The Antarctic cruise liner The Hondius.
Image: Supplied
Sammy Westfall and Kendra Nichols
The rodent-borne hantavirus is suspected in an outbreak aboard a cruise ship in the Atlantic Ocean in which three passengers have died within three weeks.
The World Health Organization said two cases of hantavirus had been confirmed and that there are five suspected cases. Oceanwide Expeditions, the operator of the Hondius expedition ship, said one passenger is in intensive care in Johannesburg and two crew members aboard the vessel have respiratory symptoms.
There are 87 surviving passengers and 61 crew members aboard the vessel, representing almost two dozen countries.
Although hantavirus is normally linked to exposure to infected rodents’ urine or feces - a particular risk while cleaning - in rare cases it can spread between people. Here’s what to know about the disease.
The Hondius, a polar-rated expedition ship, set off from Ushuaia, Argentina, on April 1 for a journey across the South Atlantic, with an itinerary including such remote and ecologically diverse locales as Antarctica, South Georgia, Nightingale Island, Tristan da Cunha, St. Helena and Ascension Island.
Details released by Oceanwide Expeditions and the WHO show an alarming timeline of events beginning about a week later.
The illnesses began April 6, when a Dutch man developed fever, headache and mild diarrhea. He died April 11 after developing respiratory symptoms, but no microbiological tests were performed, the WHO said. His wife, who was experiencing gastrointestinal symptoms, accompanied his body as it was brought off the ship on St. Helena, a remote island territory in the South Atlantic Ocean. She was flown to a hospital in Johannesburg, where she died April 26. Her case was confirmed as a hantavirus infection on May 4, the WHO said.
Aboard the ship, a British man reported shortness of breath and signs of pneumonia on April 24, and on April 27 he was medically evacuated from the South Atlantic island of Ascension to South Africa, where hantavirus was identified. That man is in the intensive care unit in critical but stable condition, Oceanwide Expeditions said Monday.
On Saturday, a third passenger died, a German national with pneumonia-like symptoms that began April 28. The cause has not been identified.
Of the passengers, 19 are British, 17 are American, 13 are Spanish and eight are Dutch. More than half of the crew members are Filipino nationals.
Hantaviruses are a family of viruses that can cause serious illness and death. They are spread mainly by rodents and can cause hantavirus pulmonary syndrome (HPS), which is more common in the United States, and hemorrhagic fever with renal syndrome (HFRS), which is found mostly in Europe and Asia, according to the Centers for Disease Control and Prevention. Both are severe and potentially deadly.
It can be contracted by contact with droppings from infected rodents, commonly through inhalation when entering or cleaning unventilated areas. Person-to-person transmission is also possible, but more rare.
Greg Mertz, emeritus professor of internal medicine at the University of New Mexico and a hantavirus research expert, said that while hantaviruses are found worldwide, they are uncommon in North and South America. However, the type of virus found in North and South America causes more serious illness and has a higher case fatality rate than that in Europe and Asia. The type of virus on the ship has not been confirmed.
Since the average incubation period is about three weeks, the timeline of the illnesses on the cruise suggest that there could have been person-to-person transmission, Mertz said. The only hantavirus transmitted that way is the Andes virus, found in Chile and Argentina.
Human-to-human transmission, which is relatively rare, requires prolonged contact with an infected person, said Gaby Frank, director of the Johns Hopkins Special Pathogens Center.
Symptoms typically start to show between one and eight weeks after first contact with the virus.
HPS affects the lungs and can cause fatigue, fever and muscle aches initially, followed by coughing and shortness of breath. Once inhaled, the virus can reach the lungs and infect cells that line tiny blood vessels in the lungs, allowing fluid to enter and making it difficult to breathe, according to the American Lung Association.
Thirty-eight percent of people who develop respiratory symptoms die of the disease, according to the CDC.
HFRS is less deadly but still serious. It affects the kidneys and causes headaches, back and abdominal pain, fever, nausea and blurred vision. Later symptoms include low blood pleasure, internal bleeding and kidney failure. Fatality rates vary between less than 1 percent and up to 15 percent.
Hantaviruses are found all around the world, but outbreaks are rare. In 1993, a mysterious outbreak of severe respiratory illness originating in the Southwest killed about 30 people. The deaths were the first documented cases in the Americas of hantavirus disease in humans and triggered a public health response that has helped prevent other similarly sized outbreaks to date, The Washington Post reported.
Hantavirus was named as the cause of death for Betsy Arakawa, pianist and wife of actor Gene Hackman, last year.
There were 890 laboratory-confirmed hantavirus cases in the United States between 1993, when the CDC began tracking the illness, and the end of 2023. More than 90 percent of those occurred west of the Mississippi River. It is commonly linked to people with occupational exposure, such as those working in construction, pest control, janitorial and agricultural work, the American Lung Association said.
Globally, there may be as many as 150,000 cases of HFRS each year, according to a review by the American Society for Microbiology.
Treatment options are limited, so the best protection against the illness is to avoid contact with rodents and to take care when cleaning their droppings, wearing a well-fitted N95 mask. Health officials also warn against vacuuming or sweeping contaminated areas to avoid releasing particles into the air.
The two symptomatic crew members are expected to be medically evacuated from the ship in Cape Verde, the company said, along with a third person associated with the German national who died Saturday. On board, passengers are isolating, and hygiene protocols are in place.
The company said it is considering sailing the remaining passengers to Las Palmas or Tenerife in Spain’s Canary Islands, where further medical screening could be coordinated by the WHO and Dutch health services.