Scientists have always believed that the smallpox virus had already existed millions of years ago. That's because mummies from ancient Egypt showed signs and marks that hint of being afflicted with the virus. However, a recent discovery might prove them wrong about the virus after all.

Scientists who have been studying several mummies in a church burial ground in Lithuania have discovered a mummy of a child which they believe holds the oldest sample of the smallpox virus. Using carbon dating, they estimated that the child, between 2 and 4 years old, lived between 1643 and 1645.

By taking some samples from the body, they discovered that it carries the variola virus revealing the fact that smallpox could have just existed around that time in contrast to the belief that it had existed as early as 3000 to 4000 BC.

By studying the smallpox virus found in the mummy, the researchers found that the mutations it possesses have similarities to the smallpox virus that came out between 1588 and 1645. That period was a time of travel and exploration so most probably, the scientists said, the virus spread all over the world through that.

According to Anna Duggan, a postdoctoral fellow at the McMaster University Ancient DNA Centre in Canada, via Live Science, if the smallpox virus existed thousands of years ago, the differences between mutations would be very great.

The analysis also revealed that the two strains of the virus - the variola major and variola minor, would have split after Edward Jenner developed a vaccine to fight the virus in 1700s.

With the recent findings, researchers will be able to trace where and when smallpox originated as well as other viruses. They also said that the discovery was just the tip of the iceberg.

The research was published in the journal Current Biology.