Last Updated on 04/05/2026 by TodayWhy Editorial
Three guests are dead as a suspected hantavirus outbreak spreads on board a cruise ship currently in the Atlantic Ocean, while three others are ill, according to an announcement from the World Health Organization (WHO) on Sunday. So what is Hantavirus and why is Hantavirus dangerous?
What Is Hantavirus?
Hantavirus (genus Orthohantavirus) is a family of RNA viruses belonging to the Hantaviridae family, order Bunyavirales. These zoonotic pathogens are carried and transmitted primarily by wild rodents — particularly deer mice, rice rats, and cotton rats — and can cause severe, potentially life-threatening illness in humans who come into contact with infected animals or their excretions.
Hantaviruses have a worldwide distribution, yet the specific strains, rodent reservoirs, and resulting diseases vary significantly by region. In the Americas, hantavirus infection typically causes Hantavirus Pulmonary Syndrome (HPS), a dangerous respiratory illness. In Europe and Asia, different strains lead to Hemorrhagic Fever with Renal Syndrome (HFRS), which primarily attacks the kidneys.
There is currently no approved vaccine or cure for either disease.
Key Statistics:
- Case fatality rate for HPS in the Americas: ~35%
- Estimated global cases per year: 150,000+
- U.S. cases reported 1993–2022: 864
- Incubation period after exposure: 1–8 weeks
Why Is Hantavirus Dangerous?
Hantavirus is considered one of the most dangerous zoonotic pathogens for several critical reasons. Understanding why hantavirus poses such a serious public health threat helps explain the urgency behind early detection and prevention measures.
No vaccine, no approved cure
As of 2025–2026, there are no FDA-approved vaccines or antiviral treatments specifically for hantavirus. While supportive care — including oxygen therapy and mechanical ventilation — can improve survival chances, patients who develop full respiratory symptoms face a mortality rate as high as 35–40% for HPS strains in North America.
Rapid disease progression
Once the late phase of Hantavirus Pulmonary Syndrome begins, deterioration can be extremely rapid — sometimes occurring over just a few hours. Blood vessels in the lungs become leaky, causing fluid accumulation (pulmonary edema), a dangerous drop in blood pressure, and ultimately respiratory failure. This speed of progression makes early hospital intervention critical.
Difficult early diagnosis
Initial symptoms are nonspecific — fever, fatigue, and muscle aches — easily mistaken for the flu or other viral infections. This makes early diagnosis challenging, and by the time respiratory distress appears, the disease may already be at an advanced stage.
Silent environmental presence
The hantavirus can remain viable in the environment for extended periods: up to 10 days at room temperature, 15 days in temperate conditions, and over 18 days at 4°C (39°F). Dried rodent droppings disturbed during cleaning or construction can re-aerosolize the virus, unknowingly exposing people during what appear to be ordinary situations.
In 2025, hantavirus gained renewed global attention after the death of Betsy Arakawa, wife of actor Gene Hackman, and after three passengers died aboard a cruise ship from suspected hantavirus — highlighting that exposure can occur in unexpected settings, not just remote wilderness areas.
Types of Hantavirus Disease
Hantavirus Pulmonary Syndrome (HPS) — Americas
HPS is the primary form of hantavirus disease in North and South America. The Sin Nombre virus (SNV), carried mainly by the deer mouse (Peromyscus maniculatus), is responsible for most HPS cases in the United States. The Andes virus (ANDV) causes most South American cases and is the only hantavirus strain with documented person-to-person transmission, albeit rare.
HPS is a severe acute respiratory infection. The case fatality rate for HPS caused by Sin Nombre virus can reach up to 40%, making it one of the deadliest rodent-borne diseases in the Western Hemisphere.
Hemorrhagic Fever with Renal Syndrome (HFRS) — Europe & Asia
HFRS is caused by Old World hantaviruses — primarily Hantaan virus (HTNV), Seoul virus (SEOV), Puumala virus (PUUV), and Dobrava virus (DOBV). Unlike HPS, HFRS targets the kidneys rather than the lungs, causing kidney swelling, excess protein in the urine, and blood in the urine. The case fatality rate for HFRS varies widely — from under 1% for milder strains to up to 15% for Hantaan virus.
China accounts for over 90% of global HFRS cases. Seoul virus is unique in that it is distributed worldwide, carried by the Norway rat (Rattus norvegicus), which has followed human trade routes across the globe.
Quick comparison: HPS attacks the lungs (Americas), while HFRS attacks the kidneys (Europe/Asia). Both can be fatal, but HPS generally carries a higher case fatality rate.
How Is Hantavirus Transmitted?
Understanding hantavirus transmission is key to preventing infection. The virus does not spread easily between people. Instead, the primary route of human infection involves direct or indirect contact with infected rodents and their bodily excretions.
Primary route: inhalation
The most common way hantavirus infects humans is through breathing in aerosolized particles. When dried rodent urine, saliva, or droppings are disturbed — during sweeping, vacuuming, opening a cabin that has been closed over winter, or disturbing nesting materials — virus particles become airborne and can be inhaled. This makes seemingly routine cleaning activities potentially hazardous in rodent-infested areas.
Other routes of transmission:
- Ingestion: Eating food contaminated with rodent saliva, urine, or droppings
- Direct contact: Touching contaminated surfaces and then touching the mouth or nose
- Rodent bites: Rare but possible if bitten by an infected rodent
- Person-to-person (very rare): Documented only with the Andes virus in South America; U.S. strains do not spread between people
Environmental factors such as rainfall, temperature, and humidity influence transmission dynamics by affecting rodent population sizes and range. Wetter years lead to more vegetation and food for rodents, resulting in population booms that increase human exposure risk.
Symptoms of Hantavirus
Hantavirus symptoms progress through two distinct phases. The early phase is often mistaken for influenza, while the late phase is a rapid, life-threatening respiratory emergency (in HPS) or kidney crisis (in HFRS).
Symptoms typically begin 9 to 33 days after exposure, though the range can be as early as one week or as late as eight weeks.
Early Phase Symptoms (Days 1–5):
- Fever (often high)
- Severe fatigue
- Muscle aches, especially in the thighs, hips, and back
- Headache
- Nausea and vomiting
- Dizziness
- Diarrhea
- Abdominal pain
Late Phase Symptoms (Days 4–10):
- Coughing
- Severe shortness of breath
- Chest tightness
- Fluid in the lungs (pulmonary edema)
- Rapid drop in blood pressure
- Internal bleeding (in HFRS)
- Kidney failure (in HFRS)
- Respiratory failure
According to the CDC, approximately 38% of people who develop the respiratory symptoms of HPS may die from the disease. If you have been exposed to rodents and develop fever, muscle aches, and difficulty breathing — seek emergency medical care immediately.
Diagnosis
Diagnosing hantavirus early is challenging because initial symptoms are nonspecific and overlap with many other viral illnesses. There is no rapid at-home test for hantavirus; diagnosis requires laboratory blood testing.
If a patient reports a history of rodent exposure along with fever, fatigue, and shortness of breath, a physician will likely order a blood test to detect hantavirus-specific antibodies (IgM and IgG). Patients should tell their doctor explicitly about any potential rodent exposure — in a home, vehicle, cabin, barn, or workplace — as this information significantly raises clinical suspicion and can accelerate testing.
Chest X-rays or CT scans may reveal fluid accumulation in the lungs during the later stages, which further supports diagnosis.
Treatment
There is currently no specific antiviral cure or FDA-approved vaccine for hantavirus infection. Treatment is primarily supportive and focuses on managing symptoms, providing oxygen, and maintaining blood pressure and fluid balance.
Supportive care
Patients with HPS often require intensive care unit (ICU) admission. Supplemental oxygen, mechanical ventilation, and extracorporeal membrane oxygenation (ECMO) may be used to support breathing. Intravenous fluids and vasopressors help manage dangerously low blood pressure.
Research & emerging treatments
Researchers continue to study antiviral drugs such as ribavirin and chloroquine as potential treatments. Early animal studies have shown some promise, but no treatment has yet been proven definitively effective in large-scale human clinical trials. Vaccine development efforts are also ongoing, including research into DNA-based vaccines targeting Sin Nombre and Andes viruses.
Early hospitalization — before respiratory failure sets in — significantly improves survival odds. This makes rapid diagnosis and early medical intervention the most powerful tools currently available.
Prevention: How to Protect Yourself
Because there is no vaccine, prevention centers entirely on avoiding exposure to infected rodents and their excretions. The following measures are recommended by the CDC and public health authorities:
- Seal your home: Close all holes and openings the width of a pencil or larger where mice can enter walls, floors, and foundations.
- Wear protective gear: Use rubber or plastic gloves and an N95 respirator mask when cleaning rodent-infested areas. Never use a regular dust mask.
- Wet before cleaning: Before sweeping or vacuuming rodent droppings, spray the area with a bleach solution (1 part bleach to 10 parts water) and let sit for 5 minutes. Never dry-sweep or vacuum dry droppings — this aerosolizes the virus.
- Ventilate before entering: When opening cabins, sheds, or storage spaces that have been closed, open doors and windows and let fresh air circulate for at least 30 minutes before entering.
- Store food securely: Keep all food — including pet food — in sealed, rodent-proof containers. Do not leave food scraps accessible.
- Use traps and exclusion: Set snap traps in areas with rodent activity. Contact a pest control professional for significant infestations.
- Camping precautions: When camping in rodent habitat areas, avoid sleeping on the bare ground; use tents with floors. Keep food stored away from sleeping areas.
Who Is at Risk?
Anyone who comes into contact with infected rodents or their excretions can develop hantavirus infection. However, certain groups face elevated risk due to occupational or recreational exposure:
- Rural residents in the western United States, particularly in the Four Corners region (New Mexico, Colorado, Arizona, Utah)
- Construction, pest control, and agricultural workers who work in environments with high rodent exposure
- Campers and hikers in wilderness areas where deer mice are prevalent
- Homeowners cleaning long-closed structures such as cabins, garages, or barns after winter
- People in areas with recent rodent population booms, which often follow wet seasons with abundant vegetation
According to CDC data, 94% of all U.S. hantavirus cases have occurred west of the Mississippi River, with New Mexico, Colorado, and Arizona historically reporting the highest case counts. The average age at diagnosis for HPS is 38, though all ages are susceptible.
Frequently Asked Questions (FAQ)
- Can hantavirus spread from person to person? In the United States, hantavirus strains — primarily Sin Nombre virus — cannot spread between people. The only documented human-to-human transmission has occurred with the Andes virus in South America, and even that remains relatively rare. You cannot catch hantavirus by being near an infected person in the U.S.
- What does hantavirus do to the body? Hantavirus invades tiny blood vessels called capillaries, particularly in the lungs (in HPS) or kidneys (in HFRS). In HPS, the virus causes capillaries to leak, flooding the lungs with fluid. This leads to pulmonary edema, respiratory failure, and a dangerous drop in blood pressure — which is the primary cause of death.
- How long does hantavirus survive outside a host? Hantavirus can survive up to 10 days at room temperature, 15 days in temperate environments, and more than 18 days at 4°C (39°F). This means dried rodent droppings in a closed space can remain infectious for weeks — another reason protective gear is essential during cleanup.
- Is there a vaccine for hantavirus? As of 2025–2026, there is no FDA-approved vaccine for hantavirus available in the United States. Vaccine development research is ongoing, but prevention through rodent avoidance and environmental control remains the only reliable protection.
- What should I do if I think I have been exposed to hantavirus? If you have had recent contact with rodents or rodent-contaminated materials and begin experiencing fever, severe muscle aches, and difficulty breathing, seek medical care immediately. Tell your doctor specifically about rodent exposure — this is critical for appropriate testing to be ordered quickly.
- Why is hantavirus found more in the western U.S.? The western United States, particularly arid and semi-arid regions, provides ideal habitat for deer mice — the primary carrier of Sin Nombre virus. Open developed areas and rural landscapes are associated with higher hantavirus risk. Climate fluctuations that increase rainfall can trigger rodent population booms, raising infection risk in these regions.
Medical Disclaimer: This article is intended for general informational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider for diagnosis and treatment of any medical condition.
Sources: CDC, Mayo Clinic, New York State Department of Health, NORD (National Organization for Rare Disorders), Cleveland Clinic — Last reviewed May 2026.