Leung T L F, Poulin R
Department of Zoology, University of Otago, PO Box 56, Dunedin, New Zealand.
J Helminthol. 2006 Sep;80(3):271-5.
There are many recorded cases of parasites that are capable of altering the behaviour of their host to enhance their transmission efficiency. However, not all of these cases are necessarily the results of the parasites actively manipulating host behaviour; they may rather be the 'by-products' of pathology caused by the parasite's presence. This study investigates the effect of the microphallid trematode Maritrema novaezealandensis on the behaviour of one of its crustacean intermediate hosts, the amphipod Paracalliope novizealandiae. Uninfected amphipods were experimentally infected by exposure to M. novaezealandensis cercariae. The activity level and vertical position of experimentally infected amphipods were compared with uninfected amphipods at 2 weeks and 6 weeks post-infection, i.e. both before and after the parasite achieved infectivity to its definitive host. Infected amphipods were found to exhibit significantly lower levels of activity and to occur significantly lower in the water column than uninfected controls during both periods. Based on the timing of the change in behaviour exhibited by infected amphipods, the results suggest that the altered behaviour exhibited by P. novizealandiae infected with M. novaezealandensis is most likely due to pathology caused by the parasite rather than a case of active, and adaptive, behavioural manipulation.
有许多记录在案的寄生虫案例，它们能够改变宿主的行为以提高传播效率。然而，并非所有这些案例都一定是寄生虫主动操纵宿主行为的结果；它们可能更像是寄生虫存在所导致病理状态的“副产品”。本研究调查了微小阴茎吸虫新西兰海睾吸虫对其甲壳类中间宿主之一——新西兰新对虾行为的影响。通过让未感染的新对虾暴露于新西兰海睾吸虫尾蚴进行实验性感染。在感染后2周和6周，即寄生虫对其终末宿主具有感染性之前和之后，将实验感染的新对虾的活动水平和垂直位置与未感染的新对虾进行比较。发现在这两个时期，感染的新对虾的活动水平显著较低，并且在水柱中的位置也显著低于未感染的对照组。根据感染的新对虾行为变化的时间，结果表明，感染新西兰海睾吸虫的新西兰新对虾所表现出的行为改变很可能是由寄生虫引起的病理状态所致，而非主动的、适应性的行为操纵。
