Aug. 11, 2021 -- There were 200 hungry mosquitoes in the Plexiglas enclosure volunteers agreed to sit in so scientists could test their new bug-resistant fabric to see whether individuals wearing it got mosquito bites.
The live, disease-free mosquitoes were starved overnight and yet they did not bite, report researchers led by senior author R. Michael Roe, from the College of Agriculture and Life Sciences at North Carolina State University in Raleigh.
The clothing consisted of a base-layer undergarment made from the newly developed fabric worn under a combat shirt designed for use by members of the military. And the mosquito-repelling clothing is working without any chemical insecticides, according to inventors.
Inside the enclosure, each volunteer stood for 10 minutes and then, to test whether the bite-resistant clothing would be affected when the fabric was stretched or when the distance between the skin and the fabric varied, each sat on a stool for 10 minutes with knees bent. All wore a beekeeper's veil in addition to the bite-resistant clothing, and had no exposed skin, as the mosquitoes can bite through some thin fabrics or clothes with a large weave.
Repelling Virus-Carrying Mosquitoes
To develop the bite-resistant fabric, the scientists used a computational model that analyzed the biting behavior of Aedes aegypti, a virus-carrying mosquito that can transmit diseases like Zika, dengue fever, and yellow fever to humans.
Specifically, they examined the dimensions of the head, antenna and mouth of the mosquito, as well as the mechanisms it uses to bite. And then they adjusted specific properties of their fabric, such as thickness and pore size, so it could prevent bites.
One test fabric is less than 1 mm thick with a pore size small enough to prevent penetration of the mosquito's proboscis that pierces the skin. The second test cloth has medium-sized pores that prevents the mosquito's head from reaching the skin. And the third fabric has larger pores but sufficient thickness to prevent the mosquito from reaching the skin.
The three fabrics they created could also be effective against other mosquito species with similar biology and biting behavior, the team suggests.
All three provided more bite resistance than fabric treated with permethrin, an insect repellant.
Insecticide-free clothing could also alleviate any concerns people have about the potential health effects of wearing chemically treated clothes. However, the researchers acknowledge, more research will be needed to assess safety and develop comfortable outfits that work in various weather conditions.