As of late September 2026, the garage of my Riverside ranch house holds the patio cushions, the potting soil, the boxes nobody opens, and now and then a little scatter of mouse droppings on the concrete. For years I handled that like any other dirt: broom, dustpan, trash can, thirty seconds, done. It was the fastest way to make it disappear, and fast felt like clean.
Riverside County’s Department of Environmental Health doesn’t treat it as dirt. Its rodent page says hantavirus has been detected in deer mice throughout the county, and that the only rodent in California known to transmit the virus is the deer mouse. It calls hantavirus pulmonary syndrome “a rare, but frequently fatal, illness caused by a virus shed by deer mice.” It also says only one human case has been reported in the county so far. Rare is the part I always remembered. Frequently fatal is the part I skipped.
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What California’s Department of Public Health says
Here in California, the state health department’s hantavirus page is direct about the broom: “do not sweep or vacuum the area. This can stir up droppings or other materials contaminated with hantavirus into the air.”…