One of Fracastoro's most notable contributions is his proposition of the germ theory of disease, which he elaborated in his seminal work "De Contagione et Contagiosis Morbis et Eorum Curatione" ("On Contagion, Contagious Diseases, and Their Treatment") published in 1546. In this text, he introduced the idea that infections are caused by minute, invisible particles or "spores" that can spread from one person to another, through direct contact, air, or contaminated objects.
