Food and waterborne diseases are the number one cause of illness in travelers. Travelers' diarrhea can be caused by viruses, bacteria, or parasites, which are found throughout the region and can contaminate food or water. Make sure your food and drinking water are safe.
Malaria is a preventable infection that can be fatal if left untreated.
For additional information on malaria risk and prevention, see Malaria Information for Travelers to Southeast Asia . A certificate of yellow fever vaccination may be required for entry into certain of these countries if you are coming from a country in tropical South America or sub-Saharan Africa. For detailed information, see Comprehensive Yellow Fever Vaccination Requirements . Dengue , filariasis , Japanese encephalitis , and plague are diseases carried by insects that also occur in this region. Because motor vehicle crashes are a leading cause of injury among travelers, walk and drive defensively.