Risky trips: All tropical and many subtropical vacations. Most countries in Latin America, as well as some parts of the Caribbean, like Puerto Rico, are home to the infected mosquito that transmits the disease. Even Key West, FL, has seen episodes.
Vital signs: The tricky part about evading the dengue virus is that there is no vaccine—all you can do is avoid the skeeter, especially during dusk and dawn hours in hot, wet weather. A few precautions, however, should help: Always stay in rooms with protective screens and mosquito nets, and, after applying sunscreen, cover yourself in insect repellant with DEET, picaridin, or oil of lemon eucalyptus. And when taking outdoors treks, double your mosquito barrier by wearing loose, long-sleeved shirts and long pants. Symptoms won’t likely occur until a week or two after your return, so see your doctor if you experience sudden fever, extreme headaches, and severe muscle and joint pain post-tropical vacation. (Keep in mind that other diseases, like malaria, can mimic dengue fever symptoms too.)