The U.S. Centers for Disease Control and Prevention (CDP) has issued a travel alert warning about the risk of "breakbone fever", more commonly known as dengue fever. The alert was issued as travelers returning from countries that have tested positive for the disease are returning from abroad. Most cases of dève occur in the US, where there have been 496 cases so far this year. The CDC warns that severe cases of the disease can be life-threatening within a few hours.