Summertime means warmer weather, spending more time outdoors and with that, a higher level of exposure to mosquito bites. Most of us want to enjoy outdoor activities, but we should educate ourselves on the safest methods to protect our families and pets from potential disease transmission as well as over-exposure to chemically-based insect repellant products.
MOSQUITO BITES: POTENTIAL HEALTH RISKS
About 10 percent of the 2000 species of mosquitoes live in North America. Thriving in humid and damp areas, mosquitoes reproduce quickly and are most active at dawn and dusk. According to the Mayo Clinic, mosquitoes can carry and transmit a myriad of diseases including West Nile Virus, Malaria, Dengue Fever, Yellow Fever, and Heartworm, a parasite affecting household pets.
DEET (chemical name N, N-diethyl-meta-toluamide) is the active ingredient in many insect repellents and is an organic solvent used in rubber and plastic cements and paint removers. According to the Centers for Disease Control (CDC), insect repellents that contain DEET offer the best protection against mosquito bites.
In the U.S., concentrations of DEET products designed for skin application range from 4% to 100%. However, Health Canada, a department of the Canadian Federal Government, has banned
products with DEET concentrations over 30%, citing health risks and evidence that increasing the percentage does not do much more to repel insects.
DEET: POTENTIAL HEALTH RISKS
DEET is absorbed through the skin and passes into the blood. The Medical Sciences Bulletin, published by Pharmaceutical Information Associates Ltd., reports, "Up to 56% of DEET applied topically penetrates intact human skin and 17% is absorbed into the bloodstream." Frequent or heavy dermal exposures of DEET have led to skin rashes, blisters, and skin and mucous membrane irritation. Reported cases involving higher DEET concentrations or more frequent applications include incidents of reproductive and developmental effects, placental transmission, and in rare cases, death.
The Duke University Medical Center News Office suggests that DEET should be used with caution due to possible damaging effects on brain cells following prolonged use. Studies involving DEET exposure in rats revealed negative impacts on muscle movement and control,
learning, memory, concentration, strength and coordination. These findings are consistent with reported human symptoms following military personnel DEET use in the Persian Gulf War and symptoms of memory loss, headache, fatigue, muscle and joint pain, tremors, and shortness of breath, which may not be evident until months or years following exposure.
Symptoms may be compounded by combining DEET with other medications or chemicals. Children are particularly vulnerable to brain-related deficits because their skin more readily absorbs chemicals in their environment and their nervous systems are still developing. Due to these findings and the fact that further studies are needed to identify long-term effects, sources including Duke University recommend adhering to the following guidelines when using DEET.