Public Health Encourages Community to Take Action in Preventing Dengue and Other Mosquito-Borne Diseases

PASADENA, Calif. — Pasadena Public Health Department (PPHD) encourages the community to take action in preventing mosquito-borne dengue, after the Centers for Disease Control and Prevention (CDC) issued a health advisory notifying the public about the increased risk of dengue virus in the United States. This year, a higher-than-normal number of cases have been identified in travelers who visited countries where dengue is found.

A person can be infected with the dengue virus from an infected Aedes mosquito, a type of mosquito that inhabits Pasadena. About one in four persons develop mild or severe dengue symptoms including fever, nausea, vomiting, rash, and body aches. Symptoms of dengue typically last two to seven days and although severe and even life-threatening illness can occur, most people recover after about a week. There are no specific medicines or vaccines to prevent this disease. Supportive treatment may include monitoring for early signs of serious illness, drinking fluids, and resting.

Risk of exposure to dengue for Pasadena residents remains low. PPHD recommends standard precautions for preventing all mosquito-borne illnesses, such as dengue, and urges the community to take simple steps to reduce mosquito populations and lower the risk of mosquito-borne diseases including:

  • Eliminating standing water in clogged rain gutters, rain barrels, discarded tires, buckets, watering troughs, and anything that holds water for more than a week.
  • Ensuring that swimming pools, spas, and ponds are properly maintained.
  • Changing the water in pet dishes, birdbaths, and other small containers weekly.
  • Reporting neglected swimming pools in your neighborhood to your vector control district.

To prevent mosquito bites, PPHD recommends the following to residents and individuals traveling internationally to countries that report a higher-than-usual amount of dengue cases:

  • Wear insect repellent containing CDC and EPA-approved active ingredients: DEET®, picaridin, IR3535, or oil of lemon eucalyptus.
  • Wear loosely fitted, light-colored, long-sleeved shirts, and long pants.

In 2023, PPHD announced the first locally-acquired case of dengue in California. After an enhanced community investigation, PPHD discovered a second dengue infection in a Pasadena resident with no recent travel history. Prior to 2023, all reported cases of dengue in Pasadena were acquired while travelling.

San Gabriel Valley Mosquito and Vector Control District conducts routine mosquito control activities in the Pasadena region. To find your local vector district agency and for tips on mosquito prevention and approved mosquito repellents, visit Additional information regarding dengue is available from the California Department of Public Health and the Centers for Disease Control and Prevention.

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