A general view of the cruise ship MV Hondius stationary off the port of Praia, the capital of Cape Verde, on May 3, 2026. An outbreak of "severe acute respiratory illness" on board a cruise ship in the Atlantic has left two people dead and a third in …
OAKLAND, Calif. - California is one of several U.S. states monitoring hantavirus after the rare disease was detected on a cruise ship and led to the deaths of three passengers in recent weeks.
The California Department of Health said Thursday that it was notified by the U.S. Centers for Disease Control that a number of California residents were onboard the cruise with passengers infected with hantavirus.
Arizona and Georgia health officials are also monitoring hantavirus after cruise passengers returned to the states.
The cruise ship, the MV Hondius, departed from Argentina on April 1. Five days later, a 70-year-old male passenger became ill. He died on April 11.
The man's wife departed the ship on April 24, and died shortly thereafter.
A German woman began showing symptoms on April 28. She died on May 2, bringing the total number of cruise ship deaths to three, officials say.
California residents were passengers on hantavirus-stricken ship
Though California residents were on board the ship, state health officials noted that the risk to public health in California is low, and no Californians are infected with the virus.
On April 24, nearly two weeks after the first passenger had died on board, more than two dozen people from at least 12 different countries left the ship without contact tracing, the ship’s operator and Dutch officials said Thursday.
This included six passengers from the U.S.
In a statement Wednesday, the CDC said the risk to the U.S. is "extremely low."
"The Administration is closely monitoring the situation with U.S. travelers onboard the M/V Hondius cruise ship with confirmed hantavirus. Our top priority remains the health and safety of all U.S. passengers," the CDC said.
Risk to public health is ‘low’
None of the remaining passengers or crew on the ship are currently symptomatic, the Netherlands-based Oceanwide Expeditions cruise ship company said.
The World Health Organization says the risk to the wider public is low. Hantavirus is usually spread by the inhalation of contaminated rodent droppings and isn’t easily transmitted between people.
"We believe this will be a limited outbreak if the public health measures are implemented and solidarity is shown across all countries," said Dr. Abdirahman Mahamud, the WHO’s alert and response director on Thursday.
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What is hantavirus?
The word hantavirus refers to a broad family of viruses, with different versions in different countries. It comes from contact with rodents or their urine, saliva or feces, particularly when it’s inhaled.
Hantavirus infections are relatively uncommon globally. In 2025, eight countries within the Americas had documented 229 cases and 59 deaths, according to the World Health Organization.
"This is not the next COVID, but it is a serious infectious disease," Maria Van Kerkhove, director of epidemic and pandemic preparedness at the World Health Organization, told The Associated Press. "Most people will never be exposed to this."
An infection can quickly become life-threatening. Death rates vary by which hantavirus causes the illness. Hantavirus pulmonary syndrome is fatal in about 35% of people infected, while the death rate for hemorrhagic fever with renal syndrome varies from 1% to 15% of patients, according to the U.S. Centers for Disease Control and Prevention.
Despite years of research, many questions have yet to be answered, including why it can be mild for some people and severe for others and how antibodies are developed. Some researchers have been following patients over long periods of time in hopes of finding a treatment.
How does hantavirus spread?
People are typically exposed to hantavirus around their homes, cabins or sheds, especially when cleaning enclosed spaces with little ventilation or exploring areas with mouse droppings.
Most U.S. cases are in western states. New Mexico and Arizona are hot spots, likely because the odds are greater for mouse-human encounters in rural areas.
The only one of the hantaviruses that’s been found to spread from person to person is the Andes virus, which has been confirmed in the current cruise ship outbreak.
Even then, transmission between people does not happen easily and requires "close and prolonged’’ contact, according to the WHO.
Argentina’s health ministry said hantavirus led to 28 deaths nationwide last year. The ministry on Tuesday reported 101 hantavirus infections since June 2025, roughly double the caseload recorded over the same period the previous year.
Hantavirus symptoms
Hantavirus symptoms can feel a lot like the flu. Fever, chills, muscle aches and maybe a headache are common.
Hantavirus pulmonary syndrome, which can cause the lungs to fill with fluid, usually presents between one and eight weeks after exposure to an infected rodent.
The other syndrome caused by hantavirus — known as hemorrhagic fever with renal syndrome, which can cause bleeding, high fever, and kidney failure — usually develops within a week or two after exposure.
Hantavirus treatment
There is no treatment or cure for hantavirus, but medical experts say early diagnosis can increase the chance of survival.
Hantavirus prevention
Public health experts say the best way to avoid hantavirus is to minimize contact with rodents and their droppings. Use protective gloves and a bleach solution for cleaning up rodent droppings. Don’t clean them up by sweeping or vacuuming, which can cause virus particles to get into the air.
The Associated Press contributed to this report.
The Source: The California Department of Public Health, The Associated Press and previous FOX Local reporting.