Scientists Have Revive An Extinct Relative Of The Smallpox Virus Using Commercial DNA

It was one of the most deadly viruses that caused millions of deaths around the world, and now scientists have revived a virus similar to smallpox. The researchers hope that the virus could be used to create more effective vaccines.

But other experts have warned that the relatively easy technique could be replicated by terrorists to create biological weapons.

HOW DID THEY RECREATE IT? 

The researchers have not revealed the details of how they recreated the horsepox virus, because their paper has not yet been published. But a report by the World Health Organisation (WHO), says the team purchased overlapping DNA fragments, each about 30,000 base pairs in length, from a company that synthesizes DNA commercially.

That allowed them to stitch together the 212,000-base-pair horsepox virus genome.

Introducing the genome into cells infected with a different type of poxvirus led these cells to start producing infectious horsepox virus particles.

The virus was then 'grown, sequenced and characterized,' according to the report.

Researchers from the University of Alberta have resurrected a virus called horsepox, which is very similar to smallpox.

Professor David Evans, who led the study, said: 'Our goal is to improve on current methods that protect the public from possible viral outbreaks.'

While horsepox itself is not harmful to humans, the technique to piece it together could be used to synthesise other dangerous viruses, including smallpox.

The researchers have not revealed the details of how they recreated the horsepox virus, because their paper has not yet been published.

But a report by the World Health Organisation (WHO), says the team purchased overlapping DNA fragments, each about 30,000 base pairs in length, from a company that synthesises DNA commercially.

That allowed them to stitch together the 212,000-base-pair horsepox virus genome.

Introducing the genome into cells infected with a different type of poxvirus led these cells to start producing infectious horsepox virus particles.

The virus was then 'grown, sequenced and characterised,' according to the report.

Professor Evans has accepted that the technique comes with its risks.

Speaking to Science, he said: 'Have I increased the risk by showing how to do this? I don't know.

'Maybe yes. But the reality is that the risk was always there.'

While WHO guidelines prevent scientists from attempting to build the full smallpox genome, this new research shows that it is possible to buy the DNA building blocks without being flagged.

And experts say the technique is fairly easy to replicate.

Speaking to The Washington Post, Peter Jahrling, a virologist at the National Institutes of Allergy and Infectious Diseases, said: 'Maybe not some guy in a cave, but a reasonably equipped undergraduate microbiology lab could repeat this trick.'

In the wrong hands, the technique to synthesise viruses could be diasterous.

Speaking to Science, Paul Keim, an expert in bioweapons at Northern Arizona University in Flagstaff, said: 'Bringing back an extinct virus that is related to smallpox, that's a pretty inflammatory situation.

'There is always an experiment or event that triggers closer scrutiny, and this sounds like it should be one of those events where the authorities start thinking about what should be regulated.'

THE HISTORY OF SMALLPOX:

• The first known victim of smallpox was Pharaoh Ramses V of Egypt, who died in 1157BC and whose mummy still bears the scars of the disease.

• When the Spanish took it into Hispaniola - now Haiti and the Dominican Republic - which they settled for sugar cane plantation in 1509, it killed every one of the 2.5 million natives within a decade.

• More than 200 years ago, physician Edward Jenner made a crucial-discovery which led to the first vaccine. He found that milkmaids who developed cowpox through working close to the animals day after day seemed to be protected from smallpox, the human form of the disease.

• In Britain, the disease was endemic until 1935.

 • The last major outbreak in Europe was in 1972 when 20 million were vaccinated after a pilgrim returning to Yugoslavia from Mecca infected 175 people.

 • Doctors waged a vaccination campaign to wipe out smallpox which succeeded by the late 1970s.

• All nations were asked to destroy stocks of the virus or hand them to high-security installations in the US or Russia. It is feared terrorists may have got supplies from Russia in the 1980s.