Kiarash Arangdad, PhD, research and development chemist with Elevate Textiles/Burlington, said in his presentation on the topic, “Application, Efficacy and Performance of Synthetic Pyrethroids vs. Plant-Based Insect Repellents,” that “mosquitoes are the most dangerous animal in the world.” Arangdad spoke at IFAI Expo’s Advanced Textiles Conference October 2 in Orlando, Fla.
Arangdad said that 80 percent of the world’s population is at risk of one or more vector-borne illnesses, which include (among others) malaria, dengue Fever, yellow fever, West Nile and Zika. More than 700,000 deaths annually are attributed to insect-borne illnesses. However, most of the diseases caused by insects are preventable with a physical barrier made with a fabric that has repellency insecticidal properties.
There are two basic types of repellents with options in each case. Spatial repellents incite the insect’s olfactory senses, and contact insecticides, generally using permethrin, affect tactile senses. Even a small amount of inhibitor, Arangdad notes, can reduce the attraction for a mosquito, and a variety of ticks, as well.
Insect repellents in textile applications need to meet a list of considerations to be useable. Broad action, so it’s effective against many insects, is important, as well as durability in laundering and normal use. They also need to prove a low impact to both the environment and to humans, in terms of toxicity or skin irritations.
The Environmental Protection Agency (EPA) regulates the commonly used insecticide permethrin content at .52 percent, so a higher concentration can’t be used for better performance. Permethrin can be rubbed off as a garment is worn, as part of normal use, so different fabrics will retain efficacy at different rates. These are tested in different ways. Testing is still underway to learn the efficacy against different insects, such as ticks versus mosquitoes.
Burlington makes No Fly Zone® insect repellent technology which is applied to gear and garments for protection against insects.