Which Mice Carry Hantavirus?

If you've spotted a mouse in your kitchen, your first thought might be "is this one of the dangerous ones?" The honest answer is more nuanced than yes or no. Different rodents carry different hantaviruses, and the species you're most likely to encounter at home is probably not the one that carries Sin Nombre virus — but you should still treat any mouse infestation seriously.

Here's what the research says about which mice carry hantavirus, what percentage are infected, and how mice spread it among themselves.

Do all mice carry hantavirus?

No — not all mice carry hantavirus.

The common house mouse (Mus musculus) — the small grey-brown mouse you typically find in kitchens, especially in cities — is not a known reservoir for Sin Nombre virus or any of the hantaviruses that cause Hantavirus Pulmonary Syndrome. House mice are still pests, can carry other pathogens (salmonella, leptospira, lymphocytic choriomeningitis virus), and shouldn't share your living space, but they're not the main hantavirus concern in North America.

The mice that matter for hantavirus in the Americas are mainly deer mice and their relatives in the genus Peromyscus — wild mice that look quite different from house mice once you know what to look for.

What mice carry hantavirus?

The main hantavirus-carrying rodents in North America are:

• Deer mouse (Peromyscus maniculatus) — the principal reservoir for Sin Nombre virus, the cause of most HPS cases in the U.S. and Canada. Range covers most of the continent except the southeastern U.S.
• White-footed mouse (Peromyscus leucopus) — reservoir for New York virus. Common in the eastern U.S.
• Cotton rat (Sigmodon hispidus) — reservoir for Black Creek Canal virus. Found in the southeastern U.S.
• Rice rat (Oryzomys palustris) — reservoir for Bayou virus. Found mainly along the Gulf Coast.

In other parts of the world, the picture changes:

• Long-tailed pygmy rice rat (Oligoryzomys longicaudatus) — Andes virus, southern Argentina and Chile.
• Striped field mouse (Apodemus agrarius) — Hantaan virus, East Asia.
• Brown rat (Rattus norvegicus) — Seoul virus, found globally wherever brown rats live, including North American cities.
• Bank vole (Myodes glareolus) — Puumala virus, Northern Europe.

The common thread: each hantavirus has a specific rodent host species, and the geographic range of the disease tracks the range of its host.

How to tell a deer mouse from a house mouse

Deer mice are easy to distinguish once you know what to look for:

• Two-tone coloring: brownish or reddish-grey on top, sharply white on the belly, feet, and underside of the tail. House mice are uniformly grey-brown.
• Larger eyes and ears, set on a more pointed face.
• Long tail with a distinct dark-on-top, light-on-bottom split.
• Habitat: deer mice prefer rural and semi-rural environments — barns, sheds, woodpiles, cabins, basements of homes near fields or forests. House mice prefer dense human habitation.

If you're in a rural or suburban area with a mouse problem and the mice have white bellies, you're probably looking at deer mice — and you should follow safe cleanup procedures from the start.

What percentage of mice carry hantavirus?

There's no single number, because infection prevalence varies wildly by:

• Species (deer mice carry Sin Nombre at higher rates than other Peromyscus species carry other hantaviruses)
• Region (some local populations are heavily infected, others have almost no detectable virus)
• Year and season (population booms drive transmission spikes)
• Age and sex (older male mice tend to have higher infection rates due to fight-related saliva exchange)

That said, here's the rough range from published surveillance:

• Deer mice and Sin Nombre virus: typically 10–20% of deer mice carry the virus in surveyed Western U.S. populations, though local hot spots have shown infection rates of 30% or higher. Some northern and Canadian populations are much lower.
• White-footed mice and New York virus: generally lower prevalence, often under 10%.
• All mice combined (counting house mice and other non-reservoir species): the percentage of mice that carry hantavirus, including rodents that don't carry it at all, comes out much lower — well under 10%.

So when people ask "what percentage of deer mice carry hantavirus?" the honest answer is roughly 10–20% on average, with significant local variation. A useful mental model: in any given deer-mouse-infested space, assume some of the mice are infected, and clean accordingly.

Do all deer mice carry hantavirus?

No. Most deer mice in any given population are not carrying Sin Nombre virus at any given moment. But because:

1. The infected ones look identical to the uninfected ones, and
2. Infected mice shed virus in saliva, urine, and droppings throughout their lives,

…the practical assumption when cleaning up after deer mice is to treat all droppings as if they could be from an infected mouse. The math works out: even at 10% prevalence, a colony of 30 deer mice in a cabin likely includes 2–4 carriers.

How common is hantavirus in mice overall?

Across all mouse species in North America, hantavirus prevalence is low — most mice don't carry it. But within the reservoir species (especially deer mice in their core range across the western and central U.S. and southern Canada), it's widespread enough that any rodent infestation should be approached with caution.

A few useful facts for context:

• Deer mice are one of the most abundant mammals in North America, with population estimates in the hundreds of millions.
• Sin Nombre virus has been detected in deer mice in every U.S. state except Alaska, Florida, Georgia, and Hawaii (and Hawaii has no native deer mice).
• Population booms — driven by mild winters, abundant pinyon nuts, or El Niño-driven wet years — are followed by HPS case spikes 6–12 months later.

How do mice get hantavirus?

Mice catch hantavirus from each other, primarily through bites and scratches during fights. The virus is shed in saliva, urine, and droppings, and infected mice deposit virus throughout their territory. Other mice pick it up by:

• Aggressive encounters — bites, especially among adult males competing over territory or mates
• Grooming and close contact within nests
• Inhaling aerosolized virus from contaminated nesting material

This is why infection rates correlate with mouse density and with the proportion of older male mice — both indicators of an actively breeding, territorial population.

Importantly, hantavirus does not appear to make the mouse sick. Hantaviruses have co-evolved with their rodent hosts over millions of years, and the rodent essentially serves as a permanent, asymptomatic carrier. The virus only causes disease when it crosses into a host it didn't evolve in — like us.

What this means for your home

The practical takeaway:

• If you live in an area with deer mice (most of North America), assume any rodent infestation could include hantavirus carriers.
• The single most important rule is don't sweep or vacuum dry droppings. Wet them down with a 1:10 bleach solution first, wait 5 minutes, then wipe up.
• Seal entry points — caulk, steel wool, hardware cloth — to prevent reinfestation. This is the single most effective long-term prevention.
• Trap aggressively and dispose of trapped mice in sealed bags after spraying with disinfectant.

For more detail on safe cleanup, see how long hantavirus survives in droppings and on surfaces. For symptoms to watch for after a possible exposure, see hantavirus symptoms.