Dengue is a disease caused by a virus that is spread through mosquito bites. Dengue is found in at least 100 countries. Within North America, dengue has been found in Mexico, the continental United States, Hawaii, Puerto Rico, and the U.S. Virgin Islands. Dengue virus was recently found locally in Arizona; prior to this, all cases had been travel-related. See current case counts in Maricopa County. To find out if dengue is in an area you are traveling to, see the CDC’s Travelers’ Health page.
Dengue is mainly spread through mosquito bites. Dengue is spread to people primarily through the bite of infected Aedes aegypti mosquitoes. Aedes aegypti mosquitoes are found in Maricopa County and other parts of Arizona; routine mosquito surveillance performed by Maricopa County Environmental Services Department in October 2022 detected the dengue virus in a mosquito trap in one neighborhood in the county. Prior to this, Maricopa County had not detected mosquitoes infected with dengue. In Arizona, dengue infections had been found only in people who were infected while traveling outside the United States. Maricopa County Department of Public Health has recently identified two individuals with dengue who might have been exposed by an infected mosquito in Maricopa County. These mosquitoes bite humans all day long so it is important to protect against mosquito bites whenever you are outside.
Dengue can be spread other ways, too. In rare cases, dengue can be spread during organ transplants or blood transfusions from infected donors, and there is some evidence of spread from an infected pregnant mother to her baby.
Illness in some people. Only 1 out of 4 people with dengue will have symptoms. Generally, younger children and those with their first dengue infection have a milder illness than older children and adults. The symptoms of dengue are high fever, severe headache, severe pain behind the eyes, joint pain, muscle and bone pain, rash, and mild bleeding (e.g., nose or gums bleed, easy bruising). Most individuals recover within 3 to 10 days.
Severe illness in a few people. Some individuals will develop dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS). These are severe and sometimes fatal types of the disease. After 3-7 days of mild symptoms the fever will disappear; at this time, warning signs of severe disease may appear.
- Severe abdominal pain or persistent vomiting
- Red spots or patches on the skin (bruising easily)
- Bleeding from nose or gums
- Vomiting blood
- Dark red or black stools (poop)
- Drowsiness or irritability
- Pale, cold, or clammy skin
- Difficulty breathing
Individuals should see a healthcare provider if they develop the symptoms described above and have visited an area where dengue is found. The provider may order blood tests to look for dengue or other similar viruses like chikungunya and Zika.
Avoid certain medications. Individuals should not take aspirin or ibuprofen as it may increase the risk of bleeding.
Protect yourself while traveling. Travelers can protect themselves by preventing mosquito bites, day and night. If you travel to an area with risk of dengue, use insect repellant containing DEET, wear long sleeves and pants, and stay in places with air conditioning or that use windows and door screens. Use a bed net if air conditioned or screened rooms are not available or if sleeping outdoors.