Mosquitoes spread the virus by biting an infected person and spreading it to another person through their bites.
ADVERTISEMENTFrench health authorities warn of the risks of imported cases of dengue fever ahead of the Olympics due to the ongoing surge of the virus in the Americas.
There are more than 5.2 million cases of dengue in the Americas, according to the World Health Organization (WHO)'s regional office, with many countries facing large epidemics.
This is up more than 400 per cent compared to the average over the past five years.
Dengue is a virus that is transmitted to humans through the bite of an infected mosquito. While many infections are asymptomatic, in some cases the virus can be severe or fatal.
The "unprecedented situation" in the Americas has resulted in an increase in imported cases from the region, French health authorities warned this week.
There have been more than 1,649 imported cases of dengue in mainland France, mostly coming from French overseas territories of Guadeloupe and Martinique.
This compared to just 131 cases over the same period last year, the country's health ministry said.
"The phenomenon that we observe [in France], with the rise in imported cases is a phenomenon that many countries have also observed," an official from the health ministry told a press briefing on Tuesday.
Warning ahead of the Olympics
French authorities called on health professionals and the public to be vigilant, especially as the tiger mosquito that transmits the dengue virus has expanded its presence in Europe.
The surveillance period in France begins from May to November for cases in the territory.
The concern is that a person infected with dengue can transmit it to a mosquito, which can in turn transmit the virus to someone else. It cannot be transmitted person-to-person, however.
A French health ministry official added the authorities were "fully mobilised" and preparing for any possible infectious disease threats during the Olympics.
When travelling to regions with high levels of dengue, people should wear loose clothes that cover the skin and try to prevent mosquito bites by using insect repellent and mosquito nets, authorities say.
When returning from those areas, Public Health France recommends consulting a doctor if you get a fever within 15 days and continuing to protect yourself from mosquitoes.
