Southern California's Dengue Outbreak Reaches San Bernardino County

According to the California Department of Public Health (CDPH), most dengue cases reported in California involve people infected while traveling abroad. As of early November 2024, CDPH reported a total of 344 dengue cases this year.

However, the mosquitoes that spread dengue (Aedes aegypti and Aedes albopictus) are found in California, especially in So-Cal, where 15 local dengue cases have been reported this year. 

As of November 10, 2024, the San Bernardino County Public Health Department reported a locally acquired dengue case in the city of San Bernardino. 

To the west, the Los Angeles County Department of Public Health recently reported 12 locally acquired dengue cases in the San Gabriel Valley.

To the south, Escondido and Visa reported local dengue cases in San Diego in mid-2024.

Last year, CDPH only reported seven locally acquired cases (Long Beach and Pasadena) in So-Cal.

Muntu Davis, MD, MPH, Los Angeles County Health Officer, recently stated in a press release, “Providers should consider dengue in any patient with fever and signs and symptoms of dengue including headache, eye pain, muscle, bone or joint pain, nausea and vomiting and order testing for dengue regardless of travel history.”

While any local dengue case may indicate a pending outbreak, two areas in the southeastern United States have already confronted travel-related and local case outbreaks.

In Florida, 720 travel-associated and 59 locally acquired dengue cases were confirmed this year.

And dengue has become endemic in Puerto Rico.

Throughout the U.S., the Centers for Disease Control and Prevention (CDC) have reported that 52 jurisdictions have confirmed 7,101 dengue cases as of October 31, 2024.

Furthermore, the Region of the Americas reports its most intense dengue outbreak season ever, with over 12.2 million cases in 2024. Unfortunately, there have been 7,420 dengue-related deaths in the Americas this year.

Since infected mosquitoes can transmit chikungunya, dengue, and zika viruses, the CDC recently issued travel advisories for various countries, such as Brazil and India. The CDC recommends that international travelers protect themselves from mosquito bites and speak with a travel vaccine expert about options at least one month before departure.

In the U.S., the newly approved chikungunya vaccine (IXCHIQ®) is offered at various travel clinics and pharmacies. However, dengue and zika vaccine availability are pending.