Explainer: What is the hantavirus?
A drone view of the cruise ship MV Hondius, carrying passengers suspected of having cases of hantavirus on board, as it prepares to leave Praia, Cape Verde, May 6, 2026.PHOTO: REUTERS
World Health Organisation (WHO) chief Tedros Adhanom Ghebreyesus said on Tuesday "our work is not over" to contain the hantavirus after evacuations from a cruise ship hit by a deadly outbreak of the illness.
The fate of the MV Hondius has sparked international alarm after three passengers died in an outbreak of the rare virus, for which no vaccines or specific treatments exist, with a Frenchwoman also in a critical condition.
Yet health officials have stressed that the global public health risk is low and rejected comparisons to the start of the Covid-19 pandemic.
"There is no sign that we are seeing the start of a larger outbreak," Tedros told a joint news conference with Spanish Prime Minister Pedro Sanchez in Madrid after overseeing the evacuation in Spain's Canary Islands.
.@WHO’s assessment on #hantavirus continues to be that the risk to health globally is low.
My latest update ⬇️ pic.twitter.com/gnm9pbqaF3"But of course the situation could change, and given the long incubation period of the virus, it's possible we might see more cases in the coming weeks," Tedros said of the Andes variant, the only one known to be transmissible between humans.
Among living patients, all of whom are passengers or crew of the ship, seven cases have been confirmed and an eighth is listed as "probable", according to an AFP tally of official figures.
However, the WHO gave the count at a total of 11 cases, including 3 deaths. It said nine of the 11 cases were confirmed, and the other 2 were probable.
Update on #hantavirus:
As of 12 May, 12h00 CEST, a total of 11 cases, including 3 deaths, have been reported. Nine of the 11 cases are confirmed, and the other 2 are probable. All are among passengers or crew on the ship.
We expect more cases given the dynamics of spread on a… pic.twitter.com/NeeLyMQFdkThe affected nationalities include the United States, Britain, France, Spain, Switzerland and the Netherlands.
One of the five French passengers flown back from the ship was in intensive care on a ventilator, battling a "severe" case of the rare disease, according to Dr Xavier Lescure.
She was older than 65 and had pre-existing conditions, the doctor told a press conference at the health ministry, without elaborating.
More than 120 passengers and crew on the MV Hondius were flown out from Spain's Canary Islands on Sunday and Monday, and countries have adopted different health measures for their returning evacuees.
Most have followed the WHO's guidelines, which include a 42-day quarantine and constant monitoring of high-risk contacts because the incubation period can take six weeks.
According to the Dutch authorities, the 26 passengers who landed back on Sunday on the first flight from the Canary Island of Tenerife to the Netherlands had tested negative.
All 26 underwent "thorough medical screening", the Dutch National Institute for Public Health and the Environment said, and despite the negative tests must quarantine. Two more repatriation flights landed later in the Netherlands, carrying 28 more evacuees who will also undergo isolation.
Tedros said he hoped countries would "follow the advice and recommendations we are making", but acknowledged that nations were free to decide their own health protocols.
Insisting that his government had the situation "under control", French President Emmanuel Macron called for strong European coordination with the WHO while speaking at a summit in Kenya.
The MV Hondius presented diplomatic challenges as different countries negotiated over who would receive it and treat its passengers.
Cape Verde refused to receive the ship, which remained anchored offshore of the capital Praia, as three people were evacuated to Europe by air last week.
Spain allowed the vessel to anchor off the Canary Islands for the evacuation of passengers and crew on Sunday and Monday, but the Atlantic archipelago's regional government fiercely opposed the measure.
Defending his government's policy, Sanchez said the "world does not need more selfishness or more fear. What it needs are countries that show solidarity and want to step forward."
The MV Hondius left the island of Tenerife with a skeleton crew on Monday and will be disinfected upon arrival in the Netherlands on Sunday.
What is hantavirus?
Hantaviruses are rodent-borne viruses that can infect people and cause illness. The WHO estimates there are 10,000 to 100,000 human cases globally each year, with severity varying by strain.
The strain identified on the ship is the Andes hantavirus, which typically circulates in Argentina and Chile. The Hondius set off from Argentina on April 1.
How is the virus spread?
Hantavirus spreads primarily through rodents, infecting people via contact with rats or mice, or their urine, droppings, or saliva — often when the virus becomes airborne during cleaning of infested areas. Less commonly, it spreads through contaminated surfaces.
The Andes virus is the only known hantavirus that can spread through close, prolonged human-to-human contact.
The WHO said on May 6 that it had not been informed of any changes in the virus that could have made it more transmissible in this way, but it believes there has been some human-to-human spread on board the Hondius.
Studies have shown that the virus tends to transmit in the early stages of a patient's sickness, when they have symptoms.
WHO Director of Epidemic and Pandemic Management Maria Van Kerkhove told Reuters in an interview that close contact meant something like sharing a cabin or bunk room on board the ship. She said experts were working to establish which passengers were high-risk or low-risk, based on their contacts with passengers who were unwell.
Also Read: Last six passengers leave Hantavirus-hit ship
What are the symptoms of infection?
Hantaviruses, common in different parts of the world, cause different symptoms or diseases, and some cause none at all.
Symptoms typically begin one to eight weeks after exposure and may include fever, muscle aches and gastrointestinal issues, according to the WHO, although a typical incubation period would be closer to two to three weeks, said Andrew Pollard, a professor at Oxford University's Pandemic Sciences Institute.
The Andes hantavirus and other hantaviruses in the Americas can cause hantavirus cardiopulmonary syndrome, which progresses quickly and leads to fluid buildup in the lungs along with heart complications. Fatality rates from hantavirus cardiopulmonary syndrome are up to 50%, the WHO says, compared to 1-15% from the infections common in Asia and Europe.
Can hantavirus infection be treated?
There is no specific treatment for infection from hantavirus, so current therapy focuses on supportive care, including rest and fluids. Patients may need breathing support such as a ventilator.
Prevention focuses on limiting contact with rodents through measures like keeping areas and surfaces clean.
During outbreaks, contact tracing can give others potentially exposed to the virus earlier access to hospital care, improving outcomes and preventing further spread.
What are the risks to the general public?
The cruise ship outbreak is unusual, although disease outbreaks of illnesses such as influenza are more common on ships due to the proximity of people on board, experts said.
The current outbreak is being investigated by experts from the WHO and various countries, but the risk to the public remains low, the UN health agency says.
Pollard said that knowing which virus was causing the outbreak meant it could be managed using public health protocols on the ship, such as containment and isolation, and in countries with returning passengers.
More broadly, hantaviruses continue to circulate worldwide, with the WHO warning of a rise in cases in the Americas in late 2025.