Use of insect repellents is strongly recommended by the CDC and the EPA to prevent Zika virus infection1,2 and other mosquito- and tickborne diseases.3 Mosquitoes can transmit chikungunya, dengue, West Nile, and yellow fever viruses, and malaria. Ticks can transmit Lyme disease and rickettsial diseases such as Rocky Mountain spotted fever.
The topical insect repellent with the best documented effectiveness against mosquitoes is N, N-diethyl-m-toluamide (DEET).4,5 Applied on exposed skin, DEET also repels ticks, chiggers, fleas, gnats, and some flies. DEET is available in concentrations of 5-100% (Table). In general, higher concentrations provide longer-lasting protection,6 but increasing the concentration above 50% has not been shown to improve efficacy. Long-acting polymer-based or liposomal DEET formulations containing concentrations of 30-34% have been shown to protect against mosquitoes for up to 12 hours. The CDC recommends using concentrations ≥20% for protection against ticks.
Insect Repellents. JAMA. 2016;316(7):766-767. doi:10.1001/jama.2016.10042