The devastating Ebola outbreak that has killed more than 800 people in West Africa has sparked fear in the United States and around the world. While a certain level of panic is understandable, because we’re talking about an incredibly fatal disease that theoretically could have been carried by an untold number of people traveling to an unknown number of countries, experts say that people in the U.S. should not be particularly concerned about contracting the virus.

Still, even though the disease has not spread to the U.S., the impact of the outbreak has been felt here in several ways.

Infected Americans

Clearly, the biggest impact comes in the form of the Americans who have been infected. Two Americans, both stricken with the disease, were brought back home in recent days for treatment.

Kent Brantly and Nancy Writebol, both of whom contracted Ebola while helping patients in Liberia, were flown in a specially equipped “air ambulance” and are being treated at Emory University Hospital in Atlanta. That facility has a special isolation unit created with the Centers for Disease Control and Prevention in order to treat patients with certain infectious diseases.

Brantly was flown to the U.S. on Saturday, while Writebol was flown in Tuesday. They are the first two people with confirmed cases of Ebola brought back to the U.S., the CDC says.

Meanwhile, an American named Patrick Sawyer — a consultant for the Liberian Finance Ministry who was traveling from Liberia — collapsed and later died in Nigeria.

Health officials are discouraging Americans from traveling to areas where the outbreak is ongoing. The CDC issued a travel warning last week telling people to avoid nonessential trips to Guinea, Liberia and Sierra Leone.

As the worst Ebola outbreak in history unfolds in West Africa, The Post's Joel Achenbach explains how the deadly virus wreaks havoc on the human body. (Davin Coburn/The Washington Post)

Potential cases and concern

As news of the outbreak dominates headlines, attention invariably turns to reports of people being tested for the disease here in the U.S.

In New York on Monday, Mount Sinai Hospital tested a patient who had some of the symptoms consistent with Ebola and who had recently visited a West African country. The city’s health department said  Monday evening that the person “is unlikely to have Ebola.” (Only a few hours elapsed  Monday between the news that a patient was being tested and the confirmation that he probably didn’t have Ebola, so obviously the tabloids reacted with their trademark caution.)

Mount Sinai said in a statement  Tuesday that the patient who was being checked remained in isolation as they awaited the results of the official testing.

A man man traveling from a West African country was placed in isolation at Bellevue Hospital last week while he was checked for Ebola (his condition improved and he was released). Similarly, a woman in Ohio who visited West Africa recently was tested for Ebola and did not have the disease, a spokesman for Columbus Public Health said Tuesday. This woman is currently recovering in isolation.

There is also a doctor in Tennessee who recently returned from treating Ebola patients in West Africa. He has voluntarily quarantined himself, saying in a statement sent to the Tennessean that he feels fine but is acting “out of caution.” The Peace Corps isolated two volunteers who were exposed to someone who later died from the virus. Neither of the volunteers — both Americans — showed any symptoms, reported CBS News. The Peace Corps said last week that it would remove its volunteers from Liberia, Sierra Leone and Geinea due to the outbreak.

Similarly, potential cases have been reported around the world in the wake of the outbreak. A woman was tested for the disease after collapsing at an airport in England, while a Saudi man who was hospitalized after traveling to Sierra Leone is also being tested. British Airways announced Tuesday that it would be suspending flights through Sierra Leone and Liberia due to the outbreak.

Of course, some of Ebola’s symptoms are also the symptoms for numerous other diseases. Which leads us to:

“There is zero danger to the U.S. public”

Infectious disease experts have said that despite the fears expressed by reality television stars, there is no actual danger facing the American people.

“There is zero danger to the U.S. public from these [two] cases or the Ebola outbreak in general,” Amesh Adalja, a member of the public health committee of the Infectious Disease Society of America and an infectious disease doctor at the University of Pittsburgh, told The Washington Post’s Lenny Bernstein.

Again and again, these experts point out that the risk faced by people in the U.S. is incredibly low. The disease spreads through contact with an infected person’s bodily fluids and it can take up to three weeks for the symptoms (which include fever and vomiting) to appear, and by the time symptoms appear the infected people aren’t really out and about all that much.

Health-care workers are the most likely to encounter the infected blood, vomit or feces, and they are using gowns and gloves. As Peter Piot, one of the people who discovered Ebola in 1976, recently told the New Yorker, Ebola “requires very close contact.” In addition, Americans aren’t out burying their dead friends or family, exposing themselves to the disease anew, which is occurring in Sierra Leone, Liberia and Guinea.

If you’re looking for a particularly cheery thought: These infectious-disease specialists also point out that a whole host of other nasty bugs and illnesses have made their way into the U.S. several times in recent years, and there have not been any problems involving these viruses spreading.

The serum

There are obvious reasons why people get particularly freaked out over Ebola: There is no cure for what is a particularly lethal disease. Outbreaks have a fatality rate of up to 90 percent, according to the World Health Organization. And the current outbreak is the worst in history: So far, more than 1,600 people have been sickened by and at least 887 people have died, according to the World Health Organization. Before that, the most recent serious outbreak, which occurred in the Congo in 2007, killed 187 people, the World Health Organization reports.

This is why federal officials said last week that they were fast-tracking development of an Ebola vaccine. But there is another potential treatment that exists: An experimental serum that had previously only been tested on monkeys. Doses of the serum were administered to Brantly and Writebol, and while it is unclear so far whether the serum did anything, initial reports suggest that their conditions did improve after the treatment.

The drug cocktail, called ZMapp, was developed by a San Diego company called Mapp Biopharmaceutical and manufactured in Kentucky. But very little of the drug is available, the company says.

[This post has been updated to add the bit about the woman in Ohio after we heard back from Columbus Public Health.]