Abstract
Michel Serres developed a strong core of his philosophical practice around the logic of parasitism. To illustrate this, I propose a bipartite reflection that plays on the external-internal relationship. In the first part I follow Serres in his reflection on the dynamic and unstable relationship between parasitism and symbiosis. The biological and ecological dimension of parasitism occurs in the relationship between viruses, humans and reservoirs. Serres tries to make explicit a parasitic function, irreducible in a single language, which allows to relate the anthropological and sociological characteristics of the parasite to the biological and ecological dynamics. According to Serres, love, humility and a sense of limitation are the global virtues that humanity willhave to rediscover to transform parasitism into symbiosis, rewriting, after Rousseau, a new Discours sur l'origine et les fondements de l'inégalité parmi les hommes. In the second part I put in perspective an extraordinarily global example of parasitism of our times: the spread of the Covid-19 virus in the context of the spillove.