Mice infected with low-virulence strains of Toxoplasma gondii lose their innate aversion to cat urine, even after extensive parasite clearance

Toxoplasma gondii chronic infection in rodent secondary hosts has been reported to lead to a loss of innate, hard-wired fear toward cats, its primary host. However the generality of this response across T. gondii strains and the underlying mechanism for this pathogen-mediated behavioral change remain unknown. To begin exploring these questions, we evaluated the effects of infection with two previously uninvestigated isolates from the three major North American clonal lineages of T. gondii, Type III and an attenuated strain of Type I. Using an hour-long open field activity assay optimized for this purpose, we measured mouse aversion toward predator and non-predator urines. We show that loss of innate aversion of cat urine is a general trait caused by infection with any of the three major clonal lineages of parasite. Surprisingly, we found that infection with the attenuated Type I parasite results in sustained loss of aversion at times post infection when neither parasite nor ongoing brai...

弓形虫（Toxoplasma gondii）在啮齿类次级宿主中的慢性感染已被报道会导致其对终末宿主（猫）失去先天的、固有的恐惧。然而，这种反应在不同弓形虫菌株中的普遍性，以及病原体介导行为改变的潜在机制仍不明确。为探究这些问题，我们评估了来自北美三大主要克隆谱系（III型和减毒I型）的两个此前未被研究的分离株感染的影响。通过为此优化的时长一小时的旷场活动实验，我们测定了小鼠对捕食者和非捕食者尿液的厌恶反应。结果表明，对猫尿先天厌恶的丧失是感染这三大主要克隆谱系中任何一种寄生虫后的普遍特征。令人惊讶的是，我们发现减毒I型寄生虫感染会导致在感染后某些时间点持续丧失厌恶反应，此时既无寄生虫存在，也无持续的脑部...