Suspected Cluster of Hantavirus Infections Reported on an Atlantic Cruise Vessel

2026-05-04 377

A suspected cluster of hantavirus infections has recently been reported aboard the polar expedition cruise vessel Hondius, sailing in the Atlantic Ocean. To date, seven cases have been identified, including three fatalities.

Hantaviruses are typically transmitted via rodents, and clustered occurrences in confined environments such as cruise ships are considered highly unusual. This incident has drawn increased attention from the global public health community.

Virological Characteristics and Genome Organization

Hantaviruses belong to the Hantaviridae family (formerly classified under Bunyaviridae) and are enveloped, single-stranded negative-sense RNA viruses with a segmented genome. Viral particles are generally spherical to pleomorphic, with diameters ranging from 80 to 120 nm. Their genome consists of three segments---L, M, and S---which is a defining feature of this virus group.

Schematic representation of hantavirus morphology (DOI: org/10.3947/ic.2009.41.6.323)

Each genomic segment encodes distinct structural and functional proteins:

The S segment (~1.7--2.1 kb) encodes the nucleocapsid (N) protein, the most abundant viral protein, which plays a central role in viral RNA encapsidation and elicits strong host antibody responses.

The M segment (~3.6 kb) encodes a glycoprotein precursor that is cleaved into two surface glycoproteins, Gn and Gc. These glycoproteins are essential for host cell receptor binding and membrane fusion, and they represent the primary targets for neutralizing antibodies.

The L segment (~6.5 kb) encodes the RNA-dependent RNA polymerase (RdRp), responsible for viral genome transcription and replication.

Gn and Gc glycoproteins are critical mediators of viral entry into host cells. Hantaviruses predominantly infect vascular endothelial cells and may involve renal and pulmonary tissues. Their pathogenicity is largely associated with increased vascular permeability. Infection can trigger host immune responses that compromise endothelial barrier integrity, leading to capillary leakage---a hallmark feature of hantavirus-associated disease.

Transmission Mechanisms

Hantaviruses are globally distributed zoonotic pathogens, with rodents serving as their primary natural reservoirs. Infected rodents can harbor the virus persistently and shed it through saliva, urine, and feces.

Human infection primarily occurs through:

• Inhalation (primary route): Aerosolized viral particles from contaminated rodent excreta
• Direct contact: Exposure of broken skin or mucosa to contaminated materials or rodent bites
• Ingestion: Consumption of contaminated food or water

Most hantavirus species do not exhibit human-to-human transmission. However, Andes virus, identified in South America, is a notable exception and can cause limited transmission among close contacts. Its transmissibility remains significantly lower than that of respiratory pathogens such as SARS-CoV-2 or influenza viruses.

Replication cycle of orthohantaviruses (PMCID: PMC12416192)

Pathogenesis and Clinical Manifestations

Hantavirus infections manifest primarily as two major clinical syndromes, depending on the viral species and geographic distribution: hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS).

HFRS is mainly observed in Europe and Asia. Following an incubation period of 1--2 weeks, patients may develop fever, headache, back pain, facial flushing, and conjunctival injection. Severe cases can progress to hypotensive shock, hemorrhage, and acute kidney injury. Case fatality rates vary widely depending on the viral strain, typically ranging from <1% to 15%.

HCPS is predominantly reported in the Americas. Early symptoms resemble influenza-like illness, including fever, myalgia, and fatigue. The disease can rapidly progress to pulmonary capillary leakage, pulmonary edema, and circulatory failure. Once cardiopulmonary involvement develops, case fatality rates are estimated at approximately 30--50%.

Despite differences in organ involvement and geographic distribution, both syndromes share a common pathogenic mechanism characterized by endothelial dysfunction and increased vascular permeability.

Prevention Strategies and Current Therapeutic Landscape

Prevention of hantavirus infection primarily relies on minimizing environmental exposure. Key measures include rodent control, safe food and water storage, and the use of personal protective equipment when cleaning rodent-contaminated areas. Enhanced environmental monitoring and biosecurity measures are particularly important in confined settings such as cruise vessels.

Currently, no widely approved specific antiviral therapy is available. Clinical management is largely supportive, including respiratory support, fluid management, and renal replacement therapy when necessary.

In terms of vaccines, inactivated vaccines have been developed and approved in China and South Korea for the prevention of HFRS. However, these vaccines have not yet received approval from regulatory agencies such as the U.S. Food and Drug Administration. DNA vaccines targeting viral glycoproteins are under early-stage clinical evaluation and have demonstrated promising safety and immunogenicity profiles.

Hantavirus Overview (PMID: 40402545)

Summary

Hantaviruses remain an ongoing global public health concern, with tens of thousands of cases reported annually. Environmental and ecological changes, including climate-driven shifts in rodent populations, may influence transmission dynamics and exposure risk.

The occurrence of suspected clustered cases in a confined setting such as a cruise vessel highlights the importance of surveillance, risk assessment, and rapid response strategies for zoonotic diseases in an increasingly interconnected world. Strengthening preparedness in travel and transportation settings will be critical for mitigating future risks.