The Ebola virus became international news this year due to a horrific outbreak in West Africa. Despite (or perhaps because of) the media attention, there remains a lot of confusion and misinformation about the virus. These maps and charts help explain what the disease and epidemic are all about — and why Americans don't have to be as worried for themselves as West Africa when it comes to Ebola.
Ebola was first discovered in 1976
The current strain of Ebola, pictured in this electron micrograph from 1976, was first discovered that same year in Zaire (now the Democratic Republic of the Congo). A different strain was also discovered that year in Sudan (now South Sudan). The epidemics in both Zaire and Sudan reached more than 600 people, killing more than 330 altogether. That’s far less than the thousands who have been infected and killed by the current epidemic.
The current strain of Ebola is the deadliest
The current strain of Ebola is the Zaire strain, which is by far the deadliest. It kills nearly 70 percent of people it infects. But there are four other strains of Ebola, three of which have been found in humans in the past: Sudan, Taï Forest, and Bundibugyo. The other strain, Reston, has only infected nonhuman primates. It's widely believe that the original animal host for the virus is the fruit bat, but scientists haven't been able to confirm that.
Ebola gets more contagious the longer a person has had it
The longer a person has Ebola, the more contagious he or she becomes. Researchers think that Ebola has a 21-day incubation period, the time after infection when a person is not contagious and shows no symptoms. Vox’s Julia Belluz described just how those symptoms appear: "Ebola typically strikes like the worst and most humiliating flu you could imagine. People get the sweats, along with body aches and pains. Then they start vomiting and having uncontrollable diarrhea. These symptoms can appear anywhere between two and 21 days after exposure to the virus. Sometimes, they go into shock. Sometimes, they bleed." In the West African outbreak, 7 out of 10 people with Ebola have died, typically after about a week after symptoms begin.
The 2014 Ebola epidemic is unprecedented
The current Ebola outbreak is by far the worst in history. It's killed more than 4,400 people so far, while all the previous Ebola outbreaks combined killed 1,590. Part of the problem is the world reacted way too slowly to the current epidemic. But this outbreak has also occurred largely in dense urban areas that are much more vulnerable to diseases spreading, while previous outbreaks were largely contained to rural places. It's also the first time West Africa has seen Ebola — previous outbreaks took place further east and south. And the countries suffering the most from the current outbreak simply don't have the resources to handle a large-scale Ebola epidemic like, say, the US might.
The outbreak keeps getting worse
The death toll has grown month by month. In April, there were 70 Ebola deaths. In the first half of October, there have been 1,054. With the exception of May, the disease has gotten worse every single month. (The numbers in May likely reflect the fact that people were afraid to come forward with their symptoms, rather than a genuine decrease in cases.) These numbers worry public health officials: As the disease reaches further, it becomes more and more difficult to stop.
Ebola is ravaging West Africa
The vast majority of Ebola deaths have happened in three countries: Sierra Leone, Guinea, and Liberia. Treating Ebola puts a strain on these countries’ healthcare systems, which are already woefully underfunded. Widespread fears of Ebola are also keeping people from getting medical care, because they’re worried they could contract the virus at a hospital or clinic treating Ebola patients. "West Africa will see much more suffering and many more deaths during childbirth and from malaria, tuberculosis, HIV-AIDS, enteric and respiratory illnesses, diabetes, cancer, cardiovascular disease, and mental health during and after the Ebola epidemic," wrote disease researchers Jeremy Farrar, of the Wellcome Trust, and Peter Piot, of the London School of Hygiene and Tropical Medicine in an article in the New England Journal of Medicine.
Ebola is an economic disaster, too
The World Bank, in a report released October 8, estimated that Ebola could cost West Africa as much as $33 billion over the next two years if it spreads unchecked. The Economist charted the possible effects, indicating that Ebola could cost Liberia up to 12 percent of its GDP, which measures a country's economic output. In comparison, the Great Recession caused US GDP to drop by 5.1 percent from December 2007 to June 2009. Although Africa in general has seen a bit of an economic resurgence in recent years, poverty and food insecurity are still big problems in all the Ebola-stricken countries — and the disease will only make matters worse by putting pressure on each country’s weak economic and health-care systems.
The number of infections is expected to rise
The CDC estimates that up to 1.4 million people could be infected with Ebola by January if the response doesn't improve. The big problem is the affected countries just don't have the resources — doctors, nurses, hospital beds — to contain the Ebola epidemic. Liberia, for instance, estimates it needs 84,841 body bags to deal with the brunt of the epidemic, but it only has 4,901 today. "We’re nine months into an exponential growth process," said infectious disease modeler David Fisman. "This is an impossibly huge epidemic, and it’s been allowed to reach a point where it's basically the biggest infectious-disease forest fire one could imagine."
Only two people have contracted Ebola in the US
As of October 16, more than 99 percent of Ebola cases were confined to three countries: Sierra Leone, Guinea, and Liberia. Only two people contracted the disease in the US — both from direct contact with Thomas Eric Duncan, who came to the US after unknowingly contracting the disease from a patient in Liberia. At the same time, the people Duncan lived with while he was symptomatic didn’t contract Ebola. Not even Duncan’s fiancé caught the disease — a clear sign of just how difficult the virus is to transmit.
The US is well-equipped to handle Ebola
This chart explains why the Ebola epidemic in West Africa is so awful and horrifying even as the disease is much less likely to get out of control in the US. The US simply has way more doctors per capita than any of the countries struggling to contain Ebola outbreaks. This applies to other aspects of the health-care system as well: While the US in 2012 spent $8,895 per person for health care, Guinea spent $32 per person, Liberia spent $66, and Sierra Leone spent $96.
There are much larger threats than Ebola in the US
Ebola’s symptoms and high mortality rate make it a genuinely terrifying virus, but it’s not a big killer in the US. The same week Thomas Eric Duncan died of Ebola in the US, thousands died of much more prevalent diseases, car accidents, guns, and even unintentional falls. If Americans want to worry about genuine threats to their health, they’re much better off exercising, quitting smoking, getting vaccinated, and driving safely than they are concerning themselves about Ebola.
Measles is nine times more contagious than Ebola
Ebola is very scary because of its high mortality rate and terrible symptoms, but it’s also much less likely to spread than other diseases. While each person with measles infects, on average, 18 other people, someone with Ebola infects two. Unlike measles and the flu, Ebola isn’t transmitted through the air — making it much less likely to spread. And people with Ebola are only infectious once they show symptoms, making it easier to isolate those with the disease and halt the spread.
Ebola is deadlier than Bubonic Plague, less deadly than untreated HIV
This chart ranks diseases by how infectious they are — and how likely they are to kill those infected. It shows that Ebola, while not particularly infectious, kills a higher percent of those those who catch the disease than many other ailments. This reinforces just how crucial it is to get medical care: The difference in the mortality rate between treated and untreated HIV is massive, and some of the most infectious diseases — whooping cough, mumps, and measles, for example — can be practically eliminated through vaccination. There is not yet a vaccine or cure for Ebola, however, which partially explains why its so deadly. The best thing doctors know how to do right now is help keep patients’ immune systems strong, so they can fight off the virus themselves.
Americans generally know how Ebola works
Nearly all of the 1,503 Americans surveyed by the Kaiser Family Foundation know that Ebola is transmitted through the blood or body fluids of a person who is sick with the disease and showing symptoms, and roughly two-thirds know it can't be transmitted through the air. Americans also seemed fairly confident there won’t be a domestic epidemic: 73 percent told Kaiser that Ebola will likely be contained to a small number of cases in the US, and the same number said they have a fair amount or great deal of confidence that the CDC could contain an Ebola outbreak if it occurred in their area.
Where Ebola is likely to go next
To construct this map, researchers used a computer model that tracks the frequency of international traffic to different countries, the progression of the disease in already affected countries, and the incubation time and other aspects of Ebola. Outside of Africa, the risk is relatively high in the UK and France, but thankfully very low in India and China. The more advanced health-care systems in the UK and France are much better equipped to deal with an Ebola outbreak, while less advanced systems in China and particularly India, which also have considerably bigger populations to manage, could struggle to deal with an epidemic. Peter Piot, who helped discover and name the virus, explained the health-care disparity to the Guardian: "[A]n outbreak in Europe or North America would quickly be brought under control. I am more worried about the many people from India who work in trade or industry in West Africa. It would only take one of them to become infected, travel to India to visit relatives during the virus’s incubation period, and then, once he becomes sick, go to a public hospital there. Doctors and nurses in India, too, often don’t wear protective gloves. They would immediately become infected and spread the virus."
A travel ban wouldn’t stop Ebola
As FiveThirtyEight’s Nate Silver demonstrated with this map, no flights go directly from Ebola-stricken countries to the US. A travel ban, then, would need to look at stopping connecting flights or banning people based on their nationality — much more daunting, sweeping tasks than simply stopping flights from West Africa. Public health experts widely believe a travel ban would be inadequate and even backfire. For one, there’s no evidence travel bans managed to contain previous epidemics. A travel ban would also make it much more difficult to get resources and health-care workers to Ebola-stricken countries, which would in turn make the epidemic in those countries worse. That could actually put the US at greater risk: If the Ebola epidemic worsens in West Africa and leaks to neighboring countries, it becomes much more likely that one infected patient will slip through and cause a contagion in Europe, Asia, and North America as well.
Budget cuts aren’t the reason we don’t have an Ebola vaccine
When the first cases of Ebola were reported in the US, the outbreak became a political issue. National Institute of Health director Francis Collins said that if there had not been budget cuts, there would "probably" be an Ebola vaccine already. But NIH funding for Ebola research has been fairly steady in recent years, only seeing a substantial drop when stimulus funding ran out between 2010 and 2011. While this loss in funding matters to some extent, public health experts caution that vaccine research is so unpredictable that it’s very hard to know whether the extra dollars would have been enough to make a breakthrough. Just look at the odds: Of the 5,000 different compounds that drug companies experiment with, five typically make it to human tests — and one gets approved for sales.
The US has committed over $200 million in aid
As the world’s biggest economy, the US is typically the biggest source of international aid. Ebola is no different, with the US donating hundreds of millions of dollars to contain the outbreak in West Africa. The Obama administration, calling the epidemic a "top national security priority," even dedicated 3,000 troops to fight Ebola. The extra manpower will help build as many as 17 additional Ebola treatment unions, with a total of about 1,700 beds, in the region, as well as recruit and train extra medical personnel. The rest of the funding will help suffering countries get other supplies, such as sanitizers, lab equipment, and experimental drugs that could treat Ebola.
The world has woken up to Ebola
This map of tweets mentioning "Ebola" shows that, while the virus has been ravaging West African countries for months, global attention, particularly in the US, only dramatically picked up once the first case of Ebola was diagnosed in the US on September 30. The increased attention could be the silver lining for West Africa: With world leaders under more pressure to contain the outbreak, they’re dedicating more resources — President Barack Obama recently appointed an Ebola czar, for instance — that could help bring the epidemic under control.
You probably don’t have Ebola
To contract Ebola, someone has to come in close contact with the body fluids of someone showing symptoms for the disease. (The only exception is semen, which appears to show signs of the virus up to three months after someone is deemed cured of Ebola.) So if a person hasn’t touched the vomit, blood, sweat, saliva, urine, feces, or semen of someone who might have Ebola, he most likely doesn’t have the disease.
Senegal and Nigeria beat Ebola, and the US will too
Senegal and Nigeria were deemed Ebola-free following what WHO called "word-class epidemiological detective work." To do this, officials in Nigeria and Senegal meticulously tracked anyone who was potentially exposed to an Ebola-stricken patient and monitored them for signs of the illness. This process, while laborious, allowed Nigeria and Senegal to stop Ebola before it became a widespread epidemic within their borders. Since the US spends even more on health care than all the West African countries and is even more experienced in this type of contact tracing, public health experts widely believe Americans will be able to similarly contain any Ebola outbreaks.
- Developer Yuri Victor
- Special Thanks Sarah Kliff, Julia Belluz