By Jen Christensen and Debra Goldschmidt, CNN
Imagine – the largest Ebola epidemic in history began with the simple act of caring for a child. Soon, it spread from the child’s remote village in Guinea. And now, the infection has wiped out entire families, created thousands of orphans in its wake, and left people terrified from Dubreka, Guinea, to Dallas, Texas. Scientists predict as many as 1.4 million people could be infected if nothing is done to help. As historians look back at how the world reacted to this epidemic, they will have to decide: who stepped up, and who could have done better? Critics say reaction to this epidemic has been too slow, or efforts to fight it have been too scattered. Take a look at how this story unfolds.
A 2-year-old boy in Guéckédou, Guinea, dies after suffering for four days with an unidentified hemorrhagic fever. The toddler's mother dies seven days later. His 3-year-old sister dies December 29.
The health care system in West Africa is extremely limited, study finds. Liberia has 0.014 physicians per 1,000 people; Sierra Leone's is 0.022 and Guinea's is 0.1 physicians per 1,000 people. In contrast, the United States, has 2.5 doctors per 1,000 people.
"Patient Zero's" grandmother dies January 1. Her village, Meliandou, is close to the Sierra Leone and Liberian borders. People come from all over for her funeral. Exposed to the virus, they bring it home, and it spreads widely.
Residents of Macenta, Nzérékoré and Kissidougou, Guinea, get sick with fever, vomiting and severe diarrhea. Health care workers and the families who cared for those with the "mysterious disease" also get sick.
Writing "5 ways diseases in other countries can kill you," for CNN.com, Dr. Thomas Frieden, director of the Centers for Disease Control and Prevention, warns that with our mobile population, Ebola is one of many diseases that could "harm Americans' health."
Tom Geisbert, a professor of microbiology and immunology at the University of Texas Medical Branch, Galveston, gets a $26 million grant from the National Institutes of Health to study treatments for Ebola and Marburg viruses. There is no cure or vaccine for either. One vaccine tested on animals is 100% effective.
As the disease spreads, the fatality rate is 86%. Median patient age is 35. More women die from the disease than men.
Two and a half months go by, and it is only now that hospitals and public health services alert the Ministry of Health in Guinea and Médecins sans Frontières (MSF) -- also known as Doctors without Borders -- about the disease clusters.
The Guinea health ministry starts tracing the outbreak in Macenta. They take blood and stool samples, but not in a “systematic fashion” nor with patients' consent, according to a New England Journal of Medicine assesment. They search for the animal that was the origin of the virus. Fruit bats are suspected.
Senegal closes the border with Guinea.
MSF sends 60 field workers to Guinea to help stop the outbreak as a part of their emergency response. Some 24 doctors, nurses, logisticians, hygiene, and sanitation experts are already in country working with the epidemic.
There are 112 suspected and confirmed Ebola cases in Guinea, including 70 deaths, according to World Health Organization reports. Liberia has two confirmed cases. Sierra Leone two suspected deaths.
WHO recommends better infection control for health workers but recommends against travel or trade restrictions for the affected countries.
Health ministries and national emergency committees in Guinea, Sierra Leone and Liberia start a coordinated response to the outbreak with WHO help, forming rapid response teams.
Some 122 patients are suspected of contracting Ebola, and 78 have died. Most victims are in Guinea, according to MSF.
MSF warns the spread of this epidemic is "unprecedented,” adding that it is concerned because past outbreaks were "contained and involved more remote locations.” The geography of this outbreak is "worrisome" because it will "greatly complicate the tasks of the organizations working to control the epidemic."
A WHO spokesperson says while the Ebola outbreak is serious, it is "relatively small, still."
A mob claiming foreigners spread Ebola, attacks an MSF clinic in rural Guinea. Families in Conakry hide sick or dead relatives in their homes.
The epidemic has "rapidly evolved," according to WHO. There are 157 cases, including 101 deaths in Guinea. In Liberia, 23 suspect cases, seven deaths. There are also suspected cases in Sierra Leone, Ghana and Mali. Eventually, scientists determine the cases in Ghana and Mali were something else.
"This is one of the most challenging Ebola outbreaks that we have ever faced," said Dr. Keiji Fukuda, WHO's assistant director-general for health security.
WHO has about 50 staff in West Africa with plans to send others. It also sends protective equipment to health care workers.
MSF, the CDC, Institut Pasteur, the International Federation for the Red Cross, UNICEF, Samaritan's Purse, The World Food Programme and Tulane University also help fight the outbreak.
CNN's Dr. Sanjay Gupta travels to West Africa to report on the epidemic.
MSF says the epidemic is now fatal in up to 90% of cases. This is the Zaire strain that is "the most aggressive and deadly."
The New England Journal of Medicine online publishes the Emergence of Zaire Ebola Virus Disease in Guinea, discussing "Patient Zero" and the cause of the outbreak.
CNN's Dr. Gupta reports from Guinea that with the outbreak spreading to the capital city of Conakry, Ebola has gone "viral." The hope is it won't go global.
Guinea's health minister reports a total of 226 Ebola cases, including 149 deaths. Liberia has 13 cases, 11 deaths. Of the infections, at least 25 are health care workers.
WHO reports 37 new cases and 21 new deaths in Guinea, bringing the total to 328, including 208 deaths. There are also 79 cases in Sierra Leone, including six deaths. WHO monitors 11 possible cases in Liberia.
One of the CDC labs that handles Ebola will have to close after it's discovered 86 workers may have been unintentionally exposed to anthrax because of the lab's mishandling of samples.
Ebola patients have been identified in more than 60 separate locations across the three West African countries -- Guinea, Sierra Leone and Liberia -- complicating efforts to slow the outbreak.
WHO says more than 600 cases and 390 deaths have been reported in Guinea, Liberia and Sierra Leone. The mortality rate can be up to 90%
WHO now characterizes the outbreak as a "challenge." It's ramped up its efforts and sent additional epidemiologists, lab and infection experts, clinical managers, logisticians and communication teams.
WHO reports there have been 759 cases, including 467 deaths in Guinea, Sierra Leone and Liberia. This makes it the "largest in terms of the number of cases and deaths as well as geographical spread."
As of June 30, MSF has sent more than 300 staff members and 40 tons of equipment and supplies to the region to help fight the epidemic.
Health ministers of 11 African nations meet in Ghana to discuss Ebola. They agree to a joint strategy with WHO to set up a subregional control center in Guinea to coordinate the response.
WHO now warns that "drastic action" is needed to halt the killer in its tracks.
Uganda announces new measures to screen people arriving from Ebola-affected countries.
WHO reports there have been 844 cases, including 518 deaths, in Guinea, Sierra Leone and Liberia. Of those deaths, at least 32 are health care workers.
Of the 1,093 confirmed, probable and suspected cases, 660 people have died, according to WHO.
A 40-year-old American citizen, Patrick Sawyer, collapses with Ebola symptoms while getting off a plane in Lagos, Nigeria. He had been working for a West African organization in Monrovia. His family lives in Minnesota.
Patrick Sawyer becomes the first American citizen to die. His case raises fears the virus could spread beyond the countries at the heart of the outbreak. He dies at a hospital in Monrovia, Liberia.
Samaritan's Purse announces its medical director in Monrovia, Liberia, has tested positive for Ebola. Dr. Kent Brantly is the second American known to have the virus.
Serving in Mission announces a second American aid worker in Monrovia, Nancy Writebol, is infected with Ebola.
Ebola is believed to have infected 1,201 people (Guinea 427, Liberia 249, Sierra Leone 525) and killed 672 people (Guinea 319, Liberia 129, Sierra Leone 224), according to the WHO.
Liberian President Ellen Johnson Sirleaf closes the borders, restricts public gatherings and orders hotels, restaurants and entertainment venues to play an Ebola safety video. She asks citizens to "bring the totality of our national resolve to fight this scourge."
The CDC emphasizes there is "little risk (from Ebola) to the U.S. general population," but with global travel in mind, it sends a health alert notice. The notice reminds health care workers to take precautions, to prepare for the "remote possibility that one of those travelers could get Ebola and return to the U.S. while sick." Health care workers should ask about a patient's travel history, know the symptoms of Ebola and know about infection control. "While it's clear there is an increased risk for working with Ebola patients, we're confident that the standard of care in the U.S. would prevent much of the transmission if a case were to show up here," said Stephan Monroe from the CDC.
The CDC also issues an alert warning travelers to avoid hospitals with Ebola patients and funerals in Liberia, Sierra Leone and Guinea.
MSF's Kamiliny Kalahne said there has never been a confirmed case of Ebola spreading to a developed country.
"This is because people generally transmit the infection when they are very sick, have a high fever and a lot of symptoms -- and in these situations, they don't travel... and even if they do get sick, once they travel to a developed country, they will be in a good hospital with good infection control, so they are very unlikely to infect others," she said.
CNN's Dr. Sanjay Gupta predicts Ebola will come to the U.S. through travelers who don't know they're infected. "It's going to happen at some point," he said.
Sierra Leone's leading Ebola doctor Dr. Sheik Humarr Khan dies after treating patients for Ebola at Kenema Government Hospital.
SIM and Samaritan's Purse issues an evacuation order for all nonessential personnel from Liberia.
"(Khan's) valiant work will not be forgotten," Dr. Penninah Iutung Amor, AIDS Healthcare Foundation's Africa bureau chief, said in a statement. "In a country that has fewer than 200 medical doctors in its entire public health sector, the loss of even one doctor is a loss too great." His government calls Khan a "national hero."
Nigerian doctors are in the middle of a national strike demanding the government give hospitals the supplies they need to safely treat patients and better pay.
CDC Director Tom Frieden tells CNN's Dr. Sanjay Gupta that Ebola "it's not going to be a huge risk in the U.S."
The two American patients, Kent Brantly and Nancy Writebol, show "a slight improvement" in their condition, but both remain in serious condition.
The Peace Corps announces it is removing all of its 340 volunteers from the affected region. Many other aid organizations follow suit.
The two American Ebola patients took a small turn for the worse and are listed in "grave" condition in Liberia.
A long-range business jet with an isolation pod leaves the United States to evacuate American Ebola patients in Liberia.
Liberian President Ellen Johnson Sirleaf and Sierra Leone's President Ernest Koroma cancel trips to the United States to focus on the outbreak. Koroma declares a state of emergency.
Sirleaf tells CNN her country is in desperate need of people with expertise in treating and dealing with Ebola.
Teams from the Nigerian health ministry search for people who had contact with the American who died after flying to that nation's capital. His plane also stopped in Accra, Ghana, and Lome, Togo, before traveling on to Lagos.
WHO, working with Guinea, Liberia and Sierra Leone, outline Ebola response plans through December. The plan requires $103 million; WHO reports a funding gap of $71 million.
The National Institutes of Health announces it will begin testing an experimental Ebola vaccine in people as early as September.
CDC raises travel alert for Guinea, Liberia and Sierra Leone from level 2 to level 3.
The CDC sends 50 additional staffers to West Africa to speed up testing, help local health care systems and start contract tracing.
There are at least 1,603 confirmed, probable or suspected cases (Guinea 485, Liberia 468, Nigeria 4, Sierra Leone 646) and 887 deaths (Guinea 358, Liberia 255, Nigeria 1, Sierra Leone 273), according to WHO.
CDC Director Tom Frieden tells CNN's Dr. Sanjay Gupta that Ebola “it's not going to be a huge risk in the U.S.”
Dr. Kent Brantly arrives in the U.S. and is sent to an isolation ward at Emory University Hospital in Atlanta. He is the first patient infected with Ebola treated on American soil.
The Sierra Leone government asks citizens to stay home from work. Its military has deployed at least 750 medical officials to 13 locations. Airport screening for Ebola starts at the country's main international airport.
Sources tell CNN the conditions of Kent Brantly and Nancy Writebol improve significantly. They have received an experimental Ebola drug called ZMapp.
WHO says three additional Ebola cases have been identified in Nigeria which they found a few days before.
President Barack Obama holds "the largest event any U.S. President has held with African heads of state and government" at the White House. The theme is "Investing in the Next Generation." Ebola is not on the official agenda.
At a news conference a few days before the White House event, a spokesperson says "we have no plans to change the agenda of the summit." The spokesperson adds the U.S. is active on the ground helping fight the outbreak.
Every key African nation leader is at the summit, with the exception of the leaders of the countries involved in the Ebola epidemic.
The presidents of Liberia, Guinea and Sierra Leone have been banning public gatherings, close schools and send the army out to protect health care workers and enforce quarantines.
USAID later announced they will provide about $14.6 million in funding, a Disaster Assistance Response Team to coordinate a response with local health workers and supplies including protective equipment, soap and water.
The World Bank announces it will give up to $200 million in funding to support immediate response efforts in Guinea, Liberia and Sierra Leone. It also plans to help build up public health systems throughout the region.
The second American with Ebola, Nancy Writebol, is flown to the Emory University Hospital isolation unit in Atlanta.
A Spanish Catholic Brother becomes sick with Ebola in Liberia.
"As bad as this situation is in three or four countries in Africa that the CDC has assessed, there is no significant risk faced by Americans here in the United states as a result of this outbreak," White House press secretary Josh Earnest says. He adds the White House is "confident that the kinds of screening measures that we have in place both on the ground in those countries but also at ports of entry here in the United States will be very effective in protecting the American public."
A businessman with Ebola dies in a hospital in Saudi Arabia. He had been to Sierra Leone for work.
Liberian President Ellen Johnson Sirleaf declares a state of emergency for 90 days because of the deadly outbreak.
The Spanish government says it will fly a priest sick with Ebola in Liberia, Brother Miguel Pajares, to Madrid's La Paz hospital.
After the African White House summit, President Obama holds a news briefing. He says countries at the heart of the epidemic "are the first to admit that what's happened here is, is that their public health systems have been overwhelmed. They weren't able to identify and then isolate cases quickly enough." Mistrust between the communities and health care workers complicate matters. So "it spread more rapidly than has been typical," Obama said.
The U.S. agrees to build international support and to send additional health experts to West Africa. "What we have done is to make sure we're surging not just U.S. resources, but we have reached out to European partners and partners from other countries working with the WHO," Obama said. "Let's get all the health workers that we need on the ground. Let's help to bolster the systems that they already have in place."
In Geneva, Switzerland, members of WHO's Emergency Committee of International Experts meet to determine whether the outbreak meets international public health emergency standards.
WHO convenes a panel to talk about the use of unlicensed medicines to combat Ebola and discuss whether it is ethical to use "unregistered interventions with unknown adverse effects" and who should get them.
There are 1,779 confirmed, suspected, and probable Ebola cases (Guinea 495, Liberia 554, Nigeria 13, Sierra Leone 717) and 961 deaths (Guinea 367, Liberia 294, Nigeria 2, Sierra Leone 298), according to WHO with 68 new cases and 29 new deaths reported August 5 and 6.
Testifying before the House Foreign Affairs subcommittee, a leader of Samaritan's Purse, an organization on the front lines of the epidemic in West Africa, calls the U.S. reaction to the Ebola epidemic a "failure."
"The Ebola crisis we are now facing is not a surprise to us at Samaritan's Purse, but it took two Americans getting the disease in order for the international community and the United States to take serious notice of the largest outbreak of the disease in history," Ken Isaacs said.
"We are confident we can contain and stop the virus," Bisa Williams, the State Department's deputy assistant secretary for the Bureau of African Affairs, testifies to the committee.
A WHO emergency committee determines Ebola is an "extraordinary event" and a public health risk to other countries. A coordinated international response is "essential" now to stop it; therefore, it declares the outbreak a Public Health Emergency of International Concern.
"We are too late. In an Ebola outbreak, you need to be a step ahead. We are two steps behind," says Anja Wolz, emergency coordinator for MSF, after WHO declared a public health emergency.
MSF has more than 670 staff responding to the crisis. It has, however, "reached its limit in terms of available staff."
The UK and U.S. promise to increase assistance to combat Ebola.
The Zambian government bans travelers from Ebola outbreak countries.
Ivory Coast bans travelers from those countries affected by Ebola.
The Spanish Catholic Brother with Ebola, Brother Miguel Pajares, dies in Madrid.
The virus is believed to have infected 1,848 people (Guinea 506, Liberia 599, Nigeria 13, Sierra Leone 730) and killed 1,013 (Guinea 373, Liberia 323, Nigeria 2, Sierra Leone 315), with 69 new cases and 52 new deaths between August 7 and 9, according to WHO.
The U.S. orders the family members of embassy employees to leave Liberia. The U.S. announces it will send 12 additional specialists from the CDC, and a 13-member disaster assistance response team from the U.S. Agency for International Development to West Africa.
WHO Director-General Margaret Chan briefs the United Nations on the Ebola epidemic, calling it a "crisis" that is "unprecedented in its size, severity, and complexity." Having met with African leaders, she says "many feel helpless and hopeless given the demands of this outbreak, which far outstrip their capacity to respond." Travel bans will not stop the outbreak, she said; preventive efforts will. WHO logisticians are coordinating international aid and are equipping the countries with IT systems to allow real-time reporting of cases.
CDC Director Tom Frieden said earlier it will "take many months, and it won't be easy, but Ebola can be stopped." "We know what needs to be done," he said.
The Liberian government says it will get sample doses of the experimental Ebola drug ZMapp to treat doctors who have contracted the deadly virus. This exhausts the company's limited supply.
The virus is believed to have infected 1,975 people (Guinea 510, Liberia 670, Nigeria 12, Sierra Leone 783) and killed 1,069 (Guinea 377, Liberia 355, Nigeria 3, Sierra Leone 334), with 128 new cases and 56 new deaths since August 10 and 11 according to WHO.
WHO reports the virus is believed to have infected 2,127 (Guinea 519, Liberia 786, Nigeria 12, Sierra Leone 810) people and killed 1,145 (Guinea 380, Liberia 413, Nigeria 12, Sierra Leone 348), with 152 new cases and 76 new deaths reported between August 12 and 13 according to a WHO report.
WHO encourages affected countries to carry out exit screenings of travelers at international airports, seaports and major land crossings.
The virus is believed to have infected 2,252 people (Guinea 543, Liberia 846, Nigeria 15, Sierra Leone 848) and killed 1,244 (Guinea 394, Liberia 481, Nigeria 4, Sierra Leone 365), with 125 new cases and 99 new deaths on August 17-18 in Guinea, Liberia, Nigeria and Sierra Leone.
Ebola patient Nancy Writebol is discharged from Emory University Hospital after have recovered from the virus and been declared safe to return to her family and community.
Kenya Airways suspends flight operations to Liberia and Sierra Leone. It prohibits passengers who passed through Sierra Leone, Guinea and Liberia from traveling on their airlines.
The virus is believed to have infected 2,473 people (Guinea 579, Liberia 972, Nigeria 15, Sierra Leone 907) and killed 1,350 in Guinea (Guinea 396, Liberia 576, Nigeria 4, Sierra Leone 374), according to WHO.
Money for Ebola research will be made available from a $10.8 million initiative funded by the trust and the UK government.
Dr. Kent Brantly is discharged from Emory University Hospital. He calls it "a miraculous day."
The virus is believed to have infected 2,615 people and killed 1,427 in Guinea, Liberia, Nigeria and Sierra Leone with 142 new cases and 77 deaths August 19-20.
Ivory Coast closes the border it shares with Guinea and Liberia.
For the first time, a health worker affiliated with WHO tests positive for Ebola in Sierra Leone. He is an epidemiologist working for the Global Outbreak Alert and Response Network.
Health leaders in the Democratic Republic of Congo notify WHO of a possible Ebola outbreak in their country. Tests show it's not the same virus strain.
A doctor in Liberia given ZMapp dies.
A British citizen infected with the virus in Sierra Leone is flown home, according to the British Department of Health.
CDC Director Dr. Tom Frieden: "It's even worse than I'd feared. Every day this outbreak goes on, it increases the risk for another export to another country."
WHO said it is monitoring the case in the Democratic Republic of Congo, one of the largest nations in Africa. It does not recommend travel or trade restrictions there.
The virus is believed to have infected 3,069 people and killed 1,552 in Guinea, Liberia, Nigeria and Sierra Leone, according to WHO.
The World Health Organization issues its first Ebola Response Roadmap Situation Report. Counting all confirmed, probable and suspected cases in Guinea, Liberia and Sierra Leone, WHO says there have been 3,052 cases, including 1,546 deaths, since the epidemic began. Some 120 health care workers have died in the outbreak.
A new case is also confirmed in Senegal. Health officials say a young man traveled to the country by road from Guinea, where he had had contact with Ebola patients.
Nigeria traces everyone who may have been exposed to a sympomatic passenger who flew to Lagos. There were 20 confirmed and probable cases in total. Some 12 of the 20 were exposed in health facilities in Lagos, four were people who came into contact with the sick passenger. Health officials now believe the outbreak is contained in Nigeria. The country's quick response is credited with the success.
Liberian President Ellen Johnson Sirleaf warns Liberia's health system is under stress. She extends the stay-at-home order for all nonessential government workers for another month. She wants more international help. "In a way, we feel saddened by the response," Johnson Sirleaf said.
The National Institutes of Health announces an Ebola vaccine human safety trial has a green light from the FDA. It's the first test of this type.
MSF President Dr. Joanne Liu criticizes what she called the "global coalition of inaction." Centers run by her group have turned away sick because they are too full.
U.S. President Barack Obama tapes a video message telling the African people America's prayers are with them. More than 500 staff from the CDC are working on Ebola.
SIM USA announced another doctor working in Monrovia has Ebola.
WHO says 3,685 cases, including 1,841 deaths, have been reported in Guinea, Liberia and Sierra Leone. Nigeria has an additional 21 cases, including seven deaths. Senegal's case count remains at one.
It's announced that another American, Dr. Rick Sacra, will be flown to Nebraska for treatment after contracting the Ebola virus while helping patients in Liberia.
Dr. Rick Sacra is flown to Omaha's Nebraska Medical Center for treatment.
President Obama says the Ebola outbreak needs to be a "national security priority." He tells NBC's "Meet the Press" that the U.S. military could help set up isolation units and provide security for public health workers. "If we don't make that effort now, and this spreads not just through Africa but other parts of the world, there's the prospect then that the virus mutates. It becomes more easily transmittable. And then it could be a serious danger to the United States," he said.
The U.S. announces it will send $10 million additional funds.
That's in addition to the $100 million the U.S. has already sent to help fight the outbreak. USAID also announced it will make $75 million extra available.
At least 2,400 people have died in the three countries; other cases seen in Nigeria and Senegal. Centers in Guinea, Liberia and Sierra Leone are overwhelmed, World Health Organization says.
One in four Americans worry about getting Ebola, according to a CNN Poll.
The U.S. says it will build treatment centers with 1,700 beds. It will send a U.S. general who may coordinate up to 3,000 military personnel. It will send 400,000 treatment kits. Medics and other uniformed professionals will be sent to train up to 500 health care workers per week in identifying and caring for people with Ebola. And the U.S. would help educate the population about the virus.
President Obama says the chances of an American epidemic are "extremely low."
WHO issues a statement applauding the U.S. response. "This massive ramp-up of support from the United States is precisely the kind of transformational change we need to get a grip on the outbreak and begin to turn it around," says Dr. Margaret Chan, director-general.
The CDC's Dr. Beth Bell, the director of the National Center for Emerging and Zoonotic Infectious Diseases testifies before the House Committee on Foreign Affairs, subcommittee on Africa Global Health that "We know how to stop Ebola with strict infection control practices which are already in widespread use in American hospitals."
Some eight people on an Ebola team are killed in southeastern Guinea, near the country's border with Liberia. Among them are health care workers and local journalists.
Sierra Leone begins a three-day, nationwide lockdown designed to stop the spread of Ebola. People are not allowed to leave their homes, giving volunteers a chance to go door-to-door to educate people.
Liberian Thomas Duncan arrives in Dallas to visit relatives. He has been unknowingly exposed to the Ebola virus.
The CDC does an analysis of the epidemic and suggests Ebola cases could reach at least 550,000 to 1.4 million by January, but says with the additional help pledged from the U.S., it may not be that bad.
The WHO reports the death toll from Ebola passed 2,800, with 5,800-plus cases reported. Fatality rate is 71% and "current epidemiologic outlook is bleak," WHO experts say.
Tekmira Pharmaceuticals Corp. says FDA will allow expanded use of an experimental Ebola drug called TKM-Ebola.
CNN's Elizabeth Cohen reports from Liberia that people sick with Ebola are lying in the dirt outside a new Ebola clinic that opened with much fanfare the day before. No worker helps them get from the ambulance outside.
Sierra Leone's three-day lockdown turns up more Ebola cases. "True picture portrays a situation worse than what was being reflected in reports," its government says.
Dr. Rick Sacra is released from the Nebraska Medical Center after recovering from the Ebola virus. Sacra received a blood transfusion from his friend Dr. Kent Brantly, which may have contained lifesaving antibodies. He also received an experimental Ebola drug called TKM-Ebola.
In a speech to the United Nations President Obama calls the West Africa Ebola outbreak "a growing threat to regional and global security" and asks the world for more help with the crisis.
Thomas Duncan returns to Texas Health Presbyterian hospital in Dallas with a high fever. He tells staff he had just come from Liberia. The hospital sends him home with antibiotics.
Liberia's top medical officer is in Ebola quarantine.
Duncan is admitted into isolation at Texas Health Presbyterian Hospital in Dallas. He is the first known case of Ebola diagnosed in the U.S.
A U.S. doctor who volunteered in an Ebola treatment center in Sierra Leone gets sick and is brought to National Institutes of Health Clinical Center in Bethesda, Maryland.
Ebola has orphaned about 3,700 children in Guinea, Liberia and Sierra Leone. Scared relatives don't want to take them in, and models predict the number of orphans could double in a month.
The CDC will be sending a team of 10 public health professionals to support contact tracing and response after learning about the patient sick with Ebola in Dallas.
WHO reports there have been 7,157 cases, including 3,330 deaths, in Guinea, Liberia and Sierra Leone. Close to 400 health care workers have been infected.
Texas Health Presbyterian Hospital "dropped the ball" with Ebola patient's travel history, NIH official says. Dallas Mayor Mike Rawlings: The patient came into contact with up to 20 people. Hospital says symptoms "did not warrant admission" the week before.
Freelance cameraman Ashoka Mukpo, 33, tests positive for Ebola while working with NBC in Liberia. He will be flown back to Nebraska for treatment.
Sen. Rand Paul, R-Kentucky, says the government is downplaying the Ebola threat, and he speculates whether the U.S. would end up with a "whole ship full" of American soldiers infected with the virus. Later he expressed concern about border security.
The administration says there is "no expectation" that U.S. troops would be "physically, geographically in a situation where they should be exposed" to Ebola.
President Obama phones Dallas Mayor Mike Rawlings to make sure he "was getting the resources he needed from the federal government." Rawlings says it "is, at best, disorganized out there."
Some Republicans call for an Ebola czar. The White House says the federal response is "sufficient."
CDC Director Dr. Tom Frieden tries to reassure people, but cautioned: "The plain truth is that we can't make the risk zero until the outbreak is controlled," he says. "What we can do is minimize that risk ... by working to ensure that there are no more individuals that will be exposed."
The FDA receives a request to use an experimental treatment to be used on Thomas Eric Duncan. The family later cries foul, saying he didn't get the necessary medicine and treatment because "he's African." Texas Health Presbyterian says he was "treated the way any other patient would have been treated."
The Department of Defense says it will send up to 4,000 troops to West Africa to fight the epidemic."
The U.S. has 205 service members in Liberia and 26 in Senegal, all dedicated to fighting the epidemic.
The White House releases a fact sheet detailing all the efforts to end the epidemic. It includes committing more than $350 million to fighting the outbreak in West Africa ($111 million in humanitarian aid), and the Department of Defense is prepared "to devote more than $1 billion to the whole-of-government Ebola response effort."
The Department of Defense says it will send up to 4,000 troops to West Africa to fight the epidemic.
A nursing assistant at Madrid's Hospital Carloss III in Spain tests positive for Ebola. Doctors believe Teresa Romero Ramos became infected while removing protective gear she'd used while treating a sick Spanish missionary. She is the first to catch Ebola outside of West Africa during this outbreak.
Some of the U.S. military personnel being deployed to Liberia to help tackle the Ebola crisis might come into contact with the virus, a Pentagon official said, despite what the administration said the week before that there would be no contact.
Thomas Eric Duncan dies at Texas Health Presbyterian Hospital at 7:51 a.m.
New airport screening measures will affect travelers from Guinea, Liberia and Sierra Leone. CDC Director Dr. Tom Frieden says: "We can't get the risk to zero here in the interconnected world."
Spain kills the dog of the Ebola patient Teresa Romero, despite a petition to save Excalibur.
A bipartisan group of congressmen writes to President Obama to step up defense against Ebola. They ask for a travel ban, but the President has said no.
Liberia's President is "a bit more confident" about avoiding most dire predictions, but she postpones elections.
Ninety U.S. Marines arrive in Liberia.
Liberia leaders say the country is short of supplies it needs to care for patients and keep health care workers safe. The ministr anticipates needing at least 85,000 more body bags.
USAID announces Administrator Rajiv Shah will travel to West Africa to meet with staff and local officials coordinating the response to Ebola.
Health workers in Liberia go on strike.
Ebola screenings begin at John F. Kennedy International Airport.
Nina Pham, 26, a Dallas nurse who cared for the Ebola patient Thomas Eric Duncan, is diagnosed with Ebola. This is the first known transmission of the virus in the United States.
Amber Vinson, a nurse at Texas Health Presbyterian who cared for Duncan reports to the CDC an elevated temperature. The CDC does not prohibit her from flying. She takes a flight to Ohio.
"We have to rethink the way we address Ebola infection control because even a single infection is unacceptable," CDC director Dr. Thomas Frieden says after news of the first case of Ebola spread within the U.S. He adds the CDC is doing a detailed investigation to better understand how the infection happened and that the CDC will "double down on training, outreach, education and assistance throughout the health care system." He also added that "we're concerned that there could be other infections in the coming days."
A second health care worker who cared for the Ebola patient in Dallas, reports to the hospital with a low-grade fever. The hospital puts Amber Vinson in isolation after Ebola tests come back positive.
The WHO tweets that by December, it predicts 5,000 to 10,000 Ebola cases per week in Guinea, Liberia and Sierra Leone.
The CDC reaches out to 132 passengers who flew with Amber Vinson on Frontier Airlines Flight 1143. The agency wants o answers questions and determine who, if anyone, needs to be monitored for Ebola symptoms. The worker "exhibited no signs or symptoms of illness" while on the flight, according to the CDC.
An ABC/Washington Post poll shows shows 43% of Americans disapprove of President Obama's Ebola response and 9 in 10 Americans support stricter screening of passengers from Africa, poll shows.
The nurses' union complains that there are no safety protocols or guidelines in the Texas hospital that treated Duncan.
The CDC says it's sending additional resources to Dallas to help the hospital that had the Ebola patient do better infection control. It sends a second team of 16 to train hospital staff and to monitor other health care workers who had contact with the patient.
The CDC is also setting up a dedicated response team that could be on the ground within a few hours at any hospital that gets a confirmed patient with Ebola.
The CDC says a new team will help hospitals around the U.S. better deal with Ebola.
NBC medical correspondent Dr. Nancy Snyderman has issued an apology after she reportedly violated the quarantine her team was under after their cameraman contracted Ebola.
The CDC predicts Ebola cases could soar to 10,000 a week in the worst-hit countries by December.
Dallas nurse Nina Pham's condition improves.
USAID announces $142 million in humanitarian assistance grants and projects for the Ebola response in West Africa.
U.S. troops assisting in the Ebola mission might be quarantined for 21 days after their mission.
CDC director Dr. Tom Frieden says the health care workers treating Duncan were dangerously exposed to the virus when "some of the forms of (personal protective equipment) used did allow exposure of some parts of the skin."
President Obama suspends campaigning to focus on Ebola.
The New York Police Department gives guidance to their officers on how to handle potential Ebola patients.
"The world as a whole is not doing enough. There are a number of countries that have capacity that have not yet stepped up," Obama says. "All of us are going to have to do more."
After learning Amber Vinson's Ebola symptoms may have started four days earlier than they initially believed, the CDC contacts additional passengers that flew with Vinson on Frontier flight 1142 on October 10.
Briana Aguirre, a nurse at Texas Health Presbyterian tells CNN's Anderson Cooper that she is tired of the "nurses being blamed for being sick." She says her hospital was "unprepared" for Ebola. "There were no special precautions," she says."It was just a little chaotic scene."
The hospital says it followed all CDC guidelines, but a hospital executive also offers an apology. "We made mistakes. We did not correctly diagnose his symptoms as those of Ebola and we are deeply sorry."
CNN is told there are plans to transfer Nurse Nina Pham to the National Institutes of Health's isolation unit in Maryland, at the request of Texas Health Presbyterian Hospital.
WHO officially declares the Ebola outbreak in Senegal over and praises the country on its "diligence to end the transmission of the virus."
WHO reports there are 9,191 suspected, probable and confirmed cases (Guinea 1519, Liberia 4262, Sierra Leone 3410), with 4546 deaths (Gunea 8962, Liberia 2,484, Sierra Leone 1,200) in the countries with widespread transmission.
CNN learns that President Obama will appoint Ron Klain, a former aide to Vice President Joe Biden, to coordinate the government's efforts on Ebola.
The CDC issues new guidance on how to use personal protective equipment when working with Ebola patients.
The U.S. restricts flights from Liberia, Sierra Leone and Guinea to landing only at the five airports with enhanced screening.
There have been 9,936 cases (Guinea 1540, Liberia 4,665, Sierra Leone 3706), and 4,877 deaths (Guinea 904, Liberia 2705, Sierra Leone 1,259) in five affected countries (Guinea, Liberia, Sierra Leone, Spain, and the U.S. and two previously affected countries Nigeria and Senegal) according to a WHO report.
Of the reported infections, 443 are health care workers, 244 have died, according to the WHO report.
The NBC freelance photojournalist who contracted Ebola in Liberia is declared "free of the virus." He Tweeted: "I fought and won, with lots of help. Amazing feeling."
The WHO releases its Ebola response roadmap situation report, It applauds Nigeria and Senegal for halting the transmission of Ebola suggesting "the critical importance of preparedness." Key factors were "strong political leadership, early detection and response, public awareness campaigns, and strong partner organizations."
President Obama says his government is "mak(ing) sure that the American people are safe and that we're dealing effectively with not just the Ebola case here, but the outbreak and epidemic that's taking place in West Africa." His administration is "making sure that we don't see a repeat of some of the problems with the protocols that took place in Dallas."
The first positive case of Ebola hits New York City. A 33-year-old Doctor's Without Borders doctor, Craig Spencer, is admitted to an isolation unit. He had been treating Ebola patients in Guinea with Doctors Without Borders.
Doctors without Borders contacts the New York Health Department after learning about Dr. Spencer's fever. The department quarantines two of his friends and his fiancé.
New York Mayor Bill DeBlasio holds a press conference he tells New Yorkers not to be alarmed. "We are fully prepared to handle Ebola," he says
The CDC sends a team to New York to help with the case.
Nurse Nina Pham is considered "free of the (Ebola) virus" and is allowed to head home. The NIH says no experimental drugs were used to treat her.
Emory University Hospital reports the virus is no longer detectable in nurse Amber Vinson's blood. She remains under close watch.
Nurse Nina Pham is flown to the White House. She meets the President who hugs her.
The New York City Department of Health Commissioner says they've "unleash(ed) the medical detectives" to trace people who have had contact with Dr. Spencer.
The governors of New York and New Jersey, Andrew Cuomo and Chris Christie abruptly issue a mandatory 21-day quarantine on all health care workers returning from West Africa after treating Ebola patients. A voluntary quarantine is not enough "it's almost an oxymoron to me," Governor Cuomo says. "The stakes are just too high."
We have the legal authority to do it. We're doing it," Governor Christie says. A federal official tells CNN the CDC, "they're not happy" about it.
Illinois governor Pat Quinn also orders his department of public health to require a mandatory 21-day home quarantine for high-risk individuals.
The MTA tells customers it is safe to ride the subway.
There have been 10,141 Ebola cases in eight affected countries since the outbreak began with, 4,922 deaths, according to WHO.
The CDC now says state and local officials do have the right to set tighter Ebola control policies. "When it comes to the federal standards set by the CDC, we will consider any measures that we believe have the potential to make the American people safer," a CDC statement says.
In a statement, the CDC expresses concerns that mandatory quarantines will discourage health care workers from volunteering for the Ebola duty. It says "health care workers volunteering to combat the Ebola epidemic in West Africa are heroes. The epidemic there won't end without them. And without their work, the U.S. will be at increased risk... we must treat them with respect when they return home."
A quarantined American nurse tells CNN that she doesn't have Ebola and is being treated inhumanely at the University Hospital in Newark where she is being kept under mandatory quarantine since she had contact with Ebola patients overseas. "I feel like my basic human rights have been violated," says Kaci Hickox. She holds Gov. Christie responsible.
On Fox News Sunday morning, Governor Christie said he has had "no second thoughts" about New Jersey's mandatory quarantine for health care workers.
Despite the announcement two days earlier, New York Gov. Andrew Cuomo now says healthcare workers who have cared for Ebola patients should remain in their homes for 21 days and the department will continue to monitor them, but they will not be automatically subjected to quarantine.
Gov. Chris Christie's office says that the nurse quarantined at a New Jersey hospital will be allowed to transfer to Maine to be quarantined at home.She has tested negative for Ebola twice.
Christie says he did not "reverse any decision" in relation to the case and adds that he has "no reason to talk to her" about his decision "my job is not to represent her, it's to represent the people of New Jersey."
Maryland Gov. Martin O'Malley announces the state will directly monitor the health of all returning travelers from the countries of Liberia, Sierra Leone, and Guinea.
Virginia and Florida announcesmandatory monitoring for all travelers returning from West Africa.
The CDC issues revised interim U.S. guidance for monitoring and movement of persons with potential Ebola virus exposure to help state and local authorities best monitor those with a high risk, some risk, a low, but non-zero risk, and no identified risk.
Nurse Amber Vinson is released from Emory University Hospital in Atlanta. She said she is "grateful to be well" and thanked former Ebola patients Brantly and Writebol for donating plasma to her and other patients.
CNN learns some 30 soldiers who had been stationed in West Africa will be under "controlled monitoring" in Italy for 21 days. There is no indication anyone on the team has symptoms.
A Maine judge rules against the request for a tighter quarantine for Hickox.
Ohio tightens resrictions on people who travel to West African countries impacted by Ebola.
Ramos, the Spanish nursing assistant leaves the hospital Ebola-free.
Dr. Craig Spencer is released from the hospital and declared Ebola-free.
The regional death toll from the deadly virus surpasses 5,000.
Clinical trials of experimental Ebola treatment will start next month in West Africa. Doctors Without Borders will conduct trials at three treatment centers in Guinea and Liberia, the medical aid agency says.
A flight carrying an American surgeon infected with Ebola leaves from Sierra Leone. Dr. Martin Salia had been splitting his professional time between Methodist hospital in New Carrollton, Maryland and Sierra Leone where he had been treating a variety of patients. Salia had grown up in Sierra Leone.
The WHO reports there are 14,413 total Ebola cases. Some 5,177 people have died.
Dr. Salia arrives at the Nebraska Medical Center in “extremely critical condition.” His kidneys and respiratory system are failing.
Dr. Salia dies at the Nebraska Medical Center. Doctors say they treated him with a dose of ZMapp and a blood transfusion from an Ebola survivor. The team says they believe he was much sicker than the other patients treated successfully in the United States.
There have been 15,145 Ebola cases in eight affected countries since the outbreak began with, 6,388 deaths, according to the WHO.
There have been 17,942 Ebola cases in eight affected countries since the outbreak began with, 5,420 deaths, according to the WHO.
TIME magazine names "The Ebola Fighters" as its 2014 "Person of the Year."
Health officials confirm the first case of Ebola in Scotland. Nurse Pauline Cafferkey, was working for Save the Children in Sierra Leone when infected. She developed symptoms after returning home. After tests confirmed Ebola she was transferred to a special isolation unit in London.
Mali is declared Ebola free after no new cases in 42 days.
American Ebola survivor, Dr. Rick Sacra, returns to Liberia five months after he left there infected with the deadly virus for treatment in the US. A volunteer for a Christian missionary non-profit, he returned to volunteer again.
Nurse Pauline Cafferkey was discharged from a London Hospital following treatment for Ebola, which she contracted while working in Sierra Leone.
The number of new Ebola cases dropped to the lowest level reported since June in the three worst hit countries of Guinea, Liberia and Sierra Leone where there were a total of 99 new cases for the week ending January 25.
Liberia reopens its land border crossings shut down during the Ebola outbreak, and Liberian President Ellen Johnson Sirleaf also lifts the nationwide curfew imposed in August to help combat the virus.
The Pentagon said all but 100 troops sent to West Africa 10 months earlier to support efforts to battle the Ebola epidemic will return home.
A British military health care worker tested positive for Ebola in Sierra Leone, the UK health agency reported.
An unidentified American health care worker for the Boston-based aid group Partners in Health arrived at the National Institutes of Health hospital in Maryland for treatment after testing positive for Ebola. The individual was infected while volunteering at an Ebola treatment center in Sierra Leone. Fourteen colleagues of this patient return to the US for monitoring over the next few days.
American, Dr. Ian Crozier, who had been treated in September for Ebola at Emory University developed eye problems two months after he was discharged from the hospital and declared free of the virus. This was detailed in a study published in the New England Journal of Medicine which explained that when Crozier returned to Emory fluid was removed from his eye that tested positive for Ebola.
The WHO declares an end to the Ebola outbreak in Liberia where more than 4,000 people died from the disease.
More than seven weeks after Liberia was declared Ebola-free, a young man was found dead of the disease, the country's deputy health minister said.
An experimental Ebola vaccine being tested in Guinea appears to be “highly effective” the WHO said. The researchers working on the vaccine trial said it could help prevent the spread of the virus in current and future outbreaks.
Liberia is once again Ebola-free, according to the WHO. The nation had been declared as such in May however six new cases emerged between June and July.
Scottish nurse Pauline Cafferkey is readmitted to the hospital due to “an unusual late complication” from her Ebola infection, according to her doctors.
The disappearance of Ebola symptoms does not mean the virus is gone. Instead, a preliminary study, published in the New England Journal of Medicine, discovered that the virus can still be found in the semen of survivors for at least nine months after the onset of symptoms.
Sierra Leone is declared free of Ebola after 14,000 cases 18 months.
Pauline Cafferkey, the Scottish nurse who was infected with Ebola while working in Sierra Leone, was given the all clear and discharged from the hospital after she’d been readmitted and diagnosed with meningitis caused by Ebola.
Liberia's health ministry announced three new, confirmed cases of Ebola have emerged in the country.
A panel of global health experts, convened by the Harvard Global Health Institute and the London School of Hygiene & Tropical Medicine, strongly criticized the WHO saying it mishandled the response to the Ebola outbreak. The called the response an, “egregious failure” and pointed to a delay in sounding the alarm.
The World Health Organization declares Guinea free of Ebola following 42 days since the last person confirmed to have the virus was tested negative for a second time.
The WHO declares West Africa Ebola-free marking an end to the outbreak there. "For the first time since this devastating outbreak began, all known chains of transmission of Ebola in West Africa have been stopped and no new cases have been reported since the end of November," a statement said. The agency warned flare-ups are expected.
The WHO and CDC confirm a new case of Ebola in Sierra Leone. The patient died. The announcement came on the heels of the outbreak being declared over.
Scottish nurse, Pauline Cafferkey is hospitalized again for “late complications from her previous infection by the Ebola virus,” according to officials at London’s Royal Free Hospital.
The WHO ended the public health emergency of international concern declaring Ebola is no longer an international threat to public health. This came after 42 consecutive days without new infections in Sierra Leone, Liberia and Guinea and an additional 90-day enhanced surveillance period.
Three days later, The WHO announced the death of a woman in Liberia was the result of Ebola. The agency noted, as they had previously, that sporadic flare-ups are expected even as the major health emergency is over. The agency also said 800 people who had come in contact with Ebola patients were being given an experimental vaccine.
Study reports ZMapp, the promising yet experimental drug that was attributed for saving lives of several high profile patients was beneficial but “did not meet the prespecified statistical threshold for efficacy,” according to a study of 72 people published in the New England Journal of Medicine.
Nurse Nina Pham, the first to contract the virus in the US, settled a lawsuit against the parent company of Texas Health Presbyterian Hospital in Dallas where she became infected while caring for patient Thomas Duncan.
An experimental vaccine is 100% effective, according to a study in the British journal The Lancet. The vaccine was tested on more than 11,000 people in Guinea. The vaccine was developed in Canada but is now owned and manufactured by Merck, Sharp & Dohme.