The Ebola epidemic has been roaring in West Africa since March — and spread to the United States in September, waking many Americans up to a crisis that had been ongoing for months.

First, there was the news that Americans working in Liberia had become infected with the virus. They survived. But it wasn't long before a Liberian national got on a plane in Monrovia, the virus incubating in his body, and turned up in Dallas, Texas. He died on October 8, and two nurses who cared for him now have Ebola. The situation has raised panic, fear, and questions about America's readiness for pandemics and how far this epidemic could spread outside of West Africa.

Ebola is a violent virus with no cure, and this epidemic is already the deadliest in history. But fear and misinformation seem to be spreading faster than this disease. To help you get the facts about Ebola, here are the nine things you were too afraid to ask.

1) How worried should I be about Ebola?

The first-ever diagnosis (and ultimate death) of an Ebola patient in the United States was a frightening event, as was the infection of two of his nurses. But it doesn't signal the start of a major American outbreak, nor does it give reason for Americans to panic about the possibility of contracting the disease.

Ebola is less contagious than most other infectious diseases we're familiar with

It's helpful to consider the circumstances leading up to the first confirmed cases of Ebola in the the US. The now-deceased "patient zero", a Liberian man named Thomas Eric Duncan, flew to Dallas from the hot zone. He is believed to have contracted Ebola from his neighbor in Liberia, whom he helped carry to a hospital when she was most infectious, just before her death from the disease.



So Duncan was living in the area of the world where the epidemic was raging, among people who are sick. That's really different from the situation that most of us live in, thousands of miles from the Ebola outbreak's epicenter.

None of Duncan's contacts in America — not the passengers who sat next to Duncan on his flights, not the school kids he met in Dallas, not even his fiance, Louise Troh — caught the virus.



He did, however, infect two of his nurses, Nina Pham and Amber Vinson. But the fact that they got sick while caring for Duncan and all of his other contacts didn't wasn't entirely unexpected: people are most contagious late in the infection.

Vinson and Pham came into contact with Duncan when the disease had taken over his body — and without the full personal protective gear that we know now they should have had access to.



This is really important because part of what makes people so afraid of Ebola is that people infected with the disease can mistake it, in its early stages, for a normal flu, and, say, board a plane. But at that point, the disease just isn't very contagious yet.



So far, the outbreak in Dallas has played out just as public-health officials expected. Still, there are some people who have cause for worry: those who are living in West Africa. Those who have a fever, and who have just returned from one of the affected countries — Liberia, Sierra Leone, and Guinea. Those who feel sick after having come into close contact with a traveler from West Africa. But if you're not in one these situations then you, personally, are not at risk.

2) What happens if you get Ebola?

Most people's views of Ebola are probably informed by Hollywood or the author Richard Preston — they think of it as a deadly and highly contagious virus that swirls around the world, striking everyone in its path and causing them to hemorrhage from their eyeballs, ears, and mouth until there is no more blood to spill.

In reality, Ebola is something different. About half of the people who contract Ebola die. The others return to a normal life after a months-long recovery that can include periods of hair loss, sensory changes, weakness, fatigue, headaches, and eye and liver inflammation.

As for the blood: While Ebola can cause people to hemorrhage, about half of Ebola sufferers ever experience bleeding.

More often than not, Ebola strikes like the worst and most humiliating flu you could imagine. People get the sweats, along with body aches and pains. They run a fever. Then they start vomiting and having uncontrollable diarrhea.

These symptoms can appear anywhere between two and 21 days after exposure to the virus. Sometimes, people go into shock. Sometimes, they bleed. Again, about half of those infected with the virus die, and this usually happens fairly quickly — within a few days or a couple of weeks of getting sick.

This is how one Ebola victim described what it feels like to get the virus and survive:

"I couldn't move from the bed. I couldn't talk. I couldn't do anything. I lost 25 pounds. I was in the hospital for one month when they discharged me... I was discharged from the hospital after one month. After two months, I started to improve. But I still had problems. I was forgetting a lot. My hair was falling out. The hair from my head was all over. My skin was peeling off. I weighed 25 pounds less. I had heart palpitations. The hair took months to grow back. My memory was bad for one year."

3) How do you get Ebola?

Ebola isn't as contagious as Hollywood depictions, either. It seems to spread through direct contact with the bodily fluids — vomit, semen, sweat, or blood — of someone who is symptomatic and shedding the virus. People who get the virus but don't yet show symptoms aren't contagious. Some people who get the virus never get sick and can't infect others. Some are "super-shedders" with a very high viral load, and are therefore very infectious. Either way, scientists know one thing we know for sure: the further along an Ebola victim is in the disease, the closer to death, the more virus builds in their bodies, and the more contagious they become. That's why corpses of people who die from Ebola are so dangerous.

To be clear, "direct contact" means these fluids need to get into your broken skin (such as a wound) or on to your mucous membranes (mouth, nose, eyes, vagina).

Ebola can also live on surfaces for a few hours, and in blood outside of the body, for up to a few days. So there is a risk of getting Ebola by touching a contaminated surface. But you'd then need to put your hands in your mouth or eyes. This is believed to be a less common mode of transmission. Again, most people seem to get infected through direct contact with bodily fluids.

The virus has been able to live in semen for up to 82 days.

4) Can you get Ebola on a plane?

Theoretically, yes. But it's unlikely. This is what would need to happen for you to get Ebola in flight:

1) You can get the Ebola virus if you have "direct contact" with the bodily fluids of a sick person, including blood, saliva, breast milk, stool, sweat, semen, tears, vomit, and urine on plane.

2) So you could get Ebola on a plane by kissing or sharing food with someone showing symptoms of Ebola. You could get it if that symptomatic person happens to bleed or vomit on you during flight, and those viral fluids hit your mouth or eyes. You could also get it if you happen to be seated next to a sick individual, who is sweating profusely, and you touch that virulent sweat to your face. At least this last scenario is unlikely, however. One of the Ebola discoverers, Peter Piot, said, "I wouldn't be worried to sit next to someone with Ebola virus on the Tube as long as they don't vomit on you or something. This is an infection that requires very close contact."

3) You can get Ebola through sex with an Ebola patient. So you could get Ebola on a plane if you join the Mile High Club with an Ebola-infected individual. The virus has been able to live in semen up to 82 days after a patient became symptomatic, which means sexual transmission — even with someone who has survived the disease for months — is possible.

4) You can get Ebola through contact with an infected surface. Though Ebola is easily killed with disinfectants like bleach, if it isn't caught, it can live outside the body on, say, an arm rest or table. In bodily fluids, like blood, the virus can survive for several days. So if someone with infectious Ebola gets his or her diseased bodily fluids on a surface that you touch — an airplane seat, for example — and then you put your hands in your mouth and eyes, you could get Ebola on an airplane.



5) This is a very unlikely situation, but: you can get the virus by eating wild animals infected with Ebola or coming into contact with their bodily fluids - on a plane. The fruit bat is believed to be the animal reservoir for Ebola, and when it's prepared for a meal or eaten raw, people get sick. So you could get Ebola in flight by bringing some under-cooked bat meat onto the aircraft and having it for supper.

5) Why did this epidemic spiral out of control?

When the Ebola outbreak was identified in March, it had already spread to three countries in West Africa: Liberia, Guinea, and Sierra Leone. The disease then appeared in Nigeria, Senegal, the United States and, most recently, Spain. Senegal has since been declared Ebola-free and a similar declaration is expected in Nigeria.



There is also an unrelated outbreak of Ebola in the Democratic Republic of the Congo involving a different type of the virus right now. So that's eight countries hit with Ebola in one year.

Before this year, Ebola was a disease mostly confined to remote African villages.

Though the outbreaks outside of West Africa so far are contained, this epidemic is big. Before this year, Ebola was a disease that was mostly confined to remote African villages and usually only affected a few people in one or two small communities at a time — unlike the thousands of cases internationally we're seeing now.

From what we know right now, the causes of the biggest Ebola outbreak in history can be boiled down to these four things:

1) The virus turned up in West Africa this year for the first time ever. Not only did this mean officials there weren't on the lookout for it — they had never seen Ebola in these countries before — but it also delayed diagnosis of the problem by about three months, and allowed the virus to circulate widely before public-health measures were introduced to stop it.

2) The three West African countries most-affected are also some of the poorest in the world. They spend less than $100 per year per person on health care. They have few health professionals, and scarce personal protective equipment to protect them. They don't have robust disease surveillance networks in place. They have poor infrastructure to carry the sick around and get samples to labs for testing. They have few labs. The literacy rates are very low, meaning public-health information campaigns have been challenging. In the case of Liberia and Sierra Leone, their economies — and people's psyches — were only just recovering from years of brutal civil war, which left the population traumatized with little public trust in officials.

3) An accident of geography sparked an Ebola outbreak in a porous border region. The outbreak started in Guéckédou, a rainforest region in southeastern Guinea. Guéckédou also happens to share a very porous border with Sierra Leone and Liberia, where people travel in and out every day to go to the market or conduct business. Right now, epidemiologists believe travelers in the area quickly spread Ebola around, so when the situation was diagnosed in March, Ebola had already gone international. Suddenly three countries were battling the virus, and had to coordinate their responses. The usual methods for containing Ebola, like contact tracing, don't work in an epidemic of this size. At this scale, responding to Ebola becomes much more challenging and the disease difficult to stop.

4) The international response was slower than the virus. It took three months for health officials to identify Ebola as the cause of the epidemic, but another five months for the World Health Organization to declare a public health emergency, and two more months to mount a humanitarian response that still isn't fully in place and might not be for a few more weeks. Meanwhile, the caseload continues to grow exponentially. We still don't fully understand why the global response was so slow, but many observers say it was an avoidable tragedy that spiraled because international organizations failed to act.

6) How bad could this epidemic get?

As of October 2014, more than 8,000 people have been infected and the death toll has surpassed 4,000. So how much worse could this get? The World Health Organization projects that 20,000 people will be infected in November. HealthMap put the number at about 14,000 if there's no improvement in the situation.

But there are fears that the supplies and health-care workers needed to bend the epidemic curve downward and save lives won't reach Africa quickly enough. Doctors need to be trained. Hospitals need to be built. Personal-protective equipment needs to be distributed.



Even more worrying: many suspect that there has been widespread under-reporting of actual Ebola cases, since people have been turned away from overflowing hospitals and others have been hiding in their homes, afraid that coming out with Ebola will mean they never see their families again or that they are ostracized by their neighbors.



Assuming the worst is true, the Centers for Disease Control and Prevention has a much bigger projection for this epidemic: up to 1.4 million people infected by January.

7) If Ebola is not that contagious, why do people wear plastic space suits to care for Ebola patients?

There are a few reasons. The first one is simple: the virus is so deadly. Depending on the strain of Ebola, it can kill between 50 and 90 percent of those infected. And there is no cure on the market. Those suits are thought to be extra protection.



Second, unlike the civilian population, health workers who wear the suits are most at-risk for catching Ebola. They come into contact with all the infectious bodily fluids — vomit, blood, and feces — of sick people, often toward the end of patients' lives when their viral load has built up and they are most infectious.



Third, though all the science we have points to the fact that transmission must happen through contact with bodily fluids, science is never certain. Until this year, Ebola has been a rare disease and the research community is still getting the full picture of its transmission. So the suits cover workers from all potential contact they may have while caring for Ebola patients.



There is some controversy over the limits of these suits, however. Some say they are too cumbersome and, without proper training in how to put them on and take them off, rendered useless.

8) How do you stop the spread of Ebola?

Once an outbreak is identified and patients who are sick have been isolated, you'll hear that one of the tried-and-true methods for stopping the disease from spreading further is "contact tracing." This public-health measure works exceptionally well for small-scale outbreaks, like the case in Texas.

According to the Centers for Disease Control and Prevention director Tom Frieden, everyone who came in contact with the deceased Texas patient, Thomas Eric Duncan, while he was infectious has been identified. From there, officials outline and investigate all of the patient's movements before the patient was in isolation and during the period when he could have been contagious.

They then build "concentric circles," the closest representing the people who the patient could have exposed, and a second with all the other people those initial contacts may have interacted with.



These contacts are watched for 21 days — the incubation period for the virus — to make sure they don't develop symptoms. Their temperatures are taken twice daily. If they show symptoms, they are placed in isolation and tested for the virus. If they don't, after 21 days, they are declared risk free. This is how officials in Senegal and Nigeria successfully halted the spread of the disease.



The CDC is also taking other precautionary measures. With the Department of Homeland Security, the agency announced that airport officials would begin screening flight passengers coming in from West Africa for signs of infection.



It's unclear whether airport screening will actually be helpful. Take Thomas Duncan's case. CDC officials said he had no fever on departing Liberia and arriving in the US. He may have lied during questioning about his contact with an Ebola patient — and his potential risk — at the Monrovia airport. So his case demonstrates the difficulty of stopping international spread of this disease through airport screening.



Again, Ebola can incubate in someone before they become symptomatic for 21 days. So like Duncan, people might be harboring the virus when they fly somewhere but no one would be able to detect it. Twenty-one days is more than enough time to hop on a plane and bring the virus to a new country — and into new people — anywhere in the world.

9) Is there a cure for Ebola?

Right now, no. But researchers are busy working on developing both treatments and vaccines. In September 2014, the drug company GlaxoSmithKline announced it took the unprecedented step of starting mass production on an Ebola vaccine that has just begun being tested in humans.

The usual drug approval processes are being condensed or skipped

That news followed a decision by the World Health Organization to allow unproven and experimental treatments on people in this public health emergency — which means the usual drug approvals process will be condensed or phases of clinical testing potentially skipped.

One such drug is ZMapp, an antibody therapy that was used in the two American medical missionaries infected with Ebola in Liberia. It's made up of a cocktail of monoclonal antibodies, which are essentially lab-produced molecules manufactured from tobacco plants that mimic the body's immune response to theoretically help it attack the Ebola virus.



The report that the Americans got the drug — dubbed by CNN as a "secret serum" — led many to wonder why they skipped to the front of the line and who else might be saved with ZMapp. While these patients did improve after receiving the drug, a third patient who got ZMapp died. We won't know whether the drug worked or whether it's harmful on the basis of data from three patients, especially since half of those infected with this strain of the virus live anyway.

Whether this Ebola drug development actually turns out to be the silver lining of the worst epidemic in history remains to be seen. For every 5,000 compounds discovered at this stage, only about five are allowed to be tried in humans. These Ebola therapies are at only the earliest stage of drug testing, and they have a long way to go before proving useful. What's more, an Ebola drug won't fix all the health systems issues that allowed the disease to spread within Africa, and potentially, outward.