The elimination of smallpox is one of humanity’s great success stories. The disease has claimed the lives of untold millions of people during its centuries of free reign. The World Health Organization estimates that in 1967 alone, two million people were killed by smallpox and an additional thirteen million contracted it. Smallpox accounts for an estimated 300-500 million fatalities during the 20th Century. After rigorous vaccination campaigns during the 19th and 20th Centuries, smallpox was finally eradicated in 1979. It is one of only two infectious diseases to have been eliminated completely. The other is rinderpest, which was eradicated in 2011.
The story of smallpox is a long one. But it may have just been abbreviated. A child mummy discovered in the crypt under a Lithuanian church has led researchers and historians to challenge many of the assumptions they held about the disease’s history.
The child, a toddler, is believed to have died between 1643 and 1665. Its body was riddled with smallpox. Analysis revealed that the smallpox DNA carried by the child was the oldest strain known to science. A study recently published in Current Biology claims that, based on these findings, smallpox may only be hundreds of years old. The standard consensus about smallpox is that it dates to around 10,000 BC.
The study, helmed by researchers from McMaster University in Canada, paired the genetic findings with a corroborating interpretation of the disease’s pattern of evolution. They constructed a “family tree” of the smallpox virus, which showed that it evolved at a pace that would place its origins sometime between 1530 and 1654.
The timing makes sense. Smallpox erupted into a pandemic in Europe during the 17th Century.
Historians have credited smallpox with being responsible for the historical record of ancient Egyptians and Chinese people dying from diseases that closely matched smallpox symptoms. But the McMaster team believes that other diseases could have been responsible.
The study’s co-author Henrik Poinar, director of McMaster University’s Ancient DNA Center, said in a press statement:
“So now that we have a timeline, we have to ask whether the earlier documented historical evidence of smallpox, which goes back to Ramses V and includes everything up to the 1500s, is real. Are these indeed real cases of smallpox or are these misidentifications, which we know is very easy to do, because it is likely possible to mistake smallpox for chickenpox and measles?”
The study’s conclusions are not definitive, and more research is being done. The McMaster researchers are now attempting to determine when, precisely, smallpox first appeared during the period of time they suspect the disease originated. They believe that the virus was originally animal-borne, and made a leap to humans sometime in the 16th or 17th Century.