Dengue fever is caused by a virus - dengue virus - spread by the bite of an infected mosquito. The mosquitoes are usually of the species Aedes aegypti, which mainly bite during the day.
Dengue fever is widespread throughout the tropics and subtropics, occurring in > 100 countries. Nearly 100 million clinical cases of dengue fever are thought to occur every year. Severe infection mainly affects infants and children living in the tropics and subtropics. Outbreaks are common and often occur in a seasonal pattern. Several outbreaks due to locally transmitted infection have been reported in Southern Europe.
Dengue is the second most commonly identified cause of fever in ill international travellers.
Most infections produce no symptoms or result in mild symptoms only. Between 4-10 days after the mosquito bite a sudden onset of fever, headache, muscle and joint pains may occur. A rash may develop. Within a few days the illness usually resolves and serious complications are uncommon. In 1 – 2 % of cases dengue can progress to a more serious form, severe dengue, which can be fatal.
There is no specific anti-viral treatment but people who are symptomatic should consult a doctor. Symptoms like headache and fever can be treated symptomatically. Hospital care is indicated if severe illness develops or if complications occur.
The best way to avoid infection is to prevent mosquito bites. As the transmitting mosquitoes bite from dawn until dusk, long clothing should be worn and repellents should be used all day. See also information about Mosquito bite avoidance. Medical attention must be sought for any feverish illness experienced whilst travelling or on your return home.
There is no vaccine against dengue fever for travellers.
A vaccine for use only in people living in dengue affected countries aged between 9–45 years is currently under review.