Hantavirus in 2026: Understanding the Andes Virus Outbreak Without Alarm

On May 2, the World Health Organization (WHO) was notified of a cluster of severe respiratory illnesses among passengers aboard a cruise ship. At the time of reporting, 147 passengers and crew remained onboard, while 34 had already disembarked. As of May 13, eleven cases, including three deaths, had been identified. Eight cases have been laboratory‑confirmed as hantavirus infections, all caused by Andes virus (ANDV).

The emergence of these cases has understandably drawn global attention.^1,2 Public health authorities emphasize that the overall risk to the general public remains extremely low.

What to Know About Hantaviruses

Hantaviruses are zoonotic RNA viruses carried primarily by rodents. Human infection most commonly occurs through inhalation of aerosolized particles from rodent urine, feces or saliva. Less commonly, infection can result from rodent bites or contact with contaminated materials.^3,4

Hantaviruses cause two main clinical syndromes:

• Hantavirus pulmonary syndrome (HPS; also called hantavirus cardiopulmonary syndrome, HCPS) – seen in the Americas
• Hemorrhagic fever with renal syndrome (HFRS) – seen worldwide

In the United States, most cases involve Sin Nombre virus, with approximately 890 cases reported since 1993.

Why ANDV Is Different

Most hantaviruses do not spread between humans. ANDV, linked to HPS and found primarily in Argentina and Chile, is a notable exception. Person‑to‑person transmission has been documented in several outbreaks, including a well‑characterized 2018-2019 cluster in Argentina’s Chubut Province. Even in that outbreak, transmission required close, sustained contact, and there was no evidence of casual community spread.⁵

Clinical Course

In HPS, after an incubation period of one to eight weeks (up to 42 days for ANDV), patients develop a prodromal illness lasting three to seven days, characterized by flu-like symptoms:

• Fever and chills
• Headache and myalgias
• Gastrointestinal symptoms (nausea, vomiting, diarrhea)

Respiratory symptoms are usually absent during this phase. Abrupt progression follows, marked by pulmonary edema and severe hypoxemia, presenting as cough and dyspnea. Diffuse pulmonary capillary leak leads to bilateral interstitial and alveolar edema, and severe cases may involve myocardial dysfunction and hypotension.

The case‑fatality rate for HPS averages 30%-40%. Treatment is supportive and often requires intensive care. Early recognition and prompt management improve outcomes.^3,4

Symptoms of HFRS usually develop one to two weeks post-exposure and include headaches, back and abdominal pain, fevers, chills, blurred vision, acute shock, internal bleeding, and/or kidney failure. Case fatality of HFRS is under 15%.^3,4

There is no specific treatment that cures hantavirus diseases, early supportive medical care is key to improving survival rates.

A Reassuring Perspective on Transmission

Unlike rapidly spreading respiratory viruses such as influenza or SARS‑CoV‑2, ANDV does not transmit easily. Surveillance data show that human‑to‑human transmission generally requires:

• Prolonged, close interpersonal contact
• Household or intimate exposure
• Sustained caregiving during the symptomatic phase

Documented transmission chains have been limited, traceable, and associated exclusively with close‑contact scenarios. Brief or casual encounters have not been implicated.^3,4,5 The WHO continues to emphasize that the global public health risk remains low, with no indication of widespread transmission.¹

How the 2026 Outbreak Unfolded

The current cluster was identified after several passengers aboard the Antarctic cruise ship MV Hondius developed febrile illnesses following travel in South America. The first suspected case boarded the ship on April 1, after more than three months of travel in Argentina, Chile, and Uruguay. He developed symptoms on April 6 and died onboard on April 11. His wife later developed symptoms and disembarked on April 24. She deteriorated during a flight to Johannesburg, South Africa, on April 25 and subsequently died. PCR testing confirmed ANDV infection. Several additional travelers developed symptoms thereafter. On May 10, the cruise ship arrived in Spain’s Canary Islands, where countries arranged special flights to take the passengers home. As of May 13, eight confirmed, two probable, and 1 inconclusive cases had been identified, although the investigation remains ongoing.^{1,2, 4}

As of May 11, 16 U.S. citizens exposed during the MV Hondius voyage arrived in Omaha, Nebraska, for quarantine and monitoring at the University of Nebraska Medical Center. All remain asymptomatic. One individual tested positive and is in specialized isolation, while others continue to be monitored. Two additional exposed patients are being followed at Emory University in Atlanta; one has mild symptoms. American passengers who left the ship and before the outbreak was discovered are also being monitored by their state or local public health departments.^3,6

Current Public Health Guidance

The Centers for Disease Control and Prevention has activated a Level 3 emergency response, the lowest tier, indicating enhanced monitoring rather than a high national threat.² The WHO continues to assess overall public risk as low.¹ Public health recommendations include:

• Monitoring exposed individuals for 42 days
• Testing symptomatic individuals with relevant exposure histories
• Considering ANDV in travelers returning from endemic areas of South America
• Using appropriate infection‑prevention measures when ANDV is suspected

Update from Kansas Department of Health and Environment

As of May 16th, the Kansas Department of Health and Environment (KDHE) is monitoring three individuals with a high-risk exposure to a person with confirmed ANDV hantavirus. The exposure occurred internationally after contact with an individual from the MV Hondius cruise ship who later tested positive for ANDV hantavirus. The three individuals in Kansas were not aboard the cruise ship and are not currently experiencing symptoms. They are being monitored at the University of Kansas.⁷

Key Points for Clinicians

Clinicians should consider hantavirus infection in patients with febrile respiratory illness and any of the following:

• Rodent exposure
• Recent travel to endemic regions
• Close contact with a confirmed ANDV case
• Linkage to the current cruise‑associated cluster

While ANDV warrants attention due to its potential for person‑to‑person transmission, it does not behave like a highly transmissible respiratory virus. Clear, accurate communication is essential to prevent unnecessary alarm while maintaining appropriate vigilance. Careful exposure histories, early recognition and prompt coordination with infection prevention and public health authorities remain critical.

References:

1. Hantavirus cluster linked to cruise ship travel, multi‑country. World Health Organization. Hantavirus cluster linked to cruise ship travel, Multi-country
2. Hantavirus: current situation. Centers for Disease Control and Prevention. May 12, 2026. https://www.cdc.gov/hantavirus/situation-summary/index.html
3. Hantavirus pulmonary syndrome. In: Kimberlin DW, Banerjee R, Barnett ED, Lynfield R, Sawyer MH; Committee on Infectious Diseases, American Academy of Pediatrics. Red Book 2024–2027, Report of the Committee on Infectious Diseases. 33rd ed. American Academy of Pediatrics; 2024. https://doi.org/10.1542/9781610027373-S3_008_002

4. Infectious Diseases Society of America. https://www.idsociety.org/ID-topics/infectious-disease/hantavirus/
5. Martínez VP, Di Paola N, Alonso DO, et al. “Super‑spreaders” and person‑to‑person transmission of Andes virus in Argentina. N Engl J Med. 2020;383:2230‑2241.
6. Live updates: Americans from hantavirus‑hit cruise arrive in US. CNN. https://www.cnn.com/2026/05/11/us/live-news/hantavirus-cruise-outbreak
7. KDHE Monitoring Individuals with Andes Hantavirus Exposure. Kansas Department of Health and Environment. https://www.kdhe.ks.gov/m/newsflash/Home/Detail/1936