- Aerosol transmissionepidemiology
- Spread by small airborne particles that can remain suspended for minutes to hours.
- Hantavirus does not transmit by sustained community-airborne spread the way SARS-CoV-2 does. ‘Aerosol exposure’ in hantavirus refers specifically to short-range inhalation of dust from disturbed rodent excreta during cleanup tasks.
- Andes virus (ANDV)virology
- The only hantavirus confirmed to spread between people; endemic to southern Argentina and Chile.
- Andes orthohantavirus is a South American hantavirus carried by the long-tailed pygmy rice rat. Unlike all other hantaviruses, it can transmit human-to-human, primarily during the prodromal phase, through respiratory droplets and direct contact. It is the agent of the 2026 MV Hondius outbreak.
- See also: Hantavirus pulmonary syndrome, Person-to-person transmission, Long-tailed pygmy rice rat
- Cardiopulmonary phaseclinical
- Stage 2 of HPS, when capillary leak causes the lungs to flood with fluid.
- Onset is often abrupt and follows a 3–5 day prodrome. Defined by sudden dyspnoea, hypoxaemia and diffuse pulmonary infiltrates on imaging. Most HPS deaths occur in this window.
- See also: Hantavirus pulmonary syndrome, Prodrome
- Case-fatality rate (CFR)epidemiology
- Proportion of confirmed cases that result in death.
- For HPS caused by Sin Nombre virus the CFR is approximately 38% among hospitalised patients. Andes virus sits in a 25–40% range. Old World HFRS-causing hantaviruses have substantially lower CFRs (often <1%).
- Deer mouse (Peromyscus maniculatus)geography
- Principal North American reservoir of Sin Nombre virus.
- A small native rodent widely distributed across North America. Approximately 15% of wild deer mice carry Sin Nombre virus; they appear healthy and shed virus throughout life.
- See also: Sin Nombre virus, Reservoir host
- ECMO (extracorporeal membrane oxygenation)clinical
- An artificial lung used for the most severe respiratory failure.
- ECMO oxygenates blood outside the body via a membrane and is the most aggressive supportive therapy available for HPS. Chilean experience suggests early ECMO can reduce HCPS mortality significantly. Requires a tertiary centre and transport capability.
- El Niñoepidemiology
- Climate pattern linked to historical hantavirus outbreaks.
- El Niño-driven precipitation increases small-mammal populations in arid regions, raising hantavirus exposure risk. The 1993 Four Corners outbreak is the canonical example; surveillance now incorporates climate signals.
- ELISA (enzyme-linked immunosorbent assay)clinical
- Antibody test used to confirm hantavirus diagnosis.
- IgM ELISA is the most useful first-line laboratory test; it is positive in most patients by the time they present with respiratory symptoms. IgG ELISA confirms seroconversion.
- Endemicepidemiology
- Consistently present in a defined geographic area.
- Andes virus is endemic to Patagonia (southern Argentina and Chile). Sin Nombre virus is endemic to the western United States. Endemicity means baseline cases occur every year without an active outbreak.
- Exclusion (pest)prevention
- Preventing rodents from entering a structure in the first place.
- The primary prevention strategy in integrated pest management for hantavirus. Sealing gaps larger than 1/4 inch, fitting hardware-cloth screens, and managing exterior habitat are more effective than reactive trapping.
- See also: Integrated pest management
- Four Corners outbreak (1993)geography
- The cluster that introduced HPS to Western medicine.
- An outbreak of severe respiratory illness in the south-western US (Arizona, New Mexico, Colorado, Utah). CDC investigation identified Sin Nombre virus and characterised hantavirus pulmonary syndrome for the first time.
- See also: Sin Nombre virus, Hantavirus pulmonary syndrome
- Haemoconcentrationclinical
- An unusually high blood-cell density as plasma leaks out of vessels.
- A diagnostic clue in the hantavirus prodrome: haematocrit rises despite no obvious dehydration, alongside marked thrombocytopenia. The combination should prompt consideration of hantavirus in an appropriate clinical context.
- Hantavirus pulmonary syndrome (HPS)clinical
- Severe lung illness caused by New World hantaviruses.
- A three-phase illness: flu-like prodrome → cardiopulmonary collapse → diuretic recovery (or death). CFR around 38%. There is no specific antiviral; care is supportive in an intensive care unit.
- See also: HCPS, Sin Nombre virus, Andes virus
- HCPSclinical
- Hantavirus cardiopulmonary syndrome - the South American form of severe hantavirus disease.
- Functionally similar to HPS but with more prominent cardiovascular involvement, including frank shock. Caused predominantly by Andes virus and related South American hantaviruses.
- HFRSclinical
- Haemorrhagic fever with renal syndrome - the Old World form of hantavirus disease.
- Caused by Hantaan, Seoul, Dobrava and Puumala viruses. More variable severity than HPS; renal involvement is prominent. Annual case totals across Eurasia run into the thousands.
- Incubation periodclinical
- Time from exposure to first symptom.
- For hantaviruses generally, 1 to 8 weeks. For Andes virus specifically, 4 to 42 days, with a median around two weeks. Person-to-person transmission of Andes virus tends to occur during the early prodromal phase of the source case.
- Index caseepidemiology
- The first confirmed case in an outbreak.
- In outbreak investigations, the index case is the entry point for tracing. In MV Hondius, identifying the most likely index case is still under investigation; current best evidence points to shore exposure in Patagonia before embarkation.
- Integrated pest management (IPM)prevention
- A layered approach to rodent control prioritising exclusion and habitat over poison.
- Standard practice in modern public-health entomology. Order of preference: exclusion → sanitation → mechanical control (traps) → chemical control as a last resort. Reduces ecological harm and secondary poisoning of wildlife.
- Long-tailed pygmy rice rat (Oligoryzomys longicaudatus)geography
- The principal reservoir of Andes virus in southern South America.
- A small rodent widespread in Patagonian forests and grasslands. Carries Andes virus lifelong without apparent disease and sheds virus in urine and droppings.
- MV Hondiusgeography
- Expedition cruise ship at the centre of the 2026 hantavirus outbreak.
- Vessel registered in the Netherlands, operating Antarctic and South Atlantic itineraries. Departed Ushuaia 1 April 2026; arrived Tenerife 10 May 2026 carrying 147 people from 23 countries. First recognised hantavirus cluster on a cruise.
- N100 / P100 respiratorprevention
- NIOSH-approved filtering facepieces effective against hantavirus aerosols.
- Used in heavy-contamination cleanup. N100 filters out at least 99.97% of airborne particles; P100 adds oil resistance. Surgical or cloth masks are not sufficient PPE for rodent cleanup.
- Person-to-person transmissionepidemiology
- Spread of infection directly between humans.
- For hantaviruses, documented only for Andes virus. Occurs primarily during close prolonged contact with a symptomatic patient. Estimated to account for 2–5% of all Andes virus cases in South American series.
- See also: Andes virus
- Prodromeclinical
- The earliest, non-specific stage of an illness before characteristic features appear.
- In HPS, the prodrome lasts 3–5 days and resembles influenza: fever, severe muscle aches, headache, gastrointestinal symptoms. Critical diagnostic window - early recognition can change outcomes.
- Reservoir hostvirology
- An animal species that carries and transmits a pathogen without serious illness.
- For hantaviruses, the reservoir is always rodents (or, for newly discovered species, shrews and moles). Different hantaviruses have different specific reservoirs; this is what gives the family its geographic structure.
- Sin Nombre virus (SNV)virology
- The principal North American hantavirus; agent of most US HPS cases.
- Identified after the 1993 Four Corners outbreak. Reservoir is the deer mouse. Has not been documented to transmit person-to-person, despite three decades of surveillance.
- See also: Deer mouse, Four Corners outbreak (1993)
- Super-spreader (hantavirus context)epidemiology
- An infected individual responsible for a disproportionate share of onward transmission.
- Described in the 2018–19 Epuyén, Argentina, Andes virus outbreak. A minority of infected patients accounted for most secondary cases, mirroring patterns seen in SARS, MERS and COVID-19.
- Thrombocytopeniaclinical
- Abnormally low platelet count.
- Profound thrombocytopenia (often <100,000/μL) is a hallmark of the hantavirus prodrome and one of the most useful early clues to diagnosis when paired with appropriate exposure history.
- Ventilation (cleanup)prevention
- Airing out a contaminated space before entry.
- Recommended pre-cleanup step: open all doors and windows for at least 30 minutes and leave the area during that time. Reduces airborne viral particle concentration before disinfection.
- WHO Disease Outbreak Newsepidemiology
- The World Health Organization's primary public outbreak-reporting channel.
- DON entries are the standard primary source for international outbreak information. The MV Hondius cluster is documented as DON599 (May 2026). Updates are issued as the situation evolves.
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