4 Things You Need to Know About Ebola

With the news that Mount Sinai Hospital in New York is testing a patient who recently returned from West Africa for Ebola, and two patients are being treated at Emory University Hospital in Atlanta, many people are starting to panic at the thought of a deadly outbreak sweeping across the United States. But even as Africa endures the worst outbreak of the virus in history, infectious disease experts say there is no reason to think the same will happen here.

"The bottom line is people shouldn't worry," says Alan Bulbin, director of infectious disease at St. Francis Hospital in Roslyn, New York. "Historically, the disease has an 80 to 90 percent mortality, which makes it sound scary, but in reality, Americans have no reason to think the disease will spread here or that it would be as deadly as it is in Africa."

[Read: Stressed About Ebola? How and Why to Calm Down.]

However, it's important that you take some time to understand what exactly the Ebola virus is, Bulbin says, because it will keep you from feeling unnecessary panic. Here are four things you need to know about Ebola.

What are the symptoms? Ebola symptoms start to show within 21 days, with most cases developing within eight to 10 days, and include headache, fatigue, nausea and fever. However, after a few days, bleeding develops, and an infected person can go into shock. "Ebola is often mistaken for the flu at first," Bulbin says. "But after 48 hours, you tend to get much sicker, at which point the virus can be detected in your blood."

Who is at risk? The good news -- and one reason why Americans shouldn't panic over Ebola -- is very few people are at risk, says Angela Vassallo, an epidemiologist and director of infection prevention at Providence Saint John's Health Center in Santa Monica, California. "The first question to ask yourself is whether you've been to West Africa recently," she says. "If no, you're in the clear. If yes, have you had any exposure to bush meat, wild animals, contaminated needles or bodily fluids? If the answer to that is also yes, then look for the signs and symptoms of Ebola."

[Read: Second American With Ebola to Arrive in Atlanta Tuesday.]

How does it spread? Even if there is a confirmed case of the Ebola virus in the United States, it's not very likely to spread, Bulbin says. "The Ebola virus spreads through contact with bodily fluids," he says. "Things like saliva, blood, urine and feces. If the virus spread through the air, there would be much more reason to worry. But you can only catch it by direct contact with someone while they are actively showing symptoms."

The World Health Organization estimates that this Ebola outbreak has killed nearly 900 people. Part of the reason it spreads so readily in Africa, Bulbin adds, is because of a lack of resources. "When American doctors deal with Ebola, they wear masks, gloves and gowns, and wash their hands thoroughly when they're done," he says. "In West Africa, they don't have access to those resources, so doctors might not be able to sterilize their hands as effectively."

[Read: How to Disinfect Germ Hotspots .]

How is it treated? Unfortunately, there isn't much you can do for someone diagnosed with Ebola, Bulbin says, but that doesn't mean the disease is always fatal. "There's some experimental treatment, but it's very much in its infancy," he says. "Right now, it's strictly supportive care. You give fluids, replace lost blood and do what you can to keep vitals like blood pressure stable. You have a better chance of surviving with that support."

Ultimately, Mount Sinai doctors say it's more likely that the patient being tested is suffering from another common condition. However, doctors plan to keep the patient isolated out of an abundance of caution. "We will continue to work closely with federal, state and city health officials to address and monitor this case, keep the community informed and provide the best quality care to all of our patients," a statement released by the hospital said.

Despite the two confirmed cases in Atlanta, Tom Frieden, Centers for Disease Control and Prevention director, tweeted that Americans should not be concerned.

The biggest risk for Ebola is in Africa & the best way to protect the US & the world is to help stop spread there. We know what's needed.

-- Dr. Tom Frieden (@DrFriedenCDC) August 4, 2014

It's important to remember that just because doctors are testing for Ebola, it doesn't mean that the U.S. is poised for an epidemic, Vassallo says. "When patients are in isolation, it's a safe environment," she says. "This isn't something people should worry about, and it's certainly not something there should be hysteria over."

Amir Khan is a Health + Wellness reporter at U.S. News. You can follow him on Twitter, connect with him on LinkedIn or email him at akhan@usnews.com.