CDC Issues Level 1 Dengue Alert for 16 Countries

The U.S. Centers for Disease Control and Prevention has issued a Level 1 travel health notice for 16 countries where cases of dengue fever, a mosquito-borne viral illness, have increased beyond expected levels. The advisory, released this week, highlights a higher-than-usual number of infections among American travelers returning from destinations including Colombia, Cuba, Bangladesh, Pakistan, the Maldives, and several Pacific island nations such as the Cook Islands. Officials urge visitors to these tropical and subtropical areas to take standard precautions against mosquito bites.

Dengue, caused by one of four related virus serotypes transmitted by infected Aedes mosquitoes, poses a year-round risk in many parts of the world, with outbreaks often occurring every two to five years. The disease is prevalent in regions across the Americas, Africa, the Middle East, Asia, and the Pacific Islands. While about one in four infected individuals develops symptoms, most cases are mild and resolve within two to seven days. Common signs include high fever, severe headache, pain behind the eyes, muscle and joint aches, nausea, vomiting, and rash.

In severe cases, which affect roughly one in...