A new study published in iScience by Yale University and the University of Pisa has settled the debate with something none of the earlier investigations could produce, the parasite's own DNA. Researchers extracted ancient DNA from Francesco's ribs and found molecular evidence of two malaria species: Plasmodium falciparum and P. malariae. The couple had recently visited the Medici villa at Poggio, which sat near swampy rice fields where mosquitoes thrived. In the bones of Cardinal Giovanni de' Medici, who died of malaria 25 years earlier at 19, researchers found a previously unknown strain of Plasmodium falciparum with two unique genetic mutations. The strain is closely related to lineages that spread across Italy, France, Spain and beyond.