Southeast Asia

Dengue is the most common travel-acquired febrile illness from Southeast Asia. Unlike malaria, the Aedes aegypti mosquito bites during daylight hours — peak activity is early morning and late afternoon. There is no prophylactic medication. DEET repellent must be applied during the day as well as at dusk. A dengue vaccine (Dengvaxia) exists but is only for those with prior dengue infection.

Rabies is endemic across all of Southeast Asia. Dog bites are extremely common — street dogs are ubiquitous throughout the region. Monkey bites (particularly at temple sites in Thailand, Bali, and Malaysia) are a growing risk. Post-exposure treatment (RIG + vaccine) is often unavailable or unreliable in rural areas. Pre-exposure prophylaxis (PrEP) is strongly recommended for all travelers, especially those visiting rural areas, trekking, or staying longer than 2 weeks.

Southeast Asia has among the world's highest typhoid burden. Transmitted through contaminated food and water, risk is especially high in street food environments and when eating at local restaurants without Western hygiene standards. Typhoid injectable vaccine should be given at least 2 weeks before departure. Note that no vaccine is 100% effective — food and water precautions remain essential.

Hepatitis A vaccine is strongly recommended for all Southeast Asian travel. TD rates of 20–40% affect visitors across the region. The local street food culture — while often delicious and relatively safe when fresh and hot — significantly increases exposure risk compared to home. See our complete Food & Water Safety guide.

The Greater Mekong Subregion (Myanmar, Thailand, Cambodia, Laos, Vietnam) is the epicentre of global antimalarial drug resistance. Mefloquine and chloroquine are ineffective in most of this region. Only atovaquone-proguanil (Malarone) or doxycycline are recommended. Malaria risk is generally limited to rural and forested border areas — most tourist areas and cities have low to no malaria risk. See our Malaria Prevention guide.

Chikungunya circulates throughout the region, causing fever and severe joint pain that can persist for months. Zika virus transmission has been reported in multiple Southeast Asian countries. Pregnant women should avoid Southeast Asia or take extreme precautions if travel is unavoidable. Both are transmitted by the same daytime-biting Aedes mosquito as dengue.

Southeast Asia has some of the highest hepatitis B prevalence globally. Hepatitis B vaccine is recommended for travelers who may receive medical or dental care, have blood exposure risk, or engage in unprotected sexual contact. HIV is also endemic across the region — standard blood and body fluid precautions apply.

Japanese Encephalitis (JE) is transmitted by night-biting Culex mosquitoes in rural agricultural areas — especially rice paddies and pig-farming regions. Risk is highest from June to September in temperate areas, year-round in tropical regions. JE vaccine (Ixiaro — 2 doses) is recommended for rural travel, adventure trekking, or stays exceeding 1 month.

Avian influenza strains circulate in poultry across Southeast Asia. Risk to tourists is very low but not zero. Avoid live bird markets, direct contact with poultry, and areas where sick birds have been reported. Ensure annual influenza vaccination is current before travel.

Schistosomiasis risk is limited compared to Africa — present in specific freshwater areas of the Philippines (Mindanao, Visayas) and Sulawesi, Indonesia. Avoid freshwater swimming or wading in these areas. Not a significant risk for most mainstream tourist itineraries.

Apply Repellent During the Day

This is the most frequently overlooked precaution in Southeast Asia. Dengue mosquitoes bite in daylight — particularly in the early morning and late afternoon. Apply DEET or picaridin repellent every morning and reapply after swimming. Do not wait for dusk.

Never Approach Stray Animals

Stray dogs and temple monkeys are ubiquitous across the region. Never attempt to feed, pet, or approach them. If bitten or scratched, wash the wound with soap and water for 15 minutes immediately and seek medical care the same day — do not wait for symptoms.

Master Street Food Safety

Street food is central to the Southeast Asian experience — and it can be safe if chosen carefully. Eat from busy high-turnover stalls. Choose food cooked fresh in front of you, served hot. Avoid raw salads, pre-cut fruit, and ice from unknown sources. See our Food & Water Safety guide.

Road Traffic — The Underestimated Risk

Road traffic injuries are one of the leading causes of death in US travelers to Southeast Asia — far outstripping infectious disease in absolute numbers. Always wear a helmet on motorbikes and scooters. Never drink and drive. Traffic flows on the left in some countries — check before crossing roads.

Fever After Return = Seek Care Urgently

Dengue classically presents 4–7 days after the infectious bite with high fever, severe headache, and bone pain ("breakbone fever"). Any fever within 2–3 weeks of return from SEA needs urgent medical evaluation. Tell your doctor you have traveled to Southeast Asia — both dengue and malaria must be ruled out.

Heat, Humidity & Sun

Equatorial heat and near-100% humidity across much of the region year-round. Heat exhaustion and heat stroke are real risks for active travelers. Stay hydrated, avoid peak midday sun, wear loose light-coloured clothing, and acclimatise gradually. SPF 50+ sunscreen is essential.

Safe Water is Not Tap Water

Tap water is unsafe for drinking in all 11 countries. Use sealed bottled water or your own purification system for drinking and brushing teeth. Carry Aquatabs as backup. Commercial ice in tourist areas is generally made from purified water but cannot be guaranteed — when in doubt, decline.

Know Your Nearest Hospital

Major cities (Bangkok, Singapore, Kuala Lumpur, Ho Chi Minh City, Manila) have excellent private hospitals. Rural areas have very limited care. Research the nearest international-standard private hospital for each destination on your itinerary before you need it. Bangkok is widely regarded as the medical hub of Southeast Asia.

Borneo / Southeast Asia

🇧🇳 Brunei

One of Southeast Asia's wealthiest and lowest-risk destinations. Dengue present year-round. Malaria risk is low and limited to rural forest areas of Temburong district. Excellent private healthcare in Bandar Seri Begawan. Islamic law applies — alcohol restrictions in place. No yellow fever risk.

Indochina

🇰🇭 Cambodia

Dengue is hyperendemic. Drug-resistant malaria in forested border areas — Angkor Wat itself is low risk. Typhoid and hepatitis A very common. Rabies is highly prevalent. Popular destination for Angkor temples — Phnom Penh and Siem Reap have acceptable private hospitals. Scopolamine is unavailable locally — stock your own medications.

Maritime Southeast Asia

🇮🇩 Indonesia

World's largest archipelago — 17,000 islands with highly variable health risk. Bali: dengue and rabies risk, low malaria. Papua and Kalimantan: high malaria. Rabies was reintroduced to Bali in 2008 — PrEP essential for Bali visitors. Schistosomiasis in Sulawesi (Lake Lindu/Napu Valley). Avian influenza present. Jakarta has good private hospitals; remote islands have very limited care.

Indochina / Mekong

🇱🇦 Laos

Malaria risk in forested areas, especially near Thai and Myanmar borders. Vientiane and Luang Prabang are low-risk for malaria but dengue is ever-present. Drug-resistant P. falciparum — only Malarone or doxycycline for malaria-risk areas. Rabies widespread. Japanese encephalitis risk in rural agricultural areas. Very limited healthcare outside Vientiane — medical evacuation to Thailand common.

Maritime Southeast Asia

🇲🇾 Malaysia

Peninsular Malaysia has dengue and typhoid but low malaria risk. Sabah and Sarawak (Borneo) have malaria — including P. knowlesi (monkey malaria), increasingly reported in forested areas. Dengue outbreaks frequently in Kuala Lumpur and urban areas. Excellent private healthcare in KL and Penang. Rabies present particularly in East Malaysia. Yellow fever certificate required if arriving from endemic country.

Indochina / Mekong

🇲🇲 Myanmar (Burma)

High malaria in forested border areas — among the worst drug-resistance hotspots in the world. Dengue year-round. Typhoid and hepatitis A high risk. Rabies endemic. Ongoing civil conflict since 2021 has severely disrupted healthcare and created significant security risks. US State Dept Level 4 (Do Not Travel) for many regions. Check advisories carefully — some areas like Bagan remain more accessible but security situation is volatile.

Maritime Southeast Asia

🇵🇭 Philippines

Dengue is hyperendemic across the archipelago. Rabies is endemic — the Philippines reports hundreds of rabies deaths annually, making PrEP especially important here. Typhoid widespread. Schistosomiasis in specific freshwater areas of Mindanao, Samar, and Leyte. Malaria risk in rural Palawan, Mindanao, and island jungle areas. Manila has good private hospitals. Yellow fever certificate required if arriving from endemic country.

Maritime Southeast Asia

🇸🇬 Singapore

Southeast Asia's safest and most medically developed destination. Malaria-free. Dengue is the primary risk — Singapore reports thousands of cases annually despite world-class mosquito control. World-class hospitals (Singapore General, Mount Elizabeth, Gleneagles) comparable to US standards. Tap water is safe to drink. No yellow fever risk. Excellent gateway city and regional medical hub.

Indochina / Mekong

🇹🇭 Thailand

Southeast Asia's most visited country. Bangkok, Phuket, Chiang Mai, Koh Samui — all dengue-risk. Typhoid and hepatitis A prevalent. Rabies endemic — monkey bites at temples are a real risk. Malaria only at Thai-Myanmar and Thai-Cambodia borders in forested areas — Bangkok and tourist islands are malaria-free. Excellent private hospitals in Bangkok (Bumrungrad, Bangkok Hospital) — regional medical hub. Japanese Encephalitis risk in rural agricultural north.

Maritime Southeast Asia

🇹🇱 Timor-Leste (East Timor)

High malaria risk across the entire country — one of the few Southeast Asian nations where malaria is still widespread in urban areas including Dili. Dengue also present. Typhoid risk high. Yellow fever certificate required if arriving from endemic country. Healthcare is extremely limited — Dili has basic facilities only. Medical evacuation to Darwin, Australia or Bali required for serious illness. Not a common tourist destination — mainly humanitarian workers and adventurous travelers.

Indochina / Mekong

🇻🇳 Vietnam

Dengue is hyperendemic year-round across all regions. Typhoid and hepatitis A are significant risks — Vietnamese street food culture is extraordinary but requires standard precautions. Rabies endemic. Drug-resistant malaria in forested highland border areas — Hanoi, Ho Chi Minh City, Ha Long Bay, and Hoi An are malaria-free. Avian influenza has been reported. Good private hospitals in Hanoi and HCMC. Japanese Encephalitis risk in rural areas.