DEET Resistance, by bite-protection expert Howard Carter
Many doctors and travel nurses in the UK are still recommending DEET to travellers abroad, most of them completely oblivious to the fact that certain mosquitoes have built up resistance or tolerance to this pesticide repellent in the last few years.
Fifteen years ago I went to India for the first time armed with the advice from a travel doctor to take DEET and anti-malarial tablets, the latter she prescribed, I went to Boots to buy a DEET-based repellent. I took the tablets religiously – I knew I was very attractive to insects, which is why I took all these precautions. Slathered up in the noxious repellent I ate outside on New Year’s Eve, under the stars, in Kochi on the Malabar Coast. Whilst watching Kathakali, mosquitoes were biting me repeatedly around my ankles – the DEET didn’t protect me – I didn’t even feel them bite at the time, only seeing the unattractive bites the next morning, when they were itching like mad. To make matters worse the anti-malarials also didn’t protect me from the malaria parasites that were now in my blood, so I contracted malaria!
It isn’t just my experience either. We’ve spoken with hundreds of travellers at events who’ve also received mosquito bites whilst using DEET. A few of these also contracted malaria at the same time they were taking anti-malarial medication: no anti-malarial tablet gives one hundred percent protection, yet some people, like Cheryl Cole, experience a false sense of security when they take them.
More people are getting bitten by mosquitoes and other insects that ever before.
At The Times Destinations Show a few years ago I met a film director in the Press Lounge who was covered from head to toe in mosquito bites whilst using a hundred percent DEET during filming in the Bolivian Amazon; his two-man crew were equally ravaged. I asked him, “do you know why you were bitten so badly”, to which he replied, “I have absolutely no idea, the DEET always used to work”. I explained about mosquitoes building up resistance to DEET repellents and that he and his colleagues had probably encountered Anopheles albimanus that is very resistant! This mutant mosquito is frequently found throughout the Americas including the Caribbean and Virgin Islands.
Interestingly I met Charley Boorman an hour later at Destinations who didn’t get a single mosquito bite in Africa whilst using incognito® repellent! He was so chuffed with the natural repellent that he came over to our stand and shared his experience.
Dr. James Logan, from the London School of Hygiene & Tropical Medicine, has identified a DEET-resistant gene that is found in all mosquitoes. Therefore, I imagine resistance will eventually spread to every mosquito species in the world.
It may be simple inertia that leads to medical professionals doling out the same advice that they have for years or in the NHS it could be the cuts; whatever the reason, people are now playing Russian roulette every time they use DEET in the Tropics or wherever mosquito-borne diseases are present.