Hantavirus, in an unusual place.
Hantavirus is a rodent-borne virus that normally never spreads between people. The May 2026 MV Hondius cluster is the rare exception — caused by the Andes strain, the only hantavirus with documented human-to-human transmission. WHO assesses global public-health risk as LOW.
Bottom line. If you weren't on the MV Hondius and don't spend time around wild rodents, your personal risk is very low. If you did, contact your national public health line and watch for fever, muscle aches, and shortness of breath for 45 days.
What is hantavirus?
Hantaviruses are RNA viruses (family Hantaviridae) that circulate in specific rodent and shrew hosts. Each strain typically has one reservoir species. Humans become infected when they inhale aerosolized rodent excreta (urine, droppings, saliva) — usually when cleaning rodent-infested spaces, working in agriculture or forestry, or sleeping in cabins or sheds with active infestations.
The viruses cause two clinical syndromes: hantavirus pulmonary syndrome (HPS), dominant in the Americas, where patients progress from a flu-like prodrome to acute respiratory distress; and hemorrhagic fever with renal syndrome (HFRS), dominant in Eurasia, where the kidneys are the primary affected organ.
How does it spread?
Inhalation is the dominant route. Sweeping a dusty shed where mice have been living can kick the virus into the air. Direct rodent bites are rare. Eating food contaminated with rodent urine or droppings is possible but uncommon.
Person-to-person transmission has only been documented for the Andes virus, and even then only in close prolonged contact (household members, healthcare workers without PPE). The May 2026 MV Hondius cluster is the second ever documented at-sea cruise-ship outbreak. WHO continues to assess global risk as low.
Symptoms, by stage
Stage 1 — Febrile prodrome (days 1–5)
- Fever, chills, sweats
- Muscle aches (especially thighs, hips, lower back)
- Headache, fatigue
- Nausea, vomiting, abdominal pain
Stage 2 — Cardiopulmonary phase (HPS) or Renal phase (HFRS)
- HPS: cough, shortness of breath, rapid progression to ARDS
- HFRS: oliguria, flank pain, petechiae, hypotension
- Both: thrombocytopenia, atypical lymphocytes on smear
If you have flu-like symptoms plus recent rodent exposure or recent travel to an endemic region, tell your clinician explicitly. Hantavirus is on no clinician's first-line differential.
Strains and where they occur
- Andes virus — Argentina, Chile; HPS; CFR ~35%; only strain with documented human-to-human transmission
- Sin Nombre virus — US Southwest; HPS; CFR ~36%
- Puumala virus — Northern Europe; mild HFRS; CFR <1%
- Hantaan virus — China, Korea; severe HFRS; CFR ~5%
- Dobrava virus — Balkans; severe HFRS; CFR ~8%
- Seoul virus — global (brown rats); mild HFRS; CFR ~1%
- Bayou virus — Southeast US; HPS; CFR ~33%
Treatment and prognosis
There is no specific antiviral and no licensed vaccine in the United States, Europe, or most of the Americas. China and South Korea use bivalent inactivated vaccines against Hantaan and Seoul viruses with strong coverage in endemic provinces.
Care is supportive: aggressive but careful fluid management, oxygen, mechanical ventilation, and ECMO for severe HPS. Survival is dramatically better when patients reach a tertiary ICU before respiratory failure.
Prevention
- Don't sweep dusty rodent-infested spaces. Wet-clean with bleach solution while wearing gloves and an N95.
- Rodent-proof entry points (steel wool around pipes, sealed pantry).
- Set traps; remove food sources.
- When camping or staying in cabins: air out, wet-clean, avoid disturbing nests, sleep on a raised cot rather than the floor.
- When traveling to endemic regions, see prevention for country-specific guidance.
Frequently asked
What is hantavirus?
Hantavirus is a genus of single-stranded RNA viruses (family Hantaviridae) carried by rodents and shrews. Spillover into humans causes hantavirus pulmonary syndrome (HPS) in the Americas and hemorrhagic fever with renal syndrome (HFRS) in Eurasia.
How does hantavirus spread?
Most infections occur via inhalation of aerosolized rodent urine, droppings, or saliva. Bites are uncommon. Person-to-person transmission has only been documented for the Andes virus in South America, and only with close prolonged contact.
What are the early symptoms?
Onset is 1–8 weeks after exposure. Early symptoms (febrile prodrome) include fever, muscle aches, fatigue, headache, abdominal pain, nausea, and vomiting. Respiratory symptoms (cough, shortness of breath) develop later in HPS; kidney symptoms develop later in HFRS.
Is hantavirus fatal?
Case fatality varies by strain: 30–40% for Andes and Sin Nombre virus (HPS form), 5–12% for Hantaan and Dobrava (severe HFRS), and below 1% for Puumala virus (mild HFRS).
Is there a treatment for hantavirus?
There is no specific antiviral. Care is supportive: oxygen, fluid management, mechanical ventilation, and ECMO for severe HPS. Early ICU referral improves outcomes. Ribavirin has shown modest benefit for HFRS in some studies but is not standard for HPS.
How can I prevent hantavirus?
Rodent-proof your home, avoid stirring up dust in rodent-infested spaces, wet-clean droppings with bleach solution while wearing gloves and an N95, and avoid sleeping in cabins or sheds with active rodent infestation.
Sources
- CDC — Hantavirus
- WHO Disease Outbreak News — Hantavirus cruise-ship cluster (DON599, May 2026)
- PAHO Epidemiological Alert — HPS Americas (Dec 2025)
- Africa CDC — Statement on multi-country hantavirus cluster
Disclaimer. This content is for general information only and is not medical advice. If you have symptoms or believe you may have been exposed, contact a qualified clinician or your national public health authority.