Toledo Rafael, Carpena Inés, Espert Ana, Sotillo Javier, Muñoz-Antoli Carla, Esteban J Guillermo
Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Av. Vicente Andrés Estellés s/n, 46100 Burjassot-Valencia, Spain.
J Parasitol. 2006 Feb;92(1):16-20. doi: 10.1645/GE-574R1.1.
Using a range of parameters, the ability of rats (Rattus norvegicus) to successfully transmit Echinostoma friedi to the next host was examined under experimental conditions. The concept of Experimental Transmission Success (TM), defined as the number of hosts that become successfully infected after exposure to a number of infective stages produced by a previous host per unit of inoculation at which this latter host was exposed, was introduced. Using data for the egg output and miracidium hatching and infectivity, the TM permits us to estimate the ability of a particular definitive host species to successfully transmit a parasite species. This concept may be also useful to compare the transmission fitness of a parasite in different definitive host species. Moreover, variations of the Experimental Transmission Success over the course of the infection were calculated by the use of the Weekly Experimental Transmission Success (TMW). Overall, considering the complete duration of the experiment, the TM of E. friedi using rats as definitive hosts was 0.68 infected snails/metacercaria. However, positive values of the TMW were only obtained from 2 to 4 wk post-infection, with a maximum during the third wk post-infection. When comparing the TM values of E. friedi in rats with those calculated in hamsters on the basis of previously published data, E. friedi appears to be more appropriate to move through this portion of its life cycle when using hamsters (Mesocricetus auratus) as the final host than rats.
利用一系列参数，在实验条件下研究了大鼠（褐家鼠）将弗里德棘口吸虫成功传播给下一宿主的能力。引入了实验传播成功率（TM）的概念，其定义为在接种单位数量的感染阶段后成功感染的宿主数量，这些感染阶段由前一宿主产生，且前一宿主暴露于该数量的感染阶段。利用产卵量、毛蚴孵化率和感染力的数据，TM使我们能够估计特定终末宿主物种成功传播寄生虫物种的能力。这个概念对于比较寄生虫在不同终末宿主物种中的传播适应性也可能有用。此外，通过使用每周实验传播成功率（TMW）来计算感染过程中实验传播成功率的变化。总体而言，考虑到实验的完整持续时间，以大鼠作为终末宿主时弗里德棘口吸虫的TM为0.68只感染的蜗牛/尾蚴。然而，仅在感染后2至4周获得了TMW的正值，在感染后第三周达到最大值。根据先前发表的数据，将大鼠中弗里德棘口吸虫的TM值与仓鼠中计算得到的TM值进行比较时，当以仓鼠（金黄仓鼠）作为终末宿主时，弗里德棘口吸虫似乎比以大鼠作为终末宿主时更适合度过其生命周期的这一阶段。
