Scientists Discover Rare Worm Bacteria Can Ward Off Malaria-Carrying Mosquitoes
Scientists reported on Wendesday that they recently dug up a new mosquito repellent found in soil and worms, which could protect millions of people from insect-borne diseases.
The new study was published in Science Advances and says that Xenorhabdus budapestensis, which is found inside nematodes, can repel mosquitos three times more effectively than DEET, the leading commercial repellent around the world.
DEET, or diethyltoluamide, has been the leading global mosquito repellent since the 1940s, but some people have long been believed it has harmful effects on human health. (The EPA says DEET is safe for consumers.)
This new discovery protects users from more than just mosquito bites. Xenorhabdus could potentially reduce the risk of contracting diseases that mosquitoes carry including malaria, Zika, West Nile virus, and dengue. These pathogens affect millions of people around the world, especially in areas with high rates of poverty.
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The bacteria naturally occurs in parasitic worms that release it into insects found in soils. Once the bacteria enters the targeted insect, its immune system collapses. Since mosquitoes don’t lurk in the soil, they avoid the bacteria altogether.
Unlike its chemical predecessor, the bacteria doesn’t have adverse environmental consequences. DEET has been found to pollute bodies of water, affecting aquatic animals and wildlife.
“As a public health entomologist, I believe that DEET is an effective and safe product to use, but I do know that some consumers are concerned about synthetic chemicals," said Susan Paskewitz, a professor of entomology at the University of Wisconsin-Madison who oversaw the study.
"What matters from my perspective is that people don't have a barrier to using repellents so that in the event of the next Zika or West Nile virus outbreak, we're prepared," continued Paskewitz.
DEET also needs to be reapplied throughout the day, which leaves users exposed to mosquitos if they forget to reapply.
A person would need to apply triple the amount DEET and eight times as much picaridin, another common mosquito repellent, to repel the same amount of mosquitos that Xenorhabdus does.
Xenorhabdus is not available for consumers at this time because more research needs to be done on the bacteria and its effects. It also hasn’t been tested on humans yet.
"DEET is almost like magic,” said Matthew DeGennaro, a neurogeneticist at Florida International University who studies mosquito genetics. “We don't find things that work as well as it does every day."
Almost half of the world’s population lives in regions that are at risk for malaria transmission. Malaria is commonly found in tropical and subtropical areas, and it disproportionately affects communities of poverty, according to the CDC. Africa is at the highest risk of Malaria transmission due to its climate, lack of resources, socio-economic status, and other contributing factors.
These new scientific developments about Xenorhabdus could potentially reduce these transmission rates around the world. However, more research still needs to be conducted to assure that the repellent is safe.