Malaria Was “the Killer” of Francesco I de’ Medici and his wife Bianca(1531-1587)

From The American Journal of Medicine:

The sudden deaths of Francesco I de’ Medici (1531-1587), Second Grand Duke of Tuscany (Figure 1a), and his wife, Bianca Cappello (1548-1587), have been shrouded in mys­tery, and the cause of death has been debated for the past 4 centuries.
Francesco was the first child of Cosimo I de’ Medici (1519-1574), First Grand Duke of Tuscany, and his wife, Eleonora of Toledo (1522-1562). He became Grand Duke of Tuscany in 1564, ruling until his death. Francesco was not interested in political affairs, which he delegated to his functionaries. Instead, he became a patron of the arts and sciences and a passionate alchemist. In 1565, he married Joan of Austria (1548-1578), and they had 7 sons. During this marriage, Francesco began a relationship with a Venetian noblewoman, Bianca Cappello, whom he married in 1579 after the death of his wife.
In October 1587, the Grand Duke and his wife died unexpectedly within 24 hours of each other. Contemporary medical documents attributed the deaths to tertian malarial fevers.1 Rumors soon spread that Francesco and Bianca had been poisoned with arsenic by Francesco’s brother, Cardinal Ferdinando I (1549-1609) (Figure 1b).2 The rumors were apparently instigated by courtiers who knew of the long-standing disagreements between the brothers.
Ferdinando I never tolerated the presence of the new Grand Duchess at the Medici court. The Cardinal also resented Bianca’s meddling in court affairs and accused his brother of behaving in a manner unbecoming his ducal role. Two weeks before their deaths, on September 25, 1587, Ferdinando, Francesco, and Bianca met at the Medici villa in Poggio a Caiano, where they were thought to have attempted a reconciliation.
Francesco I’s skeleton was unearthed from the topsoil of the Medici Chapels in San Lorenzo Church (Florence, Italy) in 2004.3 Bianca Cappello’s remains have not been recovered; her burial site remains unknown. Recently, the ancient rumors of murder have received apparent support from a toxicologic study that excluded malaria as the cause of Francesco’s death.4
Malaria was endemic in Central Italy, especially Tuscany, from the 2nd and 3rd centuries BC to the end of World War II. To determine whether the original death certificates might have been correct and the rumors false, we carried out an immunologic investigation to determine whether Plasmodium falciparum malaria might have caused the death of Francesco I.
Cancellous bone was harvested from a vertebra of Francesco I. Bone samples of Cosimo I de’ Medici, who died of pneumonia, and his daughter-in-law, Joan of Aus­tria, who died in childbirth, were used as negative controls.1 In addition, 2 medieval bone samples from 2 sites known to be free from malaria (Briançon, France, 17th century; Augsburg, Germany, 14th century) also were used as negative controls.
Extracts prepared from spongy bone samples were examined for the presence of P. falciparum histidine-rich protein 2 and P. falciparum lactate dehydrogenase using 2 commercial qualitative double-antibody immunoassays: Malaria Antigen RAPYDTEST and Malaria Detect RAPYDTEST (DiaSys, Waterbury, Conn).5
Positive results were obtained from both dipstick assays. We therefore provide the first biological evidence of the presence of both P. falciparum ancient proteins (P. falciparum histidine-rich protein 2 and P. falciparum lactate de-hydrogenase) in the skeletal remains of Francesco I de’ Medici. No mixed falciparum infections or non-falciparum infections were identified. Bone samples from Cosimo I, Joan of Austria, and control samples were all negative, as expected.
Our recent findings support the detailed medical documents recorded by court physicians who carefully described the different stages of the sudden illness that affected the Grand Duke Francesco I until his demise.1
Muscle has, thus far, been considered the best tissue for the detection of P. falciparum malaria because of its abundant red cell content.6 We now show that malaria antigens also can be detected in ancient bone samples.
With the use of modern methods, we provide robust evidence that Francesco I had falciparum malaria at the time of his death. Our immunologic results confirm the archival sources that described the onset, course, and fatal outcome of the disease. Our findings also absolve Ferdinando I from the shameful allegation of being the murderer of his brother and sister-in-law.