The mystery of when smallpox first infected humans has finally been deciphered by scientists

(SWNS)

Smallpox has plagued humans since ancient Egypt, 2,000 years earlier than previously thought, according to a new study.

The disease was once one of the most devastating diseases of mankind, but its origin was shrouded in mystery.

Believed to have originated with the Vikings 1,400 years ago, research now dates it 2,000 years back than previously thought – to the Land of the Pharaohs.

Smallpox, known medically as the varicella virus, is the only human infectious disease that has been eradicated by a global vaccination campaign.

Studying its origins could help fight future pandemics, which are likely to occur more frequently.

First author Dr. Diego Forni of the Eugenio Medea Scientific Institute said: “The Variola virus may be much, much older than we thought.”

The Italian team compared the genomes of modern and historical strains. Then the mathematical equation showed that it began to appear more than 3,800 years ago.

This confirms earlier reports of smallpox, with cases found in the analysis of Egyptian mummies.

It was the leading cause of death until the 1980s – killing at least 300 million people in the 20th century. This is roughly equivalent to the population of the United States.

Relatively recently, the earliest evidence of smallpox was as late as the 17th century. Subsequently, in 2020, multiple strains were identified in the skeletal and dental remains of Viking skeletons.

Suspicious scars on Pharaoh Ramesses V, who died in 1157 BC, have led some to speculate that the virus dates back at least 3,000 years.

The study, published in the journal Microbial Genomics, completes the ‘missing piece of the puzzle’, say the researchers.

Different strains come from one common ancestor. A small fraction of the genetic components found in Viking Age genomes survived into the 18th century.

Dr Forni and colleagues explained what they called the ‘time dependent rate phenomenon’.

Surprisingly, the rate of evolution depends on the length of time over which it is measured.

Thus, viruses seem to change faster or slower over shorter and longer periods of time, respectively. This has been well documented in DNA viruses such as smallpox.

We hope the findings will end long-running controversies and provide new insights into the history of one of humanity’s greatest killers.

Dr Forni said: “This is important because it supports the historical hypothesis that smallpox existed in ancient societies.

“It’s also important to consider that there are some aspects of viral evolution that need to be considered when doing this kind of work.”

The smallpox vaccine has been hailed as the most important milestone in global public health. This has led to the creation of universal childhood immunization programmes.

Over thousands of years, smallpox has killed hundreds of millions of people – rich, poor, young and old.

It was a disease that did not discriminate, claiming the lives of at least one person in three infected – often in the most severe forms.

The symptoms were gruesome. These included high fever, vomiting, and mouth sores, followed by fluid-filled lesions all over the body.

Death came quickly – often within two weeks. Survivors may be left with permanent impairments such as blindness and infertility.

Notable smallpox survivors included Queen Elizabeth I, Mary Shelley, Mozart, Beethoven, George Washington, and Abraham Lincoln.

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