Use of repellents by travellers: A randomised, quantitative analysis of applied dosage and an evaluation of knowledge, Attitudes and Practices (KAP)

Background: Prevention of arthropod-borne infections hinges on bite prevention. We aimed to investigate travellers' use of repellents. Methods: We measured the amount of applied repellent with a spray containing 30% DEET and 20% Icaridin versus a lotion with 20% Icaridin alone. We calculated the concentration of active ingredient reached on the skin and evaluated formulation acceptability. The travellers completed a questionnaire evaluating Knowledge, Attitudes and Practice (KAP) to anti-vectorial protective measures (AVPM). Results: Some 200 volunteers travelling to mosquito borne infection endemic areas were recruited. The mean concentration of active substance achieved on the skin of the left arm was 0.52 mg/cm(2) of DEET/Icaridin spray versus 0.21 mg/cm(2) of Icaridin lotion. These levels are below the recommended protective dose (1 mg/cm(2)) for each formulation. Women were significantly more likely to apply a higher, protective dose of repellent. Travellers to Africa, women and older participants showed higher projected adherence to AVPM. Conclusions: Only 2.5% of recruited travellers applied the recommended protective dose of repellent. Women and older travellers are the most adherent users of repellents. The pre-travel health consultation should provide more information on the application quantity and correct use of repellents.