Prevent Insect Bites Many diseases, like malaria and dengue, are spread through insect bites. One of the best protections is to prevent insect bites by: – Using insect repellent (bug spray) with 30%-50% DEET. Picaridin, available in 7% and 15% concentrations, needs more frequent application. – Wearing long-sleeved shirts, long pants, and a hat outdoors. […]