Hantavirus glossary

A New World hantavirus endemic to southern Argentina and Chile, carried by the long-tailed pygmy rice rat. Andes virus is the only hantavirus species in which limited human-to-human transmission has been documented under conditions of close prolonged contact. The 2026 MV Hondius cluster is an Andes virus outbreak. See Andes vs Sin Nombre.

A severe lung injury in which the alveolar capillaries leak fluid into the airspaces, dropping oxygen transfer despite mechanical ventilation. The pulmonary phase of HPS is functionally a form of ARDS driven by virus-induced capillary leak.

Public-health surveillance in which a person at risk is contacted twice daily for explicit symptom checks (fever, breathing trouble) for a defined window. Distinguished from passive monitoring, in which the contact is asked only to self-report new illness. WHO has recommended 42 days of active monitoring for MV Hondius repatriates.

A negative-pressure hospital ward specifically engineered for high-consequence infectious-disease cases — Ebola, Lassa, Andes virus, viral haemorrhagic fevers. The United States has three: the National Quarantine Unit / Biocontainment Unit at the University of Nebraska Medical Center, Emory University Hospital in Atlanta, and the NIH Clinical Center in Bethesda.

Bichat–Claude Bernard Hospital, Paris. One of the small number of French ECMO-capable infectious-disease centres. The French MV Hondius passenger is being treated there on ECMO under Dr Xavier Lescure.

The proportion of diagnosed clinical cases that result in death. CFR is always equal to or higher than the infection-fatality rate (IFR) because the denominator excludes mild and subclinical infections. HPS in the Americas has a CFR around 36%; Andes virus outbreaks report CFRs of 35-50%. See Survival rate by age.

The US federal public-health agency in Atlanta. For the MV Hondius cluster, CDC has activated its Emergency Operations Center at Level 3 (lowest tier), maintains the Health Alert Network notice HAN00528, and publishes the CDC HPS situation summary.

The second phase of HPS, beginning roughly 5-10 days after symptom onset. The lungs fill with fluid (ARDS), oxygen drops, and the heart's contractility falls — a combination called cardiopulmonary shock. This is the phase in which most deaths occur. See Shortness of breath.

A formal WHO situation report on an outbreak with international implications. The MV Hondius cluster has been the subject of DON599 (4 May), DON600 (9 May), and DON601 (13 May 2026).

A life-support circuit that pumps blood out of the body through a membrane that adds oxygen and removes carbon dioxide, then returns the blood warm and oxygenated. In severe HPS, ECMO bridges the patient through the four-to-seven-day capillary-leak window. The French MV Hondius passenger at Bichat is on a veno-arterial ECMO circuit. See Post: ECMO and hantavirus.

The EU's public-health surveillance agency, based in Stockholm. ECDC publishes daily updates on the MV Hondius cluster and the Rapid Scientific Advice on passenger management.

The most consistent early symptom of HPS — typically 38-40 °C, often with chills. Fever appears in the prodromal phase, 1-8 weeks after exposure, and precedes respiratory symptoms by several days. See Fever as a hantavirus warning sign.

A genus of negative-sense single-stranded RNA viruses in the family Hantaviridae (formerly Bunyaviridae), carried by specific rodent reservoirs. Different species cause either HPS (New World) or HFRS (Old World).

The cardiopulmonary syndrome caused by New World hantaviruses (Sin Nombre, Andes, Bayou, etc.). A prodromal phase of fever and muscle aches is followed by rapid pulmonary capillary leak, ARDS, and shock. Case fatality 35-50%.

The renal syndrome caused by Old World hantaviruses (Hantaan, Seoul, Puumala, Dobrava). Clinically distinct from HPS, with kidney involvement rather than lung involvement, and lower case fatality (1-15%).

The interval between exposure and first symptoms. For Andes virus the incubation period is 1-8 weeks, with the modal onset around 14-28 days. The WHO 42-day monitoring window is set at the high end of this distribution. See Post: Hantavirus exposure timeline.

The first identified case in an outbreak. For the MV Hondius cluster, the index case is a Dutch national who died on 11 April 2026. WHO's working hypothesis is that the index case acquired the infection before boarding through environmental exposure in Argentina.

Two classes of antibody. IgM appears 4-7 days after symptom onset and persists 2-3 months; IgG appears slightly later and persists for years. A positive IgM with a rising IgG is the classic serological signature of recent infection. See Hantavirus blood test.

The Dutch-flagged expedition ship at the centre of the 2026 cluster. Operated by Oceanwide Expeditions; departed Ushuaia on 1 April 2026 with 147 passengers and crew; docked at Granadilla port, Tenerife, on 10 May 2026.

A NIOSH-certified respirator that filters at least 95% of 0.3-micron airborne particles when properly fit-tested. The CDC recommends N95 or higher for any hantavirus cleanup activity. See N95 vs dust mask.

The reference laboratory that ran the first PCR confirmation of Andes virus in the MV Hondius cluster, on samples from the British national in ICU in Johannesburg. Continues to coordinate the African laboratory response.

The laboratory technique used to detect hantavirus RNA in a clinical sample. RT-PCR (reverse-transcription PCR) is the gold standard for confirmation during active infection. All confirmed cases in the MV Hondius cluster have been confirmed by PCR.

The early symptomatic phase before the disease-specific syndrome appears. The HPS prodrome (days 1-5) is non-specific — fever, severe muscle aches, headache, GI upset — and is easily mistaken for influenza.

Separation of an exposed but not-yet-symptomatic person from others, to limit transmission if the exposure proceeds to infection. Distinct from isolation, which separates a known symptomatic case. The 42-day MV Hondius window is a quarantine.

The animal species in which a virus persists without causing disease. Andes virus has the long-tailed pygmy rice rat as its primary reservoir; Sin Nombre virus has the deer mouse; Puumala has the bank vole.

The dominant North American hantavirus, discovered during the 1993 Four Corners outbreak. Causes HPS with case fatality around 36%. Reservoir: deer mouse. The Winnebago County, Illinois, suspected case under investigation is likely Sin Nombre.

A laboratory test that measures antibodies (IgM, IgG) in serum. Used to document past infection or to confirm a recent infection when PCR is no longer positive.

The presence of virus in the bloodstream. PCR can only detect hantavirus while there is sufficient viraemia, which is highest during the prodromal and early cardiopulmonary phases.

The United Nations specialised agency for public health, based in Geneva. WHO has issued three Disease Outbreak News reports on the MV Hondius cluster (DON599/600/601) and convened the WHO–UKHSA Bunyavirus CORC consultation on Andes virus countermeasures on 15 May 2026.