Hantavirus Tracker

An Andes‑strain hantavirus cluster aboard the cruise ship MV Hondius — linked to 11 confirmed infections (nine identified as Andes virus) and three deaths — has prompted WHO and PAHO alerts, international repatriations, and quarantine after hospital biosafety lapses, focusing efforts on containment and prevention of secondary transmission.

That international alarm intersects with CDC data showing 883 cumulative U.S. HPS cases since 1993 with a ~36% case fatality and no specific treatment or vaccine, underscoring dual risks: potential additional Hondius cases from a long incubation window and seasonal/climate-driven increases in rodent reservoirs (a possible “super El Niño”) that could raise domestic HPS risk.

Tracking: hantavirus

Geography: United States, Canada, Mexico, South America, Argentina, Chile, Bolivia, China, South Korea, Russia, Europe, global

1. Hantavirus outbreak on MV Hondius kills three, infects passengers across countries

An outbreak of hantavirus linked to cruise ship MV Hondius has produced multiple international cases and three deaths; the World Health Organization reported 11 confirmed cases as of May 13 and earlier reported eight cases and three deaths as of May 8.

Nine of the 11 confirmed infections have been identified as Andes virus; evacuees include patients quarantined in Madrid and a French patient in intensive care, while 18 American passengers were monitored and one tested positive in the United States.

Public-health responses focus on containment and preventing secondary transmission.

Harvard epidemiologist William Hanage noted hantavirus is deadlier on a per-case basis than COVID but harder to spread, typically requiring extended close contact; a shipboard physician was among infected.

Hospital biosafety lapses prompted quarantine of 12 staff in the Netherlands, the MV Hondius is returning to the Netherlands for disinfection, and WHO warns a long incubation period could reveal additional cases.

Key facts:

- WHO: 11 confirmed cases, three deaths (May 13)

- WHO earlier reported eight cases, three deaths (May 8)

- Nine of 11 cases confirmed as Andes virus

- 18 American passengers monitored; one tested positive

- Ship evacuations included patients quarantined in Madrid

Why it matters: Andes virus detection and a clinician infected aboard indicate potential for limited person-to-person spread in settings with prolonged close contact, elevating risk to caregivers and close contacts.

Cross-border evacuations and repatriations complicate contact tracing and increase the need for coordinated international surveillance and quarantine protocols.

Biosafety lapses at a treatment center that triggered staff quarantines highlight vulnerability in laboratory and clinical handling of samples.

Watch for additional confirmed cases during the long incubation window, and monitor national public-health briefings for expanded case counts, cluster links, and guidance for healthcare worker protection.

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2. PAHO warns of rising hantavirus cases as cruise ship outbreak spreads

The Pan American Health Organization issued an epidemiological alert after Argentina reported 134 confirmed HPS cases in 2024 and Chile documented 62, with transmission peaking in late spring and summer when human activity overlaps rodent habitats.

PAHO highlighted the Andes virus as the primary South American agent and one of the few hantaviruses capable of person-to-person spread, and urged stronger surveillance, laboratory capacity, and public awareness.

A hantavirus cluster aboard the MV Hondius has intensified international response: a Spanish evacuee tested positive, bringing the ship’s confirmed total to 11 with three deaths, and WHO identified nine of those cases as the Andes strain.

Authorities began repatriating passengers from Tenerife, 147 people from more than 20 countries remain under monitoring, and evacuees were escorted in full protective gear and disinfected during transfer.

Key facts:

- PAHO issued an epidemiological alert on rising hantavirus in the Americas.

- Argentina reported 134 confirmed HPS cases in 2024.

- Chile documented 62 confirmed HPS cases in 2024.

- Andes virus is primary South American cause and can transmit person-to-person.

- MV Hondius cluster: 11 confirmed cases, including three deaths.

Why it matters: The combination of seasonal rodent exposure, a virus capable of limited person-to-person transmission, and an international cruise cluster raises the stakes for cross-border surveillance and laboratory confirmation.

Health systems in affected countries face pressure to scale diagnosis and risk communication; travel and maritime operators will need stronger infection control and repatriation protocols.

Watch for case-count updates from PAHO and WHO, genomic confirmation of strains, and any secondary transmission linked to the MV Hondius evacuees.

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3. CDC Reports 883 U.S. HPS Cases Since 1993

CDC surveillance shows 883 cumulative hantavirus pulmonary syndrome (HPS) cases in the United States since 1993, reported across 36 states.

The Sin Nombre virus remains the primary North American cause; most cases occur in rural areas of the western United States, especially New Mexico, Colorado, Arizona, and California.

The case fatality rate is approximately 36 percent, and there is no specific treatment or vaccine.

A potential "super El Niño" could raise risk this summer by boosting deer mouse populations in the U.S. Southwest, according to forecasting commentary; NOAA's Climate Prediction Center issued a forecast earlier this month.

Public awareness has increased after a recent Andes-strain cluster tied to the cruise ship MV Hondius that caused several deaths and prompted international monitoring and quarantine efforts.

Key facts:

- 883 cumulative HPS cases in United States since 1993 (CDC update)

- Cases reported across 36 states

- Sin Nombre virus remains primary North American cause of HPS

- Most U.S. cases occur in rural western states: New Mexico, Colorado, Arizona, California

- U.S. HPS case fatality rate approximately 36 percent

Why it matters: If a strong El Niño increases deer mouse numbers, rural communities in the U.S. Southwest face higher exposure potential; because HPS has roughly a 36% case fatality rate and no specific antiviral or vaccine, any rise in cases would raise demand for early recognition and intensive supportive care, which improves outcomes.

Public health authorities should prioritize rodent-control messaging and surveillance and watch NOAA forecasts, regional rodent trends, and new clusters (for example, the MV Hondius event) as near-term indicators of changing risk.

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