Malaria in the Medici era

The powerful dynasty buried its dead according to a special ritual: during embalming, the entrails were removed and placed in large terracotta vessels called orci which were buried together with the coffins in the Basilica di San Lorenzo in Florence. In 2010, researchers were allowed to sample nine of these orci which were decorated with the family’s coat-of-arms. Of the nine, two bore the names of specific family members. Using long tweezers, the team retrieved something that at first glance seemed to Anthropologist Albert Zink who was leading the investigation, to be “rather insignificant,”. He went on to explain, “However, these fragments, which to the untrained eye, could have been pieces of cloth, were in fact mummified tissues of unknown origin. So, our first interest was to find out what we were actually looking at. Then, to find out if the structure of the organ was intact enough to see if we could identify the organ it came from.” The researchers took a total of 24 samples, which they then subjected to microscopic and molecular analyses.

The molecular investigations did not lead much further. The material was too degraded, the Arno had flooded Florence several times since the Medici period and acute temperature fluctuations had done the rest, “proteins or DNA were almost no longer present,” explains first author of the study, Microbiologist Frank Maixner. “But it wasn’t all bad news, the microscopic structure was in fact, very exciting.” Thin tissue sections revealed a potential blood vessel that still contained collections of red blood cells. When a special method called Giemsa staining was used, evidence of a parasite inside these blood cells was revealed. What Maixner described “a surprising finding” was not conclusive. The parasites could have been plasmodia – a parasite responsible for malaria or even another parasite called babesia.

The team went on to employ an even more precise technique, atomic force microscopy whereby the tissue surface was scanned with a nanoscopic needle which rendered even the tiniest differences in height and three-dimensional structure visible. This analysis revealed the typical ring-shaped structures that characterize one of the developmental stages of the plasmodia parasites. However, the same shapes can also be formed by babesia

An even more precise technique was used, atomic force microscopy: surfaces are scanned with a nanoscopically fine needle, making even the tiniest differences in height and three-dimensional structures visible. And indeed, the typical ring-shaped structures that characterize one of the developmental stages of the plasmodia parasites - but which can also be formed by babesia - could be seen.