Human-to-human transmission of killer hantavirus suspected in cruise ship outbreak
After deaths and diseases caused by a hantavirus outbreak on a cruise shiphealth officials now suspect that human-to-human transmission may have played a role in the spread of this potentially deadly disease.
Investigators are also scrambling to identify whether the virus involved in the MV Hondius crisis is one known for high death rates and previous cases of human-to-human transmission.
“Some of these cases were very close, and of course human-to-human transmission is inevitable, so as a precautionary measure, this is what we are thinking,” Dr. Maria Van Kerkhove, director of epidemiology and pandemic preparedness and prevention at the World Health Organization (WHO), told reporters on Tuesday in Geneva.
While those possibilities may be reminiscent of the early days of the COVID-19 pandemic — and the potential for the spread of this rare, rodent-borne disease — scientists are quick to stress that the hantavirus is not a major global threat.
“People really need to understand that there are different rates of person-to-person transmission,” said Angela Rasmussen, a virologist with the University of Saskatchewan’s Vaccine and Infectious Disease Organization.
In the case of hantavirus, individuals are often the end of the line, Rasmussen told CBC News, making this cluster of cases unusual.
There are also many different types of this virus, one of them is located in Argentinawhere sailing began. Those complications have been linked to transmission between people in hospital settings, but those cases remain rare and isolated, Rasmussen stressed.
“So this virus – right now anyway – doesn’t seem to be as dangerous as something like the flu.”
7 diseases, 3 deaths
At least seven of the 150 or so passengers and crew of the Dutch-flagged MV Hondius fell ill at different times during the ship’s month-long voyage to remote islands across the Atlantic Ocean.
All seven are now hantavirus cases, with two infections officially confirmed so far, the WHO said. Four Canadians are also on the stranded ship as it waits in waters near the West African country of Cape Verde, but there are no reports of infection among those people.
Symptoms for passengers and crew infected with the virus include fever, stomach flu and rapid progression to pneumonia, acute respiratory distress syndrome and shock – with people starting to get sick in different areas between April 6 and April 28, WHO noted. latest status report.
Three people have now died, namely a German passenger and a Dutch couple. The couple fell ill at different times, the man died on the ship on April 11 and his wife died in a hospital in South Africa after falling ill on a flight to Johannesburg. The WHO is contacting and tracing the passengers on that flight, the organization said.
Several people on the Hondius are still awaiting evacuation, including two people in need of “urgent care,” and a person connected to one of the dead passengers, the company that operated the luxury cruise on Tuesday. Two special flights are now en route to Cape Verde to assist with that evacuation, reads the latest update from Oceanwide Expeditions.
The risk to the general public remains low, said WHO’s Van Kerkhove. Any person-to-person transmission would have occurred between people who are closely related, such as married couples, she said.
Usually, people catch hantavirus directly from infected rats or mice – or by inhaling their droppings – and do not pass it on.
“This is not a virus that spreads like the flu or like COVID,” Van Kerkhove said. “It’s very different.”
A separate exploration of the Andes continues
Among the sick, a British man who became the first passenger to be diagnosed with hantavirus remains in hospital in South Africa.
Based on the history of the group going to Argentina, tests are underway to confirm whether the passenger had the South American strain of the virus, said Nazir Ismail, executive director of the National Institute of Communicable Diseases of South Africa.
That strain, known as the Andes variant, is among the “New World” strains found throughout the Americas, which can cause a serious disease known as hantavirus pulmonary syndrome (HPS).
Although symptoms may not appear for weeks, the condition can quickly progress, leading to severe respiratory failure with a mortality rate of nearly 40 percent.
The Andes variant is also unique in causing human-to-human transmission events.
“Although rare, limited human-to-human transmission of HPS due to the Andes virus has been reported in public areas involving close and long-term contact. Secondary infections among health care workers have previously been documented in health facilities, although they remain rare,” WHO said in its status report.
The World Health Organization says cruise ship passengers sick with hantavirus may have contracted the virus on board, and person-to-person transmission may have occurred on the MV Hondius. Three people died in this shipwreck and about 150 people are still stuck on the ship.
Previous collections involved person-to-person transmission
Medical journal article since 1997for example, documented a cluster of 20 Andes virus cases in southern Argentina, including many physicians who were directly involved in the care of patients with severe hantavirus infections.
“Epidemiologic links between all but four cases and evidence of low local rodent densities strongly suggest human-to-human transmission … during this outbreak,” the research team noted.
The next paper, published in June 2025discussed an outbreak of Andes virus in the village of Epuyén, in southern Argentina, seven years ago.
“This strain has demonstrated a high rate of ongoing transmission within the population that requires the implementation of quarantine measures, strict contact tracing, isolation of close contacts, and effective clinical surveillance to prevent further spread,” the researchers wrote.
Last December, the American branch of the WHO also warned that human hantavirus infections are increasing in the region, especially in Bolivia, Brazil and Argentina, as well as the number of deaths.
Argentina reported more than 60 cases of hantavirus pulmonary syndrome last year, with a fatality rate of 32 percent – an increase in the average death rate of 15 percent four years ago.
“Old World” hantaviruses, in contrast, are found in Europe and Asia and usually have a very low mortality rate related to hemorrhagic fever with renal syndrome, which includes kidney failure and internal bleeding.
Cruise ship outbreaks remain common
While scientists will be closely monitoring the spread of the Andes strain of the virus, infection with all types of hantavirus is extremely rare, and person-to-person transmission remains extremely rare.
The WHO estimates that there are 10,000 to 100,000 human cases worldwide each year. In Canada, only 168 confirmed cases of hantavirus pulmonary syndrome have been reported since surveillance began in 1994, health officials told CBC News.
So why are so many people getting sick back and forth from such a rare virus in MV Hondius?
Rasmussen, of the University of Saskatchewan, said it was completely unexpected that a cluster of hantavirus infections would emerge inside a cruise ship — either from a person who first became infected in Argentina and brought the virus on board or from multiple rodent-related infections on the ship itself.
WATCH | Cruise ship stranded at sea due to suspected deadly hantavirus outbreak:
At least three people have died and several others have fallen ill after an outbreak of suspected hantavirus – a virus usually spread by rodents – on a cruise ship off the coast of West Africa. Four Canadians are among the 150 passengers trapped on the ship.
The different locations of these vessels, unfortunately, can help facilitate the spread of viral diseases, Rasmussen said. “Cruise ships are places where people live alone in one place. They share common infrastructure, like plumbing … they share the same air and indoor spaces.”
Norovirus, known to cause short-term gastrointestinal illness, is a common source of cruise ship outbreaks. And in 2020, a tragedy involving hundreds of cases of COVID-19 on a cruise he was also in the headlines in the early days of the epidemic.
Rasmussen said this unprecedented hantavirus outbreak serves as a reminder that there is a lot of rodents circulating everywhere, including in many parts of Canada — that pose a greater risk to Canadians than a cluster of infections on a cruise ship.
“Wear a respirator when sweeping up old mouse droppings, because you don’t want to breathe in those inhaled aerosols,” he warns.
