A Palha das Palavras e o Grão das Coisas.

Based on the notion of discourse presented by Michel Foucault, this paper attempts to demonstrate the construction of aids through the medical discourse that began to designate the HIV virus as an ethiological agent, instead of coming from multicausal factors. It sought to evaluate the extension of such change in the nosographic categories that defined the concepts of risk group, risk behavior and vulnerability. The article sustains that the notion of risk group was responsible for the subjective and social representation of aids and for its changing into an epidemic. It pleads that the power of such representation was an impediment for the prevention campaigns' effectiveness, due to the particularities of the Brazilian culture. It concludes by pointing out that the present designation of aids as a controllable chronic infection can serve as a prevention strategy and also to the transdisciplinary researches. [ABSTRACT FROM AUTHOR]