Insect repellent is 'safe' to use, scientists say
Repellents that contain Deet are safe to use, say scientists who are warning that protection is vital for UK people travelling to tropical destinations, including the World Cup in Brazil.
Deet protects against diseases such as malaria and dengue fever, passed on by mosquitoes and other insects.
Some have been concerned that it could be toxic and pose a risk to health.
But the London School of Hygiene and Tropical Medicine scientists say Deet is "the safest you can get".
They recommend applying repellents containing 20-50% Deet to the skin when in countries with diseases spread by insects.
They say that with foreign travel becoming more popular, greater awareness is needed about insect bite risks and prevention.
The number of people travelling to tropical countries increased by two million between 2002 and 2012, and Public Health England recently warned of increasing rates of dengue fever in returning UK travellers.
Fatality link 'speculation'
Deet was developed by the US Army in 1946 following its experience of jungle warfare during World War Two.
Previous concerns about Deet's safety had been raised after fatal cases of encephalopathy, or swelling of the brain, had been reported in children who had used it during the 1980s, said the study.
But the LSHTM scientists say the role of the repellent in the deaths was "purely speculative" and they could have been down to other medication the people were taking at the time.
After trawling through the available medical literature, they concluded that the 14 cases of Deet-related encephalopathy recorded since 1957 was "small" compared with 200 million applications of the repellent across the world every year.
'No evidence' for Marmite
The paper looked at other commonly held beliefs about bite prevention and concluded there was "no evidence" that eating Marmite or garlic worked.
Lead researcher Dr James Logan, at the LSHTM, said there were "always a lot of rumours" around Deet, and that it was often "mixed up" with the pesticide DDT, which was used to kill insects.
Independent expert Prof Steve Lindsay, at Durham University, agreed with the study findings.
People should use bed nets, immersed in insecticide, along with repellent, he added.
The research was published in the journal Parasites & Vectors.