Dengue fever cases rise to 6,800 in US amid 2 new infections in Los Angeles: CDC
Eleven cases have been reported in Los Angeles County so far this year.
The total number of dengue fever cases in the U.S. is now more than double the number recorded all of last year, federal data shows.
More than 6,800 cases of dengue have been reported nationally so far this year, according to data from the Centers for Disease Control and Prevention (CDC). Of those cases, more than 4,400 were locally acquired and more than 2,300 are travel associated.
Locally acquired cases mean that those infected have no history of traveling to an area where dengue normally spreads, including tropical and subtropical areas of the world.
The 6,800 figure is more than double the 3,352 dengue cases reported during all of 2023, CDC data shows.
Currently, Puerto Rico makes up the bulk of cases this year with more than 4,200 reported there, according to CDC data. Earlier this year, the territory declared a public health emergency amid a rise in dengue case
Recently, two new locally acquired cases of dengue fever were confirmed by the the Los Angeles County Department of Public Health (DPH). One of the two new cases was identified in an area that has seen continued circulation of dengue due to infected mosquitoes, while the other infected person had no history of recent travel prior to developing symptoms, the DPH said.
The total number of cases reported in Los Angeles County this year now stands at 11.
The CDC issued a health alert warning in June of an increased risk of dengue infections, noting that many countries are reporting higher than usual case numbers.
The federal health agency said there are three reasons behind this year's increase in cases: a warmer, wetter year increasing the mosquito population; more people traveling, especially to areas where dengue is common; and dengue being a cyclical virus, with large outbreaks every few years.
"The uptick in locally transmitted dengue cases across parts of the United States is concerning, as it signals how shifting environmental factors – such as warmer temperatures and increased travel – are creating conditions for mosquitoes to spread in new areas," said Dr. John Brownstein, an epidemiologist and chief innovation officer at Boston Children's Hospital and an ABC News contributor. "While the virus remains rare in much of the U.S., small outbreaks emphasize the need for public awareness and preventive steps to curb further spread."
Dengue viruses are spread through bites from infected Aedes species mosquitoes, mostly found in tropical and subtropical regions, according to the CDC. These mosquitoes are also responsible for spreading Zika and chikungunya viruses.
About one in four people who contract dengue develop symptoms, which usually appear two weeks after being bitten by an infected mosquito. Symptoms typically last two to seven days and are usually mild and may include fever, rash, nausea, vomiting, muscle pain, joint pain and bone pain. Because these symptoms are not specific to dengue, they're often thought to be symptoms of other illnesses, according to the CDC.
About one in 20 infected people will develop severe dengue, which can lead to shock, damage to the body's organs, internal bleeding and even death, although deaths are rare, the CDC said.
There are no disease-specific treatments for dengue. The CDC recommends rest, fluids, and over-the-counter medications to relieve symptoms. Patients with severe illness often need to be hospitalized and receive additional supportive treatments, such as intravenous fluids.
The CDC warns not to take aspirin or ibuprofen if you suspect you may have dengue, because it can trigger inflammation or bleeding of the stomach lining.
A dengue vaccine is available in the U.S. and is approved by the U.S. Food and Drug Administration for children between ages 9 and 16 who have a laboratory-confirmed previous dengue virus infection and who live in areas where dengue is endemic. The vaccine also is available in Puerto Rico and is part of the territory's routine childhood immunization schedule, the CDC said.
Dengue can be caused by dengue virus strains 1, 2, 3 or 4. A person also can be infected with dengue multiple times over the course of their life. The dengue vaccine may be able to help prevent infection from a different strain.
Methods to help prevention dengue infection include using effective mosquito repellents, wearing long-sleeve shirts and long pants when outside, and staying in places with air conditioning, when possible. The CDC also recommends emptying containers of still or stagnant water, to eliminate places where mosquitos can breed.
ABC News' Youri Benadjaoud contributed to this report.