On Oct. 6, 2024, San Diego County officials announced they were investigating the first ever case of locally acquired dengue. The Escondido resident who became sick with dengue did not travel to an area where the mosquito transmitted illness was common. No additional locally acquired cases had been identified to date. 

To protect the public’s health and keep mosquitoes from potentially spreading the dengue virus, County Vector Control began spraying this weekend for mosquitos at about 170 homes in Escondido. Treatments started on Friday and will continue through Thursday, Oct. 10. 

Dengue is a tropical viral disease that is not commonly found in the United States. Since the invasive Aedes mosquitoes were first detected in San Diego County in 2014, there had been no locally acquired case of dengue until now.  

People who travel to countries where dengue is common can get infected with dengue through mosquito bites. So far this year, there have been 49 cases of travel-related dengue in San Diego County.   The arrival of locally acquired dengue in San Diego County is not a surprise. Los Angeles County recently reported five cases of locally contracted dengue this year. Long Beach and Pasadena had their first cases of locally acquired dengue in late 2023.  

Vector Control did similar treatments in Oceanside in September and in the Mount Hope area of San Diego in July of this year.  Both of those treatments were initiated as a precaution to prevent potential local spread of dengue due to travel-associated dengue cases and the high numbers of Aedes mosquitos in the neighborhoods.