Sharon DeWitte, 38, is a bioarchaeology professor at the University of South Carolina who commutes to work from Winston-Salem, where her husband, Eric Jones, is an archaeologist at Wake Forest.
Where does she spend her summers? In the storage room of a London museum, carefully examining bones of people who died in the mid-1350s of bubonic plague. It was a terrifying disease that swept across Europe, killing entire villages and reducing some cities population by half.
It struck quickly. People who awoke feeling well could, by noon, find their skin erupting with telltale black pustules. Their carcasses would be stacked into burial pits by nightfall.
It was called the Black Death.
Her findings are turning up what could be described as, well, relatively good news.
Q. What exactly are you doing in London?
A. Ive been coming to the Museum of London every summer since 2007; it has around 20,000 skeletal remains, from Roman times to the 1700s. The apartment Im staying in is about a 10-minute walk from East Smithfield Cemetery, near the Tower of London. It was one of the few burial sites only used during the Black Death. The cemetery site now has high-rise buildings, but Black Death victims buried there were excavated in the 1980s.
The exhumed individuals are each in a labeled box in a storage facility. I take the bones from a box, lay them out on a table to form the skeleton, and examine the bones.
Most people have assumed that because the Black Death killed so many people that it killed indiscriminately. I wanted to determine whether there was any variation of risk: I wanted to see if an individuals age, sex or health made a difference.
I use an Excel spreadsheet to record my findings, one body at a time. For my original project and dissertation, I looked at almost 1,000 individuals. Ive looked at 1,000 more for my current project.
Q. What exactly do you look for?
A. I look for indicators of their estimated ages when they died. If its the body of a child, I look at teeth. Did they, for example, have their molars?
For adults, I mostly look at the pelvis. There are two joints that change in pretty regular ways with aging. For adults, I also determine if they were, on average, short. Studies show that people who are short tend to be at higher risk: During their developmental period, if they dont get enough food or suffer from diseases, they are not as tall as they should have been.
For determining how tall a person was, I use length of bones as an indicator of stature.
I also look at lesions that form on the teeth called enamel hypoplasia grooves across the surface of a tooth that reflects illness or malnutrition during childhood. Also, I look for shinbones for extra bone growth, which can form from disease or trauma.
Q. Whats the bottom line?
A. The Black Death targeted people who were poor or in poor health. After it passed, there were fewer people, so there was more food and more goods to go around for those who survived. Due to whom the Black Death killed off, or improvements in diet, the result was a population that was at least temporarily healthier than the population before.
Q. If they were buried in mass pits, wouldnt they all be poor people?
A. There were hundreds at Smithfield buried in mass trenches, but not how most people would picture it. The dead were stacked carefully and buried in a manner as close to a normal Christian burial as possible. Also, some there were buried in individual graves.
There are no records. And there are no grave goods to indicate social status. A typical Christian burial in the medieval times meant wrapping the body in a shroud and not including any worldly goods. Under normal circumstances, for a wealthy person there might have been a plaque to say who the deceased was. But that wasnt the case during the Black Death because of the speed with which victims had to be buried.
Multiple trenches may have been used at the same time. Trenches may have been used for poor people or when mortality was at its height, with thousands dying every day contain a mix of the poor and the not-poor.
Q. Yet Black Death also killed aristocrats.
A. The poor and ailing were not the only ones killed but they were disproportionately killed. They were a larger proportion of those who died of Black Death.
Q. What exactly was Black Death?
A. It was an epidemic caused by Yersinia pestis, the same pathogen that causes bubonic plague today. Black Death was a really, really terrible outbreak of a disease that goes back to the Plague of Justinian in the 6th century, if not longer. Bubonic plague continues to kill people every year.
Q. So this is still going on in the Third World?
A. Not just in the Third World. It has killed people in the southwest United States, where it tends to persist because the pathogen lives in rodents out there. Bubonic plague doesnt kill a huge number of humans.
The modern plague is primarily a disease of rodents transmitted by fleas. But it can become pneumatic carried by air and be spread from one person to another more easily.
The speed with which Black Death spread across the Old World from city to city, from home to home suggests to some it was a person-to-person transmissible form in the lungs. Rats dont move across the countryside that far and that fast. People have looked for things like rat skeletons in archaeological sites, but found nothing that would offer definitive evidence Black Death was largely spread by rat fleas.
Q. Then or now, it seems like theres a societal implication: Survival of the fittest.
A. There are records that suggest some who became infected survived. Maybe they were lucky enough not to be lethally exposed to it. Maybe they had better access to food and had better nutritional status. Maybe they had better immune systems.
If you or I were exposed to bubonic plague today, we would be given antibiotics and would be fine. Where people run into problems is when they dont have access to good medical care and that would be disproportionately poor people.
The Black Death could have been an episode of natural selection, certainly. If that were case, the assumption is there was some sort of genetic trait that allowed the survivors to live.
These question opens up opportunities for additional work.