On Oct. 15 the Los Angeles County Dept. of Public Health, in collaboration with San Gabriel Valley Mosquito and Vector Control District, stated it was investigating further local spread of dengue virus infection in Baldwin Park. Two additional cases of locally acquired dengue have been identified, bringing the total to five cases concentrated in this area of the County. These new cases have no history of travel to areas where dengue is typically found.

This small local outbreak raises concern about the continued spread of dengue in Baldwin Park due to infected mosquitoes and the potential for spread to other areas of Los Angeles County as people travel throughout the County. It is essential for people living and working in Baldwin Park and other areas where a case of dengue has been identified to prioritize mosquito control and prevention measures to reduce the risk of spread.

Dengue spreads through the bite of infected Aedes mosquitoes, particularly Aedes aegypti and Aedes albopictus. Sustained spread of dengue in a neighborhood occurs when infected mosquitoes bite and spread dengue to people who are then bitten by other mosquitoes. Those mosquitoes become infected and continue the cycle.

Aedes mosquitoes are most active during the daytime. Their peak biting (feeding) times are generally early in the morning (around dawn, just after sunrise) and late afternoon (just after sunset when the sky begins to darken).

Taking proactive measures and the cooperation of the community in these areas are vital for addressing this issue. Residents and businesses are strongly encouraged to take advantage of free vector control services including inspection and abatement of mosquito breeding sites at their homes. This is essential to helping identify and reduce the risk of further local spread of dengue.

About one in four people infected have symptoms of the infection, which can range from mild to severe. Symptoms of dengue may appear two to seven days after being bitten by an infected mosquito. Persons infected with dengue may be asymptomatic or experience flu-like symptoms, such as a fever, followed by severe headache, pain behind the eyes, joint and muscle pain, rash and, possibly, mild bleeding. In severe cases, dengue can lead to severe bleeding and shock and a severe drop in blood pressure that can lead to organ failure, which requires immediate medical care. Residents experiencing symptoms should see their healthcare provider as a blood test is needed to confirm dengue infection.

Public Health continues to work closely with vector control districts on enhanced surveillance and active engagement with the community to help with mosquito control.

To prevent mosquito breeding:

• Eliminate standing water where mosquitoes can lay eggs.
• Clear standing water in flowerpots, 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 the patio or yard that can hold water; e.g., old car tires and children’s toys. Call 2-1-1 or the local vector control agency to report persistent problems.

This year, there have now been eight cases of locally acquired dengue reported in LA County. Panorama City and El Monte have each seen one and two cases respectively suggesting the virus has infected the local mosquito population in those cities. So far, none of these people have developed severe disease. 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 departments of health in fall 2023.

There are no antiviral medicines approved to treat dengue. Treatment is supportive and may require carefully managing fluid levels.

For questions or to find a nearby clinic or doctor, call the Public Health InfoLine at (833) 540-0473, open every day from 8 a.m. to 8 p.m.