Voices: Volunteer doctors protect us from Ebola
Ebola is much harder to spread than many people realize. While hospital workers are at high risk, most people are not.
A disease such as Ebola inspires so much fear that it can cloud our thinking — so much so that someone who has behaved heroically can start to seem like the enemy.
Many Americans are furious that a New York doctor took the subway and went bowling after returning home from Guinea, where he treated Ebola patients. The physician, Craig Spencer, was diagnosed with Ebola on Thursday.
But people might feel less anger at Spencer — and maybe even grow to respect his sacrifice — if they think about the USA's first Ebola patient, Thomas Eric Duncan.
Dallas officials quarantined Duncan's family because they shared a small apartment with him.
His family would have had a very high risk of becoming sick if Duncan had a respiratory infection, such as MERS, SARS or avian flu. Those viruses spread through the air. Ebola doesn't.
One month later — well past the 21-day incubation period for Ebola — none of them has become sick. In fact, Texas health officials have cleared 67 people who were being observed because of their contact with Duncan.
The fact that Duncan's family is thriving — while two of his nurses became infected – illustrates the unusual nature of the Ebola virus, and why it poses a threat to hospital workers, but not to the average person.
Ebola doesn't spread easily in the general population, says Peter Hotez, dean of the National School of Tropical Medicine in Houston. That's because people with Ebola aren't contagious until they begin showing symptoms, such as a fever, which only occurs when they have detectable levels of virus in their blood. So no matter how mobile a patient is — and no matter how many public places they visit — people with Ebola aren't going to spread the disease until they develop a fever or other tell-tale signs, Hotez says.
That can be a hard concept to accept. After all, Ebola is incredibly deadly, with a 70% mortality rate. But we should remember that deadliness is not the same as infectiousness. Pancreatic cancer is almost universally fatal. But it's not contagious.
As Duncan's case illustrates, even symptomatic Ebola patients aren't that contagious in the early stages. That's because there isn't a lot of Ebola virus in a patient's blood at that point, Hotez says.
If Duncan's family didn't get Ebola after living with him, what are the odds that people will get sick because they ran into Spencer on a subway platform?
Now, I'm not saying that Ebola isn't contagious. The virus has infected 10,000 people in West Africa, with no sign of letting up.
But the key here is when Ebola becomes contagious. In the later stages of disease, the virus begins to multiply wildly, using the human body as its copying machine. As viral levels rise, even a small amount of blood is teeming with Ebola, says Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
This puts hospital workers — such as Spencer or the two nurses who cared for Duncan — at very high risk, Osterholm says.
It also illustrates why the average Ebola patient in West Africa spreads the disease to one or two other people.
The average measles patient, on the other hand, spreads the virus to up to 18 susceptible people. If Ebola spread as easily as measles or flu, there would be millions of cases, not thousands.
But here's why you and I don't need to worry: Patients at advanced stages of Ebola don't go bowling. They're usually too sick to circulate in the general population. In the USA, patients this sick end up in a hospital's intensive care unit.
Most of us turn away from people this sick. Spencer didn't. And by helping to control the disease in Africa, Osterholm says, Spencer helped to protect Americans.
The bigger the Ebola outbreak in Africa gets, the greater the chance that it could spread — not just across the continent, but around the world. And that puts us all at risk.
"The big risk is not stopping the outbreak in Africa, and that will happen if health care workers don't go there," Osterholm says. "The very low risk posed by any health care worker coming back here pales in comparison to the consequences of not controlling the outbreak in Africa."
Szabo covers medicine for USA TODAY