one knows what caused the Plague of Athens in the 5th century B.C. One popular
theory is Ebola—but to discover the source of an outbreak millennia after the
fact, scientists need victims’ remains and a bit of luck.
the summer of 430 B.C., a mass outbreak of disease hit the city of Athens,
ravaging the city’s population over the next five years. In his History of the
Peloponnesian War, the historian Thucydides, who witnessed the
epidemic,described victims’ “violent heats in the head,” “redness and
inflammation in the eyes,” and tongues and throats “becoming bloody and
emitting an unnatural and fetid breath.” Patients would experience hot flashes
so extreme, he wrote, that they “could not bear to have on [them] clothing or
linen even of the very lightest description.” In the later stages of infection,
the disease would end with “violent ulceration” and diarrhea that left most too
weak to survive.
than 2,000 years later, the Plague of Athens remains a scientific mystery.
Thucydides’ account—the only surviving description of the epidemic—has been the
basis for dozens of modern-day theories about its cause, including bubonic
plague, cholera, typhoid fever, influenza, and measles. And in June, an article
in the journal Clinical Infectious Disease suggested another answer: Ebola.
article, written by the infectious-disease specialist Powel Kazanjian, is the
latest in a string of papers arguing that Athens was once the site of an Ebola
outbreak. The surgeon Gayle Scarrow first raised the suggestion in The Ancient
History Bulletin in 1988. Eight years later, the epidemiologist Patrick Olson
published a letter in Emerging Infectious Diseases, a journal of the Centers
for Disease Control and Prevention, comparing the symptoms of the Athens plague
to those of Ebola, which had broken out in the Democratic Republic of Congo
(then Zaire) and Sudan in 1976. “The profile of the ancient disease,” he concluded,
“is remarkably similar.”
not everyone was on board with Olson’s theory. In a 1996 interview with theThe
New York Times, the epidemiologist David Morens argued that Thucydides wasn’t
the most reliable source: Unlike his contemporary, Hippocrates, he wasn’t a
physician, and many of the terms he used to describe the disease’s symptoms
were ambiguous. For example, the ancient Greek phlyktainai could refer to
either blisters or callouses. Noting Thucydides’ claim that the epidemic had
originated “in the parts of Ethiopia above Egypt” (today’s sub-Saharan Africa),
Morens also questioned how people with Ebola, a highly contagious and deadly
disease, could make it all the way to Greece without dying along the way.
Ebola was spreading millennia ago, why didn't it reappear anywhere on Earth
duration of the Athens epidemic also presented another problem: At five years,
it was much longer than any known Ebola outbreaks, the majority of which lasted
less than a year. And finally, Morens asked, if Ebola had made it out of Africa
millennia ago, why were there no other accounts of the disease re-appearing
anywhere on Earth until 1976?
for both Olson and Morens, however, neither had a more concrete way to back up
their arguments. Their efforts to identify the Plague of Athens, like all the
other efforts before them, could only rely on the written record left by
Thucydides, which made confirmation more or less impossible.
in a nutshell, is the challenge of ancient pathology: With DNA testing, it’s
often possible to identify the cause of an epidemic that took place centuries
or even millennia ago. Finding remains of those victims to test, though, is
for Germs in an Ancient Graveyard
scientists get lucky. In 2001, for example, a mass grave was uncovered at a
construction site in Vilnus, Lithuania. Based on uniform fragments found in the
grave, the bodies were identified as belonging to soldiers in Napoleon’s
army—somewhere between 2,000 and 3,000 of them, hurriedly buried during the
retreat from Moscow. When a team of anthropologists examined dental pulp taken
from the bodies, they found that around one-third of them had died of typhus, a
finding confirmed by tests of dead lice found at the site (the disease is
transmitted through lice). Researchers had long suspected that typhus had
contributed to Napoleon’s eventual defeat, but because knowledge of the disease
was scant during his lifetime, historical accounts alone had never been enough
to confirm it.
the Plague of Athens, it seemed like a similar turning point had arrived in
1994, when during excavations for a planned Athens metro station at Kerameikos,
an ancient graveyard used from the early Bronze age through Roman times. The
excavators uncovered thousands of previously undiscovered tombs—including a set
of seemingly hurried, unceremonious mass burials dating to 430 B.C., the year
of the Plague of Athens.
of the site was turned over from the construction company to the Greek Ministry
of Culture, which handles the discoveries of ancient ruins. In 2000,
archaeologists turned over three teeth found at the site to a University of
Athens team led by Manolis Papagrigorakis, an orthodontist and professor of
dentistry, for DNA testing. Examining the dental pulp found in the teeth,
Papagrigorakis’ team ran tests for seven diseases that had previously been
suggested by other scholars: plague, typhus, anthrax, tuberculosis, cowpox,
cat-scratch disease, and typhoid fever. The only match they identified on all
three teeth was with the pathogen for typhoid fever. The researchers published
the findings from their analysis in the International Journal of Infectious
Diseases in 2006.
from solving the mystery, though, Papagrigorakis’s team only muddled it
further. In a letter to the editor in the same journal, zoologists from Oxford
University and the University of Copenhagen argued that Papagrigorakis’s
methodology was flawed because he failed to do a phylogenetic analysis (a way
of examining evolutionary relationships) on the teeth. Using the DNA data
published in Papagrigorakis’s study, they conducted their own phylogenetic
analysis, concluding that the DNA of the tooth bacteria was related to, but not
the same as, that of the pathogen for typhoid fever. “The Athens [DNA] sequence
and typhoid would have shared a common ancestor in the order of millions of
years ago,” they wrote.
authors also suggested another possibility: that the DNA found in the teeth
wasn’t from the Plague of Athens pathogen at all. “While we cannot exclude the
possibility that the Athens sequence is a previously unidentified infectious
agent,” they concluded, “it is quite reasonable to assume that the sequence is
actually that of a modern, free-living soil bacterium, a possibility that could
have been explored by extracting DNA from surrounding soil samples as
additional negative controls.”
when remains are available, they may not be enough to identify a disease.
currently has a new study underway, using more modern techniques and a greater
number of tooth samples, that he hopes will help to settle the debate. In the
decade since he published his Athens study, advancements in DNA-sequencing
technology have enabled scientists to answer a number of lingering questions
about ancient epidemics, making new discoveries from very old tooth samples. In
2011, for example, scientists used teeth taken from bodies in one of London’s
so-called “plague pits” to sequence the genome of the bacterium y. pestis, the
source of the Black Death epidemic that had swept Europe in the 14th century.
By comparing the old genome to modern-day strains, the researchers were able to
reconstruct the bacterium’s evolutionary path over the centuries, finding
support for the idea that the 14th-century pathogen was likely the root of the
evolutionary tree leading to more recent outbreaks.
in a 2014 study published in the Lancet Infectious Diseases, scientists were
able to prove for the first time that the Plague of Justinian—which killed about
50 million people in Europe and the Byzantine Empire between 600 and 800
A.D.—was actually a strain of y. pestis, making it the first known outbreak.
The team made its discovery by sequencing DNA from teeth taken from human
remains that had been found in a German graveyard and dated to the time of the
when ancient specimens are available, though, they may not be enough to
identify a disease. Bacteria, like typhoid and plague, can be identified
through DNA sampling, but this isn’t always the case with viruses. Many of
them, including the viruses for Ebola, influenza, and measles, require an RNA
sample for positive identification—and thus far, the oldest preserved RNA viral
genome belongs to a 700-year-old specimen of caribou feces, much more recent
than the Athens samples from in the 5th century B.C. The structure of RNA makes
it much more unstable—and therefore more prone to degradation—than DNA, meaning
that if the Plague of Athens was viral rather than bacterial, its source may
remain a mystery.
Ebola virus was there, we will never know,” said Vinent Racaniello, a professor
of microbiology at Columbia University professor and the host of the podcast
This Week in Virology. “For that, we’ll need a time machine to bring us back to
due to these limitations, Kazanjian’s recent study doesn’t delve into
dental-pulp analysis data. His argument is based on the similarity between the
symptoms of the Plague of Athens and those of Ebola, an argument that he
believes is strengthened by observations from the latest Ebola outbreak. The
paper ends with a chart of the symptoms described by Thucydides, listed
side-by-side against the symptoms of eight modern diseases that had previously
been floated as possible explanations; of all of them, the symptoms for Ebola
have the most overlap.
so, Kazanjian cautioned against referring to Ebola as a “probable” or even a
“likely” cause. “The most accurate statement is that the cause remains unknown,
and there are several possibilities,” he said, including that the Plague of
Athens may have been a now-extinct disease with Ebola-like symptoms.
also acknowledges the difficulty of making rigorous comparisons between
Thucydides’s descriptions and modern-day medical knowledge: “I try not to get
into the trap of saying what the most likely thing is,” he said.
for Kazanjian—also a historian—solving the puzzle of the Plague of Athens is
less compelling than exploring all the possibilities. The inquiry is “clearly
fun to do,” he said, “no matter what your background is.”