**1. Introduction**

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Mosquito-transmitted diseases are a major, global human health problem [1]. Pathogens transmitted by mosquito bites cause illnesses that kill an estimated 700,000 people each year [2]. Personal protection from mosquito-borne diseases has largely involved the use of chemical repellents applied to clothing and skin or insecticides either sprayed on garments before use or bound to textiles or garments to survive multiple uses and washes. Insecticide-treated textiles in the form of long-lasting insecticidal bed nets (LLINs) are also used for mosquito control in malaria-endemic areas. According to the World Health Organization, pyrethroid-treated bed nets have played a vital role in reducing malaria in Africa

**Citation:** Luan, K.; West, A.J.; McCord, M.G.; DenHartog, E.A.; Shi, Q.; Bettermann, I.; Li, J.; Travanty, N.V.; Mitchell, R.D., III; Cave, G.L.; et al. Mosquito-Textile Physics: A Mathematical Roadmap to Insecticide-Free, Bite-Proof Clothing for Everyday Life. *Insects* **2021**, *12*, 636. https://doi.org/10.3390/ insects12070636

Academic Editor: Rosemary S. Lees

Received: 15 June 2021 Accepted: 9 July 2021 Published: 13 July 2021

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(World Health Organization (2019), World Malaria Report, WHO, Geneva, Switzerland [3]). Between 2000 and 2015, an estimated 663 million clinical cases of malaria were averted, of which 68% were attributed to the wide-area deployment of LLINs [4]. The use of insecticidetreated curtains [5,6], long-lasting insecticidal bed nets, and insecticide-treated clothing [7] have substantially reduced the transmission of vector-borne pathogens. Unfortunately, the widespread use of insecticides has also led to the development of insecticide-resistant mosquitoes, and the insecticides are now ineffective in many places [8].

Furthermore, in spite of the benefits from insecticide-treated textiles, there are potential deleterious health effects [7]. Since the garments are in continuous contact with the skin, the potential for insecticide exposure is increased. Permethrin is the principal insecticide used to treat clothing [9]. Development of safe, alternative insecticides for textiles is costly and requires regulatory approvals for new chemistry. Because of the potential health risks from the use of pesticides, people today given a choice prefer to avoid insecticide exposure. Development of mosquito-bite-resistant garments without insecticides that are comfortable and as effective (or more effective) than insecticide-treated garments would be a "game changer" and provide to the public, for the first time, a choice. We have achieved this objective.

Fabrics inherently are favorable structures for producing physical barriers against insects. Textiles have a three-dimensional structure assembled with interlacements or intermeshing fibers and yarns in organized patterns [10]. The design of fibers and yarns produce textile structures with a diverse range of properties, some of which could provide insect protection [11]. Fabrics have been specifically designed as physical barriers against environmental factors such as water [12], airflow [13], or heat and cold [14]. The existence of open spaces between fibers and yarns ensures fabric breathability and thermal comfort [15]; however, these spaces produce pores through a fabric allowing penetration of human olfactory (smell) and thermal (temperature) cues that attract mosquitoes [16]. The fabric pores serve as channels for the mosquito to take a blood meal. The objective of our research is to develop a mathematical model to predict blood feeding across textiles that could be used to develop a practical, non-insecticidal, bite-resistant garment.

#### **2. Materials and Methods**
