Dengue is a key Thailand issue. The mosquitoes that spread it bite mainly during the day and are often found in towns and built-up areas, not only jungle settings. Zika risk is also reported, so pregnancy or planned pregnancy needs a careful discussion before travel. Chikungunya can occur too. There is no simple tablet that covers these infections, so repellent, covered skin and accommodation with screens or air conditioning still do a lot of work. Hepatitis A is commonly recommended for previously unvaccinated travellers because it spreads through contaminated food and water. Tetanus should be up to date. Typhoid vaccination may be considered if you are staying longer, eating in lower-hygiene settings or visiting friends and relatives. Hepatitis B is worth discussing for longer stays, sexual exposure, contact sports, medical work, tattoos, piercings or possible medical treatment abroad. Rabies is present in Thailand. Dog bites are the classic concern, but scratches and licks to broken skin also need urgent advice. Pre-travel rabies vaccination is particularly relevant for children, cyclists, runners, animal work, rural travel and longer trips. Japanese encephalitis occurs countrywide, with higher concern for rural areas, especially around rice fields and pig farming areas. Risk tends to peak from May to October, including northern regions such as the Chiang Mai Valley. Malaria risk is low in rural forested border areas with Cambodia, Laos and Myanmar, very low in many other areas, and not considered a risk in Bangkok, Chiang Mai, Chiang Rai, Pattaya, Koh Samui or Koh Phangan. Bite avoidance still applies.