We are witnessing an outbreak of a virus that is new to most individuals, a species of hantavirus called the Andes virus. Most hantavirus outbreaks are associated with outdoor adventuring, such as unknowingly camping with rodents, or merely cleaning a house where rodents have left droppings. But this one seemingly began on a cruise ship navigating the Atlantic. Many of us expect the risk of viruses such as norovirus, Covid-19 and influenza on these types of voyages. Less so hantavirus, especially a species that seems to be transmitted person to person. This has understandably put people on edge, with the specter of January 2020 lingering prominently in our collective memory.
Having more questions than answers at this stage also drives anxiety. So let’s start with what we know about the outbreak:
On April 1, the ship MV Hondius departed from Ushuaia, Argentina, and began moving through the south Atlantic. On April 6, one passenger began to feel ill, reporting a fever, diarrhea and a headache. He died on April 11. His body remained on board for two weeks. His wife fell ill on April 24 and died two days later, having made it to South Africa with her husband’s body. Lab testing of samples from two patients confirmed that the infection is due to the Andes virus, and one viral genome has already been sequenced.
Because the incubation period of the virus can be as long as six weeks, more cases may surface.
As of May 8, there are nine cases of infection associated with the ship. Three people have died: the first couple and a German woman who died on board the ship. The most recent case identified is that of a Swiss man who disembarked with approximately 30 others while the ship was stopped in Saint Helena island on April 24. He was tested in Switzerland after he developed symptoms. A flight attendant who came into contact with the first woman who died developed an illness but tested negative for the Andes virus. A Spanish woman who came into contact with the case has been hospitalized and is awaiting test results. The ship is heading to the Canary Islands, where those still on board will be quarantined.
Because the incubation period of the virus can be as long as six weeks, more cases may surface; several countries, including the United States, are working on tracing the individuals who left the ship, as well as their contacts.
This is certainly a worrying chain of events. The three deaths and the illnesses experienced by six others show how serious Andes virus infections can be; the fatality rate for hantaviruses is generally around 30%. Although the passengers’ experiences are dramatic — and in some cases tragic — the World Health Organization cautioned that “the risk to the global population from this event [is] low.” The virus does not seem to spread efficiently from person to person, and continued close contact is necessary, as one would expect on cruise ships with shared cabins, ventilation, dining and leisure activities.
Many unknowns remain. It is suspected that the first couple to show illness became infected with the Andes virus during their precruise travels through Argentina, but this has not been confirmed. It is likely that close contact with other patients spread the virus from the early to the later cases, but the potential for infected rodents on the ship has not been ruled out. In the 2012 outbreak of hantavirus at Yosemite National Park, tent cabins were cleared by inspectors who saw no evidence of rodents. But when the cabin walls were dismantled, rodent nests were found. This may be unlikely given the relative rarity of rodents on ships, but every aspect should be investigated once the vessel is empty.
The most consequential aspect here, though, is not really an element of the outbreak itself. It is the response, which has involved not only the WHO but also coordinated efforts from many different countries.
The most consequential aspect here, though, is not really an element of the outbreak itself. It is the response, which has involved not only the WHO but also coordinated efforts from many different countries: treating patients, determining testing and diagnosis, sequencing virus, trapping rodents in areas the Dutch couple visited, receiving the vessel and more. International coordination and information exchange are key in these situations. It underscores the value that was compromised when withdrawal from WHO was one of President Donald Trump’s early executive orders in January 2025.
Scientific expertise in virology, epidemiology, diagnostics, environmental sampling and basic medicine are critical to the response. Unfortunately, funding for our key scientific agencies has been slashed and thousands of scientists have been fired by Trump and his health and human services secretary, Robert F. Kennedy Jr. Other weaknesses in our federal agencies include the Centers for Disease Control and Prevention having no permanent director, and the interim head, Jay Bhattacharya, being busy running the National Institutes of Health. Media reports citing CDC employees say the agency is “flying blind” and work has “slowed to a crawl.” Many NIH and National Science Foundation grants that have been cut focused on topics of infectious disease, vaccinology and pandemic preparedness, reducing our knowledge and readiness for the next pandemic. This includes the canceling of multiple projects investigating mRNA vaccine development, which was critical for Covid response and has been seen as a likely tool for fighting future emerging diseases. Specific to cruise lines, even the CDC’s dedicated cruise line inspectors were recently cut. No federal authorities have even given a press conference regarding this epidemic, which experts have noted is unusual and concerning.
Ultimately, at least for now, the Andes virus outbreak is frightening, but the risk to the global population is low. The next outbreak may not be. We need to restore our scientific capacity internally, our relationship with the WHO externally and right our own ship before we are faced with a pathogen that we cannot control alone.
Tara C. Smith is a professor of epidemiology at Kent State University's School of Public Health. Before that, she spent nine years in the Department of Epidemiology at the University of Iowa College of Public Health, where she directed the college’s Center for Emerging Infectious Diseases.