Dengue, a virus transmitted by infected mosquitoes that causes illness in about 1 in 4 infected people, can lead to symptoms ranging from mild fever to shock or death. In an article this month in JAMA, Centers for Disease Control and Prevention researchers in Puerto Rico say the virus must be better controlled in U.S. territories.
Outbreaks have occurred in some states in the past, with the most recent in Florida, Hawaii and Texas. People visiting areas where dengue is common — including some Pacific islands and Central and South America — can also pick up the illness. But the majority of cases in the United States are acquired in U.S. territories.
Between 2010 and 2020, the CDC logged nearly 31,000 dengue cases in U.S. territories. Over 96 percent of these occurred in Puerto Rico, followed by American Samoa, the U.S. Virgin Islands and Guam. Approximately half were among people under age 20.
A dengue vaccine is available but not recommended for children who have not had a prior infection. Despite barriers that include screening and making sure children complete the entire three-dose course of the vaccine, the researchers write, vaccination in Puerto Rico alone could prevent 3,000 hospitalizations in 10 years, and dengue vaccinations in development could help a wider age range or people without a previous infection.
Another potential solution is on the horizon: modifying mosquitoes to prevent dengue transmission. The CDC has authorized the use of genetically modified mosquitoes in some Florida and Texas counties. Elsewhere in the world, researchers have released mosquitoes infected with the Wolbachia bacterium, which reduces transmission of dengue and similar viruses. The United States is also helping to fund a World Health Organization research project in French Polynesia that sterilizes dengue-transmitting mosquitoes with radiation so they cannot produce offspring.