Recent findings from a mass grave in the Ancient Cemetery of Kerameikos in central Athens show typhoid fever may have caused the plague of Athens, ending centuries of speculation about what kind of disease killed a third of the city’s population and contributed to the end of its Golden Age.
Examined by a group of Greek scientists coordinated by Dr Manolis Papagrigorakis of Athens University’s School of Dentistry, the findings provide clear evidence that Salmonella enterica serovar Typhi was present in the dental pulp of teeth recovered in remains from the mass grave.
The plague that decimated the population of Athens in 430-426 BC was a deciding factor in the outcome of the Peloponnesian Wars, ending the Golden Age of Pericles and Athens’s predominance in the Mediterranean.
It broke out during the siege of the city by the Spartans in the early summer of 430 BC; after a brief hiatus in 428 BC, the epidemic returned in the winter of 427 BC and lasted until the winter of the following year. It is assumed that one-third of the Athenians, including one-fourth of their army and their charismatic leader, Pericles, perished in the epidemic.
All data pertaining to the disease’s outbreak and its clinical characteristics were until now based on the account by the fifth-century-BC Greek historian Thucydides, who himself fell ill with the plague but recovered. In his famous history of the Peloponnesian Wars, Thucydides gives detailed descriptions that have formed the basis of several hypotheses regarding its nature. However, researchers had never managed to agree on the identity of the plague due to the lack of definite microbiological proof in the absence of paleopathologic evidence. Several pathogens have been putatively implicated in the emergence and spreading of the disease.
In recent decades, molecular biology tools (DNA PCR and sequencing techniques) have made it possible to detect and, furthermore, specifically identify microbial DNA fragments in ancient human skeletal remains, thus making possible the retrospective diagnoses of ancient diseases.
In 1994-1995, under the supervision of archaeologist Effi Baziotopoulou-Valavani for the Fourth Prehistoric and Classical Antiquities Ephorate, excavations of a mass burial pit unearthed in the Ancient Cemetery of Kerameikos in Athens provided the required skeletal material for the investigation of ancient microbial DNA.
The grave yielded the remains of about 150 individuals and were dated, through archaeological site documentation, to around the time of the plague outburst between 430-426 BC. The remains were found piled up in a manner that indicated a hasty burial without the usual care dictated by the respect that ancient Greeks usually showed for the dead.
Dental pulp was the material of choice in this research, as its good vascularization, durability and natural sterility has proven to be an ideal source of ancient DNA, also providing for the recovery of adequate genetic material of specific septicemic microorganisms which after death remain trapped in the dental pulp and become mummified.
Using modern laboratory methods under strict sterile conditions at the molecular neurobiology laboratory at Athens University’s medical school, the research team first found the existence of microbial DNA in the dental pulp. This DNA was then separated and subjected to successive tests to identify which of the possible microbes was linked in the past with the Athens plague.
Teeth from three different skeletons were examined. After six negative results from six candidate microbes, a positive reaction was found for Salomonella enterica serovar Typhi, which is responsible for the appearance of typhoid fever.
The correspondence with the genes examined in the ancient DNA with known sequences of the contemporary form of the microbe was as high as 99 percent.
This evidence allowed for a definite conclusion regarding the microbes found in the teeth of the three bodies from the mass burial pit — the presumed victims of the Athens plague.
Typhoid fever almost certainly played a part in causing the Athens plague, either exclusively or in combination with another — and so far unknown — infection.
Even today, typhoid fever is a major health problem on a global scale. Every year there are about 20 million new cases that lead to about 600,000 deaths in the developing world where overpopulation, inadequate water supplies and hygiene, as well as poor access to health services, allow epidemics to spread with tragic results.
Overcrowding and resultant public health problems — as well as standards of personal hygiene — in the besieged city of Athens in 430 BC as described by Thucydides would have been sufficient to allow the disease to appear and then develop into a deadly epidemic.
The scientifically documented diagnosis of typhoid fever is in accordance with many of the clinical characteristics of the Athens plague as described by Thucydides. The differences in the modern form of the disease from Thucydides’ references pose another challenge for the Greek research team.
Studying the historical aspects of infectious diseases can be a powerful tool for several disciplines to learn from. We believe this report to be of outstanding importance for many scientific fields, since it sheds light on one of the most debated enigmas in medical history. Archaeology, paleontology, history, paleopathology, certain fields of medicine, anthropology and even genetics, molecular biology and studies on evolution are clearly implicated in such matters and can benefit from relevant studies.
The results of this particular study are extremely important as they shed light on one of the greatest mysteries in world history. Also important is the fact that the research was organized, carried out and completed by Greek scientists at Greek research centers, under the aegis of Athens University.
(1) Dr Papagrigorakis is an assistant professor at Athens University’s School of Dentistry.
The other authors of the study, published today in the International Journal of Infectious Diseases, are geneticist Christos Yiapitzakis, orthodontist Philippos Synodinos and archaeologist Effi Baziotopoulou-Valavani.