Updated

May 8, 2023 at 6:00 PM

Published

May 8, 2023 at 9:47 AM

Are you more likely to be bitten by mosquitoes than those around you? Well, help may be on the way.

Researchers at the Hebrew University of Jerusalem have developed a new repellent, according to a report in The Guardian newspaper.

Applying a thin coating of the repellent serves as “chemical camouflage” and can reduce the number of mosquito bites by 80 per cent, noted an Israeli study published in PNAS Nexus, an open access scientific journal.

The repellent is made from a combination of naturally occurring cellulose nanocrystals (CNCs), a renewable raw material found in the likes of cotton and wood, and indole, an organic compound with an unpleasant odour.

The combination is “unprecedented”, according to Dr Jonathan Bohbot, a senior lecturer at the university and one of the paper’s co-authors. This is because the combination wrecks the cues that mosquitoes use to select their victims.

The results are considered to be promising enough to have led to proposals for further human studies. The plan is to have the coating approved by regulators ahead of commercial use.

“The CNC-repellent combination will have a longer efficacy and range of action than other products currently available on the market,” Dr Bohbot said.

He added that the researchers expect “high levels of product adoption” if and when it does hit shelves.

According to some estimates, genes account for 85 per cent of a person’s propensity to get bitten by mosquitoes.

DNA testing company 23andMe said it has identified 285 heritable genetic markers that are responsible for the frequency of mosquito bites, the size of those bites, and how itchy they are.

Human beings emit volatiles, or organic compounds, in their breath, and this attracts mosquitoes.

However, it is the volatiles – lactic acid and ammonia – we release through our skin that directs them to where they should feed from.

In this case, the more lactic acid you produce, the more attractive you are to mosquitoes. Add to this misery the fact that you can do little to change your physiology.

For this reason, repellents are the only defence people have for now, and the market for them is expected to reach US$9 billion (S$12 billion) by 2026.

Little wonder that the researchers at the Israeli university are not the only ones trying to solve the problem.

Earlier in 2023, a group of Italian scientists developed a repellent they said was four times as effective as Deet (diethyltoluamide) – the chemical compound that makes up a large tranche of repellent sprays and creams.

The product was tested against the Asian tiger mosquito, Aedes albopictus. It was found to protect 95 per cent of people for eight hours at a time. Deet lasts for only about two hours.

The Italian product is also less toxic and odorous compared with those currently available.

The results, published in the Journal of Agricultural and Food Chemistry, could make the product another welcome addition to the market.

University of Florence associate professor of zoology Francesca Dani said: “We didn’t think it would be that easy to find new repellent.”

She added: “We were pretty satisfied.”

In the United States, research is ongoing to develop a product that could possibly provide protection for not just a matter of hours with each application, but up to two weeks.

To this end, the Defence Advanced Research Projects Agency, the research and development agency of the US, is investigating the possibility of altering the skin’s microbiome – where the community of bacteria and fungi live.

The aim is to create a product that can be applied just hours before entering an area with a large mosquito population.