Dengue Fever Is Rising in the US. Should You Be Concerned About Your Mosquito Bites?

Mosquito bites are never a good thing, but it's more important than ever to stay protected from the creepy crawlers. The Centers for Disease Control and Prevention (CDC) recently issued a health advisory after the Americas had a record-breaking number of dengue fever cases spread by mosquitoes, with more than 9.7 million infections seen in 2024.

The increase in dengue fever cases is likely due in part to a global temperature increase, which allows mosquitoes to breed all year long, says Sharon Welbel, MD, a board-certified infectious disease physician at Cook County Health. "Hotter temperatures may cause the viruses to replicate faster, therefore making it more likely that a person could be bitten by an infected mosquito," she explains.

People who live and/or travel to tropical and subtropical regions of the Caribbean, Central America, South America, and Southeast Asia, are at the highest risk of getting infected with dengue fever, says Carla Garcia Carreno, MD, a board-certified pediatric infectious disease specialist and chief of infectious diseases at Children's Health Plano. In addition, infants, pregnant people, adults over 65 years old, and people with weakened immune systems are more vulnerable to severe dengue fever, she explains.

That said, the CDC reports that a "higher-than-expected number of cases have been identified among U.S. travelers," so it's important to know what causes dengue fever in the first place. With cases on the rise and summer travel in full swing, doctors break down everything you need to know about dengue fever and how to best stay protected.

Carla Garcia Carreno, MD, is a board-certified pediatric infectious disease specialist and chief of infectious diseases at Children's Health Plano.

Sharon Welbel, MD, is a board-certified infectious disease physician at Cook County Health.

Laura Purdy, MD, is a board-certified family medicine physician and founder of Swell Medical.

Nikhil Bhayani, MD, is a board-certified infectious disease physician and assistant professor at Burnett School of Medicine at Texas Christian University.

Dengue fever is a viral infection that spreads from the bite of an infected mosquito, says Nikhil Bhayani, MD, a board-certified infectious disease physician and assistant professor at Burnett School of Medicine at Texas Christian University. The virus is most commonly found in tropical and subtropical regions and can cause flu-like symptoms lasting between two to seven days, he says. According to the World Health Organization (WHO), roughly half of the world's population is now at risk.

Dengue fever is a viral disease transmitted through the bite of infected mosquitoes of the Aedes species, Dr. Welbel says. More specifically, dengue fever is caused by any one of four types of dengue viruses (DENV 1 - 4), she says.

You cannot get dengue fever from being around an infected person (AKA it is not contagious), and it's rarely transmitted from mother to baby during pregnancy, or through blood and organ donation, Dr. Carreno says. Instead, a mosquito becomes infected by feeding on a person who has dengue fever. If that infected mosquito then bites you, it transmits the virus, causing you to become sick and potentially experience symptoms, says Laura Purdy, MD, a board-certified family medicine physician and founder of Swell Medical.

Dengue fever can be asymptomatic, but many cases present with mild to severe illness, Dr. Carreno says. The following flu-like symptoms typically occur within three to 14 days after exposure, lasting between two to seven days, according to Dr. Carreno and Dr. Welbel.

The key to preventing dengue fever is to protect yourself against mosquito bites, especially when traveling to an area with high dengue transmission like the Caribbean, Central America, South American, Southeast Asia, Pacific Islands, or the southern United States (particularly Texas, Hawaii, Florida, Arizona, and parts of California), Dr. Welbel says.

Proper measures include using U.S Environmental Protection Agency (EPA)-approved mosquito repellent and wearing long sleeves, pants, and socks. Using mosquito nets over strollers, baby carriers, and beds is also recommended. Dr. Carreno suggests avoiding areas with stagnant water, too.

Unfortunately, there is no specific antiviral medication for dengue fever, so treatment consists of supportive care that includes hydration, rest, fever control, and pain management, Dr. Purdy says. However, you should not use Aspirin or aspirin-related products like ibuprofen or Advil as it may increase the risk of internal bleeding, Dr. Carreno adds. Instead, you should only treat fever and pain with acetaminophen, like Tylenol, per the Cleveland Clinic.

Symptoms typically subside within a week, but severe dengue occurs in one in 20 people, most commonly seen in infants, pregnant people, adults older than 65 years old, and those who are immunocompromised, Dr. Carreno says. As a result, if you have traveled abroad and present symptoms (specifically if symptoms start within 14 days from arrival), it's best to visit your doctor ASAP for a proper diagnosis, she says.

Additionally, if you experience abdominal pain, persistent vomiting, body swelling, difficulty breathing, or changes in your mental status, visit a doctor for immediate care, Dr. Carreno says. From there, a healthcare provider will order a blood test to diagnose dengue fever and/or rule out additional infections.

Andi Breitowich is a Chicago-based freelance writer and graduate from Emory University and Northwestern University's Medill School of Journalism. Her work has appeared in PS, Women's Health, Cosmopolitan, and elsewhere.