Health authorities warned that the Los Angeles area is experiencing more cases of dengue in people who have not traveled outside the continental United States, a year after the first such case was reported in California.
Public health officials said at least three people apparently became ill with dengue fever after being bitten by mosquitoes in the Baldwin Park neighborhood, east of downtown Los Angeles.
“This is an unprecedented cluster of locally acquired dengue cases in a region where dengue has not previously been transmitted by mosquitoes,” said Barbara Ferrer, director of the Los Angeles County Department of Public Health.
This 2024, other cases resulting from mosquito bites originating in the United States have been recorded in Florida, the United States Virgin Islands and Puerto Rico, where The authorities have declared a dengue epidemic. In 2024 there have been 3,085 such cases in the United States, of which 96% occurred in Puerto Rico, according to the United States Centers for Disease Control and Prevention.
Dengue cases have increased globally as climate change brings warmer weather allowing mosquitoes to expand their range.
Dengue fever is commonly spread through the bite of infected Aedes mosquitoes in tropical areas. While Aedes mosquitoes are common in Los Angeles County, local infections were not confirmed until 2023, when cases were reported in Pasadena and Long Beach.
Before that, all cases in California were associated with people traveling to a region where dengue commonly spreads, such as Latin America, said Aiman Halai, director of the department’s Vector-Borne Diseases Unit.
So far this year, 82 cases of this type have been reported in Los Angeles County by people returning from travel, Halai said. Across California, there have been 148 cases.
Dengue can cause high fever, rashes, headaches, nausea, vomiting, muscle pain, and bone and joint pain. About one in four infected people will have symptoms, which usually appear five to seven days after the bite of a mosquito dengue carrier. One in 20 people with symptoms will develop severe dengue, which can cause severe bleeding and be life-threatening.
Public health officials will conduct outreach activities in homes located within 492 feet of the homes of people who have been stung. That is the typical flight range of the mosquitoes that transmit the virus, according to Ferrer.
Ferrer recommended to the population use insect repellent and eliminate standing water around your homes where mosquitoes can breed.
Authorities have been testing mosquitoes for the disease and so far have not found any with dengue in the San Gabriel Valley.
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