Early signs of West Nile in Bay Area birds

A Familiar Threat Resurfaces

Two dead crows—one in Newark and another in San Jose—have set off alarms in Northern California, signaling the seasonal return of West Nile virus. These birds were part of routine surveillance programs that monitor the virus before it reaches human populations.

While the disease has circulated in California for years, it primarily thrives in a bird-mosquito cycle, with humans and horses as rare, accidental hosts. Most infections occur when an infected mosquito bites an unsuspecting person.

Why Dead Birds Are a Critical Warning

Dead birds serve as the early red flag in tracking West Nile virus. Mosquitoes contract the virus by feeding on infected birds before spreading it to humans or other animals. Though tests on thousands of mosquito pools have come back negative so far, rising temperatures could accelerate transmission.

How Weather Fuels the Spread

Heavy rains followed by sweltering heat create ideal conditions for mosquitoes to breed. Even a few days of warmth can speed up the process, making mosquitoes infectious faster than anticipated. The primary culprits? Culex mosquitoes, which are most active at night and drawn to stagnant water.

Simple Steps to Stay Protected

Officials urge residents to take preventive measures as summer approaches:

• Eliminate standing water (buckets, plant saucers, clogged gutters)
• Cover up at dusk when mosquitoes are most active
• Use EPA-approved repellent when spending time outdoors

With vigilance, the risk of West Nile virus can be minimized before it escalates.