Hantavirus — Causes, Symptoms, and Prevention

Intro

Hantavirus is a family of viruses carried by rodents. People can become infected by breathing in tiny airborne particles from the urine, droppings, or saliva of infected rodents — even without direct rodent contact. There are two main disease syndromes: hantavirus pulmonary syndrome (HPS), which affects the lungs, and haemorrhagic fever with renal syndrome (HFRS), which primarily affects the kidneys. Both can be serious. Recognising early symptoms and seeking prompt care are the most important steps.

Key Points

Hantavirus is spread by infected rodents, not person to person (with one documented exception).
Infection occurs mainly through inhaling dust contaminated with rodent urine, droppings, or saliva.
HPS begins like influenza — fever, fatigue, muscle aches — then can progress to severe breathing difficulty.
HPS requires urgent hospital care; there is no specific approved treatment.
HFRS, more common in Europe and Asia, primarily affects the kidneys and varies in severity.
Prevention centres on reducing rodent exposure and following safe cleanup practices.

Background

Hantaviruses belong to the family Hantaviridae. Different species are carried by different rodent hosts. In North and South America, Sin Nombre virus (carried by the deer mouse) is the main cause of HPS. Andes virus (also found in South America) is notable because it has shown documented limited person-to-person transmission — the only hantavirus known to do this. In Europe and Asia, Puumala virus (carried by bank voles) and Hantaan and Seoul viruses cause HFRS.

HPS was first formally identified in the south-western United States in 1993. HFRS has been recognised for much longer and accounts for more cases globally. Rodent populations fluctuate with food availability and climate, which influences how many human infections occur in any given year.

How Hantavirus Spreads

Hantavirus spreads primarily when people inhale aerosolised particles from material contaminated by infected rodent urine, droppings, or saliva. This most commonly happens when:

Sweeping, vacuuming, or disturbing dusty spaces such as sheds, barns, cabins, or storage areas where rodents have nested
Entering enclosed spaces that have been uninhabited and show signs of rodent activity
Handling rodents or nesting materials without adequate protection
Camping or sleeping in areas with active rodent populations, particularly in endemic regions

Infection through a rodent bite is possible but uncommon. Touching contaminated surfaces then touching the face is a less common route.

Person-to-person spread is not a feature of most hantavirus species. Andes virus is an important exception: close contact with an infected person — particularly in household or healthcare settings — has been documented in limited outbreaks in Argentina and Chile.

Symptoms and Warning Signs

Hantavirus Pulmonary Syndrome (HPS)

HPS typically develops in two stages after an incubation period of 1–8 weeks following exposure.

Early stage (approximately days 1–5):

Fever, chills, and fatigue
Muscle aches — particularly the thighs, hips, and back
Headache and dizziness
Nausea, vomiting, diarrhoea, or abdominal pain

These symptoms resemble influenza and are easily mistaken for other common illnesses. There is usually no rash and no respiratory symptoms at this stage.

Cardiopulmonary stage (approximately days 4–10):

Cough and shortness of breath that can worsen rapidly
Fluid accumulating in the lungs (pulmonary oedema)
Low blood pressure; in severe cases, circulatory shock

This progression can be rapid. The case fatality rate for HPS in the United States is estimated at around 35–38%. Not everyone progresses to severe illness, but there is currently no reliable way to predict who will deteriorate.

If you have been exposed to rodents and develop fever followed by breathing difficulty, seek emergency medical care immediately. Do not wait.

Haemorrhagic Fever with Renal Syndrome (HFRS)

HFRS varies widely in severity — from mild illness to life-threatening. It typically progresses through phases:

Febrile phase: sudden fever, headache, back pain, abdominal pain, and facial flushing
Hypotensive phase: blood pressure drop; possible shock in severe cases
Oliguric phase: reduced urine output; acute kidney injury
Diuretic phase: recovery of kidney function; risk of fluid imbalance during this period
Convalescent phase: gradual recovery, which may take weeks to months

Puumala virus infection (common in northern and central Europe) tends to cause milder HFRS with low mortality. Hantaan virus infections in Asia are more commonly severe.

Diagnosis and Treatment

Diagnosis

Early HPS and HFRS symptoms overlap with influenza, gastroenteritis, and other common illnesses. A history of potential rodent exposure is critical for clinicians to know to test for hantavirus. Diagnosis is confirmed with blood tests detecting:

Hantavirus-specific IgM antibodies (present early in infection)
IgG antibodies (develop later and indicate prior or recent infection)
PCR testing to detect viral RNA (available at reference and public health laboratories)

Chest X-ray or CT scanning can reveal lung involvement in HPS. Kidney function tests (creatinine, urine output) are central to monitoring HFRS.

There are no rapid point-of-care tests widely available for most settings.

Treatment

There is no specific approved antiviral treatment for HPS. Management is entirely supportive:

Careful fluid management — excess fluid worsens lung filling and must be avoided
Supplemental oxygen; in severe cases, mechanical ventilation in an ICU
Management of blood pressure and circulatory shock
Early transfer to a specialist centre, before severe respiratory failure develops

For HFRS, ribavirin (an antiviral) has shown some benefit in reducing severity when given early in the febrile phase, particularly for Hantaan virus infection. It is not routinely used for HPS.

Patients with shortness of breath or pneumonia-like illness following possible rodent exposure should be evaluated urgently. Early referral to intensive care can be life-saving in HPS.

Prevention

Reduce Rodent Exposure at Home

Seal gaps in walls, floors, roofs, and around pipes — mice can enter through very small openings.
Store food (including pet food and bird seed) in sealed, rodent-proof containers; remove food scraps promptly.
Use tight-fitting lids on indoor and outdoor bins.
Set snap traps if rodent activity is suspected indoors; check and clear them regularly.
Keep woodpiles, compost heaps, and outdoor clutter away from the house.

Safe Cleanup of Rodent-Infested Areas

Do not vacuum or sweep dry rodent droppings — this aerosolises particles and increases infection risk. Instead:

Ventilate the space for at least 30 minutes before entering (open windows and leave the area).
Wear rubber, latex, or vinyl gloves and, in heavily contaminated areas, a well-fitted N95 respirator or equivalent.
Wet the area thoroughly with a disinfectant (a 1:10 dilution of household bleach in water, or an approved disinfectant) and leave it to soak for at least 5 minutes.
Wipe up the wetted material with paper towels and place them directly into a sealed plastic bag.
Mop hard floors with disinfectant after removing visible contamination.
Dispose of gloves in a sealed bag and wash hands thoroughly.

Outdoor and Occupational Settings

When camping, use a tent with a waterproof floor and avoid sleeping directly on bare ground.
Do not disturb rodent nests, burrows, or droppings outdoors.
Workers in agriculture, forestry, or pest control should use appropriate personal protective equipment when rodent exposure is likely.
In endemic areas, be aware of local rodent activity levels — public health authorities may issue advisories during periods of elevated risk.

FAQ

Q: How do people catch hantavirus? A: Mainly by breathing in tiny particles from infected rodent urine, droppings, or saliva — often when disturbing dust in enclosed areas where rodents have been active.

Q: Can hantavirus spread from person to person? A: Most hantavirus species do not spread between people. Andes virus, found in South America, is an exception and has documented limited person-to-person transmission in close household and healthcare contacts.

Q: What is the difference between HPS and HFRS? A: HPS (hantavirus pulmonary syndrome) primarily affects the lungs and is most common in the Americas. HFRS (haemorrhagic fever with renal syndrome) primarily affects the kidneys and is more common in Europe and Asia.

Q: Is there a vaccine or specific treatment for hantavirus? A: There is no licensed antiviral treatment for HPS in most countries. Management is supportive — oxygen, careful fluid balance, and in severe cases mechanical ventilation in an ICU. Ribavirin has shown some benefit for HFRS when given early in the febrile phase.

Q: When should I seek urgent medical care? A: Go to the emergency department immediately if you develop fever followed by breathing difficulty — especially after any possible rodent exposure. HPS can progress from mild flu-like symptoms to severe respiratory failure within days.

Q: Can pets spread hantavirus? A: Cats and dogs are not known to carry or transmit hantavirus to humans. They may bring infected rodents closer to the home, which increases the chance of indirect exposure.

Q: Is hantavirus common? A: Hantavirus infection is rare but cases occur regularly in the Americas, Europe, and Asia. Risk depends on local rodent populations and how much contact you have with rodent habitats.