Toledo R, Muñoz-Antoli C, Pérez M, Esteban J G
Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Spain.
J Helminthol. 1999 Jun;73(2):177-82.
The survival characteristics of the cercariae of Hypoderaeum conoideum and Euparyphium albuferensis (Trematoda: Echinostomatidae) at 20 degrees C and 30 degrees C are described, and the age dependency of their infectivity at 20 degrees C is studied to determine their respective transmission efficiencies. Cercarial survival was found to be age-dependent and was higher at 20 degrees C. For both cercariae, the maximum life-span was 26 h at 20 degrees C and 16 h at 30 degrees C, and their respective times to 50% mortality were similar at each temperature. Both cercariae seem to be well adapted to transmission in their natural habitat, though cercarial infectivity of H. conoideum was higher than that of E. albuferensis, this being correlated with their prevalences in nature. The age-dependency of cercarial survival may be related to steadily diminishing endogenous energy levels, though the delay in attaining maximum infectivity suggests that other factors not related to energy considerations are involved in the delimitation of the cercarial infective period. However, this latter observation may constitute an adaptative mechanism allowing cercarial dissemination.
描述了锥状低颈吸虫和白腹真缘吸虫（吸虫纲：棘口科）尾蚴在20℃和30℃下的存活特征，并研究了它们在20℃下感染力的年龄依赖性，以确定它们各自的传播效率。发现尾蚴的存活具有年龄依赖性，且在20℃下更高。对于这两种尾蚴，在20℃下的最长寿命为26小时，在30℃下为16小时，并且在每个温度下它们各自达到50%死亡率的时间相似。尽管锥状低颈吸虫的尾蚴感染力高于白腹真缘吸虫，且这与它们在自然界中的流行率相关，但这两种尾蚴似乎都很好地适应了在其自然栖息地中的传播。尾蚴存活的年龄依赖性可能与内源性能量水平的稳步下降有关，尽管达到最大感染力的延迟表明在确定尾蚴感染期时涉及其他与能量无关的因素。然而，后一种观察结果可能构成一种允许尾蚴传播的适应性机制。
