Hantavirus hit the American radar in 1993. That spring, a healthy young Navajo man and his fiancée died suddenly in the Four Corners area, where the borders of Arizona, New Mexico, Colorado, and Utah meet. Both had suffered acute respiratory failure, which means that they couldn’t breathe. An Indian Health Service doctor, going over death records, discovered five similarly healthy young people who’d all died under similar circumstances. Over the next few weeks, more patients turned up with the same symptoms. Because many victims were Navajo or came from the reservation region, the media initially dubbed it the Navajo flu.
Finally, virologists at the Centers for Disease Control and Prevention (CDC), working with tissue samples from the victims, discovered a genetic link to hantaviruses, a family of European viruses previously unknown in North America. The European virus caused kidney failure, but the Four Corners victims died of lung failure. What emerged in the Southwest that spring was a new strain of hantavirus endemic to North America. Scientists called the strain Sin Nombre, Spanish for nameless. Thirty percent of deer mice trapped in the Four Corners area were found to be carrying the Sin Nombre strain.
Once a human inhales the virus, it can take up to five weeks to incubate. Then the victim comes down with flu-like symptoms that can linger for days. The symptoms might actually lessen for a bit. Then, all of a sudden, things take a turn for the worse. Much worse.
The turn from flu to respiratory failure happens so fast that one hantavirus survivor group on Facebook advises people who suspect they’ve been infected to designate a friend to monitor them around the clock. If things go south, a victim may be too sick to reach the hospital alone.
If the disease reaches that point—and it’s unclear what percentage of those infected with hantavirus actually do—it’s bad. Breathing begins to fail. Some victims describe the feeling of a band tightening around their chest or of being smothered with a pillow. “They put me on oxygen because it was becoming hard to breathe,” says Lindsey. “I remember the doctor telling me, ‘Listen, your oxygen saturation is at 60 percent and dropping fast. Once it hits 40 percent, major organs are going to fail and you’re going to die.
“We had a 75 percent mortality rate in those Four Corners cases,” says Smolinski. “We wanted to know: Did this just pop up, or did something change? And were there some ecological pressures that caused it to evolve to the point where we started to recognize it?”
There were two answers. A study of autopsies in the Southwest indicated that there had been fatal cases of hantavirus pulmonary syndrome, or HPS (as the disease associated with the Sin Nombre strain came to be called), dating back to the 1950s. At that time, doctors had attributed the deaths to respiratory distress, cause unknown. In fact, CDC investigators found that traditional Navajo medicine recognized a similar disease—and associated its occurrence with mice.
