Dengue in Thailand: Risk, Season and Bite Prevention

Dengue is endemic throughout Thailand, with peak transmission in the rainy season but cases reported all year. No medicine prevents it and no dengue vaccine is recommended for travellers in the United States, so protection means avoiding bites: screened rooms or air conditioning, long sleeves at dawn and dusk, and repellent.

Treat dengue as a risk across the whole country, not a few hotspots: it is endemic throughout Thailand, and travellers are told to protect themselves from mosquito bites to prevent chikungunya, dengue and Zika.

How likely it is, and when

Large epidemics occur every several years. Peak transmission is during the rainy season, although cases are reported year-round even in non-epidemic years. Risk increases with the length of your trip and during local epidemics or the rainy season. Plan around the months in our weather by month guide.

Many infections pass quietly: an estimated 40 to 80% of dengue infections are asymptomatic, and no more than 5% of people with symptoms develop severe, life-threatening disease.

Avoiding bites

No specific medication is available to prevent dengue, so the bite is what you control. Pick accommodation with well-screened windows and doors or air conditioning where you can, because Aedes aegypti mosquitoes live indoors and outdoors.

Wear long sleeves and trousers that cover your arms and legs, especially in the early morning and late afternoon, when the risk of being bitten by Aedes mosquitoes is greatest. Use an EPA-approved insect repellent. On a longer stay, empty, clean or cover standing water around your home, such as water storage tanks and flowerpots.

Is there a vaccine?

There are currently no dengue vaccines recommended for travellers in the United States. The vaccine Qdenga has been approved in several countries, including Thailand. Which vaccines suit your trip is a question for a travel clinic; the vaccinations guide covers the others.

What dengue feels like

Symptoms begin abruptly after an incubation period of 5 to 7 days, within a range of 3 to 10 days. Fever typically lasts 2 to 7 days, with severe headache, pain behind the eyes, bone, joint or muscle pain, and sometimes a rash.

The critical phase begins as the fever subsides and typically lasts 24 to 48 hours. Most patients improve during it, but those with plasma leakage may progress to severe dengue.

If you get it

No specific antiviral agents exist for dengue. Stay well hydrated and avoid aspirin and other anti-inflammatory drugs such as ibuprofen; acetaminophen and tepid sponge baths control fever. Severe dengue requires hospitalization and close observation, and pregnant women with dengue should always be hospitalized.

Thai hospitals require a guarantee of payment before treating patients, so carry travel insurance. The local emergency medical number is 1669. For hospitals with English-speaking staff, see the Bangkok hospitals guide and for fees the hospital costs guide.

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Not confirmed: We found no current Thai case counts, because the Department of Disease Control site blocks automated access. CDC does not name a peak month, only the rainy season. Whether clinics in Thailand give the Qdenga vaccine to visitors is not stated by the sources we read.

General health information checked against the sources listed above, not medical advice. Rules, vaccine schedules and prices change; see a doctor or the hospital before you act. See how guides are checked.

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