Get first dibs

Dengue and Travel: What to Know Before You Go

Dengue is spread by Aedes mosquitoes that bite during the day and at night, across the tropics and subtropics, and the CDC says about 4 billion people live in areas with risk. Before you go, check CDC travel notices, pack an EPA-registered repellent and acetaminophen, and learn the warning signs. Severe dengue is a medical emergency.

Most travelers who pick up dengue never find out: the CDC puts it at about one in four infected people getting sick at all. The ones who do get sick can go from fever to hospital in hours, and the drug most people reach for is the wrong one.

Where is dengue actually a risk?

Broadly, the warm half of the world. The CDC: "Almost half of the world's population, about 4 billion people, live in areas with a risk of dengue." Transmission "is common in tropical and subtropical areas of the world," and outbreaks are reported frequently across the Americas, Africa, the Middle East, Asia, and the Pacific Islands, including popular tourist destinations.

Altitude is the one real qualifier. Mosquitoes that spread dengue "usually live in places below 6,500 feet," and the CDC says the chances of getting dengue above that are very low. Cities are no refuge: the Yellow Book notes "dengue is more of a risk in urban and residential areas than malaria."

The traveler numbers are not small. The Yellow Book reports that during 2010 through 2021, a total of 7,528 travel-related dengue cases were reported in the United States; a total of 3,135 patients required hospitalization, and 19 died. A 2026 paper in the CDC journal Emerging Infectious Diseases notes 3,742 travel-associated cases were reported in 2024, far exceeding the previous peak of 1,474 cases in 2019.

Where dengue runs hot changes month to month, so the CDC keeps a live travel notice. As of the July 2026 update it listed Bolivia, Cambodia, Colombia, Kenya, Malaysia, Maldives, New Caledonia, Samoa, Sri Lanka, Tonga, and Vietnam as countries "reporting higher than usual numbers of cases," or where CDC has found a higher-than-expected number of cases among U.S. travelers returning. The caveat matters: "Not all countries with dengue transmission are on this list."

Why does the daytime-biting pattern change what you do?

If your mosquito habits were built around dusk, dengue breaks them. The CDC states plainly that "Aedes species mosquitoes can bite during the day and night." The WHO: "You can lower your risk of dengue by avoiding mosquito bites, especially during the day." The Yellow Book names the peak as "early morning and late afternoon."

Per the Yellow Book, "almost all DENV transmission occurs through the bite of infected Aedes species mosquitoes, primarily Aedes aegypti and Aedes albopictus." Their living arrangements matter in a hotel room: "While Aedes albopictus mosquitoes live mainly outdoors, Aedes aegypti mosquitoes live indoors and outdoors," often in dark, cool places like closets and bathrooms.

They also do not travel far. The CDC says these mosquitoes "don't fly long distances. In their lifetime, these mosquitoes will only fly a few blocks," and they "typically lay eggs in containers that hold water, like buckets, bowls, animal dishes, flowerpots, and vases." A few blocks of range plus container breeding means the standing water where you are staying counts for more than the swamp across town.

What are the symptoms, and when do they start?

Most infections are quiet. The CDC: "About one in four people infected with dengue will get sick." The Yellow Book estimates 40 to 80 percent of dengue virus infections are asymptomatic.

When illness shows up, fever leads. The CDC lists the most common symptom as fever with any of the following: aches and pains, including eye pain typically behind the eyes and muscle, joint, or bone pain; nausea; vomiting; rash; or any warning sign. Symptoms "usually begin within 2 weeks after being bitten by an infected mosquito," typically last 2 to 7 days, and most people recover after about a week.

Early dengue looks like everything else. The CDC warns "mild symptoms of dengue can be confused with other illnesses that cause fever," and a blood test "is the only way to confirm the diagnosis." To tell an ordinary bite reaction from the start of an illness, see mosquito bite treatment.

What are the warning signs of severe dengue?

Memorize this part before you leave. The CDC: "About 1 in 20 people who get sick with dengue will develop severe dengue. Severe dengue can result in shock, internal bleeding, and death." Note the scope. That is 1 in 20 among people who got sick, not among everyone infected.

The cruel twist is the timing. The CDC says warning signs usually begin in the 24 to 48 hours after the fever has gone away. People feel better and stop watching. The list:

  • Belly pain or tenderness
  • Vomiting, at least 3 times in 24 hours
  • Bleeding from the nose or gums
  • Vomiting blood, or blood in the stool
  • Feeling extremely tired or restless

Any of those means go now: "Immediately go to a local clinic or emergency room." And: "Symptoms of dengue can become severe within a few hours. Severe dengue is a medical emergency." The CDC's travel notice says severe cases can involve "hemorrhage (uncontrolled bleeding), shock (seriously low blood pressure), organ failure, and death."

Repeat travelers should not get complacent. There are four dengue viruses, and infection with one "confers long-term immunity to that virus but only short-lived protection against the other three." The Yellow Book: "the risk for severe dengue is greater during a second DENV infection, but severe dengue also can occur during the first or any subsequent infection."

Why are ibuprofen and aspirin avoided when dengue is suspected?

Because dengue can cause bleeding, and those drugs make bleeding worse. The WHO: "Non-steroidal anti-inflammatory medicines such as ibuprofen and aspirin should be avoided as they can increase the risk of bleeding." The Yellow Book tells clinicians to advise ambulatory patients "to avoid medications with anticoagulant properties, including aspirin (acetylsalicylic acid), aspirin-containing drugs, and other nonsteroidal anti-inflammatory drugs (e.g., ibuprofen)."

The CDC's public guidance is blunt: "Take acetaminophen (also known as paracetamol outside of the US) to control fever and relieve pain. Do not take aspirin or ibuprofen!" Which is why it tells travelers to pack acetaminophen, since "these medications can be used to manage fever and body pain in case you get dengue." CDC guidance for West Nile virus carries the same caution for anyone living in an area with dengue. Ask a clinician rather than self-medicating abroad.

What does the CDC recommend before, during, and after a trip?

Before your trip. Review country-specific travel recommendations, health notices, and warnings. Visit a travel clinic or your healthcare provider. Pack an Environmental Protection Agency registered insect repellent and acetaminophen.

During your stay. "Stay in places with air conditioning and with window/door screens." "Use a bed net if air conditioned or screened rooms are not available or if sleeping outdoors." Wear long-sleeved shirts and long pants outdoors. See a healthcare provider if you develop a fever or symptoms of dengue.

After your trip. The step travelers skip. The CDC: "Even if you do not feel sick, travelers returning from an area with risk of dengue should take steps to prevent mosquito bites for 3 weeks so they do not spread dengue to mosquitoes that could spread the virus to other people."

On repellents, the CDC lists six active ingredients in EPA-registered products: DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, and 2-undecanone. It tells people to "look for an EPA registration number (EPA Reg. No.) on the insect repellent product label." The EPA is explicit: "EPA and the U.S. Government do not endorse any product or service." CDC travel guidance adds 0.5 percent permethrin for clothing and gear, never on skin.

Is there a dengue vaccine for travelers?

Not for U.S. travelers. The CDC Yellow Book: "There are currently no dengue vaccines recommended for travelers in the United States." The only dengue vaccine currently available in the United States is recommended for children 9 through 16 with laboratory confirmation of a previous dengue infection who live in areas where dengue is common, and the CDC carries a notice that the manufacturer is discontinuing it. For everyone else: "The vaccine is not approved for use in U.S. travelers who are visiting but not living in an area where dengue is common."

What if you get sick after you get home?

Tell whoever sees you where you have been. The Yellow Book instructs clinicians to consider dengue in patients who develop symptoms within 14 days of returning from an endemic area. Then protect the people around you. The CDC: "During the first week of illness, dengue can be found in the blood. The virus can be passed from an infected person to a mosquito through mosquito bites."

That is not theoretical. The CDC reports most dengue cases in the 49 continental U.S. states occur in travelers infected elsewhere, but that "limited local spread of dengue has been reported in Florida, Hawaii, Texas, Arizona, and California." For mild illness its advice is rest, acetaminophen, and fluids. Decisions about testing or treatment belong with your clinician.

Where Longsleeve fits

Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients.

Common questions

What are the odds of getting seriously ill from dengue?

The CDC says about one in four people infected with dengue will get sick, and about 1 in 20 people who get sick will develop severe dengue. That second number applies to people who became ill, not to everyone infected. Severe dengue can result in shock, internal bleeding, and death.

When during the illness does dengue get dangerous?

Usually right after you start feeling better. The CDC says warning signs typically begin in the 24 to 48 hours after the fever has gone away. Belly pain, repeated vomiting, bleeding from the nose or gums, blood in vomit or stool, or extreme tiredness or restlessness all mean go to a clinic or emergency room now.

Can I take ibuprofen for the aches?

Not if dengue is suspected. The CDC says to take acetaminophen, also known as paracetamol outside the United States, and not to take aspirin or ibuprofen. The WHO explains why: NSAIDs such as ibuprofen and aspirin can increase the risk of bleeding. Ask a clinician before taking anything.

Do I need to do anything after I get home?

Yes. The CDC says travelers returning from an area with risk of dengue should prevent mosquito bites for 3 weeks, even if they feel fine, so they do not pass the virus to local mosquitoes.

Sources

  1. CDC, About Dengue. https://www.cdc.gov/dengue/about/index.html
  2. CDC, Symptoms of Dengue and Testing. https://www.cdc.gov/dengue/signs-symptoms/index.html
  3. CDC, How Dengue Spreads. https://www.cdc.gov/dengue/transmission/index.html
  4. CDC, Preventing Dengue. https://www.cdc.gov/dengue/prevention/index.html
  5. CDC, Manage Dengue. https://www.cdc.gov/dengue/treatment/index.html
  6. CDC, Areas with Risk of Dengue. https://www.cdc.gov/dengue/areas-with-risk/index.html
  7. CDC, Data and Statistics on Dengue in the United States. https://www.cdc.gov/dengue/data-research/facts-stats/index.html
  8. CDC, About a Dengue Vaccine. https://www.cdc.gov/dengue/vaccine/index.html
  9. CDC Yellow Book, Dengue. https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/dengue.html
  10. CDC Travelers' Health, Global Dengue travel health notice. https://wwwnc.cdc.gov/travel/notices/level1/dengue-global
  11. CDC Travelers' Health, Avoid Bug Bites. https://wwwnc.cdc.gov/travel/page/avoid-bug-bites
  12. CDC, Preventing Mosquito Bites. https://www.cdc.gov/mosquitoes/prevention/index.html
  13. CDC, Life Cycle of Aedes Mosquitoes. https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html
  14. CDC, About West Nile. https://www.cdc.gov/west-nile-virus/about/index.html
  15. Rysava K, Madewell ZJ, Thayer MB, et al. Using Routine Surveillance Data to Assess Dengue Virus Transmission Risk in Travelers Returning to the United States. Emerging Infectious Diseases, 2026;32(2). https://wwwnc.cdc.gov/eid/article/32/2/25-1217_article
  16. WHO, Dengue and severe dengue fact sheet. https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue
  17. EPA, Find the Repellent that is Right for You. https://www.epa.gov/insect-repellents/find-repellent-right-you

Last reviewed 2026-08-06 · every claim on this page is sourced above