Deadliest outbreak of Ebola virus: What you need to knowBy Susannah Cullinane and Nick Thompson, CNNUpdated 6:51 AM ET, Thu September 18, 2014Just WatchedThe facts about EbolareplayMore Videos ...The facts about Ebola 03:44Story highlights There are more than 1,300 confirmed and suspected Ebola cases, hundreds of deathsLiberia closes all schools, sets day "for the disinfection ... of all public facilities""This epidemic is without precedent," a humanitarian official saysEbola is a viral hemorrhagic fever, affecting multiple organs and accompanied by bleedingThe deadliest outbreak of Ebola virus on record has sparked fears that the killer virus could spread from West Africa to other regions and continents.The outbreak began with just a handful of cases in Guinea in March. Since then, that number has grown to 909 confirmed cases and another 414 probable or suspected in that country, Sierra Leone and Liberia and Nigeria, according to the World Health Organization.Some 729 people of the 1,323 total confirmed and possible infections have died, reports WHO as of July 27.The WHO says "drastic action is needed" to contain Ebola, warning that previously undetected chains of transmission are boosting the numbers of sick and increasing the chances that the disease spreads from Africa."This epidemic is without precedent," said Bart Janssens, director of operations for Médecins Sans Frontières, also known as Doctors Without Borders. "It's absolutely not under control, and the situation keeps worsening. ... There are many places where people are infected but we don't know about it."What's the latest?The Ebola outbreak has been centered in Guinea, Sierra Leone and Liberia, where authorities have been working to contain the virus. In Liberia, President Ellen Johnson Sirleaf announced Wednesday that, "without exceptions, all schools are ordered closed pending further directive from the Ministry of Education." She also declared Friday a nonworking day "to be used for the disinfection and chlorination of all public facilities."Photos: The Ebola epidemic 47 photosPhotos: The Ebola epidemic 47 photosThe Ebola epidemic – Red Cross workers, wearing protective suits, carry the body of a person who died from Ebola during a burial in Monrovia, Liberia, on Monday, January 5. Since the epidemic started a little more than a year ago in a remote village in Guinea, the world has seen more than 8,400 deaths, according to the latest numbers from the World Health Organization. And that number is believed to be low, since there was widespread under-reporting of cases, according to WHO.Hide Caption 1 of 47Photos: The Ebola epidemic 47 photosPauline Cafferkey, a Scottish woman diagnosed with Ebola, is put on a plane in Glasgow, Scotland, on Tuesday, December 30. Cafferkey, a 39-year-old nurse who volunteered in Sierra Leone, was being transported to London for treatment.Hide Caption 2 of 47Photos: The Ebola epidemic 47 photosLiberian President Ellen Johnson Sirleaf has her temperature taken before the opening of a new Ebola clinic Tuesday, November 25, in Monrovia.Hide Caption 3 of 47Photos: The Ebola epidemic 47 photosA child who survived the Ebola virus is fed by another survivor at a treatment center on the outskirts of Freetown, Sierra Leone, on Tuesday, November 11.Hide Caption 4 of 47Photos: The Ebola epidemic 47 photosHealth workers in Monrovia cover the body of a man suspected of dying from the Ebola virus on Friday, October 31.Hide Caption 5 of 47Photos: The Ebola epidemic 47 photosKaci Hickox leaves her home in Fort Kent, Maine, to take a bike ride with her boyfriend on Thursday, October 30. Hickox, a nurse, recently returned to the United States from West Africa, where she treated Ebola victims. State authorities wanted her to avoid public places for 21 days -- the virus' incubation period. But Hickox, who twice tested negative for Ebola, said she would defy efforts to keep her quarantined at home.Hide Caption 6 of 47Photos: The Ebola epidemic 47 photosCrew members at an airport in Accra, Ghana, unload supplies sent from China on Wednesday, October 29.Hide Caption 7 of 47Photos: The Ebola epidemic 47 photosHealth officials in Nairobi, Kenya, prepare to screen passengers arriving at the Jomo Kenyatta International Airport on Tuesday, October 28.Hide Caption 8 of 47Photos: The Ebola epidemic 47 photosU.S. President Barack Obama hugs Ebola survivor Nina Pham in the Oval Office of the White House on Friday, October 24. Pham, one of two Dallas nurses diagnosed with the virus, was declared Ebola-free after being treated at a hospital in Bethesda, Maryland. The other nurse, Amber Vinson (not pictured), was treated in Atlanta and also declared Ebola-free.Hide Caption 9 of 47Photos: The Ebola epidemic 47 photosHealth workers in Port Loko, Sierra Leone, transport the body of a person who is suspected to have died of Ebola on Tuesday, October 21.Hide Caption 10 of 47Photos: The Ebola epidemic 47 photosHealth workers bury a body on the outskirts of Monrovia on Monday, October 20.Hide Caption 11 of 47Photos: The Ebola epidemic 47 photosGarteh Korkoryah, center, is comforted during a memorial service for her son, Thomas Eric Duncan, on Saturday, October 18, in Salisbury, North Carolina. Duncan, a 42-year-old Liberian citizen, died October 8 in a Dallas hospital. He was in the country to visit his son and his son's mother, and he was the first person in the United States to be diagnosed with Ebola.Hide Caption 12 of 47Photos: The Ebola epidemic 47 photosBoys run from blowing dust as a U.S. military aircraft leaves the construction site of an Ebola treatment center in Tubmanburg, Liberia, on Wednesday, October 15.Hide Caption 13 of 47Photos: The Ebola epidemic 47 photosAid workers from the Liberian Medical Renaissance League stage an Ebola awareness event October 15 in Monrovia. The group performs street dramas throughout Monrovia to educate the public on Ebola symptoms and how to handle people who are infected with the virus.Hide Caption 14 of 47Photos: The Ebola epidemic 47 photosEbola survivors prepare to leave a Doctors Without Borders treatment center after recovering from the virus in Paynesville, Liberia, on October 12.Hide Caption 15 of 47Photos: The Ebola epidemic 47 photosA woman crawls toward the body of her sister as a burial team takes her away for cremation Friday, October 10, in Monrovia. The sister had died from Ebola earlier in the morning while trying to walk to a treatment center, according to her relatives.Hide Caption 16 of 47Photos: The Ebola epidemic 47 photosA person peeks out from the Dallas apartment where Thomas Eric Duncan, the first person diagnosed with the Ebola virus in the United States, was staying on Friday, October 3.Hide Caption 17 of 47Photos: The Ebola epidemic 47 photosA girl cries as community activists approach her outside her Monrovia home on Thursday, October 2, a day after her mother was taken to an Ebola ward.Hide Caption 18 of 47Photos: The Ebola epidemic 47 photosA health official uses a thermometer Monday, September 29, to screen a Ukrainian crew member on the deck of a cargo ship at the Apapa port in Lagos, Nigeria.Hide Caption 19 of 47Photos: The Ebola epidemic 47 photosWorkers move a building into place as part of a new Ebola treatment center in Monrovia on September 28.Hide Caption 20 of 47Photos: The Ebola epidemic 47 photosMedical staff members at the Doctors Without Borders facility in Monrovia burn clothes belonging to Ebola patients on Saturday, September 27. Hide Caption 21 of 47Photos: The Ebola epidemic 47 photosMedics load an Ebola patient onto a plane at Sierra Leone's Freetown-Lungi International Airport on Monday, September 22.Hide Caption 22 of 47Photos: The Ebola epidemic 47 photosA few people are seen in Freetown during a three-day nationwide lockdown on Sunday, September 21. In an attempt to curb the spread of the Ebola virus, people in Sierra Leone were told to stay in their homes.Hide Caption 23 of 47Photos: The Ebola epidemic 47 photosSupplies wait to be loaded onto an aircraft at New York's John F. Kennedy International Airport on Saturday, September 20. It was the largest single shipment of aid to the Ebola zone to date, and it was coordinated by the Clinton Global Initiative and other U.S. aid organizations.Hide Caption 24 of 47Photos: The Ebola epidemic 47 photosA child stops on a Monrovia street Friday, September 12, to look at a man who is suspected of suffering from Ebola.Hide Caption 25 of 47Photos: The Ebola epidemic 47 photosHealth workers in Monrovia place a corpse into a body bag on Thursday, September 4.Hide Caption 26 of 47Photos: The Ebola epidemic 47 photosAfter an Ebola case was confirmed in Senegal, people load cars with household items as they prepare to cross into Guinea from the border town of Diaobe, Senegal, on Wednesday, September 3.Hide Caption 27 of 47Photos: The Ebola epidemic 47 photosCrowds cheer and celebrate in the streets Saturday, August 30, after Liberian authorities reopened the West Point slum in Monrovia. The military had been enforcing a quarantine on West Point, fearing a spread of the Ebola virus.Hide Caption 28 of 47Photos: The Ebola epidemic 47 photosA health worker wearing a protective suit conducts an Ebola prevention drill at the port in Monrovia on Friday, August 29. Hide Caption 29 of 47Photos: The Ebola epidemic 47 photosVolunteers working with the bodies of Ebola victims in Kenema, Sierra Leone, sterilize their uniforms on Sunday, August 24. Hide Caption 30 of 47Photos: The Ebola epidemic 47 photosA burial team from the Liberian Ministry of Health unloads bodies of Ebola victims onto a funeral pyre at a crematorium in Marshall, Liberia, on Friday, August 22.Hide Caption 31 of 47Photos: The Ebola epidemic 47 photosDr. Kent Brantly leaves Emory University Hospital on Thursday, August 21, after being declared no longer infectious from the Ebola virus. Brantly was one of two American missionaries brought to Emory for treatment of the deadly virus.Hide Caption 32 of 47Photos: The Ebola epidemic 47 photosAn Ebola Task Force soldier beats a local resident while enforcing a quarantine on the West Point slum on August 20.Hide Caption 33 of 47Photos: The Ebola epidemic 47 photosLocal residents gather around a very sick Saah Exco, 10, in a back alley of the West Point slum on Tuesday, August 19. The boy was one of the patients that was pulled out of a holding center for suspected Ebola patients after the facility was overrun and closed by a mob on August 16. A local clinic then refused to treat Saah, according to residents, because of the danger of infection. Although he was never tested for Ebola, Saah's mother and brother died in the holding center.Hide Caption 34 of 47Photos: The Ebola epidemic 47 photosA burial team wearing protective clothing retrieves the body of a 60-year-old Ebola victim from his home near Monrovia on Sunday, August 17. Hide Caption 35 of 47Photos: The Ebola epidemic 47 photosWorkers prepare the new Ebola treatment center on August 17.Hide Caption 36 of 47Photos: The Ebola epidemic 47 photosLiberian police depart after firing shots in the air while trying to protect an Ebola burial team in the West Point slum of Monrovia on August 16. A crowd of several hundred local residents reportedly drove away the burial team and their police escort. The mob then forced open an Ebola isolation ward and took patients out, saying the Ebola epidemic is a hoax.Hide Caption 37 of 47Photos: The Ebola epidemic 47 photosA crowd enters the grounds of an Ebola isolation center in the West Point slum on August 16. The mob was reportedly shouting, "No Ebola in West Point."Hide Caption 38 of 47Photos: The Ebola epidemic 47 photosA health worker disinfects a corpse after a man died in a classroom being used as an Ebola isolation ward Friday, August 15, in Monrovia.Hide Caption 39 of 47Photos: The Ebola epidemic 47 photosHealth workers in Kenema screen people for the Ebola virus on Saturday, August 9, before they enter the Kenema Government Hospital.Hide Caption 40 of 47Photos: The Ebola epidemic 47 photosAid worker Nancy Writebol, wearing a protective suit, gets wheeled on a gurney into Emory University Hospital in Atlanta on August 5. A medical plane flew Writebol from Liberia to the United States after she and her colleague Dr. Kent Brantly were infected with the Ebola virus in the West African country. Hide Caption 41 of 47Photos: The Ebola epidemic 47 photosMembers of Doctors Without Borders adjust tents in the isolation area in Kailahun on July 20.Hide Caption 42 of 47Photos: The Ebola epidemic 47 photosBoots dry in the Ebola treatment center in Kailahun on July 20.Hide Caption 43 of 47Photos: The Ebola epidemic 47 photosDr. Jose Rovira of the World Health Organization takes a swab from a suspected Ebola victim in Pendembu, Sierra Leone, on Friday, July 18.Hide Caption 44 of 47Photos: The Ebola epidemic 47 photosRed Cross volunteers disinfect each other with chlorine after removing the body of an Ebola victim from a house in Pendembu on July 18.Hide Caption 45 of 47Photos: The Ebola epidemic 47 photosA scientist separates blood cells from plasma cells to isolate any Ebola RNA and test for the virus Thursday, April 3, at the European Mobile Laboratory in Gueckedou, Guinea.Hide Caption 46 of 47Photos: The Ebola epidemic 47 photosHealth specialists work Monday, March 31, at an isolation ward for patients at the facility in southern Guinea.Hide Caption 47 of 47EXPAND GALLERYJust WatchedEbola outbreak kills an AmericanreplayMore Videos ...Ebola outbreak kills an American 02:38PLAY VIDEOJust WatchedFighting Ebola on the front linesreplayMore Videos ...Fighting Ebola on the front lines 04:11PLAY VIDEOJust WatchedAmerican doctor battling EbolareplayMore Videos ...American doctor battling Ebola 03:01PLAY VIDEOOn the same day, the Peace Corps said it was temporarily removing its 340 volunteers from Liberia, Sierra Leone and Guinea due to the outbreak.The announcement comes as two Peace Corps volunteers were isolated after coming in contact with someone who ended up dying of Ebola, a spokeswoman for the group said. She said these two Americans "are not symptomatic," and the Peace Corps will work to return them to the United States once they get medical clearance to travel.Concerns about Ebola aren't confined to those three countries. Last week, a Liberian government official who had contracted the virus died in isolation at a hospital in Lagos, Nigeria. Patrick Sawyer, a naturalized American citizen who worked in Liberia, flew to Nigeria intending to attend a conference. After exhibiting symptoms upon arrival July 20, he was hospitalized and died on July 25. He's the first American to die in the outbreak, though two other U.S. aid workers in Liberia have contracted Ebola and are being treated. Sawyer's was the only known case in Nigeria, WHO said.And the British government convened an emergency meeting to discuss the threat of Ebola to the UK, even though no case has been reported there. Officials discussed what measures could be taken if UK nationals in West Africa should become infected, Foreign Secretary Philip Hammond said.Why was someone infected with Ebola allowed on a plane?It is unknown whether Sawyer was displaying symptoms before he flew from Monrovia, Liberia's capital, to Ghana and then to Togo to switch planes to fly to Lagos.His Minnesota-based widow, Decontee Sawyer, told CNN that he had cared for his ill sister in Liberia, though she said he didn't know at the time that his sister had Ebola. When he arrived in Nigeria, he told officials that he had no direct contact with anyone who had the disease.Because it takes between two and 21 days before Ebola symptoms to show, there's little health officials can do to stop an asymptomatic person from flying to another country, said CNN Chief Medical Correspondent Sanjay Gupta.So, serious viruses such as Ebola may be just "a plane ride away" from reaching the developed world, according to Marty Cetron of the U.S. Centers for Disease Control and Prevention (CDC).Mindful of this, Nigeria-based airline companies ASKY and Arik Air suspended operations at the end of July into Monrovia and Freetown, the capitals of Liberia and Sierra Leone, respectively. ASKY said passengers departing from Conakry, Guinea, would be screened for signs of the virus.Cetron says it is unlikely the virus would spread on an airplane unless a passenger were to come into contact with a sick person's bodily fluids.Stressing the key role that those working at airports play in keeping Ebola in check, the CDC spokesman said: "Being educated, knowing the symptoms, recognizing what to do, having a response to protocol, knowing who to call -- those are really, really important parts of the global containment strategies to deal with threats like this." What else is being done to stop the spread of the disease?Ebola patients are being isolated by health officials in West Africa, and those who have come into contact with them are being told to monitor their temperatures. President Sirleaf has closed most of Liberia's borders with neighboring countries, and the few points of entry that are still open will have Ebola testing centers. The President also placed restrictions on public gatherings and ordered hotels, restaurants and other entertainment venues to play a five-minute video on Ebola safety.The CDC has issued an alert to health workers in the United States to watch out for any patients who may have recently traveled to West Africa and could have contracted the virus.Why does Ebola generate such fear?Medecins Sans Frontieres (MSF) describes Ebola as "one of the world's most deadly diseases." "It is a highly infectious virus that can kill up to 90% of the people who catch it, causing terror among infected communities," it says. The death rate in this outbreak has dropped to roughly 55% because of early treatment. There is also no vaccination against it.Of Ebola's five subtypes, the Zaire strain -- the first to be identified -- is considered the most deadly.The WHO said preliminary tests on the Ebola virus in Guinea in March suggested that the outbreak there was this strain, though that has not been confirmed. What is Ebola, and what are its symptoms?Just WatchedTracking the Ebola virus in NigeriareplayMore Videos ...Tracking the Ebola virus in Nigeria 01:40PLAY VIDEOJust WatchedEbola scientist: 'It's spectacular'replayMore Videos ...Ebola scientist: 'It's spectacular' 02:39PLAY VIDEOJust WatchedEbola epidemic 'out of control'replayMore Videos ...Ebola epidemic 'out of control' 03:44PLAY VIDEOJust WatchedFighting Ebola in urban AfricareplayMore Videos ...Fighting Ebola in urban Africa 04:51PLAY VIDEOThe Ebola virus causes viral hemorrhagic fever, which according to the U.S. Centers for Disease Control and Prevention (CDC), refers to a group of viruses that affect multiple organ systems in the body and are often accompanied by bleeding.The virus is named after the Ebola River in the Democratic Republic of Congo (formerly Zaire), where one of the first outbreaks occurred in 1976. Early symptoms include sudden onset of fever, weakness, muscle pain, headaches and a sore throat. These symptoms can appear two to 21 days after infection.The WHO says these nonspecific early symptoms can be mistaken for signs of diseases such as malaria, typhoid fever, meningitis or even the plague.MSF says some patients may also develop a rash, red eyes, hiccups, chest pains and difficulty breathing and swallowing.The early symptoms progress to vomiting, diarrhea, impaired kidney and liver function and sometimes internal and external bleeding.Ebola can only be definitively confirmed by five different laboratory tests.How is it treated? There are no specific treatments for Ebola. MSF says patients are isolated and then supported by health care workers."This consists of hydrating the patient, maintaining their oxygen status and blood pressure and treating them for any complicating infections," it says.There have been cases of healthcare workers contracting the virus from patients, and the WHO has issued guidance for dealing with confirmed or suspected cases of the virus. Carers are advised to wear impermeable gowns and gloves and to wear facial protection such as goggles or a medical mask to prevent splashes to the nose, mouth and eyes.MSF says it contained a 2012 outbreak in Uganda by placing a control area around its treatment center. An outbreak is considered over once 42 days -- double the incubation period of the disease -- have passed without any new cases.How does it spread?The WHO says it is believed that fruit bats may be the natural host of the Ebola virus in Africa, passing on the virus to other animals.Humans contract Ebola through contact with the bodily fluids of infected animals or the bodily fluids of infected humans. MSF says that while the virus is believed to be able to survive for some days in liquid outside an infected organism, chlorine disinfection, heat, direct sunlight, soaps and detergents can kill it.MSF epidemiologist Kamiliny Kalahne said outbreaks usually spread in areas where hospitals have poor infection control and limited access to resources such as running water."People who become sick with it almost always know how they got sick: because they looked after someone in their family who was very sick -- who had diarrhea, vomiting and bleeding -- or because they were health staff who had a lot of contact with a sick patient," she said.Ebola outbreakHow the world reacted as Ebola spreadThe largest Ebola epidemic in history began with the simple act of caring for a child. Soon, it spread from the remote village in Guinea.Countries with travel restrictionsThe worst-ever outbreak of Ebola virus is stretching the medical capacities of Guinea, Liberia and Sierra Leone.Who is patient zero?Before the deaths soared into the thousands, before the outbreak triggered global fears, Ebola struck a toddler named Emile Ouamouno. The messy truth about EbolaWhat happens when you get Ebola? CNN's Miguel Marquez explains.Millions of vaccines planned by 2015 Health experts are fast-tracking tests for various vaccines, and hope to have millions of experimental doses by next year.How the Ebola virus spreadsEbola is a scary infectious disease but the first thing you should know is that it's not very contagious. Here is how it spreads.What you need to knowThese questions and answers will give you the latest information on the deadly virus and what's being done to stop its spread.3 with Ebola will fly each monthUp to three Ebola-infected travelers might board an international flight each month in West Africa, according to a new study, and potentially spread the deadly virus.Why some survive, some don'tThere's no cure for Ebola. So why have some patients walked away healthy while others in the West died? Inside the world's worst outbreakA doctor at a government-run Ebola treatment center in Monrovia is too busy to mince words.Stigmatized, abandoned orphansTwo children orphaned by Ebola play in the empty corner of a Liberian orphanage. Their parents died last month, and none of the extended family is willing to claim them. Five ways the CDC got it wrongPublic health experts are asking whether the CDC is partly to blame for problems with Ebola in the U.S. Here are 5 things they say the CDC is getting wrong.Can pets get or spread Ebola? The lack of solid protocol on what to do with Ebola victims' pets and what little is known about the risk has caused one dog to be euthanized and another quarantined. A look at Ebola protective gearRosie Tomkins takes a look at the protective suits that are worn by some Ebola medical workers in Africa.How hospitals handle Ebola patientsWhat's the protocol for health care workers if they suspect a patient has the virusEbola outbreak in West AfricaClick through our gallery as we track the Ebola outbreak in West Africa. Complete coverage on EbolaA look at CNN's complete coverage on the Ebola crisis. 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How the world reacted as Ebola spreadThe largest Ebola epidemic in history began with the simple act of caring for a child. Soon, it spread from the remote village in Guinea.
Countries with travel restrictionsThe worst-ever outbreak of Ebola virus is stretching the medical capacities of Guinea, Liberia and Sierra Leone.
Who is patient zero?Before the deaths soared into the thousands, before the outbreak triggered global fears, Ebola struck a toddler named Emile Ouamouno.
Millions of vaccines planned by 2015 Health experts are fast-tracking tests for various vaccines, and hope to have millions of experimental doses by next year.
How the Ebola virus spreadsEbola is a scary infectious disease but the first thing you should know is that it's not very contagious. Here is how it spreads.
What you need to knowThese questions and answers will give you the latest information on the deadly virus and what's being done to stop its spread.
3 with Ebola will fly each monthUp to three Ebola-infected travelers might board an international flight each month in West Africa, according to a new study, and potentially spread the deadly virus.
Why some survive, some don'tThere's no cure for Ebola. So why have some patients walked away healthy while others in the West died?
Inside the world's worst outbreakA doctor at a government-run Ebola treatment center in Monrovia is too busy to mince words.
Stigmatized, abandoned orphansTwo children orphaned by Ebola play in the empty corner of a Liberian orphanage. Their parents died last month, and none of the extended family is willing to claim them.
Five ways the CDC got it wrongPublic health experts are asking whether the CDC is partly to blame for problems with Ebola in the U.S. Here are 5 things they say the CDC is getting wrong.
Can pets get or spread Ebola? The lack of solid protocol on what to do with Ebola victims' pets and what little is known about the risk has caused one dog to be euthanized and another quarantined.
A look at Ebola protective gearRosie Tomkins takes a look at the protective suits that are worn by some Ebola medical workers in Africa.
How hospitals handle Ebola patientsWhat's the protocol for health care workers if they suspect a patient has the virus
Ebola outbreak in West AfricaClick through our gallery as we track the Ebola outbreak in West Africa.