Parasitology, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia.
Parasitology, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia.
Adv Parasitol. 2014;85:109-42. doi: 10.1016/B978-0-12-800182-0.00003-9.
The ubiquitous protozoan parasite Toxoplasma gondii has been associated with behavioural changes in various hosts, including humans. In rodents, these behavioural changes are thought to represent adaptive manipulation by T. gondii to enhance transmission from intermediate hosts to the feline definitive host. In this review, we have tabulated evidence of changes in motor coordination, learning, memory, locomotion, anxiety, response to novelty and aversion to feline odour in rodents experimentally infected with T. gondii. In general, there was no consistent indication of the direction or magnitude of behavioural changes in response to infection. This may be due to the use, in these experimental studies, of different T. gondii strains, different host species and sexes and/or different methodologies to measure behaviour. A particular problem with studies of behavioural manipulation is likely to be the validity of behavioural tests, that is, whether they are actually measuring the traits that they were designed to measure. We suggest that future studies can be improved in three major ways. First, they should use multiple tests of behaviour, followed by multivariate data analysis to identify behavioural constructs such as aversion, anxiety and response to novelty. Second, they should incorporate longitudinal measurements on the behaviour of individual hosts before and after infection, so that within-individual and between-individual variances and covariances in behavioural traits can be estimated. Finally, they should investigate how variables such as parasite strain, host species and host sex interact with parasite infection to alter host behaviour, in order to provide a sound foundation for research concerning the proximate and ultimate mechanism(s) responsible for behavioural changes.
普遍存在的原生动物寄生虫刚地弓形虫与各种宿主的行为变化有关，包括人类。在啮齿动物中，这些行为变化被认为是刚地弓形虫对中间宿主到猫科终宿主的增强传播的适应性操纵。在这篇综述中，我们列出了实验感染刚地弓形虫的啮齿动物在运动协调、学习、记忆、运动、焦虑、对新奇的反应和对猫科气味的厌恶方面的变化的证据。一般来说，没有一致的迹象表明感染后行为变化的方向或幅度。这可能是由于在这些实验研究中使用了不同的刚地弓形虫株、不同的宿主物种和性别以及/或不同的行为测量方法。行为操纵研究的一个特殊问题可能是行为测试的有效性，即它们是否真的在测量它们设计测量的特征。我们建议未来的研究可以从三个主要方面得到改进。首先，它们应该使用多种行为测试，然后进行多元数据分析，以确定回避、焦虑和对新奇的反应等行为结构。其次，它们应该在感染前后对个体宿主的行为进行纵向测量，以便估计行为特征的个体内和个体间方差和协方差。最后，它们应该研究寄生虫株、宿主物种和宿主性别等变量如何与寄生虫感染相互作用，以改变宿主行为，为研究负责行为变化的近因和最终机制提供坚实的基础。
