A suspected hantavirus outbreak aboard a cruise ship has gained global attention to the rare but potentially deadly virus. Three passengers have died and several others fell ill after traveling on the MV Hondius cruise ship, raising concerns about possible human-to-human transmission of the Andes strain of hantavirus. The outbreak comes months after Betsy Arakawa, wife of actor Gene Hackman, reportedly died from hantavirus pulmonary syndrome in New Mexico earlier this year.

In a post on X, World Health Organization Director-General Tedros Adhanom Ghebreyesus said the United Kingdom had notified the WHO under the International Health Regulations about a cluster of passengers with severe respiratory illness aboard the Dutch-flagged cruise ship MV Hondius, which had travelled from Argentina to Cabo Verde. According to the WHO, eight cases have been reported so far, including three deaths.

It further added, Five of the eight cases have been confirmed as hantavirus, while the remaining three are suspected cases. The WHO has also informed 12 countries whose nationals disembarked in Saint Helena, including Canada, Denmark, Germany, the Netherlands, New Zealand, Saint Kitts and Nevis, Singapore, Sweden, Switzerland, Türkiye, the United Kingdom and the United States.

What is hantavirus and why is it dangerous?

Hantaviruses are a group of viruses found across the world that rodents usually carry. In the United States, the most serious form is hantavirus pulmonary syndrome (HPS), which mainly attacks the lungs and can rapidly become life-threatening. The disease has a mortality rate of nearly 38%.

ALSO READ

Symptoms often begin one to eight weeks after infection and initially resemble the flu. Patients may experience fever, fatigue, muscle pain, headaches, chills, nausea, vomiting and abdominal pain. Within a few days, the illness can worsen dramatically, leading to coughing, breathing difficulty and severe respiratory distress that may require intensive care or intubation.

ALSO READ

The virus commonly spreads through contact with rodent urine, saliva or droppings, especially when contaminated particles become airborne and are inhaled. In rare cases, infection may occur through rodent bites or by touching contaminated surfaces and then touching the nose or mouth.

Why are experts closely watching the cruise ship outbreak?

Health officials are particularly concerned because the outbreak may involve the Andes strain of hantavirus, found mainly in South America. Unlike most hantavirus strains, Andes virus has shown limited human-to-human transmission in the past.

Maria Van Kerkhove, epidemiologist and technical adviser to the World Health Organisation, told NBC, “Our assumption is they were infected off the boat and then joined the cruise. However, we do believe that there may be some human-to-human transmission that’s happening among the really close contacts, the husband and wife, people who’ve shared cabins, etc.”

The cruise ship departed from Ushuaia on April 1 with 88 passengers and 59 crew members. According to the WHO, eight people onboard developed symptoms and three cases have been laboratory-confirmed as hantavirus. A British passenger remains in intensive care in South Africa, however, several others reported mild symptoms. Most passengers are still quarantined on the ship near Cape Verde.

Scientists believe the outbreak may have started during a birding expedition or from rodent exposure in Argentina before boarding the ship. Some experts also suggested infected rodents could have entered the ship through food or supplies.

Why is person-to-person spread considered extremely rare?

Experts stressed that hantavirus is very different from viruses like Covid-19 and does not spread easily between people. Human transmission has only been linked to the Andes strain and usually requires extremely close contact.

“The majority of hantaviruses cannot be spread through human-to-human spread,” said Sabra Klein, professor at the Johns Hopkins Bloomberg School of Public Health told NBC. “This happens to be the only one. It is still unbelievably rare.”

Klein further explained, “Andes virus, as a hantavirus, requires a significant degree of contact with bodily fluids. In the original reports that came out in the early 2000s, case studies show spread between married couples, people who live together and are intimate. That is where you have the spread.”

Doctors and researchers say there is still limited understanding of exactly how the virus spreads between humans or how much exposure is needed for infection. Dr. Shauna Gunaratne from Columbia University said, “It’s not really understood.”

How is hantavirus diagnosed and treated?

Diagnosing hantavirus can be difficult because early symptoms resemble common viral illnesses. Laboratory tests look for antibodies in blood samples, but these antibodies may not appear immediately, leading to false-negative results during the first week of illness. In some cases, the disease is confirmed only after death through tissue testing and PCR analysis.

There is currently no specific cure or antiviral treatment for hantavirus. Doctors mainly provide supportive care such as oxygen therapy and blood pressure support to stabilise patients with severe illness.

Scientists are now racing to identify the exact strain responsible for the cruise ship outbreak. Morgan Gorris, a scientist at Los Alamos National Laboratory, said identifying the strain could help determine where the infections began. “There are many different hantaviruses that cause disease, and a lot of them are regionally located,” she said. “So if we can identify which hantavirus caused this disease, that will give us a clue to where the cases originated.