On the menu today: No, the Morning Jolt is not in reruns from early 2020; today’s edition is about a completely different report of a viral outbreak in a far-off corner of the world, where the World Health Organization says there is little reason to worry. Today, we’ll be talking about hantavirus.
A New Outbreak
The good news is that the odds of any given viral outbreak turning into a global pandemic are exceptionally low.
This is because most viruses are not harmful to humans; scientists “estimate that there are 10 nonillion (10 followed by 30 zeroes) individual viruses existing on Earth.” Pre-Covid-19 research in 2019 found that the world has “only” 40,000 kinds of mammalian viruses (the previous estimate had been about 1.5 million) and that “only” 10,000 to 12,000 viruses in mammals are potentially harmful to humans. There are “only” about 200 viruses that virologists spend much time worrying about infecting humans.
You probably don’t have much to worry about with the current hantavirus outbreak, traced to the MV Hondius, a Dutch-flagged cruise ship that had been venturing around the South Atlantic. One of the reasons this outbreak is raising so many eyebrows is the curious location; people get hantavirus from contact with rodents like rats and mice, especially when exposed to their urine, droppings, and saliva. It can also spread through a bite or a scratch by a rodent, but this is rare.
The strain of the virus found on the infected passengers is orthohantavirus andesense, sometimes called “Andes virus.” According to the World Health Organization, “Although uncommon, limited human‑to‑human transmission of HPS due to Andes virus has been reported in community settings involving close and prolonged contact. Secondary infections among healthcare workers have been previously documented in healthcare facilities, though remain rare.”
And when they say rare, they mean only two confirmed human-to-human-driven outbreaks in recorded history: “The outbreak currently plaguing the Hondius is only the second confirmed outbreak where hantavirus was transmitted from person to person. In 2018, 34 people were infected and 11 died in an outbreak that started at a party in Argentina. Prior to that, there had been reports of human-to-human spread, but researchers couldn’t rule out that they had both been exposed to rodents.”
The most ominous thing you’re going to hear from WHO is, “Hantavirus infections are associated with a case fatality rate of <1–15 percent in Asia and Europe and up to 50 percent in the Americas. While there are no specific treatment nor vaccines for hantavirus infections, early supportive care and immediate referral to a facility with a complete ICU can improve survival.”
Now, where the current outbreak gets complicated is the fact that these passengers had been getting around . . . and a portion of them disembarked and went home. From the WHO, “The vessel departed Ushuaia, Argentina, on April 1, 2026 and followed an itinerary across the South Atlantic, with multiple stops in remote and ecologically diverse regions, including mainland Antarctica, South Georgia*, Nightingale Island, Tristan da Cunha, Saint Helena, and Ascension Island. The extent of passenger contact with local wildlife during the voyage, or prior to boarding in Ushuaia remains undetermined.”
(Those who have read Dueling Six Demons will recognize Ushuaia, Argentina, as the southernmost city in the entire world, the city closest to Antarctica, and about as close as you can get to “the end of the earth.”)
According to WHO, “Seven cases (two laboratory confirmed cases of hantavirus and five suspected cases) have been identified, including three deaths, one critically ill patient and three individuals reporting mild symptoms. Illness onset occurred between April 6 and 28 2026 and was characterized by fever, gastrointestinal symptoms, rapid progression to pneumonia, acute respiratory distress syndrome and shock.”
The cruise ship carried 88 passengers and 59 crew members from 23 countries. The ship is currently moored off the coast of Cabo Verde, which is on the coast of West Africa.
Apparently “around 40” passengers disembarked on Saint Helena, an island in the middle of the Atlantic Ocean. It is one of the world’s most isolated islands. (It is the place where Napoleon Bonaparte was exiled from 1815 until his death in 1821.) There is usually one flight in and out each week, to Johannesburg, South Africa. The South African Health Minister, Dr. Aaron Motsoaledi, stated contact tracing identified 62 individuals as possible contacts with the infected person, and 42 individuals have been traced and monitored.
There’s a similar ongoing hunt to trace the contacts of an infected man in Zurich, Switzerland:
Swiss officials are rushing to trace the contacts of a man who has been hospitalized in Zurich with a strain of the hantavirus that is capable of human-to-human transmission.
The patient became ill in Switzerland after returning from a three-week April cruise that took him and his wife from the tip of South America to the South Atlantic island of St. Helena, officials said Wednesday. . . .
Swiss officials said they are investigating whether the Zurich patient came into contact with other people during his infectious period. The U.S. Centers for Disease Control and Prevention says symptoms of a hantavirus infection usually take one to two weeks to emerge, but in some cases can take as long as eight weeks.
The Spanish publication El Pais reported that a Spanish passenger still on the ship told them, “Twenty-three people got off in Saint Helena. There are 23 people wandering around there, and until three days ago, no one had contacted them. . . . The Australian went back to Australia, the one from Taiwan to Taiwan, the Americans to all corners of North America. The Englishman to England, the Dutch to their homes. . . . I don’t remember the rest, but no Spaniards.”
If there’s anything we learned during Covid, it was that the more accurate information you have ,the earlier in the outbreak, the better off everyone is. Unfortunately, according to Ruhi Cenet, one of the passengers on the ship, the initial communications from the ship’s crew proved inaccurate:
On April 12, the ship’s captain began making an announcement to the passengers.
Cenet said he immediately felt that something was wrong because the captain had not participated in previous briefings. He decided to record the announcement.
“I felt something odd,” Cenet said. . . .
“This is my sad duty to inform you that one of our passengers suddenly passed away last night,” the captain says in the video.
“Tragic as it is, it was due to natural causes, we believe,” he continued. “And also whatever health issues he was struggling with, I’m told by the doctor, were not infectious, so the ship is safe when it comes to that.”
He said that life largely continued as normal on the ship given the messaging that the passenger who died was not infectious.
“Knowing that we didn’t get isolated and we didn’t take any caution for a solid 12 days, for my part, is a very sad situation.”
Cenet mentioned that many of the passengers on the cruise ship were elderly; on average, elderly people have less robust immune systems than younger people.
As noted above, human-to-human spread of hantavirus is rare. Dr. Gustavo Palacios, a microbiologist at the Icahn School of Medicine at Mount Sinai in New York, told CNN that “the window for transmission of the Andes virus appears to be short, about a day. People are at their peak of infectiousness on the day they develop a fever.”
One of the reasons that SARS-CoV-2, the virus that causes Covid-19, became the hugely consequential global pandemic that it did is that it strangely and inexplicably spread so quickly and effectively among human beings, almost as if this perfectly normal, naturally occurring horseshoe bat coronavirus had been engineered in a lab to gain a function or two.
This, so far, appears to be a familiar rodent virus, that unfortunately spread to a location where elderly people were in close contact, and where the ship’s medical staff might not immediately diagnose or recognize it. A sad story, but not any reason for panic.
ADDENDUM: In case you missed it yesterday, examining simultaneous war and peace in the Persian Gulf.