Zika virus may be one step away from new global outbreak

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

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

American scientists say the world should be on the lookout for new mutations.

The laboratory work, described in the scientific journal Cell Reports, points out that the virus can change easily, creating new variants.

Recent infection studies indicate that these variants may be effective at transmitting the virus, even in countries that have built up immunity from previous Zika outbreaks, say the team at the La Jolla Institute of Immunology.

Experts said the findings, while theoretical, were interesting — and a reminder that viruses other than the one causing Covid could pose a threat.

Virus changing shape

Zika is transmitted through the bites of infected Aedes mosquitoes. Insects are found throughout the Americas — except Canada and Chile, where it’s too cold for them to survive — and across Asia.

While for most people Zika is a mild illness with no lasting effects, it can have catastrophic consequences for babies still in the womb.

If a mother contracts the virus during pregnancy, it can harm the developing fetus, causing microcephaly and damage to brain tissue.

the zika virus

• Although the virus is mainly transmitted by mosquitoes, it can also be transmitted sexually;
• Few people die from Zika, and only one in five infected people are thought to develop symptoms. These can include fever, rash, and joint pain;
• As there is no treatment, the only option is to reduce the risk of being bitten by the insect;
• Scientists have started work on a Zika vaccine to help protect pregnant women.

The researchers recreated what happens when Zika passes between mosquitoes and humans, using live cells and mice in their experiments.

When Zika passed between mosquito cells and mice in the laboratory, small genetic changes occurred.

That means it was relatively easy for Zika to mutate in a way that allowed the virus to thrive and spread, even in animals that had some previous immunity from an infection carried by the same mosquito: dengue.

more investigation

The study’s principal investigator, Professor Sujan Shresta, said that “the variant of Zika we identified had evolved to the point where the cross-protective immunity provided by previous dengue infection was no longer effective in mice.”

“Unfortunately for us, if this variant becomes prevalent, we could have the same problems in real life.”

“We’ve heard a lot about the rapid evolution and emergence of coronavirus variants lately, but this is a timely reminder that shapeshifting is a common resource shared by so many viruses,” Professor Jonathan Ball, a virus expert at the University of Nottingham, said. told the BBC.

“This work shows how quickly a single-letter change in a virus’s genome sequence can emerge and the strong impact it can have on a virus’ disease ability. But viruses that share these changes are not often seen in outbreaks, and as the authors point out, these intriguing insights require a more thorough investigation.”

Clare Taylor of the Society for Applied Microbiology warns that “while these findings have been observed in laboratory experiments and therefore have limitations, they show that there is potential for worrisome variants to emerge during the normal cycle of Zika transmission and in reminds us that monitoring is important to keep up with viruses as they evolve”.

She says it may be possible to predict which variants could cause significant problems in the future and intervene early.

Professor Paul Hunter, a professor of medicine at the University of East Anglia, said past Zika infections could still offer some protection against new variants — as seen with Covid.