Southern California sees surge in West Nile‑carrying mosquitoes

Mosquito activity has risen sharply across Southern California as summer approaches, prompting public‑health officials to warn of an increased risk of West Nile virus. The California Department of Public Health reports that infected Culex quinquefasciatus mosquitoes have been found in numbers usually seen later in the season, and two human cases have already been confirmed this summer – one in the Antelope Valley and another in Long Beach. At the same time, populations of the invasive Aedes aegypti, capable of transmitting dengue, Zika and yellow fever, are expanding rapidly.

In response, local vector‑control agencies are releasing millions of genetically modified mosquitoes to suppress the overall mosquito population. Health officials emphasize that while most infections are asymptomatic, severe cases can cause brain inflammation and paralysis, especially among older adults and those with pre‑existing conditions. No vaccine or specific treatment exists for West Nile virus, underscoring the importance of mosquito‑reduction measures.

The heightened mosquito presence is expected to continue from May through late fall, increasing the likelihood of additional human cases as the season progresses.