Public Health Investigating Fifth Case of Locally Acquired Dengue

The Los Angeles County Department of Public Health is investigating a new case of locally acquired dengue in a resident of El Monte. The person had no history of travel to areas where dengue is endemic. This case of local transmission does not appear to be related to the cases previously reported by Public Health and is the fifth case of locally acquired dengue reported in LA County this year. LA County is seeing an emergence of locally acquired dengue that is extremely rare for a region where the virus has not previously been transmitted by mosquitoes.

It can take 4-7 days for a person to develop symptoms after being bitten by a mosquito infected with dengue. Persons infected with dengue may have flu-like symptoms including high fever, severe headache, pain behind the eyes, joint and muscle pain, rash, and mild bleeding. Severe dengue can result in shock, severe bleeding and severe organ impairment which require immediate medical attention. Residents who have symptoms of dengue should see their healthcare provider. A blood test is the only way to confirm dengue infection.

Public Health urges healthcare providers to consider dengue in patients with acute febrile illness and test for and report suspect cases of mosquito-borne diseases. Providers should also routinely discuss mosquito bite prevention with patients and travelers.

Everyone in LA County can take proactive steps to reduce mosquito breeding, avoid mosquito bites, and prevent the ongoing local transmission of dengue. This includes:

• Wearing Mosquito Repellent:Mosquito repellents can keep mosquitoes prevent mosquito bites. EPA-registered repellents containing DEET, picaridin, IR3535, 2-undecanone, and oil of lemon eucalyptus are the longest lasting and most effective. They are available as sprays, wipes, and lotions. Consider wearing long-sleeved clothes and pants when outside.
• Keeping mosquitoes out of their homes: Make sure that doors and windows have tight-fitting screens to keep out mosquitoes. Repair or replace screens with tears or holes.
• Preventing mosquito breeding: Eliminate standing water where mosquitoes can lay eggs.
  • Clear standing water in flower pots, saucers, birdbaths and other outdoor containers. Empty items that hold water inside and outside your home once a week. Mosquito eggs only need a thimbleful of water to hatch.
  • Cover water storage containers such as buckets and rain barrels. For containers with no lid, use wire mesh with holes smaller than an adult mosquito.
  • Clean and maintain swimming pools, spas and drain water from pool covers.
  • Throw away old items in your patio or yard that can hold water, e.g., old car tires and children’s toys.
  • Call 2-1-1 or your local vector control agency to report persistent problems to your mosquito control district

Public Health’s first confirmed case of locally acquired dengue was reported Sept. 9. Cases of locally acquired dengue were previously confirmed by Long Beach and Pasadena in fall 2023.