Hantavirus is suspected of spreading aboard a luxury cruise ship, killing three passengers and raising new concerns as a once-unknown disease, with an extraordinarily high mortality rate, rises amid changing climate conditions.
Authorities are still trying to determine what happened aboard the ship, which charges fees of up to $28,845 for a 46-day voyage that includes a tour of the Antarctic Peninsula and stops in Tierra del Fuego, on the southern tip of Argentina.
In addition to the three deaths, a fourth passenger was evacuated to a South African hospital and was in intensive care, and two crew members fell ill. The Dutch-flagged ship remained off the coast of Cape Verde, an island nation about 400 miles west of Senegal, where it was scheduled to dock on Monday.
Hantavirus is quite rare in the Americas, but its high fatality rate makes it a disease of major public health concern, says the World Health Organization. Hantavirus is most common in Asia and Europe, where circulating strains are less deadly, with a case fatality rate ranging from less than 1% to 15%.
Hantavirus is most commonly transmitted by inhaling particles contaminated with the virus, such as urine, saliva, or dried mouse droppings.
But there is a strain of hantavirus, known as Andes virus, that can be transmitted from person to person and has been transmitted in Thailand and Argentina.
It is unclear which strain of hantavirus affected the ship.
The first death on the ship occurred on April 11 somewhere in the Atlantic Ocean and the cause of the man's death could not be determined on board, the ship's operator said. The body was transported off the ship on April 24 when the ship docked at the island of Saint Helena, about 1,100 miles from Africa, and the man's wife accompanied his remains.
The wife became ill during the trip home and later died. The cruise operator was notified of the woman's death on April 27. The couple was of Dutch nationality. On the same day, another passenger, a British citizen, became seriously ill on the ship and was medically evacuated to South Africa. That patient was confirmed to have hantavirus.
A German passenger died aboard the ship on Saturday. And on Monday, the ship's operator said two crew members, a Briton and a Dutchman, had acute respiratory symptoms, one mild and one severe, but both required urgent medical attention.
Possibilities that could explain the suspected outbreak, according to Dr. Peter Chin-Hong, an infectious disease expert at the University of California, San Francisco, include the entry of rodents aboard the ship and exposing people to the virus, or human-to-human transmission.
“Could a member of the cruise ship have been cleaning an area and, in the process, aerosolized some rodent droppings?” said Dr. Elizabeth Hudson, regional chief of infectious diseases for Kaiser Permanente in Southern California. “Was there a shore excursion that passengers and crew attended where they were exposed to aerosolized rodent droppings?”
Because hantavirus is so rare, it's hard to say what effect these deaths could have on the cruise industry. COVID-19 hit the industry hard, but it was a global pandemic in which a virus spread rapidly through person-to-person contact. A key question for researchers is how the virus spread.
The MV Hondius is operated by Oceanwide Expeditions, which has a fleet of four ships and bills itself as an eco-friendly cruise tour operator with trips to the Arctic and Antarctic. The Hondius has capacity for 170 passengers in 80 cabins.
As of Monday, there were 148 people on board, including 17 American passengers. One deceased passenger remained on board.
The MV Hondius set sail on March 20 from Ushuaia, the capital of Tierra del Fuego in the southern tip of Argentina, on a round trip to the Antarctic Peninsula, returning to port 11 days later. On April 1, the ship left Argentina and headed back to Cape Verde, with stops in the islands of the Atlantic Ocean: South Georgia, Tristan de Cunha and Saint Helena.
Strains of hantavirus in the Americas are attracted to the small blood vessels in the lungs and cause the blood vessels to leak, which is bad, because the lungs need air, Chin-Hong said.
“So people can't breathe,” he said. “It's like you're drowning. The lungs are leaking, so fluid fills up in the lungs.”
There are 50 species of hantavirus. The virus found in America tends to cause cardiopulmonary syndrome, a condition that affects both the heart and lungs, said Dr. Gaby Frank, director of the Johns Hopkins Center for Special Pathogens.
Hantavirus is associated with a case fatality rate of up to 50% in the Americas. It was the cause of Gene Hackman's death. Wife of 65 years, Betsy Arakawa.at his home in Santa Fe, New Mexico. Arakawa died days before Hackman, 95, died as a result of heart disease. There were signs of rodent entry in some structures on the couple's property. Last year, three people in Mammoth Lakes He died after contracting hantavirus. There was evidence of mice where the three deceased had worked, and one person had numerous mice in their home, according to the public health office in Mono County, home to Mammoth Lakes.
There is no vaccine or specific antiviral medication for hantavirus. In America, doctors can help infected people by placing them on a life-support machine known as ECMO, for extracorporeal membrane oxygenation, which breathes for the patient, oxygenating the blood. “It's very, very intense, and that's why the mortality rate is so high,” Chin-Hong said.
Some experts expect hantavirus to be a greater concern in the future in some parts of the world due to climate change, as rising temperatures favor animals and insects that transmit diseases, such as the rise of Lyme disease as the climate becomes more hospitable to the ticks that transmit it.
Since rainfall patterns change as global temperatures rise, “then the rodent population would be expected to increase over time,” Chin-Hong said. With climate change over time, then you would expect the rodent population to increase over time,” Chin-Hong said. For example, people who became ill and died from rat-borne diseases, such as leptospirosis, after Hurricane Maria hit Puerto Rico in 2017.
In the United States, an average of 30 cases of hantavirus are reported each year, a figure that has remained relatively stable. But “there has been more media attention,” Hudson said.
Times staff writer Karen Garcia contributed to this report.
