The Centers for Disease Control (CDC) has been quick to issue public warnings about the threat of contracting Zika virus, for people who plan on traveling to at-risk areas. Medical researchers are still learning about effects of the Zika virus, which is believed to be spread mostly by Aedes aegypti mosquitoes, as well as how it is transmitted and how it can be treated. At this time, there is no cure or widely available vaccine, so disease experts are warning that preventive measures should be taken. Among other techniques, the CDC suggests the use of clothing treated with permethrin, a toxic chemical pesticide, for reducing the risk of becoming infected with Zika virus, Lyme disease, and other insect-borne illnesses. But is this clothing actually safe to wear?
Right now, the CDC says the Caribbean, Central America, Mexico, Puerto Rico, and South America are the biggest hot spots for new Zika cases, a virus which results in reduced infant head and brain size if contracted during pregnancy. The agency suggests people living in or traveling to those areas take special precautions to avoid mosquito bites. Insect repellent sprays may be fairly effective in keeping the mosquitoes from biting, but it’s often difficult to get adequate coverage, so the CDC recommends—among other things—wearing special clothing treated with permethrin, a synthetic chemical pesticide used to ward off mosquitoes. This type of clothing is suggested for anyone who may be at an increased risk of getting bitten by one of the virus-spreading bugs, including children older than two years of age, and pregnant women.
Permethrin is one of the “EPA-registered pesticides” the CDC recommends for preventing mosquito bites but it comes with stern warnings about prolonged or frequently repeated skin contact, which can cause irritation or allergic reactions. Even the CDC says that permethrin-treated clothing can be used to reduce risk of mosquito bites, coupled with instructions that state, “Do NOT use permethrin products directly on skin.” Although the CDC clearly supports the use of permethrin-treated clothing, the advice seems counterintuitive alongside the warnings.
There is also evidence that suggests that the human body not only absorbs these chemicals, but stores them. Another type of pesticide, glyphosate (the active ingredient in Roundup), has been found in the breast milk of American mothers. Early childhood exposure to pesticides has been linked with a risk of reduced breathing capacity in recent studies. The use of another common pesticide, DEET, during pregnancy has also been linked to an increased risk in breast cancer for daughters later in life.
Despite these red flags, some companies—like Seattle-based InsectShield—are capitalizing on the CDC recommendations by marketing not only clothing pretreated with permethrin pesticides that lasts for up to 70 washes, but also by offering customers the option to mail in their own clothes to be treated. The company started by supplying permethrin-treated uniforms for the U.S. military, and now sells a collection of clothing to the public — from maternity leggings to hoodies and T-shirts to fit the entire family. The company, along with the CDC and EPA, insist that clothing treated with the toxic pesticide can be safely worn to reduce the risk of mosquito bites, but the technology is relatively new, developed in 1996, so the long-term risks have not yet been fully evaluated.