Hantavirus status report: This virus will continue to mutate and the incubation period is too long to provide rapid response

Report published in the New York Magazine Intelligencer by Nia Prater and Chas Danner.

Julie note- Although I am not a virology expert, my experience preparing for viral epidemics in hospital planning sessions is that viruses mutate.  So, I am not convinced about some of what is reported about what is happening with the Hantavirus today, because, by tomorrow the virus could replicate. That is what viruses do. Nevertheless, the article is a good status report.

An outbreak of the rare and dangerous hantavirus aboard the Dutch-flagged cruise ship MV Hondius has left three passengers dead, forced the medical evacuation of several others, and triggered an international health scare. While the unsettling news has prompted concerns of another widespread virus outbreak akin to COVID-19 or avian flu, the World Health Organization has stressed that the overall public-health risk from the Hondius outbreak is low. Here’s what we know so far.

How did the outbreak start? In a bulletin on Monday, the WHO said that it was first contacted about a “cluster of severe acute respiratory illness” aboard the Hondius on May 2, including two deaths and one passenger who was critically ill. Per the organization, the ship left Ushuaia, Argentina, on April 1 and made numerous stops including mainland Antarctica, Tristan da Cunha, Saint Helena, South Georgia, Nightingale Island, as well as Ascension Island in the South Atlantic Ocean.

In the days since, the number of deaths has risen to three. According to the WHO, the first case was a man presenting with a fever, mild diarrhea, and a headache on April 6; he died on April 11 after developing respiratory distress. The second was a woman who left the ship from Saint Helena on April 24 while reportedly experiencing gastrointestinal symptoms. Her condition worsened while traveling on an April 25 flight to Johannesburg, South Africa, and she passed away after arriving at a hospital on April 26. 

In the third case, a woman died on May 2 after presenting with symptoms on April 28.
The New York Times reports that the first two deaths from the outbreak were a couple, a 70-year-old man from the Netherlands and his 69-year old wife, and the pair had reportedly traveled in South America, specifically Argentina, prior to boarding the ship. PCR testing later confirmed hantavirus infection in the wife’s case. The third fatal case is reported to be a German woman.

According to the Associated Press, Argentina’s Ministry of Health has been tracing the travel of the Dutch couple, who had been on a South American road trip, and the authorities are investigating the possibility that the couple was exposed to hantavirus during a bird-watching trip to a landfill in the southern town of Ushuaia, which is also where they boarded the Hondius.

What is hantavirus? According to the U.S. Centers for Disease Control, hantaviruses are a family of viruses that humans can contract following contact with rodents, which frequently carry the virus, typically by breathing in particles from their dried saliva, urine, and droppings, like when sweeping a shed where rodents have been living.

Hantavirus infections are typically rare, with an estimated 200,000 to 300,000 cases per year globally, but they can result in severe illness and death. Hantaviruses found in the Americas, also known as New World hantaviruses, can cause hantavirus pulmonary syndrome, which presents with common symptoms like fever, fatigue, and muscle aches before progressing to more severe effects such as shortness of breath and fluid in the lungs. HPS has a fatality rate of 12 to 45 percent depending on the strain.

For variants more common in Europe and Asia, also known as Old World hantaviruses, patients can develop hemorrhagic fever with renal syndrome, which can cause kidney failure and has a fatality rate of one to 15 percent.

The strain of hantavirus linked to the cruise ship appears to be what’s known as the Andes strain, which, per the CDC, is common in South America and has been linked to human-to-human transmission. However, transmitting the hantavirus person-to-person is rare and typically requires close contact in an enclosed space. The Washington Post reports that Argentina, which appears to have a connection to this recent outbreak, has seen an increase of hantavirus cases in recent years and is frequently ranked by the WHO as the nation with the highest rate of the virus in Latin America.

Hantavirus also has a long incubation period with symptoms typically appearing a few weeks after infection but sometimes as many as eight weeks after. On Thursday, Tedros Adhanom Ghebreyesus, director-general of the WHO, said during a briefing that it is “possible” more cases could be reported down the line.
There is currently no cure nor widely available vaccine for hantavirus — surviving severe illness caused by the infection requires prompt medical intervention and ICU treatment.
One of the most prominent cases of hantavirus emerged last year after Betsy Arakawa, the wife of renowned actor Gene Hackman, was found to have contracted hantavirus pulmonary syndrome after the pair were found dead in their New Mexico home. Per the New York Times, it’s believed that Arakawa was likely infected from exposure to deer mice, which typically carry the virus in the state. In 2025, three people in Mammoth Lakes, California, died after contracting hantavirus.

For even more information about hantavirus, infectious-disease expert and doctor Céline Gounder has written an excellent explainer here.

On Thursday, Dutch officials confirmed that approximately 40 people from at least 12 different countries departed the ship at St. Helena to return home on April 24 without contract tracing, per the AP. Oceanwide Expeditions has put the figure at around 30 passengers, six of whom are Americans. Ghebreyesus said the organization has notified the 12 different nations, which, in addition to the U.S., are Canada, Denmark, Germany, the Netherlands, New Zealand, Saint Kitts and Nevis, Singapore, Sweden, Switzerland, Turky, and the United Kingdom.

Public-health authorities have been working to track the passengers down and perform contact tracing. Two British citizens who left the ship beforehand and returned to the U.K. are self-isolating, as are a small number of their close contacts. Citing Dutch officials, the Dutch news outlet RTL reported that a flight attendant who was aboard the same Johannesburg flight as the cruise passenger who later died from hantavirus is currently experiencing mild symptoms and is being tested at a hospital. France24 reports that a French national is being monitored after traveling on the same flight.
U.S. health officials in Georgia, California, and Arizona confirmed that American passengers from the Hondius are being monitored in their states for infection since returning to the United States, per the New York Times. The Washington Post reports that passengers in Texas and Virginia are also being observed. So far, none of the passengers have shown any symptoms. In a statement, the CDC said it’s “closely monitoring the situation” and that the State Department is “leading a coordinated, whole-of-government response including direct contact with passengers, diplomatic coordination, and engagement with domestic and international health authorities.”
“At this time, the risk to the American public is extremely low,” the statement said.
What is the current status of the ship?
On Monday, Oceanwide Expeditions said there were 149 people onboard the Hondius representing 23 different nationalities. Of the three people who were medically evacuated Wednesday, two were crewmembers who presented with “acute respiratory symptoms” while the third is an asymptomatic individual with a connection to the passenger who passed away on May 2.
On Thursday, the operator shared updated figures regarding the number of passengers at the start of the voyage, saying 114 guests were on board on April 1 when the Hondius left Ushuaia, Argentina.

On April 15, six more guests boarded at Tristan da Cunha, bringing the total to 120 including the one deceased passenger.

As of Wednesday, the Hondius has departed Cape Verde, where it was moored off the coast following the detection of the outbreak, en route to Spain’s Canary Islands, which Oceanwide Expeditions estimates it will reach following three to four days of travel. On Thursday, the operator estimated that the Hondius would reach the port of Granadilla, Tenerife, early Sunday.
The remaining people aboard the ship are currently asymptomatic and are reportedly taking precautions like wearing masks and practicing social distancing.
The WHO confirmed Thursday that one of its experts boarded the ship in Cabo Verde and was later joined by two doctors from the Netherlands and an expert from the European Centre for Disease Prevention and Control. The four will assess all the remaining people on board and will stay on board the vessel until it reaches the Canary Islands.
What are experts saying? On Wednesday, Ghebreyesus signaled that the outbreak doesn’t pose any wider risk so far. “At this stage, the overall public-health risk remains low,” he said.
Maria Van Kerkhove, a top infectious-disease epidemiologist at the WHO, echoed that sentiment on Tuesday. “This is not the next COVID, but it is a serious infectious disease,” she said, per the Associated Press. “Most people will never be exposed to this.”In an interview with STAT News, Michael Osterholm, director of the University of Minnesota’s Center for Infectious Diseases Research and Policy, put it simply. “It’s not the next pandemic,” he said.
Osterholm continued, “This is one where everyone should just take a breath and know that we are going to bring this to resolution. With adequate respiratory protection, [they could] very well stop all transmission from this point forward.”
Stanford infectious-disease doctor and epidemiologist Abraar Karan also emphasized in an X thread that this poses nothing close to a COVID-like threat, though this particular hantavirus outbreak may be worse than others:
The hantavirus outbreak won’t be anything like COVID — I think that is the wrong comparison. But it can be worse (or at least more complicated) than the usual local outbreaks that occur in Argentina.
First, I suspect there could be a few more generations of infection. Those who left the ship before the outbreak was detected pose the key risk because they may have exposed others unknowingly via close contact. Case 2 who flew on the plane to Johannesburg and the Switzerland case seem to be the only reported ones thus far. Close contact is the key point here.
So it’s likely that more cases will be detected, but there is no reason for any kind of widespread panic.