The protozoan parasite Toxoplasma gondii infects a wide range of intermediate hosts. The parasite produces brain cysts during the latent phase of its infection, in parallel to causing a loss of innate aversion in the rat host towards cat odors. Host behavioral change presumably reflects a parasitic manipulation to increase predation by definitive felid hosts, although evidence for increased predation is not yet available. In this opinion piece, we propose a neuroendocrine loop to explain the role of gonadal steroids in the parasitized hosts in mediating the behavioral manipulation. We argue that the presence of tissue cysts within the host brain is merely incidental to the behavioral change, without a necessary or sufficient role.

原生动物寄生虫弓形虫感染范围广泛的中间宿主。寄生虫在其感染的潜伏期产生脑囊肿，同时导致大鼠宿主对猫气味的先天厌恶丧失。宿主行为的变化可能反映了一种寄生操纵，以增加最终猫科动物宿主的捕食，尽管目前尚无证据表明捕食增加。在这篇评论文章中，我们提出了一个神经内分泌循环来解释寄生宿主中性腺类固醇在介导行为操纵中的作用。我们认为宿主大脑内组织囊肿的存在仅仅是行为改变的附带，没有必要或充分的作用。