This article focuses on the structural metaphor of autism as epidemic as a potential theoretical framework to critically study discursive practices surrounding the term autism. Metaphors of danger and contagion are widely present in articles and news items on the topic of autism, and people encounter these daily. George Lakoff and Mark Johnson interpret the metaphor as a structure of language, an enactment that consists of grasping one concept in terms of another. In a reading of a small corpus of everyday texts on autism as epidemic, the article argues that this metaphorical concept should be understood as a more comprehensive social and cultural desire to perceive signs of deviance in order to enable urgent human action and, thus, to regain control over normalcy and threatening excess. It offers a theoretical exploration of this desire with a discussion of Anne McGuire's analysis of warning signs on educational posters on autism and C. S. Peirce's notion of the index. A short reading of the film Extremely Loud & Incredibly Close (2011) clarifies the workings of the broader interpretation of epidemic metaphor employed in this essay, and its significance in the critical study of autism, truth, and power.