Hantavirus: What the CDC Actually Says (and What to Do About It)

Hantavirus is rare, serious, and surrounded by bad information. Here's what the CDC actually says in plain English, plus the prevention steps that genuinely matter.

Orthohantavirus is rare in North America — about 30–50 cases per year in the US. When it strikes, it's serious: Hantavirus Pulmonary Syndrome has a 30–40% mortality rate. This isn't something to panic about; it is something to prevent intelligently if you live or recreate in affected areas.

How it spreads

Aerosolized rodent waste. The virus lives in deer mice in the western US. People get infected when they disturb dust contaminated with rodent urine, feces, or saliva — typically in cabins, sheds, basements, or abandoned structures that mice have nested in. It is not spread person-to-person in North America (the South American variant is different).

Symptoms to know

One to eight weeks after exposure: fever, fatigue, muscle aches. Days four to ten: severe shortness of breath, cough. If you have known rodent exposure and develop these symptoms, get to an ER immediately. Time to treatment matters significantly.

Prevention that actually works

Seal entry points larger than 1/4 inch in any structure you spend time in — steel wool plus caulk. Mice get through smaller gaps than most people expect. Don't dry-sweep or vacuum mouse droppings; the aerosol risk is real. Use a 1:10 bleach solution, let it sit five minutes, then wipe with paper towels while wearing an N95. Air out closed structures before working inside — open windows and doors, leave for 30 minutes. Store food in sealed containers; mice that can't find food in your structure don't stay.

For backcountry users

Don't pitch tents on rodent-active sites with visible burrows or droppings. A hard-sided cooler keeps food sealed from rodents in camp. A water bottle with a sealed lid for drinking water.

For rural homeowners

Rodent-proof the foundation perimeter. Snap traps work better than glue traps and are significantly cheaper than electronic devices. Check sheds and outbuildings monthly during fall and winter.

What to skip

Ultrasonic rodent repellers — the research is consistent: they stop working within one to two weeks as rodents habituate. "Natural" repellents like peppermint oil have limited evidence, and mothballs are a household-pet hazard on top of being unreliable.

Hantavirus is rare enough that it shouldn't change how you live. It's serious enough that if you spend time in cabins or recreate in affected regions, a 30-minute prevention routine is worth doing. The CDC's hantavirus page is the authoritative source — ignore most other coverage you'll find.