Unclean food and water can cause travelers’ diarrhea, a common illness in travelers. Colds and influenza (flu) are common and are spread through the air or by touching surfaces. Contact with sick people also increases the risk of these and other respiratory tract infections. Insects, like mosquitoes and ticks, and other animals including pets can carry diseases. Examples of serious diseases spread through insect bites include malaria and dengue fever. Rabies is a disease that is almost always fatal and is spread through animal bites and scratches.
Other travel-related health considerations:
Hepatitis A, polio, measles, and typhoid fever are most common outside of the United States but can be prevented by vaccines.
Motor vehicle crashes are a leading cause of death among travelers.
Travelers who become sexually active with a new partner may be at risk of sexually transmitted diseases.
Long-distance travelers are at increased risk of developing blood clots.