Fifth Locally Acquired Dengue Case Confirmed in Los Angeles County

Los Angeles County health officials said on Wednesday, Oct. 2, that they are investigating a fifth locally acquired case of dengue, a mosquito-borne illness. The latest patient is a resident of El Monte.

According to the county Department of Public Health, the new case does not appear to be connected to the four infections reported earlier. Officials again emphasized that locally acquired cases are extremely rare in areas where mosquitoes have not previously spread the virus.

The county earlier reported a cluster of three infections in the Baldwin Park area. Last week, a fourth case was confirmed in a resident of Panorama City. Health officials described the series of local cases as "unprecedented." None of the patients had a history of travel to places where dengue is endemic.

Local transmission has been seen in the region before, though only in isolated instances. In October and November of last year, health officials confirmed single locally acquired cases in Pasadena and Long Beach.

"This case further indicates that dengue can spread in our community," said Dr. Muntu Davis, the county health officer, in a statement on Wednesday. He added that preventing mosquito bites and mosquito breeding is the best way to stop local transmission, noting that mosquitoes thrive in hot weather, which raises the risk of bites and mosquito-borne diseases.

Davis urged residents to use insect repellent, remove standing water that can attract mosquitoes, and install or repair window screens to keep the insects out of homes.

Dengue is generally spread through the bite of an infected Aedes mosquito. Most people who are infected never show symptoms, but about one in four will develop signs such as fever, nausea, vomiting, rash, and aches and pains in the eyes, joints or bones.

Symptoms usually last no more than a week, and most people fully recover within two weeks. Health officials said deaths from the virus are extremely rare.

Because dengue symptoms often resemble those of other viruses, officials asked healthcare providers to be "vigilant for dengue fever in patients with acute febrile illness and test for and report such cases of mosquito-borne diseases."