Hantavirus Tracker

The dominant theme is an international Andes virus outbreak centered on the MV Hondius—reported at 11–12 confirmed cases with three deaths—that highlights both cross-border containment challenges and laboratory-safety risks.

PAHO and WHO flag rising hantavirus activity in the Americas and the unique person-to-person transmission risk of Andes, while U.S. and regional data (WSU, CDC) remind that endemic rodent-borne Sin Nombre remains a persistent, high-fatality threat; watch the 42-day monitoring window for additional cases, further strain confirmations, and how surveillance, lab capacity, and quarantine protocols hold up.

Tracking: hantavirus

Geography: United States (Four Corners region, Southwest US), Argentina, Chile, Bolivia, Brazil, Paraguay, Uruguay, Mexico, China, South Korea, Russia, Sweden, Finland, Norway, Germany, Europe (general), Americas (general)

1. Hantavirus cluster on MV Hondius reaches 12 cases, three deaths

A hantavirus cluster tied to the MV Hondius cruise ship has produced 11–12 confirmed cases and three deaths, according to WHO and national authorities.

Most early confirmations were Andes virus; passengers and crew were evacuated, all 147 people quarantined, and the vessel is docked in Rotterdam for decontamination.

WHO Director-General Tedros said the situation is "stable for now" but warned the virus's long incubation could yield additional cases; ECDC monitoring runs through June 21 (42 days after last exposure).

Operational complications include a newly confirmed Spanish case in Madrid, a French evacuee in Paris in intensive care, a Netherlands case identified after home quarantine, and a Radboud hospital lab-handling lapse that prompted 12 staff quarantines.

Key facts:

- 11 confirmed cases reported by WHO on May 13

- Later updates cited 12 confirmed cases

- Three deaths among MV Hondius passengers or crew

- Nine of 11 cases initially confirmed as Andes virus

- All 147 passengers and crew quarantined and monitored

Why it matters: Multinational evacuation, quarantine, and WHO/ECDC coordination have likely limited wider spread, preserving public health control options.

However, the long incubation window, at least one case identified after home quarantine, and a documented hospital biosafety lapse increase the risk of secondary cases; authorities should prioritize contact tracing outcomes, lab safety reviews, and monitoring through June 21 as indicators of whether containment holds or wider response measures are needed.

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2. PAHO alerts rising hantavirus cases in Americas; cruise ship outbreak reported

PAHO issued an epidemiological alert noting rising hantavirus pulmonary syndrome (HPS) cases across the Americas, with Argentina reporting 134 confirmed cases and Chile 62 in 2024; transmission typically rises in late spring and summer when outdoor activities overlap rodent habitats.

The agency notes Andes virus as the primary South American agent — notable for documented person-to-person transmission — and urges strengthened surveillance, laboratory diagnostic capacity, public awareness, and early clinical recognition.

A separate outbreak aboard the cruise ship MV Hondius has produced 11 confirmed cases, including three deaths; WHO confirmed nine of those cases are the Andes virus strain, and one evacuated Spanish passenger recently tested positive.

Authorities report 147 passengers and crew from more than 20 countries are under monitoring as the ship heads to Tenerife; evacuees were escorted in full-body protective gear and disinfected, illustrating international coordination and containment challenges.

Key facts:

- PAHO released an epidemiological alert (article dated 2026-05-08).

- Argentina reported 134 confirmed HPS cases in 2024.

- Chile documented 62 HPS cases in 2024.

- Andes virus remains the primary causative agent in South America.

- Andes virus is notable for documented person-to-person transmission.

Why it matters: Rising HPS incidence in Argentina and Chile, combined with an Andes-virus cruise outbreak, concentrates risk for public health agencies, hospitals, and international travel operators and will increase surveillance and clinical burdens.

Because Andes virus can transmit person-to-person and 147 people from over 20 countries are under monitoring, priorities should be scaling laboratory capacity, targeted seasonal risk communication, and close-contact cluster detection to prevent secondary spread.

Hantavirusreports

3. Nebraska lab rapidly deployed hantavirus test as MV Hondius passengers arrived

Two additional U.S. passengers from the cruise ship MV Hondius tested positive for hantavirus as Americans affected by the ship's outbreak arrived in Omaha for quarantine on May 11, 2026.

Kalitta Air 492 landed at Eppley Airfield and medical personnel escorted passengers to the University of Nebraska Medical Center's Davis Global Center and Biocontainment Unit; Governor Jim Pillen provided a public update.

Staff at the Nebraska Public Health Laboratory quickly stood up a new hantavirus test in days after learning the quarantined Americans were inbound, using existing lab equipment and personnel experienced during the COVID-19 response.

Deputy director Emily McCutchen is pictured operating laboratory extraction equipment as the state mobilized testing and transport resources for the quarantine operation.

Key facts:

- Two additional U.S. passengers tested positive for hantavirus

- MV Hondius passengers arrived Omaha May 11, 2026

- Kalitta Air 492 landed at Eppley Airfield May 11, 2026

- Passengers escorted to UNMC Davis Global Center Biocontainment Unit

- Nebraska Public Health Laboratory developed a hantavirus test in days

Why it matters: Rapid local deployment of a hantavirus test shortens diagnosis turnaround and supports onsite quarantine and clinical triage, improving containment and patient management.

Leveraging equipment and staff experienced during the COVID-19 response demonstrates state lab surge capacity, which benefits public health responders and quarantined patients but also pressures laboratory resources and quarantine operations.

What to watch next: additional test results and clinical outcomes from quarantined passengers, validation and throughput of the new test, and whether other state or federal labs will confirm results or assume further diagnostic burden.

Omaha

4. Taiwan confirms third hantavirus case of 2026

Taiwan confirmed its third hantavirus syndrome case of 2026: a man in his 40s from northern Taiwan who was bitten by a rat at work on April 7, developed fever, chills and limb weakness on May 2, and was hospitalized and diagnosed.

The Taiwan Centers for Disease Control notes three cases this year, comparable to 2–3 annual cases reported in 2022–2025; since 2017 there have been 46 cases (31 males, 31 aged 40 and above).

Authorities monitored contacts, conducted rat trapping at the patient’s home and workplace, and reiterated CDC guidance on rodent-proofing, safe disposal of food and pet food, and using masks and gloves and ventilating when cleaning rodent-contaminated areas.

Key facts:

- 3 confirmed hantavirus syndrome cases in Taiwan in 2026.

- Case: man in his 40s from northern Taiwan; rat bite at work on April 7.

- Symptoms began May 2: fever, chills, limb weakness; hospitalized and diagnosed.

- Since 2017 Taiwan has recorded 46 hantavirus cases.

- Of 46 cases, 31 were male and 31 were aged 40 or older.

Why it matters: Sustained low-level case counts (three in 2026, similar to prior years) indicate ongoing endemic hantavirus risk in Taiwan and justify continued rodent-control operations, contact monitoring, and public outreach.

Immediate priorities are occupational and environmental risk reduction—especially for workers with rodent contact—plus clinician vigilance for febrile respiratory presentations following rodent exposure, and continued surveillance to detect any change in case frequency or severity.

Outbreaknewstoday

5. WSU study finds 29% of Palouse deer mice show past hantavirus infection

A Washington State University study across the Palouse found 29% of deer mice had evidence of prior hantavirus infection and about 10% were actively infected in Whitman County, Washington, and Latah and Benewah counties, Idaho.

Co-author Stephanie Seifert said she was surprised by the high prevalence and the scarcity of recent regional data; a Virginia Tech study last year reported 13. 4% prior infection nationally.

Researchers including Pilar Fernandez warned the virus appears endemic among regional deer mice, posing a persistent exposure risk despite human infections remaining rare.

The dominant North American strain is Sin Nombre (deer mouse reservoir); there have been 890 U.S. cases since 1993, including 61 in Washington, and the Andes strain—linked to recent Dutch cruise-ship deaths—is the only strain known to transmit person-to-person.

Key facts:

- 29% of deer mice showed prior hantavirus infection in the Palouse

- About 10% of deer mice were actively infected and potentially shedding virus

- Study locations: Whitman County WA; Latah and Benewah counties, Idaho

- WSU researchers: Stephanie Seifert and Pilar Fernandez

- Virginia Tech study: 13.4% rodents showed prior infection across US

Why it matters: Elevated rodent prevalence signals sustained spillover risk for local public health, clinicians, occupational health services, and residents who work or recreate outdoors; targeted surveillance, clinician awareness, testing access, and rodent-control outreach should be prioritized.

Because deer mice appear to maintain an endemic Sin Nombre reservoir, elimination is unlikely; watch for regional human case reports, follow-up rodent surveillance data, and any international alerts about Andes-strain person-to-person transmission.

Spokesman

6. CDC reports 883 cumulative HPS cases since 1993

The Centers for Disease Control and Prevention updated hantavirus pulmonary syndrome (HPS) surveillance, reporting 883 cases across 36 states since the first recognized Four Corners cluster in 1993.

Sin Nombre virus remains the primary cause in North America, and most U.S. cases occur in rural western states, with New Mexico, Colorado, Arizona, and California reporting the highest numbers.

HPS in the United States carries an approximately 36% case fatality rate and has no specific treatment or vaccine, so prevention is the critical intervention.

The CDC recommends sealing holes to prevent rodent entry, using traps to reduce rodent populations, and safely cleaning droppings with proper respiratory protection; early recognition of symptoms and prompt supportive care in intensive care settings can improve outcomes.

Key facts:

- 883 cumulative HPS cases reported in the United States since 1993

- Cases reported across 36 states

- Sin Nombre virus is the primary cause of North American HPS

- Most U.S. cases occur in rural western states

- New Mexico, Colorado, Arizona, and California report highest numbers

Why it matters: With no vaccine or specific antiviral, public health and community prevention are the main defenses; communities and households that implement rodent-proofing and safe cleanup directly reduce risk.

Rural residents and people with occupational or recreational rodent exposure remain most vulnerable, while clinicians and ICUs benefit from vigilance because early recognition and supportive care can improve survival.

Watch local case reports, regional rodent-control efforts, and public outreach to assess whether prevention messages and interventions are being sustained.

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