SANTIAGO, Chile — When a rare but deadly rodent-borne virus struck passengers on a cruise ship and seemed to be spreading, there were no treatments for those who fell ill and no vaccines to protect others.
That was the case even though it wasn’t a novel germ that the world had never seen before, like the virus that caused the coronavirus pandemic. It was a hantavirus, one of a family of viruses that have been known for decades and are thought to exist around the world.