Wanas M Q, Thompson S N, Allah A T
Department of Zoology, Faculty of Science, Al-Azhar University, Cairo, Egypt.
J Egypt Soc Parasitol. 1998 Aug;28(2):583-94.
The effects of the heavy metal pollutants, lead, mercury and cadmium on the survival and behaviour of miracidia and cercariae of Schistosoma mansoni were examined. Concentration ranges of 100-900 microM lead chloride, 0.25-20 microM mercuric chloride and 0.25-9.0 microM cadmium chloride were tested. Inversely proportional relationships between metal concentration and survival were evident with all the metals. The LC50 of miracidia was 600 microM for lead, 1 microM for mercury and 2.5 for cadmium. The LC50 of cercariae was 600 microM for lead, 6 microM for mercury and 2.5 microM for cadmium. Movement and behavior of miracidia and cercariae were severely affected by exposure at the higher end of the concentrations of heavy metals tested. Infectivity of cercariae to mice was reduced by nearly half when cercariae were pre-exposed to lead, mercury or cadmium for five hours at the LC50 concentrations, compared with the infectivity of unexposed cercariae.
研究了重金属污染物铅、汞和镉对曼氏血吸虫毛蚴和尾蚴存活及行为的影响。测试了100 - 900微摩尔/升氯化铅、0.25 - 20微摩尔/升氯化汞和0.25 - 9.0微摩尔/升氯化镉的浓度范围。所有金属的浓度与存活率之间均呈现反比关系。毛蚴的半数致死浓度（LC50）铅为600微摩尔/升，汞为1微摩尔/升，镉为2.5微摩尔/升。尾蚴的半数致死浓度铅为600微摩尔/升，汞为6微摩尔/升，镉为2.5微摩尔/升。在所测试的重金属浓度上限下暴露时，毛蚴和尾蚴的运动及行为受到严重影响。与未暴露的尾蚴相比，当尾蚴在半数致死浓度下预先暴露于铅、汞或镉5小时后，其对小鼠的感染力降低了近一半。
