Researchers in Canada have shown that smallpox disease developed recently in contrast to traditional beliefs that it affected humans thousands of years ago.
Researchers from multiple universities including McMaster University, University of Helsinki, Vilnius University and the University of Sydney extracted heavily fragmented DNA from the partial mummified remains of a Lithuanian child believed to have died between 1643 and 1665 – a period in which several smallpox outbreaks were documented throughout Europe with increasing levels of mortality.
Published in journal Current Biology, the study compared and contrasted the 17th Century strain to those from a modern databank of samples dating from 1940 up to its eradication in 1977. Scientists found that the evolution of smallpox virus occurred far more recently than previously thought, with all the available strains of the virus having an ancestor no older than 1580.
Till now, it was thought to have appeared in human population thousands of years ago in ancient India, China and Egypt but this study has furnished a fact that is otherwise. The pathogen that caused millions of deaths worldwide may not be an ancient disease but a much more modern killer that went on to become the first human disease eradicated by vaccination, researchers said.
The findings raise new questions about the role smallpox may have played in human history and fuels a longstanding debate over when the virus that causes smallpox, variola, first emerged and later evolved in response to inoculation and vaccination, they said.
“Scientists don’t yet fully comprehend where smallpox came from and when it jumped into humans,” said senior study author, Hendrik Poinar from McMaster University in Canada. “This research raises some interesting possibilities about our perception and age of the disease,” said Poinar.