Hantavirus symptoms every Iowa homeowner should know

Hantavirus Pulmonary Syndrome is rare, but it kills roughly 1 in 3 people who get it — and the early symptoms look exactly like the flu. If you've been cleaning out a barn, cabin, or shed in Iowa, here's what to watch for.

Hantavirus has been back in the news after several high-profile cases, and we've gotten a wave of calls from Iowa homeowners asking the same question: what are the symptoms, and how would I even know? Here's the honest breakdown — not from WebMD, but from what the CDC and state health departments actually publish.

The incubation period: 1 to 8 weeks

After exposure to deer mouse urine, droppings, or nesting material, symptoms typically start anywhere from 1 to 8 weeks later. Most people get sick around weeks 2–3. That's a long enough window that most people don't connect 'I cleaned out the barn last month' with 'I feel terrible today,' which is exactly why hantavirus gets misdiagnosed early.

Early symptoms (days 1–5)

• Fever, often 101°F or higher
• Severe muscle aches — especially the thighs, hips, back, and shoulders
• Fatigue significantly worse than a normal flu
• Headache
• Chills
• Sometimes nausea, vomiting, abdominal pain, or diarrhea

At this stage hantavirus looks identical to influenza or COVID. There is no test routinely run unless your doctor knows to ask about rodent exposure — which is why telling them matters.

Late symptoms (days 4–10): the dangerous phase

• Coughing
• Shortness of breath, even at rest
• A feeling like a pillow is being pressed over your face
• Rapid breathing or rapid heart rate
• Fluid filling the lungs (pulmonary edema)

Why Iowa is a real exposure risk

The deer mouse is the primary hantavirus carrier in the U.S., and deer mice are extremely common in rural Iowa — barns, sheds, grain bins, hunting cabins, acreage homes, detached garages. House mice (the gray ones in city homes) are not a meaningful hantavirus risk, but if you're in the country and you have brown mice with white bellies and big ears, you have deer mice.

What to do if you think you've been exposed

• Don't panic — exposure does not equal infection. Most exposures don't result in disease.
• Watch for fever and severe muscle aches over the following 1–8 weeks.
• If symptoms appear, go to the ER and specifically tell them you were exposed to mouse droppings.
• Get the mouse problem dealt with so it doesn't happen again.

Mortality rate: why this matters

Hantavirus Pulmonary Syndrome has a case fatality rate of roughly 38%. That's not a number to scare anyone — confirmed cases are rare in Iowa — but it's the reason 'wait and see' is the wrong answer. The treatment is supportive (oxygen, fluid management, sometimes ECMO), and it works much better when started early.