A city stay in Chiang Mai and an overnight trek get different malaria advice.
- Travel clinic CDC recommends medicine or vaccines for some areas · which ones
- No CDC travel notice for mosquito-borne disease
The CDC reports only rare to few malaria cases in the cities of Chiang Mai and Chiang Rai, but it lists prevention medicine for the provinces that border Myanmar, and both do. In town, day-biting mosquitoes carry dengue and chikungunya, and Chiang Mai led Thailand's 2025 chikungunya count.
Yes. Day-biting mosquitoes spread dengue and chikungunya in both cities, and Chiang Mai had more chikungunya cases than any other Thai province in 2025. For malaria, the CDC reports only "rare to few cases" in the cities of Chiang Mai and Chiang Rai, but both provinces border Myanmar and the CDC lists prevention medicine for the border provinces as a whole, which makes an overnight trek, a hill-tribe homestay or a night at an elephant sanctuary a travel-clinic conversation.
City stay or overnight trek
City stays with day trips
Rare to few malaria cases in both cities, per the CDC. Dengue and chikungunya are the risks, and their mosquito bites by day.
- Repellent from the morning on
- No Japanese encephalitis vaccine advised for short city stays
Rural nights in a border province
The CDC's malaria-medicine listing covers the whole province, with no elevation exemption, so hill treks are inside it.
- Travel clinic 4–6 weeks out, with the route
- Repellent and long sleeves from dusk to dawn
- Ask about Japanese encephalitis vaccine
Malaria, in the CDC's words
The CDC's Thailand page reports "Rare to few cases in other parts of Thailand, including the cities of Bangkok (the capital), Chiang Mai, and Chiang Rai." Transmission is concentrated in the border provinces, especially their rural forest and forest-fringe areas, and the CDC draws its medicine line by province.
The border-province line. For prevention medicine, the CDC lists "Provinces that border Burma (Myanmar), Cambodia (except Buri Ram Province), and Malaysia: Atovaquone-proguanil, doxycycline, tafenoquine." Chiang Mai and Chiang Rai provinces both border Myanmar. If your plan includes a trek, a homestay or a sanctuary night in either province, book a travel clinic 4–6 weeks before departure and bring the route. Whether a city-only stay calls for medicine is the clinician's call.
Dengue, chikungunya and Japanese encephalitis
Dengue is endemic, but 2026 has been quieter nationally. Thailand's Department of Disease Control counted 25,026 cases by September 15, about 1.8 times fewer than in 2025, with the rise concentrated in the south.
The CDC says "There is elevated chikungunya risk in Thailand," and the World Health Organization counted 411 of the country's 1,128 cases from January 1 to September 14, 2025, in Chiang Mai, the most of any province. Both spread through the same day-biting mosquito, found around temples, gardens and cafes, so the morning repellent covers them. Our dengue & Zika routine has the schedule.
For Japanese encephalitis, the CDC recommends the vaccine for "a month or more" in areas with the disease and says to consider it for shorter trips with "activities that increase risk of infection, such as visiting rural areas, hiking or camping, or staying in places without air conditioning, screens, or bed nets."
Sanctuaries, treks and when to go
The elephant sanctuaries in the Mae Taeng and Mae Wang valleys sit beside rivers and forest, so wear long, light clothes and reapply repellent after river time with the elephants. The cool, dry months, roughly November to February, are the easiest for bites and treks. The rainy season, roughly June to October, brings more mosquitoes, muddy trails and Thailand's dengue rise, though dengue is reported in every month.
Where you're going
Chiang Mai Old City & Nimman
The CDC reports rare to few malaria cases in Chiang Mai city and doesn't recommend Japanese encephalitis vaccine for a short city stay. The dengue and chikungunya mosquito lives around temples, gardens and cafes, so wear repellent from the morning on.
Mae Taeng & Mae Wang elephant sanctuaries
Rural Chiang Mai province, inside the CDC's border-province malaria listing. A day visit is mostly daytime exposure; an overnight or volunteer stay adds the malaria hours, so mention it at the clinic and sleep under the net.
Doi Inthanon & Doi Suthep-Pui treks
Treks and village homestays in a Myanmar-border province, where the CDC lists malaria medicine and gives no elevation exemption. Rainy-season treks tend to bring more mosquitoes.
Chiang Rai, the White Temple & the Golden Triangle
The CDC reports rare to few malaria cases in Chiang Rai city. Rural nights toward Chiang Saen, Mae Sai or hill-tribe villages fall under the border-province listing, so bring them up at the clinic.
Heading south afterward? The Phuket & Krabi and Thailand briefings cover the rest of the route.
The northern Thailand kit
- Picaridin 20% travel sprays: odorless in the heat and layers over sunscreen. One 3.4 oz bottle covers about a week of daily use for one person.
- Permethrin 0.5% for trekking clothes: treat a long-sleeved shirt, trousers and socks at home 48 hours before you fly. Treated fabric repels and kills mosquitoes on contact through several washes. It goes on clothing, never on skin.
What travelers report
Paraphrased from TripAdvisor forum threads and linked so you can read them in full. None is dated, and the season and where you sleep change the picture more than anything else.
- Chiang Mai · year-round
A poster said there are mosquitoes in Chiang Mai year round; their numbers drop in the dry winter season but they do not disappear. TripAdvisor ↗
- Elephant Nature Park (Mae Taeng)
In a thread about malaria on a trek and at Elephant Nature Park, a volunteer said all the rooms have mosquito nets over the beds and that, although some say there are more mosquitoes around the elephants, they never had a problem. TripAdvisor ↗
- Lisu village trek, Chiang Mai province · January
Replies about mosquitoes on a January trek were mixed: one visitor found hardly any, while another said there were definitely mosquitoes in late December and early January. TripAdvisor ↗
- Chai Lai Orchid (elephant camp lodge)
A poster who stayed overnight said there was a net over the bed. TripAdvisor ↗
One rule outlasts the trip. Any fever during or after your trip means a doctor visit, and you tell them you were in northern Thailand and whether you trekked. Thailand's Department of Disease Control advises paracetamol rather than ibuprofen or aspirin until dengue is ruled out.
Traveler questions
Do I need malaria pills for Chiang Mai?
For the city itself, the CDC reports "Rare to few cases" of malaria. Its medicine listing covers the "Provinces that border Burma (Myanmar), Cambodia (except Buri Ram Province), and Malaysia," though, and Chiang Mai and Chiang Rai provinces both border Myanmar. The CDC names atovaquone-proguanil, doxycycline and tafenoquine for them, and treks, hill-tribe homestays and sanctuary nights fall inside the listing. Whether a city-only stay calls for medicine is a clinician's call, so see a travel clinic 4–6 weeks before departure with your route. Our malaria-zone checklist covers the rest.
Is there chikungunya in Chiang Mai?
Chiang Mai had more chikungunya cases than any other Thai province in 2025: 411 of the country's 1,128 from January 1 to September 14, according to the World Health Organization. The CDC says there is elevated chikungunya risk in Thailand and suggests the vaccine only for stays of an extended period, for example 6 months or more. The mosquito that spreads it bites in daylight, so repellent from the morning on is the main defense.
Do I need the Japanese encephalitis vaccine for northern Thailand?
The CDC recommends it for travelers spending a month or more in areas with Japanese encephalitis. It says to consider it for shorter trips that include rural areas, hiking or camping, or places without air-conditioning, screens or bed nets, and it doesn't recommend it for short-term travel to urban areas. A city break in Chiang Mai sits in the last group; a trek or a sanctuary night may not. Ask at the travel clinic.
Is an elephant sanctuary visit a malaria risk?
The Mae Taeng and Mae Wang sanctuaries are in rural Chiang Mai province, inside the CDC's border-province malaria listing. A day visit is mostly daytime exposure, when the dengue mosquito is active rather than the malaria one, which bites from dusk to dawn. An overnight or volunteer stay adds those hours, so mention it at the travel clinic, wear long, light clothes and sleep under the net provided.
Sources
Health authorities, surveillance reports and news coverage of official bulletins used for this briefing, last checked October 2026. Traveler reports are linked where they appear. This page summarizes public-health guidance and is not medical advice.