Egyptian mummies trace malaria's roots
Malaria DNA has been found in two mummies from the ancient Egyptian capital of Thebes, providing clear evidence for the earliest known cases of the disease, say researchers.
Pathologist Dr Andreas Nerlich and colleagues, from the Academic Teaching Hospital München-Bogenhausen in Munich, Germany, presented their research this week in Naples at an international conference on ancient DNA.
Nerlich and colleagues studied 91 bone tissue samples from ancient Egyptian mummies and skeletons dating from 3500 to 500 BC.
Using special techniques from molecular biology, such as DNA amplification and gene sequencing, the researchers identified ancient DNA for the malaria parasite Plasmodium falciparum in tissues from two mummies.
"We now know for sure that malaria was endemic in ancient Egypt. This was only been speculated on the basis reports by [the 5th century BC Greek historian] Herodotus and some very faint evidence from ancient Egyptian papyri," says Nerlich.
Caused by four different kinds of parasites belonging to the Plasmodium family - falciparum, malariae, ovale and vivax - malaria is transmitted to humans through a bite from an infected female Anopheles mosquito.
Of the four, P. falciparum is the most deadly. It produces the most severe form of malaria, characterised by symptoms that include undulating high fever, chills, anaemia and an enlarged spleen.
Although it is believed that malaria widely affected humanity long before the Greek physician Hippocrates wrote the first clinical description of the disease in 400 BC, until now only one study, which used molecular analysis, clearly identified P. falciparum from that period.
The ancient DNA for the parasite was found in a Roman infant dating back to the 5th century AD.
"In our finding, both positive cases came from two different tomb complexes at Thebes-West, dating from the New Kingdom until Late Period (1500 to 500 BC)," Nerlich says.
Upper class Egyptians
The capital of Egypt around 1500 BC, Thebes, hosts a huge necropolis, which mostly contains the remains of upper class ancient Egyptians.
"Both infected mummies were adults and had some mild signs of chronic anaemia. Unfortunately, no further information is available since they came from 'no name burials'. However, the location of their tombs in the necropolis strongly suggests that they were of high class local descent," Nerlich says.
The wealth of these people did not provide them with protection against diseases. In a previous study, Nerlich and colleagues discovered that most people buried at the site died between the ages of 20 and 30.
"Our discovery adds another infectious disease to the spectrum of palaeomicrobiology in ancient Egypt, further explaining the influence of infectious diseases on such low life expectancy," says Nerlich.
The ancient scourge, which has shaped history by decimating invading armies and making villages in the grip of the fever hard to colonise, still plagues humanity.
Today the disease kills between one and three million people, most of whom live in the world's poorest countries.
Significance for today
Nerlich and colleagues believe that their work in identifying one of the earliest forms of the disease may help develop new treatments.
"We are now hopeful we can identify the 'precursor' of malaria pathogens," says Nerlich.
According to anatomist and palaeopathologist Dr Frank Rühli, head of the Swiss Mummy Project at the University of Zurich, the discovery is important because it is "based on reliable molecular detection of pathogen ancient DNA."
"This study adds new insights into the evolutionary prevalence of a disease which still kills millions of people worldwide. It also highlights again the enormous importance of ancient mummy research for modern clinical medicine," says Rühli.