Last 28 Days Positive Samples in California

As part of California's vector control efforts, samples from a variety of sources are regularly tested for the presence of West Nile virus, St. Louis encephalitis and Western equine encephalomyelitis. The map below is provided to illustrate the ongoing efforts to detect and control the these diseases. Use the layer checkboxes below the map to enable or disable the various layers.

Available Layers

Checked layers are visible in the map above.


All map data are updated every 30 minutes. All data coordinates are randomized estimations within half a degree of the true collection site.