DEET insect repellent 'is safe for human use'

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Tue 11 August 2009

Scientists hit back at French researchers' claims

A widely reported claim that the main ingredient in most insect repellents, DEET, is toxic to humans has been disputed by leading scientists.

The report, which we covered here, was not based on extensive human tests which is why it is now being called in to question.

Prof. Brian Greenwood of the London School of Hygiene and Tropical Medicine commented that "DEET has been used for decades with few reported side effects". He also pointed out that most people use insect repellents only occasionally and would therefore never be exposed to a level of DEET that could possibly harm them.

Others pointed out that the dosage of DEET used in the French study was 200 to 4,000 times greater than the amounts obtained if products were used according to instructions.

In a 2002 study American scientists concluded: "DEET has a remarkable safety profile after 40 years of use and nearly 8 billion human applications. When applied with common sense, DEET-based repellents can be expected to provide a safe as well as long-lasting repellent effect. Despite the substantial attention paid by the lay press every year to the safety of DEET, this repellent has been subjected to more scientific and toxicological scrutiny than any other repellent substance."

Although there have been a small number of cases of adverse reaction to DEET, these have occurred due to inappropriate usage of the product containing the chemical. Contrary to the advice given by the French scientists, experts urge that DEET is safe for use by children and pregnant woman.

It is also worth noting that the effects of insect bites can be fatal - there are an estimated 300 to 500 million clinical cases of malaria each year resulting in 1.5 to 2.7 million deaths, with children aged between 1 and 4 most at risk of death. In the UK in 2006, 1,758 cases of malaria were reported in travellers who returned to the UK, eight of which were fatal. As I am sure you are aware, malaria is spread by mosquitoes biting humans.