NATICK, Mass. (Oct. 14, 2014) -- When it comes to insect repellent, the Natick Soldier Research, Development and Engineering Center, or NSRDEC, makes sure Soldier uniforms are treated just right.
The Textile Materials Evaluation Team, or TMET, evaluates uniforms before they are issued. The team verifies that the insect repellent treatment meets the requirements of the specification, which are derived from the Environmental Protection Agency, or EPA, application rate. The verification ensures that the uniforms are treated at the appropriate levels with permethrin and provide adequate protection from biting insects.
In the past, the Individual Dynamic Absorption Kit, or IDA Kit, was used by Soldiers in the field to apply permethrin to individual combat uniforms. A two-gallon sprayer (hand can) was also used to treat multiple uniforms, but it could only be used by certified applicators.
For many uniforms, these methods were later replaced by industrial application in factories, which provides more uniformity and consistency in permethrin application. It also helped ease the logistical burden since uniforms that are issued to Soldiers are already treated. Therefore, the Soldiers don't need to carry the supplies with them, and they don't have to dispose of containers and repellents after use.
"Logistically, it gets rid of that extra step," said Amy Johnson, NSRDEC textile technologist. "So when Soldiers are getting ready to deploy, it is not yet another thing they have to do. A senior commander doesn't need to make sure that everyone did it. It's already done. And a big benefit is that (factory application) lasts through multiple launderings. We found in testing that it lasts much longer than the aerosol individual treatment methods."
"Factory Treatment has better durability," said Melynda Perry, an NSRDEC textile chemist.
"It is good for the life of the garment," Johnson said.
Although the factory application improved the consistency in the amount of permethrin applied to the uniforms, the garments still need to be evaluated by NSRDEC through an extraction process.
"Permethrin, because it is an insect repellent, is regulated by the Environmental Protection Agency," Perry said. "Extraction and analysis must be done to make sure the uniforms are meeting EPA-approved levels. Prior to moving forward with factory treatment, the doses were run through the U.S. Public Health Command to ensure that the amount of permethrin being applied was well below toxicity levels for people."
"Insect repellent textiles that require testing are sent to TMET for extraction of the active ingredient, which is measured and quantitated on the gas chromatograph/mass spectrometer," said Lauren Heim, a textile technologist/technician with Battelle Memorial Institute (contractor)/NSRDEC. "This testing is performed on treated end items and on developmental fabric and garments."
The team works collaboratively with project officers to provide input into fabric and end-item specifications.
"We require a certain dose rate based on the fabric weight," said Perry. "We provide the minimum and maximum requirements that go into the specifications (for the factory application). "(Percent) Bite Protection" requirements are based on the fabric type. It's not just the permethrin that helps prevent bites -- it's the permethrin in conjunction with the fabric construction. The fiber type or blend and the weave type also come into play."
"So there is a lot of work done upfront," Johnson said.
Insect bites are not only a nuisance, they can be dangerous. Mosquitoes, sand flies, ticks and other insects can carry diseases, such as malaria, leishmaniasis, Lyme disease and West Nile disease. Illnesses carried by insects can impact Soldier morale, health, performance and survivability.
"Some of these diseases can cause death or cause a Soldier to be incapacitated for a period of time, which can affect the mission," Perry said.
Perry emphasized that the permethrin-treated clothing is only one element in the Department of Defense Insect Repellent System.
"It is important to note that permethrin is a contact repellent," Perry said. "It will not repel mosquitoes from exposed areas of skin. So even if you are wearing a permethrin-treated uniform, if you are not wearing your topical repellent, such as DEET, on your hands, face and other exposed areas, you're not going to be protected on those areas. All components of the DoD Insect Repellent System must be used. The system consists of the treated uniform, worn properly, and topical insect repellent on exposed skin, applied as necessary."
The system also includes using bed netting while sleeping and taking anti-malarial medication. NSRDEC's work protects those serving in the Army, Navy, Marines and Air Force.
Currently, permethrin is only approved for use on outer garments. NSRDEC is looking to expand protection through the development of novel textiles and methods that will help prevent insect bites, especially from insects that are known to carry pathogens. NSRDEC is also starting to investigate the development of base camp protection to minimize the threat of insect-carried diseases within the camp.
"We're not just focusing on permethrin, we're investigating other ways to protect the Soldiers, as well," Perry said. "NSRDEC is investigating natural oils and spatial repellents (to be used in base camps or on gear). DEET and permethrin are contact repellents. We want to prevent the mosquitoes from even reaching the Soldiers. Soldiers are often most vulnerable when they get back to the base camp and they take off their (treated) uniforms. So, we are looking into repellents that could possibly be incorporated into PT (physical training) uniforms and other items.
"We are also looking into spatial repellents that could potentially be used to treat a shelter or even a latrine or placed around base camps. In the future, we could look into placing attractants outside the base camp, where we could lure insects away."
The team is dedicated to its work.
"It's rewarding to know that the work we do protects the Soldier and that the work we do is relevant to morale, mission and comfort," Perry said.
"It helps keep them more mission ready," said Johnson. "It keeps them safe."
"It keeps me going in the lab," Heim said. "I just focus on the Soldier. This is why I am driven to keep the extraction testing process going every day."
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The Natick Soldier Research, Development and Engineering Center is part of the U.S. Army Research, Development and Engineering Command, which has the mission to develop technology and engineering solutions for America's Soldiers.
RDECOM is a major subordinate command of the U.S. Army Materiel Command. AMC is the Army's premier provider of materiel readiness -- technology, acquisition support, materiel development, logistics power projection, and sustainment -- to the total force, across the spectrum of joint military operations. If a Soldier shoots it, drives it, flies it, wears it, eats it or communicates with it, AMC provides it.
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