Electron micrograph of malaria parasite, Plasmodium falciparum, latched onto a red blood cell (photo from Wikimedia)

12 July 2026

In today’s social media climate rumors spread quickly and persist despite the truth. This is nothing new in human history. When Francesco I de’ Medici, the Grand Duke of Tuscany, died of a fever at age 46 in 1587, the rumor mill said his younger brother Ferdinando had poisoned him. The rumor lived on, even though Francesco’s doctors said he died of malaria.

Francesco I de’ Medici and his younger brother Ferdinando I de’ Medici (images from Wikimedia)

Malaria? It’s been among humans for 2.5 to 30 million years, spread by Anopheles mosquitos that carry Plasmodium parasites, the most deadly being Plasmodium falciparum. The parasite reproduces in the liver then moves into the bloodstream to latch onto and destroy red blood cells (photo at top), causing fever, fatigue, vomiting, headaches, jaundice, seizures and often death.

Anopheles merus, gambiae complex (photo from Wikimedia)

There are many species of Anopheles mosquitoes around the world, including one in Europe and one in the eastern U.S. that no longer carry malaria.

Anopheles species range map from Wikimedia

The disease was in Italy for a very long time until it was eradicated in 1956. (1882 map below)

Malaria map in Italy, 1882 (photo from Wikimedia)

It was also a serious problem in the southern U.S. For instance, malaria affected 30% of the population in the Tennessee Valley Authority’s land area when TVA began in 1933. Fortunately malaria was eradicated from the U.S. in 1951.

In 2024 the worldwide malaria map looked like this with orange areas having the highest incidence.

Global malaria incidence, 2024 . Pf metric = Plasmodium falciparum parasite

Where did human malaria come from? DNA solved the mystery in 2020 by examining the similarities of Plasmodium in primates to Plasmodium falciparum.

They found at least nine species of Plasmodium, three unknown before. When compared to human P. falciparum, the most closely related came from western gorillas from Cameroon, the Central African Republic and the Republic of Congo. In fact one was nearly identical to all known human plasmodium sequences.

P. falciparum only had to jump once and it became ours. Thus it is no surprise that Africa is a malarial hotspot. It stays that way because it takes a lot of money to eradicate malaria, money that many African countries do not have.

And what about the Medici rumor? A DNA study solved that too.

A study published last month in iScience examines ancient DNA from the era—including that of the duke—and confirms the mosquito-borne protozoan disease as his killer. 

In the end, the change of power benefited Tuscany’s citizens. Francesco (the guy who died of malaria) was often despotic, heavily taxed his subjects, and sent the money to Austria. Ferdinando who succeeded him was a benevolent ruler who cared about the welfare of his people. He re-established the justice system and returned prosperity to Tuscany.