and Fite Bite Plant-Based Insect Repellent (Travel Medicine). We evaluated this type of repellent using the same testing methods in six subjects (five men and one woman). In one subject, a localized cutaneous re- action developed after the first test, and the subject discontinued the study. All other subjects completed three tests each of the repellent. The repellent had a mean (±SD) complete-protection time of 120.1±44.8 minutes, with a range of 60 to 217 minutes.
DISCUSSION
Protection against arthropod bites is best achieved by avoiding infested habitats, wearing protective cloth- ing, and applying insect repellent.11,12 The insect re- pellents that are currently available to consumers are
either synthetic chemicals or are derived from plants. The most widely marketed chemical-based insect re- pellent is DEET, which has been used worldwide since 1957. DEET is a broad-spectrum repellent that is ef- fective against many species of mosquitoes, biting flies, chiggers, fleas, and ticks.17 The protection provided by DEET is proportional to the logarithm of the dose; higher concentrations of DEET provide longer-lasting protection, but the duration of action tends to plateau at a concentration of about 50 percent.18 Most com- mercially available formulations now contain 40 per- cent DEET or less, and the higher concentrations are most appropriate to use under circumstances in which the biting pressures are intense, the risk of arthropod- transmitted disease is great, or environmental condi-