90-Second Read: What the (rather brief) history of Hantavirus reveals about its spread

Scientists think the Hantavirus, the deadly pathogen that has infected 11 passengers on a Dutch cruise ship, could be as old as humans. The first known outbreak came during the Korean War in the 1950s, when around 3,000 United Nations troops developed a mysterious illness that scientists would later recognize as Hantavirus. The limited number of past outbreaks could offer clues about how the cruise ship passengers got sick, but doctors who have studied Hantavirus said there's more to learn. But it wasn't until some 20 years later, in 1978, that scientists linked the virus to a rodent near the Hantan river in South Korea, which gave Hantavirus its name. Up to half of Hantavirus cases can be fatal, depending on the strain and method of transmission.

There were physicians that recognized, through seeing or hearing about multiple cases, that maybe we were seeing something that we didn't understand and we hadn't learned about in medical school," said Mertz, who helped investigate the outbreak. Most human cases of Hantavirus in North America are the Sin Nombre strain and are acquired through contact with the aerosolized urine, feces or saliva of infected rodents. Tom Boo, the public health officer for Mono County, a rural area in California that has recorded 27 Hantavirus cases since 1993, the most in the state. Here's what we know about the major outbreaks over the last several decades. The first case to raise alarm was a 19-year-old long distance runner in New Mexico whose fiancée had just died of an unknown respiratory illness.

Hantavirus is rarer, but far deadlier than respiratory viruses like Covid or flu. The Andes strain is the only Hantavirus known to spread from person to person. Scientists learned more about human transmission after so-called "super-spreader" events in Argentina in 2018 and 2019. Before those measures were taken, one infected person was spreading the virus to about two others, on average. In 1993, public health officials began investigating a mysterious cluster of illnesses in the "Four Corners" region of the United States, where Arizona, Colorado, New Mexico and Utah meet.

The Centers for Disease Control and Prevention ultimately confirmed the illnesses as Hantavirus based on antibody testing and autopsies. Hantavirus gained further attention last year after Betsy Arakawa, the wife of Oscar-winning actor Gene Hackman, died of the virus at the couple's home in Santa Fe, New Mexico. Public health authorities eventually contained the outbreak by isolating symptomatic patients and telling their close contacts to stay home. A 2020 paper in the New England Journal of Medicine determined that patients with a high viral load were more likely to spread the virus, and that transmission was more likely to occur at massive social gatherings or if someone had extensive contact with an infected person. At least in terms of the behavior of the virus currently, how we're seeing these cases.