Football fans preparing to follow the England team to Brazil have been urged by scientists to be extra vigilant of insect bites.
Experts are reminding fans travelling to the World Cup and others planning trips to other exotic places to use repellents to protect themselves against bites and the diseases they spread.
The warning comes after experts reviewed the safety of insect repellent which contains N,N-diethyl-m-toluamide, popularly known as DEET.
Previous research has hotly contested the safety of the use of DEET - which is the most common active ingredient in repellents.
But a new review of previous studies conducted by experts the London School of Hygiene and Tropical Medicine has concluded that the there is "insufficient evidence" to show that DEET is unsafe.
Their review, published in the open access journal Parasites and Vectors , also found that the benefits of avoiding disease-spreading insect bites outweigh any risks associated with applying DEET to the skin.
The researchers recommend applying repellents containing 20% to 50% DEET to the skin when in countries with diseases spread by insects, such as malaria and dengue fever.
A spokeswoman for the London School of Hygiene and Tropical Medicine said that dengue fever - a viral infection that is transmitted to humans by Aedes mosquitoes - is present in Brazil.
It can cause life-threatening illness and there is there is no cure and no vaccine against it. The main protection against dengue fever is insect repellents, she said.
"Biting arthropods can transmit a whole range of diseases to humans and it is vital to protect ourselves," said Dr James Logan, senior lecturer in medical entomology at the London School of Hygiene and Tropical Medicine.
"Vaccines and treatments are available for some diseases, but not all, and so the best way to keep as safe as possible is to use an insect repellent containing DEET and reapply it regularly.
"We want people to enjoy their holidays and tropical trips - we don't want them ruined by illness so we want to do all we can to help inform and educate people about the facts rather than the many myths surrounding this issue."