Hantavirus Is in the News. Is It Already in Your Attic?

Here's what I tell every homeowner who calls Sick Building Group when rodent activity turns up during an attic inspection: the cruise ship Hantavirus and the attic Hantavirus are different strains — but the attic version has been killing Americans for decades, and almost nobody talks about it.

Since 1993, the CDC has recorded over 864 confirmed cases of Hantavirus Pulmonary Syndrome (HPS) in the United States. The fatality rate: 30–50%. There is no vaccine. There is no approved treatment. And the most common way people get it is by doing something that feels completely harmless: going into their attic and disturbing what looks like a little dirt and some mouse droppings.

Two Different Viruses. One Thing in Common.

The strain currently in international headlines — Andes virus — is associated with South American rodents and is unusual in that it can spread person-to-person. That is what made the MV Hondius outbreak so alarming to public health authorities and why cases are being traced across multiple countries.

The strain that threatens Georgia homeowners is different: Sin Nombre virus, carried by the deer mouse (Peromyscus maniculatus). It does not spread person-to-person. But it kills at the same rate — and it is already here, in our region, in attics and crawlspaces that haven't been inspected in years.

Both strains share the same transmission pathway: aerosolized rodent waste. Dried urine, droppings, and nesting material shed microscopic virus particles into the air when disturbed. You breathe them in. That is all it takes.

Why Your Attic Is the Real Risk

Most homeowners go into their attic once or twice a year — to grab holiday decorations, to check for a leak, to store something. It feels mundane. But for the deer mouse, your attic is a five-star hotel: warm, undisturbed, packed with nesting material.

Because attics are left alone for months at a time, rodent waste accumulates unseen. As it dries, the virus becomes aerosolized — meaning a single afternoon of cleaning can put you at serious risk. The problem is almost never visible on the surface.

• Urine saturation is invisible. It soaks into insulation and seeps into floor joists, creating a reservoir for the virus that surface cleaning cannot reach.
• Nesting sites go deep into fiberglass or cellulose insulation. Picking up the visible droppings doesn't touch the contamination hidden inside the thermal barrier.
• Cross-contamination travels through pipe penetrations and the ventilation system — spreading from the attic into the living space.

The One Rule That Could Save Your Life

This is the single most common mistake we see. A homeowner spots droppings, grabs a broom, spends 20 minutes cleaning — and has no idea they've just performed the most dangerous possible action. The CDC's own guidance is unambiguous: wet methods, PPE, and professional protocols only.

Know the Symptoms — Don't Mistake It for the Flu

HPS is deadly in part because it mimics the flu in its early stages. Most people don't connect the attic cleaning they did two weeks ago to the symptoms they're experiencing now.

If you've recently been in an attic with visible rodent activity and you develop flu-like symptoms, tell your doctor immediately — and specifically mention the potential rodent exposure. Standard flu tests will not detect HPS. You need to ask for it.

What Professional Decontamination Actually Involves

Decontaminating a rodent-contaminated attic isn't difficult if you have the right protocols. But it is impossible to do safely without them. At Sick Building Group, here's exactly what our process looks like:

The Georgia Context: What You Should Do Right Now

The people currently being monitored in Georgia are associated with the MV Hondius. The Andes strain is not circulating in Atlanta neighborhoods. But this outbreak is a useful reminder that Hantavirus is not hypothetical — it's here, it's been here, and the local strain is already in attics across the Greater Atlanta area.

If you haven't had your attic inspected recently — especially if you've noticed any of the following — now is the time to call:

• Scratching or movement sounds in the attic, especially at night
• Droppings visible on insulation, near vents, or on stored items
• Gnaw marks on wiring, wood, or stored materials
• A faint ammonia or musky odor when you open the attic hatch
• Any family member with persistent respiratory symptoms or unexplained fatigue

You don't need to panic. You do need to be informed. And if there's any question about what's up there, the answer is to call a professional — not to investigate it yourself with a flashlight and a broom.

A Note on the Current Outbreak

The WHO and CDC have both stated clearly that the risk of widespread transmission from the MV Hondius outbreak is considered low. The Andes strain, unlike the Sin Nombre strain, has limited documented person-to-person spread. Health authorities have characterized this as a containable outbreak, not the beginning of a pandemic.

That said, three people are dead. Cases are still being traced. And the outbreak has done something genuinely valuable: it has forced a conversation about a class of diseases that kills a third to half of everyone it infects and has no treatment.

That conversation shouldn't end when the cruise ship news cycle moves on. It should start with the space above your ceiling.