90-Second Read: Hantavirus on a cruise ship: What to know about the Andes virus

By now, we've seen the headlines about the outbreak of Hantavirus aboard a cruise ship earlier this month. It's known as the Andes virus, and it's deadlier than most other forms of Hantavirus. Based on genetic sequencing that's been performed on samples taken from several passengers on the cruise ship, it appears to be a strain quite similar to the Andes virus that caused the new outbreak. The Hantavirus is what's known as a zoonotic virus, meaning it originates in animals and can be spread to humans.

As with all forms of Hantavirus, there are no targeted treatments or approved vaccines for the Andes virus. Symptoms can be treated with oxygen therapy and fluid replacement, but the Andes virus causes severe respiratory failure and has an estimated fatality rate of 35% to 50%. This bodes well for the cruise ship outbreak, where symptomatic passengers are being isolated and all others will continue to be monitored. Even if a human catches the virus from rodent exposure, different species of the virus are carried by different rodents, and it most commonly spreads by breathing in particles of dried rodent droppings or urine, that's where it ends.

However, there is an extremely rare strain of the virus that has the ability to spread from human to human. In 2018, the Andes virus spread through a small town in Argentina, infecting 34 people, 11 of them fatally. An analysis found that the outbreak began when one person, infected from a rodent, attended a birthday party of about 100 people. And more than 80 health care workers who had unprotected contact with patients weren't infected, which shows how inefficiently the virus moves between people.

This suggests that one passenger may first have gotten sick from rodent exposure, then transmitted the virus to other passengers. Fortunately, the Andes virus doesn't jump efficiently from human to human. This, along with the virus' relative inability to hop from one person to another, should limit the outbreak.