Dengue occurs year-round in Vietnam and SEA, with the peak usually in rainy seasons, April to October in the north and June to December in the south. However, in 2017, Dengue has become an outbreak in many provinces and cities across the countries.
Most affected areas include An Giang, Bing Duong, Da Nang, Dong Nai, Dong Thap, Hanoi, Ho Chi Minh City, Khanh Hoa, Soc Trang and Tien Giang.
Tropical and subtropical areas of Central America, South America, Africa, Asia and Oceania every year have a certain risk of Dengue. All travellers are at risk during outbreaks. Travellers going to areas where Dengue is endemic or tropical areas in rainy seasons are at higher risk.
Dengue is caused by Dengue virus, borne only by mosquitoes. There are four types of viruses (DENV-1 to 4), which means a human can be infected 4 times throughout his/her lifetime. The viruses are transmitted through the bite of infected Aedes aegypti and Aedes albopictus female mosquitoes that feed both indoors and out outdoors during daytime, especially from 8:00-10:00 in the morning and before nightfall. Standing water, including puddles, water tanks, containers and old tires are places where mosquitoes thrive.
Symptoms typically begin three to fourteen days after infection, might including high fever, headache, vomiting, muscle and joint pains and characteristic skin rash. However, in most cases (80%), infected persons do not exhibit symptoms. Children often experience symptoms similar to those of common cold and gastroenteritis (vomiting and diarrhoea).
The high fever, potentially over 40 °C (104 °F), usually lasts from two to seven days. The rash is accompanied with symptoms of flushed skin, described as “islands of white in a sea of red”. Also, mild bleeding from mucous membranes of the mouth and the nose might appear.
Dengue is related to Zika Virus, Yellow Fever, West Nile Virus, and Japanese Encephalitis. It can be misdiagnosed for Chikungunya, Zika Virus, or Yellow Fever.
Fever in Vietnam
Vietnam and its particularly cities that are severely affected by Dengue fever-like Hanoi, Ho Chi Minh and Da Nang are putting a large effort in preventing the spreading of the outbreak. In total, there are more than 80,000 people infected, 24 died across the country until now and it has shown no signs of dying down or being controlled. Ho Chi Minh City has most infected cases; Hanoi has the fastest speed of infection. The peak season of Dengue fever annually falls in September and October but this year, the outbreak started right from May-June.
There is a vaccine for the endemic population being tested right now. However, a vaccine for travellers is still unavailable. Travellers from endemic areas of Yellow Fever will be required to be vaccinated by the Vietnamese government.
A Dengue vaccine for travellers can help a lot in the prevention of transmission of disease.
- The only way to prevent the infection of Dengue is to prevent mosquito bites during the daytime.
- Use a repellent containing 20%-30% DEET or 20% Picaridin on exposed skin. Re-apply as instructed.
- Wear long-sleeved, breathable, neutral-coloured (beige, light grey) garments as much as possible.
- If available, pre-soak or spray outer layer clothing and gear with permethrin.
- Get rid of water containers around dwellings and ensure that door and window screens work properly.
- Use mosquito netting while sleeping and resting.
Things that attract mosquito
Sweat: researches showed that mosquitoes really like the scent of acid lactic in sweat.
Beer: mosquitoes also like to linger around those who just drank beer.
Blood Type O: O type does attract mosquitoes more than other types.
Pregnant women: tiger mosquitoes bite pregnant women more frequently than other people