A new outbreak of Zika virus is entirely possible, and a single mutation could be enough to trigger an explosive spread, the researchers warn.

The disease caused a global medical emergency in 2016, with thousands of babies born with brain damage after their mothers were infected during pregnancy.

American scientists say the world should pay attention to new mutations.

Laboratory work described in the journal Cell Reports shows that the virus can easily transfer and generate new variants.

The La Jolla Institute for Immunology team said recent infection studies suggest that these variants may prove to be effective at transmitting the virus, even in countries that have built immunity to previous Zika outbreaks.

Experts say the results, while theoretical, are intriguing — a reminder that viruses other than Covid could pose a threat.

Metamorphic virus

Zika virus is spread through the bite of an infected Aedes mosquito. These insects are found throughout the Americas – except Canada and Chile, which are too cold to survive – and throughout Asia.

While Zika is a mild disease with no lasting effects in most people, it can be disastrous for a baby in the womb.

If a mother contracts the virus during pregnancy, it can harm the developing baby, causing microcephaly (an abnormally small head) and damage to brain tissue.

Using cells and live mice, the researchers recreated what happens when Zika virus migrates back and forth between mosquitoes and humans.

When Zika virus spread between mosquito cells and mice in the lab, tiny genetic changes occurred.

That means Zika is relatively prone to mutating, allowing the virus to thrive and spread, even in animals that previously had some immunity to a similar mosquito-borne infection called dengue.

more investigation

Lead researcher Professor Sujan Shresta said: “The Zika virus variants we discovered have evolved to the point where the cross-protective immunity previously conferred by dengue infection is no longer effective in mice.

“Unfortunately for us, if this variant prevails, we might have the same problem in real life.”

Professor Jonathan Ball, a virus expert at the University of Nottingham, told the BBC: “We’ve been hearing a lot lately about the rapid evolution and emergence of coronavirus variants, but this is a timely reminder that metamorphosis is a trait shared by so many viruses.

“This work shows how quickly changes to a single letter in a virus’s genome sequence can occur, and how much this affects the virus’ ability to become sick. But viruses with these changes are not often observed in outbreaks, as the authors show. pointed out that these interesting findings warrant more thorough investigation.”

Claire Taylor, Ph.D., of the Society for Applied Microbiology, said: “While these results were observed in laboratory experiments and therefore have limitations, they do suggest that potentially worrisome can arise during the normal cycle of Zika virus transmission. mutation, and reminds us that monitoring is important in order to. “Follow the evolution of the virus. “

It is possible to predict which variants could cause major problems in the future and intervene early, she said.

Professor Paul Hunt, professor of medicine at the University of East Anglia, said previous infection with Zika virus could still offer some protection against the new variant – as has been seen with Covid.