Dengue, Mosquitoes and Everyday Health Hazards in Phuket

Dengue: the main risk

Dengue is a viral illness spread by Aedes mosquitoes, and it is established across Thailand, including Phuket. Cases rise in the rainy season, which runs roughly from May to October, but it can occur at any time of year. The mosquitoes bite mainly in the daytime, especially in the morning and late afternoon, and they breed in even small amounts of standing water. National figures for 2026 recorded more than 21,000 cases by mid-August, according to the Department of Disease Control as reported in the press, and Phuket has been named in past years as a high-rate area in the upper south, so do not treat the island as risk-free.

Symptoms and when to get help

Typical symptoms include a sudden high fever, headache, pain behind the eyes, muscle and joint pain, nausea and sometimes a rash. Health officials advise seeing a doctor if you have a high fever lasting more than two days during the rainy season. Go to a hospital urgently if there are warning signs such as severe stomach pain, repeated vomiting, bleeding from the gums or nose, black stools, extreme tiredness or drowsiness, cold clammy skin, or a fever that drops and the person gets worse, because these can signal severe dengue.

A rapid test can confirm dengue at most hospitals and clinics, often the same day. Do not take aspirin or ibuprofen if you might have dengue, because they can increase bleeding risk, and ask the doctor which pain relief is safe. Children are among those most affected, so take a child with fever to a doctor early. Keep insurance details with you, as hospital stays cost money, and the health and insurance guide explains what to check.

Prevention at home

The main defence is removing the places where mosquitoes breed.

• Empty standing water weekly from plant saucers, buckets, bottle caps, old tyres, bird baths and clogged gutters.
• Change vase water at least every seven days, and cover water storage containers tightly.
• Clear rubbish that can hold rainwater, and clean drains.
• Use screens on windows and doors, and a fan or air conditioning, which also keep mosquitoes away.
• Wear long, light clothing at dawn and dusk, and use an insect repellent, following the label.
• Use mosquito nets, plug-in devices or coils where needed, and take care with smoke indoors.
• Tell your landlord or building management about standing water in common areas.

Officials suggest the same three habits: keep the home clean, do not leave rubbish that holds water, and cover water containers. If you rent a house with a garden, ask who looks after drains and ponds.

Vaccination and advice

A dengue vaccine is available at some Thai hospitals, and doctors may recommend it for long-stay residents and children in some circumstances. Whether it suits you depends on your history, age and health, so ask a doctor. Vaccination does not replace mosquito control.

Sun and heat

The sun is strong all year. Use sunscreen, a hat and sunglasses, avoid the middle of the day and drink water regularly. Heat exhaustion is common among newcomers, so rest in the shade or in air conditioning if you feel dizzy, nauseous or unusually tired. Our guide to rainy and hot days has ideas for the middle of the day.

Water, food and stomach upsets

Many residents drink bottled or filtered water, and use tap water only for washing and cooking where the building says it is safe. Eat at busy places with high turnover, wash fruit, and be careful with ice and raw seafood if you have a delicate stomach. Keep oral rehydration salts at home, and see a doctor for severe diarrhoea, fever, blood in the stool or signs of dehydration.

Sea hazards

Jellyfish stings are a risk in some seasons. Follow beach signs and flags, and wash a sting with vinegar if it is available, then get medical help for a severe reaction. The beach safety guide explains rip currents and warning flags. Do not touch or feed street dogs and cats, and see a doctor at once after any bite or scratch from an animal, because rabies is present in Thailand, as the pets guide notes.

Emergency numbers

• Ambulance: 1669.
• Tourist Police: 1155.
• Department of Disease Control hotline: 1422.
• Choose a hospital near your home in advance and save its number.