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North Carolina State University researchers have made insecticide-free, mosquito-resistant clothing from textile materials that they have confirmed to be bite-resistant in experiments with live mosquitoes. They developed the materials using a computer model they developed themselves that describes the biting behavior of Aedes aegypti, the mosquito that transmits viruses that cause human diseases such as Zika, dengue fever and yellow fever.

Ultimately, the researchers reported in Insects magazine that they could prevent 100 percent of the bites if a volunteer put their clothing – a functional underwear and a combat shirt originally designed for the military – in a cage with 200 live, disease-free mosquitoes. Vector Textiles, a startup based in the state of NC, has licensed the pertinent patent rights and intends to manufacture clothing for commercial sale in the United States.

The researchers believe their computer model could be used more widely to develop clothing to reduce disease transmission.

“The fabric has been shown to work – that’s the great thing we discovered,” said Andre West, study co-author, associate professor of fashion and textile design at NC State, and director of Zeis Textiles Extension for Economic Development. “It’s revolutionary for me. We found that we could prevent the mosquito from penetrating the fabric while others were thick enough to prevent it from reaching the skin. “

To develop the computational model to develop textile materials that could prevent A. aegypti bites, the researchers studied the dimensions of the head, antenna, and mouth of A. aegypti and the mechanics of how it bites. They then used the model to predict textile materials that, depending on their thickness and pore size, would prevent bites. The researchers said they believe that the materials could be effective against other mosquito species in addition to A. aegypti due to the similarities in biology and biting behavior.

“There are several uses for clothing,” said the study’s lead author, Kun Luan, a postdoctoral researcher in forest biomaterials at NC State. “The idea is to have a model that covers all kinds of clothing a person could ever want.”

To test the accuracy of their model, the researchers tested the materials that were believed to be firm to the bite. In experiments with live, disease-free mosquitoes, the researchers surrounded a blood reservoir with plastic materials that were manufactured according to the parameters predicted by the model. Then they counted how many mosquitoes had soaked themselves with blood.

One material they initially tested was very thin – less than a millimeter thick – but had a very small pore size to prevent the mosquito from sticking its mouthparts or proboscis through the material. Another material had a medium pore size to prevent the mosquito from pushing its head through the fabric far enough to reach the skin; and a third material had larger pores but was so thick that the mosquito’s mouth still couldn’t reach the skin.

In a subsequent test, the researchers selected a range of knits and fabrics that met the bite parameters determined by the model and validated them in experiments with the blood reservoir and human volunteers. The researchers tested the number of bites volunteers received when study participants inserted a protective sleeve-covered arm into a mosquito cage. The researchers also compared the fabrics’ ability to prevent bites and repel mosquitoes with fabrics that had been treated with an insecticide.

Based on the findings of previous experiments, the researchers developed the firm, body-hugging underwear made of thin material and a long-sleeved shirt that was originally intended as a military shirt.

When a volunteer wore the garments for 10 minutes while sitting and 10 minutes standing in a walk-in cage with 200 hungry mosquitos, the volunteer found that the combat shirt was 100 percent effective in preventing bites. In a first attempt testing the base layer, the volunteer received stings on the back and shoulders – seven stings for 200 mosquitos. The researchers attributed the bites to the stretching and deformation of the tissue so that they doubled the layer of material around the shoulders and ultimately prevented 100 percent of the bites. They also tested the clothes for comfort and to see how well they trap heat and release moisture.

“The finished garments that were produced were 100 percent firm to the bite,” said Michael Roe, William Neal Reynolds Distinguished Professor of Entomology at NC State. “Everyday clothes that you wear in summer are not resistant to mosquitoes. Our work has shown that it doesn’t have to be that way. Clothes that you wear every day can be made bite-proof. Ultimately, it’s about having a model that covers all kinds of clothing you would ever want – both for the military and for private use. “

The study “Mosquito Textile Physics: A Mathematical Roadmap to Insecticide-Free, Bite-Resistant Clothing for Everyday Life” was published online on July 13, 2021 in the journal Insects. It was written by Luan, Roe, West, Charles Apperson, Marian McCord, Emiel DenHartog, Quan Shi, Nicholas Travanty, Robert Mitchell, Grayson Cave, John Strider and Youngxin Wang from NC State University and Isa Bettermann, Florian Neumann and Tobias Beck from . written by Aachen University, Germany. The study was sponsored by the National Science Foundation, the Department of Defense’s Deployed War Fighter Program, the Department of Defense’s Natick Contracting Division, the NC State Chancellor Innovation Fund, the Southeast Center for Agricultural Health and Injury Prevention, PILOTS, and the NC Agricultural Research Experimental Station.

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