Hantavirus Outbreak on an Atlantic Cruise Ship: Facts, Figures and Public Health Implications

Although it seldom makes headlines, hantavirus infects an estimated 10, 000 to 100,000 people globally each year.¹ A recent outbreak on a cruise ship on the Atlantic Ocean has, however, made news around the world, with many fearing it may be the beginning of another COVID-19-style pandemic. Fortunately, the evidence says otherwise, and experts are equally reassuring. “With appropriate isolation, quarantine, and infection control procedures, this outbreak should be limited. There is little reason for concern about another global pandemic from this Andes virus outbreak,” says Alexandra Yonts, MD, an infectious disease specialist with the Children's National Hospital, Washington, DC.

Hantaviruses belong to the family Hantaviridae and the order Bunyavirales. They are enveloped, negative-sense, single-stranded RNA viruses with a genome comprising small (S), medium (M), and large (L) segments. These segments encode a nucleocapsid protein, glycoproteins Gn and Gc, and the RNA-dependent RNA polymerase.² Gn and Gc allow for entry into a host through integrins on endothelial cells.

An infection with hantavirus produces 2 main clinical syndromes: hantavirus cardiopulmonary syndrome (HCPS), which is more prevalent in the Americas, and hemorrhagic fever with renal syndrome (HFRS), which is common in Eurasia. HCPS is a more severe disease, with a case fatality rate of between 40 and 50%.³ Since there are no approved antiviral medications or vaccines for hantavirus, early diagnosis and prevention are particularly important.^4,5

Rodents are the primary hosts of these viruses. A specific hantavirus species lives in a specific kind of rodent without making that rodent sick. These infected rodents then transmit the infection to humans, who are incidental hosts. Hantaviruses are typically transmitted to humans by inhaling the “aerosolized feces, urine or saliva from infected rodents,” says Yonts.

Hantaviruses are categorized into two groups based on the geographic regions where they are found and the clinical symptoms they cause. Old-world hantaviruses, including Hantaan, Seoul, Sobrava, and Puumala, cause hemorrhagic fever with renal syndrome (HFRS), a syndrome characterized by acute kidney injury and hemorrhage. “Despite the scarier name, HFRS is generally milder and has a lower mortality rate 91-15%) ed rus Caithe New World hantaviruses," says Yonts

New world viruses such as Sin Nombre virus (SNV), found in the Southwestern US, and Andes virus (ANDV), found in Argentina and Chile, cause a severe cardiopulmonary clinical syndrome called Hantavirus Cardiopulmonary Syndrome (HCPS), which has a higher mortality rate (20 to 50%).²

SNV causes most of the HCPS cases in North America. While ANDV causes more HCPS cases in South America. ANDV is the only hantavirus that can be transmitted person-to-person, making it an important strain.¹ The virulence of hantavirus varies widely from strain to strain, with Hantaan and ANDV causing the most severe disease.

High viral loads and an overactive immune response carry a poor prognosis in both HFRS and HCPS, suggesting that dysregulated immunity plays a role in the disease’s pathogenesis.⁷

“Historically. HCPS cases have been associated with exposures involving prolonged or intense contact with dried rodent feces or urine, “ says Yonts. Such exposures typically occur while dry cleaning or sweeping a cabin, basement, or empty home at the beginning of spring, or the deconstruction or remodeling of structures in which rodents are present,” she adds.

The ANDV is usually carried by long-tailed pygmy rice rats in rural Chile and Argentina. Inhalation is more likely to happen in poorly ventilated spaces.⁸ This may be in domestic environments or in the workspace. Infection can also occur through direct contact with infected material or by being bitten by a rodent, though this is uncommon.

Person-to-person transmission is extremely rare and likely occurs through inhaling the respiratory droplets of infected individuals during the acute febrile phase.

Symptoms of HCPS typically develop 2 to 4 weeks after exposure, although they can happen anywhere from 1 to 8 weeks. For HFRS, the incubation is shorter, somewhere between 2 and 3 weeks.³

HCPS has 4 clinical phases. There is a nonspecific prodromal phase that lasts 3 to 5 days. During this phase, patients experience fever, myalgia, fatigue, and gastrointestinal symptoms. Afterward, there is a cardiopulmonary phase characterized by rapid noncardiogenic pulmonary edema, hypoxia, and shock in severe cases.⁹ The disease is often severe enough for patients to require mechanical ventilation and vasopressin support.

“Hantavirus infections, particularly those causing HCPS, can be severe because the virus targets the vascular endothelium. This leads to increased capillary permeability, causing fluid leakage into tissues (especially the lungs). The result can be rapid progression to pulmonary edema, respiratory failure, and shock, often within 24–48 hours in severe cases,” says Luis Marcos, MD, an infectious disease expert at Stony Brook Medicine who has studied hantavirus and published a case in Suffolk County, NY.

A diuretic phase signals the start of recovery and a convalescent phase where symptoms subside (despite persistent fatigue) can take weeks.

HFRS with acute kidney injury and hemorrhage as its key features has 5 phases: febrile, hypotensive, oliguric, diuretic, and convalescent phases.⁶ In some cases, especially during the oliguric phase, there is a need for dialysis.

Hantavirus should be suspected in people who have a suspicious, unexplained febrile illness with nonspecific symptoms, especially with a background of rodent exposure. Geographical location can offer more clues. During the cardiopulmonary phase, a presumptive diagnosis can be made if the patient meets 4 of 5 criteria: thrombocytopenia, left shift in the granulocytic lineage, absence of toxic granulation in the myeloid series, hemoconcentration, and an immunoblast population greater than 10% of the total leukocyte count.⁹

Other laboratory findings suggestive of HCPS include thrombocytopenia, elevated lactate dehydrogenase, and immunoblasts on peripheral blood film.² Hantavirus is confirmed by serology, which detects specific antibodies, or by reverse transcriptase-polymerase chain reaction.

There are no FDA-approved drugs for the treatment of hantavirus. Therefore, supportive care is crucial. In HCPS, fluid management is critical. Pulmonary edema can be worsened by aggressive fluid resuscitation. In HFRS, patients may need dialysis, especially during the oliguric phase.

Rodent control is the mainstay of prevention, reducing contact with rodents and their droplets. Rodent access to homes and outbuildings should be sealed, their breeding grounds destroyed, and their food sources eliminated.

When cleaning areas likely to have been contaminated by rodents, individuals should wear gloves and a face mask. Wetting areas with disinfectants or bleach before cleaning can stop droplets from rising into the air.¹⁰

“Families should avoid sweeping or vacuuming rodent-contaminated areas,” warns Dr. David Dyjack, executive director of the National Environmental Health Association. “Consider wet wiping procedures for dry or dusty spaces,” he adds.

In settings where person-to-person transmission risks exist, people with nonspecific symptoms resembling hantavirus should be kept away from others. Clinicians should consult reputable sources such as the US CDC for updates. They should consider hantavirus in patients presenting with respiratory symptoms who have a compatible exposure history, including possible rodent exposure in high-risk areas, such as the Southwest US, or during travel or aboard ships.

“Early recognition is important because patients can deteriorate rapidly and may require intensive supportive care. Providers should obtain detailed travel and environmental exposure histories and coordinate promptly with local or state public health authorities if hantavirus is suspected. While rare, awareness is critical because the initial presentation can resemble more common respiratory infections,” says Dyjack.

Development of vaccines against hantavirus is ongoing and has seen some progress. Phase 1 trials of vaccines for Hantaan virus and Puumala virus showed that these vaccines were well tolerated and safe.¹¹ The vaccine performance was satisfactory in inducing an immune response. More research is urgently needed on vaccines, treatments, diagnostics, and genomic sequencing to track emerging strains and understand outbreaks better.¹²

Hantavirus disease has been a neglected zoonotic disease that has infected thousands for centuries. The current outbreak with human-to-human transmission involving people in the upper economic groups has brought the condition to the fore, highlighting gaps in our understanding and management of the condition. We can only hope this translates to stronger political will to tackle this condition and improve the current tools for prevention, diagnosis, and treatment.

References

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4. Hantavirus. CDC. Updated 2024. Accessed May 2026.
5. Africa CDC. Statement on multi-country hantavirus cluster associated with cruise ship travel. Accessed May 2026.
6. Mir S. Hantavirus-induced kidney disease. Frontiers in Medicine. 2022;8:795340. doi:10.3389/fmed.2021.795340
7. Saavedra F, et al. Immune response during hantavirus diseases: implications for immunotherapies and vaccine design. Immunology. 2021;163(3):262-277. doi:10.1111/imm.13322
8. You can prevent hantavirus. CDC hantavirus brochure. Accessed May 2026.
9. Kennedy M, Mctabi O, Rickman C. Hantavirus cardiopulmonary syndrome: another reason to avoid mice. Journal of Investigative Medicine High Impact Case Reports. 2024;12:23247096241274572. doi:10.1177/23247096241274572
10. Canadian Centre for Occupational Health and Safety. Hantavirus. Accessed May 2026.
11. Hooper JW, Kwilas SA, Josleyn M, et al. Phase 1 clinical trial of Hantaan and Puumala virus DNA vaccines delivered by needle-free injection. npj Vaccines. 2024;9:221. doi:10.1038/s41541-024-00998-7
12. Vaheri A, Henttonen H, Mustonen J. Hantavirus research in Finland: highlights and perspectives. Viruses. 2021;13(8):1452. doi:10.3390/v13081452