing Echinococcus eggs; and UV radiation is a potential tool. To determine the effective UV lamp and its optimum duration of exposure to inhibit the infectivity of taeniid eggs, three UV lamps (UVA, UVB and UVC) with peak emissions at different wavelengths were used to irradiate eggs of Taenia taeniaeformis. Irradiation was done in durations of 30, 90, 270, 810, 2,430 and 7,290 s. Infectivity of the irradiated eggs was tested by oral inoculation into rats. The inhibitory effect of the UV lamps at different exposure durations was determined by the reduction in the larval cyst establishment and by the delay of larval development. The UVC lamp (narrow peak at 254 nm) was found to be the most effective lamp at an exposure duration of more than 2,430 s (2,430 mJ/cm2), attaining 100% reduction. Also, shorter exposure durations produced a significant effect on the development of irradiated eggs in a greater percentage of small cysts (> 1 mm) among the metacestodes. Irradiation delayed the development of some cysts, as observed in histopathological sections. UVA and UVB lamps were not able to attain 100% reduction. It is concluded that the UVC lamp can be used as a tool in sterilizing taeniid eggs and is thus a promising method to control echinococcosis, although it may require a higher intensity of exposure.
日本北海道肺泡型棘球蚴病分布范围不断扩大，因此有必要寻找控制措施，尤其是杀灭棘球绦虫卵的措施；紫外线辐射是一种潜在手段。为确定抑制带绦虫卵感染力的有效紫外线灯及其最佳照射时长，使用了三种峰值发射波长不同的紫外线灯（UVA、UVB和UVC）照射泡状带绦虫卵。照射时长分别为30、90、270、810、2430和7290秒。通过经口接种大鼠来检测照射后虫卵的感染力。根据幼虫囊肿形成的减少情况以及幼虫发育的延迟情况来确定不同照射时长下紫外线灯的抑制效果。发现UVC灯（254纳米窄峰）在照射时长超过2430秒（2430毫焦/平方厘米）时最为有效，可实现100%的杀灭率。此外，较短的照射时长对辐照后虫卵的发育也有显著影响，在中绦期出现较大比例的小囊肿（>1毫米）。组织病理学切片显示，照射会延迟一些囊肿的发育。UVA和UVB灯无法实现100%的杀灭率。结论是，UVC灯可作为一种杀灭带绦虫卵的手段，因此是控制棘球蚴病的一种有前景的方法，尽管可能需要更高的照射强度。
