Questions about this new Ebola drug

Two American missionary workers infected with the deadly Ebola virus were given an experimental drug that seems to have saved their lives.

Dr. Kent Brantly was given the medication, ZMapp, shortly after telling his doctors he thought he would die, according to a source familiar with his case. Within an hour, doctors say his symptoms -- labored breathing and a widespread rash -- dramatically improved. Nancy Writebol, another missionary working with Samaritan's Purse, received two doses of the medication and has also shown significant improvement, sources say.

As there is no proven treatment and no vaccine for Ebola, this experimental drug is raising lots of questions.

Who makes the drug?
Secret serum likely saved Ebola patients
Why isn't there an Ebola vaccine?
Ebola transport team speaks to CNN
West African Ebola epidemic

The drug was developed by the biotech firm Mapp Biopharmaceutical Inc., which is based in San Diego. The company was founded in 2003 "to develop novel pharmaceuticals for the prevention and treatment of infectious diseases, focusing on unmet needs in global health and biodefense," according to its website.

Mapp Biopharmaceutical has been working with the National Institutes of Health and the Defense Threat Reduction Agency, an arm of the military responsible for weapons of mass destruction, to develop an Ebola treatment for several years.

Are there other experimental Ebola drugs out there?

Yes. In March, the NIH awarded a five-year $28 million grant to establish a collaboration between researchers from 15 institutions who were working to fight Ebola.

"A whole menu of antibodies have been identified as potentially therapeutic, and researchers are eager to figure out which combinations are most effective and why," a news release about the grant said.

Tekmira, a Vancouver-based company that has a $140 million contract with the U.S. Department of Defense to develop an Ebola drug, began Phase 1 trials with its drug in January. But the FDA recently halted the trial, asking for more information.

At least one potential Ebola vaccine has been tested in healthy human volunteers, according to Thomas Geisbert, a leading researcher at the University of Texas Medical Branch. And last week, the NIH announced a safety trial of another Ebola vaccine will start as early as September.

How does ZMapp work?

Antibodies are proteins used by the immune system to mark and destroy foreign, or harmful, cells. A monoclonal antibody is similar, except it's engineered in a lab so it will attach to specific parts of a dangerous cell, according to the Mayo Clinic, mimicking your immune system's natural response. Monoclonal antibodies are used to treat many different types of conditions.

This medicine is a three-mouse monoclonal antibody, meaning that mice were exposed to fragments of the Ebola virus and then the antibodies generated within the mice's blood were harvested to create the medicine.

Why did American missionary workers get the drug?

Many have asked why these two workers received the experimental drug when so many -- around 1,600 -- others in West Africa also have the virus.

Samaritan's Purse reached out to an NIH scientist who was on the ground in West Africa, according to the National Institute of Allergy and Infectious Diseases. "The scientist was able to informally answer some questions and referred them to appropriate company contacts to pursue their interest in obtaining experimental product," NIAID said.

The World Health Organization says it was not involved in the decision to treat Brantly and Writebol. Both patients had to give consent to receive the drug, knowing it had never been tested in humans before.

The process by which the medication was made available to the American patients may have fallen under the U.S. Food and Drug Administration's "compassionate use" regulation, which allows access to investigational drugs outside clinical trials.

Did doctors know it would work?

No. The drug had shown promise in primates, but even in those experiments, just eight monkeys received the treatment. In any case, the human immune system can react differently than primates', which is why drugs are required to undergo human clinical trials before being approved by government agencies for widespread use.

The two Americans' cases will be studied further to determine how the drug worked with their immune systems.

Will the drug be made available to other Ebola patients?
Second Ebola patient heading to U.S.
Can camera help detect Ebola?

It's unclear. Doctors "cannot start using untested drugs in the middle of an outbreak, for various reasons," World Health Organization spokesman Gregory Hartl said.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, says scientists have to be careful about assuming this drug will work in other patients as it appears to have worked in Brantly.

"Having worked with administering antibodies for people for a really long time, that would be distinctly unusual," he told CNN. "As we all know in medicine ... you have to withhold judgment."

Does the company have more vials of the drug?

The company has very few doses ready for patient use, Fauci told CNN. "Apparently the company is trying to scale up, (but) it's not easy to scale up to very large number of doses."

Who paid for the drug and how much did it cost?

We don't know. Samaritan's Purse covered the cost of Brantly and Writebol's evacuations but did not pay for the drug, according to a spokesman.

When a patient gets an experimental drug, the drug company can donate the product under compassionate use. Mapp Biopharmaceutical Inc. might have done that in this case.

Health insurance companies typically do not pick up the tab for treatments that have not been approved by the FDA. But they would usually cover the cost of any doctor fees associated with giving the drug and any costs associated with monitoring how the drug is working.

Would this drug stop the Ebola epidemic?

If it were widely available, it certainly couldn't hurt. An effective Ebola drug could help doctors treat the deadly virus, which is killing about 60% of the people infected in West Africa. But a vaccine would be a much more effective tool in stopping this, and future, epidemics.

Vaccines are given to healthy people to prevent them from ever becoming infected. One challenge with Ebola, experts say, is that companies don't believe they could make much money from developing a vaccine, so few companies show interest.


http://edition.cnn.com/2014/08/04/health/ebola-drug-questions/index.html?hpt=hp_c1

Experimental drug likely saved Ebola patients

It's a story that could have come from a cinematic medical thriller: Two American missionary workers contract Ebola. Their situation is dire. Three vials containing a highly experimental drug are flown into Liberia in a last-ditch effort to save them.

And the drug flown in last week appears to have worked, according to a source familiar with details of the treatment.

Dr. Kent Brantly's and Nancy Writebol's conditions significantly improved after receiving the medication, sources say. Brantly was able to walk into Emory University Hospital in Atlanta after being evacuated to the United States last week, and Writebol is expected to arrive in Atlanta on Tuesday.

On July 22, Brantly woke up feeling feverish. Fearing the worst, Brantly immediately isolated himself. Writebol's symptoms started three days later. A rapid field blood test confirmed the infection in both of them after they had become ill with fever, vomiting and diarrhea.
Photos: Ebola outbreak in West Africa Photos: Ebola outbreak in West Africa
Why isn't there an Ebola vaccine?
Second Ebola patient heading to U.S.
Doctors struggle to treat Ebola patients

It's believed Brantly and Writebol, who worked with the aid organization Samaritan's Purse, contracted Ebola from another health care worker at their hospital in Liberia, although the official Centers for Disease Control and Prevention case investigation has yet to be released.

As the Americans' conditions worsened, Samaritan's Purse reached out to a National Institutes of Health scientist who was on the ground in West Africa, according to the National Institute of Allergy and Infectious Diseases.

"The scientist was able to informally answer some questions and referred them to appropriate company contacts to pursue their interest in obtaining the experimental product," NIAID said.

The experimental drug, known as ZMapp, was developed by the biotech firm Mapp Biopharmaceutical Inc., which is based in San Diego. The patients were told that the treatment had never been tried before in a human being but had shown promise in small experiments with monkeys.

Questions about this new Ebola drug

According to company documents, four monkeys infected with Ebola survived after being given the therapy within 24 hours after infection. Two of four other monkeys that started therapy within 48 hours after infection also survived. One monkey that was not treated died within five days of exposure to the virus.

Brantly and Writebol were aware of the risk of taking a new, little-understood treatment and gave informed consent, according to two sources familiar with the care of the missionary workers. In the monkeys, the experimental serum had been given within 48 hours of infection. Brantly didn't receive it until he'd been sick for nine days.

The medicine is a three-mouse monoclonal antibody, meaning that mice were exposed to fragments of the Ebola virus and then the antibodies generated within the mice's blood were harvested to create the medicine. It works by preventing the virus from entering and infecting new cells.

The Ebola virus causes viral hemorrhagic fever, which refers to a group of viruses that affect multiple organ systems in the body and are often accompanied by bleeding.

Early symptoms include sudden onset of fever, weakness, muscle pain, headaches and a sore throat. They later progress to vomiting, diarrhea, impaired kidney and liver function -- and sometimes internal and external bleeding.

The ZMapp vials, stored at subzero temperatures, reached the hospital in Liberia where Brantly and Writebol were being treated Thursday morning. Doctors were instructed to allow the serum to thaw naturally without any additional heat. It was expected that it would be eight to 10 hours before the medicine could be given, according to a source familiar with the process.

Brantly asked that Writebol be given the first dose because he was younger and he thought he had a better chance of fighting it, and she agreed. However, as the first vial was still thawing, Brantly's condition took a sudden turn for the worse.

Brantly began to deteriorate and developed labored breathing. He told his doctors he thought he was dying, according to a source with firsthand knowledge of the situation.

Knowing his dose was still frozen, Brantly asked if he could have Writebol's now-thawed medication. It was brought to his room and administered through an IV. Within an hour of receiving the medication, Brantly's condition dramatically improved. He began breathing easier; the rash over his trunk faded away. One of his doctors described the events as "miraculous."

By the next morning, Brantly was able to take a shower on his own before getting on a specially designed Gulfstream air ambulance jet to be evacuated to the United States.

Writebol also received a vial of the medication. Her response was not as remarkable, according to sources familiar with the treatment. However, doctors on Sunday administered Writebol a second dose of the medication, which resulted in significant improvement.

She was stable enough to be evacuated back to the United States.

The process by which the medication was made available to Brantly and Writebol is highly unusual.

World Health Organization spokesman Gregory Hartl cautioned that health authorities "cannot start using untested drugs in the middle of an outbreak, for various reasons."

Doctors Without Borders similarly weighed in on the side of caution.

"It is important to keep in mind that a large-scale provision of treatments and vaccines that are in very early stages of development has a series of scientific and ethical implications," the organization said in a statement.

"As doctors, trying an untested drug on patients is a very difficult choice since our first priority is to do no harm, and we would not be sure that the experimental treatment would do more harm than good."

ZMapp has not been approved for human use and has not even gone through the clinical trial process, which is standard to prove the safety and efficacy of a medication. It may have been given under the U.S. Food and Drug Administration's "compassionate use" regulation, which allows access to investigational drugs outside clinical trials.

Getting approval for compassionate use is often long and laborious, but in the case of Brantly and Writebol, they received the medication within seven to 10 days of their exposure to the Ebola virus.

On July 30, the Defense Threat Reduction Agency, an arm of the military responsible for any chemical, biological, radiological, nuclear and high-yield explosive threats, allotted additional funding to MAPP Biopharmaceutical due to "promising results."

http://edition.cnn.com/2014/08/04/health/experimental-ebola-serum/index.html?hpt=hp_c1

Ebola Cure Hope

Four out of five people who get infected die

A plant has been found to halt the deadly Ebola virus in its tracks in laboratory tests, scientists have said.

The extract can be eaten or rubbed into the skin

They used a compound from Garcinia kola, a plant commonly eaten in West Africa. Compounds from the plant have also proved effective against some strains of flu. If the anti-Ebola compound proves successful in animal and human trials, it will be the first medicine to successfully treat the virus that causes Ebola haemorrhagic fever - an often-fatal condition.
The discovery was announced at the 16th International Botanical Congress in St Louis in the US.
Four deaths per five cases
The Ebola virus was first documented in 1976 after an outbreak in Zaire - now the Democratic Republic of the Congo - where 88% of the 318 human cases died.

The Ebola-Zaire virus close up

More recently, a 1995 outbreak in the same country had a death rate of 81% of the 315 infected. There are four types of the virus - Ebola-Zaire, Ebola-Sudan and Ebola-Ivory Coast all affect humans, while Ebola-Reston has so far only affected monkeys and chimpanzees.
However, doctors have been unable to stop the virus once infection has taken hold - hence the disease has gained a terrifying reputation.
Traditional origins
Dr Maurice Iwu, who set up and heads the Bioresources Development and Conservation Programme, led the research.

Dr Maurice Iwu said the discovery was a breakthrough

It started 10 years ago when researchers were led to the plant by traditional native healers who have used the plant for the treatment of infectious diseases for centuries. "This is a very exciting discovery," said Dr Iwu, who himself comes originally from a family of traditional healers.
"The same forest that yields the dreaded Ebola virus could be a source of the cure."
Fighting chance
The virus multiplies rapidly in the human body and quickly overwhelms it, and in advanced cases the patient develops high fever and severe bleeding.

Towns are quarantined following an outbreak

The Garcinia kola compound has been shown to halt multiplication of the virus in the laboratory. If repeated in humans, this would give the body a chance to fight off the virus. The active compound is what is known as a dimeric flavonoid, which is two flavonoid molecules fused together.
Flavonoids are non-toxic and can be found in orange and lemon rinds as well as the colourings of other plants.
Drug hopes
The tests are in the early stages still, but the researchers hope that if they continue to prove successful the compound the US Food and Drug Administration will put it on a fast track - making a drug available to humans within a matter of years.
"The discovery of these important properties in a simple compound - flavonoids - was very surprising," said Dr Iwu.
"The structure of this compound lends itself to modification, so it provides a template for future work. "Even if this particular drug does not succeed through the whole drug approval process, we can use it to construct a new drug for this deadly disease."

Source: BBC News

Ebola: How easily do germs spread on planes?

The Ebola outbreak is stoking fears of a deadly virus spreading across the world through air travel. We talked to experts to discover the risks of catching the disease mid-flight.

Why Ebola is so dangerous

The Ebola outbreak in West Africa is the world's deadliest to date. More than 670 people have died as health officials in Guinea, Liberia and Sierra Leone struggle to control the virus.

Are plane cabins hotbeds of disease? Frequent flyers are often on guard against sneezing or coughing co-passengers, in fear of catching what they have. And the possibility that much more serious epidemics or pandemics could spread by air travel has been a worry for years, whether it is avian flu, Sars or tuberculosis.
Now we are in the middle of one of the deadliest outbreaks of Ebola virus ever: the outbreak started in Guinea last March and soon reached Liberia, Sierra Leone and Nigeria. Concern in the West has heightened after it emerged that a man had flown on internal flights while carrying the virus, with fears growing that air travel could quickly carry the terrifying disease around the world. British Prime Minister David Cameron described Ebola as a “serious threat”.

A member of Doctors Without Borders puts on protective gear to treat patients infected by the recent Ebola outbreak in Nigeria (Getty Images)

How likely is it to catch a deadly disease mid-flight, and what might stop a sick passenger carrying it between countries? To get a sense of the risks involved, BBC Future talked to infectious disease researchers to find out what we know about transmission during air travel – and what this can tell us about the risk of Ebola spreading across the world.

Transmission problems
The risks of catching an infection from an ill passenger are not as high as you would think, says Christine Pearson, a spokesperson for the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia. “It’s not any more dangerous than any place where you are in touch with lots of people – like a shopping mall food court for example.
John Oxford, a virologist at Queen Mary University, London, agrees. He points out that the aeroplane ventilation goes from the ground to the ceiling, where the air is filtered for bacteria and viruses before it recirculates. Simulations looking at the potential spread of germs have found that they are generally confined to just a couple of rows either side of the carrier. Even then, the chances appear to be small, according to a study published in the British Medical Journal. The paper looked at a flight involving nine school children who were later found to be carrying the swine flu virus. Just two other passengers, of more than 100 questioned, later developed the illness – and they were both sitting within two rows of the ill school kids. As a result, the researchers concluded that there was just a 3.5% risk of catching the illness if you were sitting in those seats. A handful of other studies, looking at measles and TB, also suggest that in-flight transmission rates are similarly low. From studies such as these, Oxford says that “the biggest risk is not on the plane, but in the taxi on the way to the airport”.
However, John Edmunds, professor of infectious disease modelling at the London School of Hygiene and Tropical Medicine, points out that it is difficult to come to any firm conclusions, even for the more prevalent diseases. The number of studies is small, he says, meaning you can’t find absolute figures for the risk and compare that to the risk of infection in a school, say. So it is even harder to assess the risk of in-flight transmission of rare and unstudied diseases like Ebola.

How much do crowded plane cabins increase the risk of catching and spreading infectious diseases beyond national borders? (Getty Images)

Mode of transmission is clearly a factor. There are a few documented cases of norovirus spreading among passengers – probably due to people sharing the same toilet. But we know that Ebola is relatively difficult to catch: unlike respiratory diseases like colds and flu, it can only be transmitted through contact with bodily fluids like saliva, vomit, or blood, which begins to secrete out of every orifice. Although it is unlikely that someone suffering the full-blown attack would attempt to fly, it is not impossible. Patrick Sawyer, a US citizen who died from the virus last week, showed some of these symptoms on a flight from Liberia to Nigeria, raising fears for the other passengers. Airline staff and public health officials should be more aware of the dangers now, however, and should place anyone suspected of having the disease in quarantine. “Everyone is on the lookout,” says Oxford.
There is always the chance that a passenger could board a flight before they have developed the full-blown symptoms. But so far, the evidence suggests you are unlikely to catch it from someone in the early stages of the disease, before they have started vomiting and bleeding. “I wouldn’t want to be a passenger next to a guy with Ebola,” admits Edmunds. “But if they are just sitting there with a fever, I can’t imagine the situation being high risk.” Oxford points out that basic hygiene measures should further reduce the chance of infection – even if it can’t eliminate the danger completely. “The Ebola virus is very easily killed; you can kill it with hot water and soap,” he says. “Alcohol rubs get rid of it in a microsecond.”
“Small risk”
If an apparently healthy person carrying the virus lands in a country, there is still room for a second stage of contagion. This is perhaps the greater risk for a global epidemic – undetected carriers are the way that swine flu and Sars spread across the world. “The history of the spread of infectious diseases is infinitely entwined with improvements in travel,” says Edmunds. He points out that in the past, the spread of diseases was limited by the length of travel; measles develops quickly, so all the cases would have burnt out by the end of a long voyage. Since Ebola has an incubation period of up to 21 days, carriers could arrive in a country weeks before symptoms develop – potentially transmitting it to the people they know. “It is an issue,” admits Oxford, but he is optimistic that the infection could still be contained. Anyone showing the symptoms would have a rapid diagnosis before being quarantined, and health authorities would also check anyone who had been in contact with them – such as air crews, passport officials and their families. “All of that can stop it spreading – and it will be stopped.”

Thermal screens were used to identify plane passengers that may have been carrying Sars (Getty Images)

A spokesperson for the World Health Organization, Gregory Härtl, says its official stance currently is that a global epidemic is a “small risk”, although it is currently working with the International Air Transport Association to review their recommendations. Currently, it does not recommend screening passengers at airports – since the thermal scanners used to detect a fever are unlikely to find people incubating the first stages of the disease – and there are no recommended travel restrictions.
However; the situation is evolving fast and the recommendations may change in the coming days. At the moment, no one can yet predict whether other air travellers have been infected with the disease, but the hope is that heightened vigilance will help to minimise any potential risk. However, even if it is successfully contained and the outbreak peters out, Ebola shows, yet again, the fact that no disaster or epidemic is too distant in the highly-connected modern world.

Source: http://www.bbc.com/future/story/20140731-can-ebola-spread-on-planes

Why Ebola is so dangerous

Health care workers are among those most at risk of catching Ebola

Ebola crisis

The Ebola outbreak in West Africa is the world's deadliest to date. More than 670 people have died as health officials in Guinea, Liberia and Sierra Leone struggle to control the virus.

What is Ebola? Ebola is a viral illness of which the initial symptoms can include a sudden fever, intense weakness, muscle pain and a sore throat, according to the World Health Organization (WHO). And that is just the beginning: subsequent stages are vomiting, diarrhoea and - in some cases - both internal and external bleeding.

The disease infects humans through close contact with infected animals, including chimpanzees, fruit bats and forest antelope.
It then spreads between humans by direct contact with infected blood, bodily fluids or organs, or indirectly through contact with contaminated environments. Even funerals of Ebola victims can be a risk, if mourners have direct contact with the body of the deceased.

This molecular model shows the parts of the Ebola virus scientists are studying in the hopes of finding drugs that will slow the spread of the disease

The incubation period can last from two days to three weeks, and diagnosis is difficult. The human disease has so far been mostly limited to Africa, although one strain has cropped up in the Philippines.
Healthcare workers are at risk if they treat patients without taking the right precautions to avoid infection.
People are infectious as long as their blood and secretions contain the virus - in some cases, up to seven weeks after they recover.
World Health Organization guidance on Ebola
In pictures: Battling Ebola in West Africa

Where does it strike? Ebola outbreaks occur primarily in remote villages in Central and West Africa, near tropical rainforests, says the WHO.

Bushmeat - from animals such as bats, antelopes, porcupines and monkeys - is a prized delicacy in much of West Africa but can also be a source of Ebola

It was first discovered in the Democratic Republic of Congo in 1976 since when it has affected countries further east, including Uganda and Sudan. This outbreak is unusual because it started in Guinea, which has never before been affected, and is spreading to urban areas.

From Nzerekore, a remote area of south-eastern Guinea, the virus has spread to the capital, Conakry, and neighbouring Liberia and Sierra Leone.
A Liberian man who flew to Lagos in July was quarantined on his arrival and later died of Ebola - the first case in Nigeria.
The medical charity Medecins Sans Frontieres (MSF) says the outbreak is "unprecedented" in the way the cases were scattered in multiple locations across Guinea, hundreds of kilometres apart, and says it is a "race against time" to check people who come into contact with sick people.

WHO: West Africa Ebola outbreak figures as of 27 July

• Guinea - 319 deaths, 427 cases
• Liberia - 129 deaths, 249 cases
• Sierra Leone - 224 deaths, 525 cases

The virus detective who discovered Ebola

What precautions should I take? Avoid contact with Ebola patients and their bodily fluids, the WHO advises. Do not touch anything - such as shared towels - which could have become contaminated in a public place.

Washing hands and improving hygiene is one of the best ways to fight the virus

Carers should wear gloves and protective equipment, such as masks, and wash their hands regularly.
The WHO also warns against consuming raw bushmeat and any contact with infected bats or monkeys and apes. Fruit bats in particular are considered a delicacy in the area of Guinea where the outbreak started.
In March, Liberia's health minister advised people to stop having sex, in addition to existing advice not to shake hands or kiss. A BBC reporter in the Liberian capital Monrovia says that public awareness campaigns around Ebola have been stepped up following the death in July of renowned Liberian doctor Samuel Brisbane.
Liberia has now closed most of its border crossings and communities hit by an Ebola outbreak face quarantine to try to halt the spread of the virus.
Nigeria's main airliner Arik Air has suspended flights to Liberia and Sierra Leone and more stringent screening is being put in place at some airports. When the outbreak first began, Senegal closed its border with Guinea.
Fighting the fear and stigmatisation surrounding Ebola is one of the greatest challenges health workers face.

Deadliest ever outbreak of Ebola virus: What you need to know

 

It began with a just a handful of cases in Guinea in March. But it spread quickly to two other countries and is now the deadliest outbreak of Ebola virus on record.

At least 1,201 people in Guinea, Sierra Leone and Liberia have been infected by what is believed to be Ebola virus since its symptoms were first observed in March, according to the World Health Organization. 672 of them have died. That's a 55% percent mortality rate.

The WHO says "drastic action is needed" to contain Ebola, which has spread from rural areas to cities in West Africa and sparked fears that the killer virus could spread to other continents.

What's the latest?

Until recently the Ebola outbreak had been contained to three West African countries: Guinea, where it began, Liberia and Sierra Leone.

But this week a Liberian government official who had contracted the virus died in isolation at a hospital in Lagos, Nigeria.

Photos: Ebola outbreak in West Africa

Ebola outbreak kills an American

Fighting Ebola on the front lines

American doctor battling Ebola

Patrick Sawyer, a naturalized American citizen who worked in Liberia, had stopped in Nigeria for a conference but died before he could board a plane home to the U.S. He's the first American to die in the latest outbreak, though several other U.S. aid workers in Liberia have also contracted Ebola and are being treated.

Why was someone infected with Ebola allowed on a plane?

It is unknown whether Sawyer was displaying symptoms of Ebola 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 Ebola-stricken sister in Liberia, though she said he didn't know at the time that she had the virus. When he arrived in Nigeria he told officials that he had no direct contact with anyone who had Ebola.

But since it takes between 2 and 21 days before someone infected with Ebola begins to show symptoms, there's little health officials can do to stop an infected but non-symptomatic person from flying to another country, said CNN's Chief Medical Correspondent Sanjay Gupta.

"When I left Conakry (Guinea's capital), they took my temperature at the airport and asked me to fill out a questionnaire, and that was really about it," said Gupta. "If I had been exposed for whatever reason and it was 21 days later before I got sick, there was nothing that would have prevented me from getting on that plane.

"I think it's going to happen at some point. Just from observing the whole process it's almost impossible from happening," Gupta said, before adding that he believes the virus would stand little chance of spreading very far in a developed country.

How easily could Ebola spread on a plane?

Serious viruses like Ebola may be just "a plane ride away" from reaching the developed world, according to Marty Cetron of the Centers for Disease Control and Prevention (CDC), but it is unlikely the virus would spread on a plane unless a passenger were to come into contact with a sick person's bodily fluids.

The CDC has sent guidance to American air carriers on how to identify and deal with passengers displaying Ebola symptoms -- and how they should disinfect aircraft after an infected passenger leaves a plane.

"Airline carriers, crew members, and airports can be very important partners in that front line," Cetron told CNN. "Being educated, knowing the symptoms, recognizing what to do, having a response protocol, knowing who to call -- those are really really important parts of the global containment strategies to deal with threats like this."

Health officials are also trying to track down everyone who was on any of the three flights Patrick Sawyer took to get to the heavily populated city of Lagos, in order to test them for Ebola.

What else is being done to stop the spread of the disease?

Ebola patients are being isolated by health officials in Western Africa, and those who have come into contact with them are being told to monitor their temperatures. The family of a second infected American aid worker had been living with him in Liberia, but they left before he started showing symptoms. While it's unlikely they contracted Ebola, the CDC is keeping the family on a 21-day fever watch.

The president of Liberia has closed most of the 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.

Arik Air, one of Nigeria's biggest airlines, has also suspended operations into Monrovia and Freetown, the capitals of Liberia and Sierra Leone, respectively, according to AllAfrica.com.

The UK government is also convening an emergency meeting Wednesday to discuss the threat of Ebola to Britain. There have been no cases of Ebola reported in the UK as of yet.

The CDC has also issued an alert to health workers in the U.S. 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 sub-types, 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, although that has not been confirmed.

Tracking the Ebola virus in Nigeria

Ebola scientist: 'It's spectacular'

Ebola epidemic 'out of control'

Fighting Ebola in urban Africa

What is Ebola?

The Ebola virus causes viral hemorrhagic fever (VHF), 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. The same year there was another outbreak in Sudan.

The WHO says there are five different strains of the virus -- named after the areas they originated in. Three of these have been associated with large outbreaks of hemorrhagic fever in Africa.

These are the Bundibugyo -- an area of Uganda where the virus was discovered in 2007 -- Sudan and Zaire sub-types.

There has been a solitary case of Ivory Coast Ebola. This subtype was discovered when a researcher studying wild chimpanzees became ill in 1994 after an autopsy on one of the animals. The researcher recovered.

Finally, Reston Ebola is named after Reston in the U.S. state of Virginia, where this fifth strain of the Ebola virus was identified in monkeys imported from the Philippines.

The CDC says while humans have been infected with Ebola Reston, there have been no cases of human illness or death from this sub-type.

What are Ebola's symptoms?

Early symptoms of the Ebola virus 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 non-specific 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 World Health Organization 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.

The WHO says in Africa there have been documented cases of humans falling ill after contact with dead or ill chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines.

It says Ebola later spreads from human-to-human via contact with bodily fluids containing the virus. The virus can be spread through contact with an object contaminated with infected secretions.

Direct contact with the corpses of Ebola victims can also result in infection and the virus can be transmitted via infected semen up to seven weeks after clinical recovery.

MSF says while the virus is believed to be able to survive for some days in liquid outside an infected organism, it is fragile and chlorine disinfection, heat, direct sunlight, soaps and detergents can kill it.

MSF epidemiologist Kamiliny Kalahne says 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 says.

How many cases have there been?

The CDC estimates there have been more than 1,800 cases of Ebola and more than 1,300 deaths.

The last recorded outbreaks before the current one in Guinea were in 2012 -- in Uganda and Democratic Republic of Congo.

The Uganda outbreak involved a total of 24 probable and confirmed cases, and 17 deaths, according to the WHO, which declared it had ended in October 2012.

MSF said the Uganda outbreak had been the Sudan strain, while the virus found in DRC was the Bundibugyo sub-type.

According to the CDC, the most deadly outbreak was the 1976 outbreak in then Zaire, when 280 of 318 infected people died. In 2000, there were 425 cases of Ebola Sudan in Uganda, which resulted in 224 fatalities.

Ebola Virus Ravaging West Africa. 539 Deaths Reported & Counting [Video/Pics]

Video And Pics After The Jump
DAKAR, Senegal (Associated Press) — Deep in the forests of southern Guinea, the first victims fell ill with high fevers. People assumed it was the perennial killer malaria and had no reason to fear touching the bodies, as is the custom in traditional funerals.
Some desperate relatives brought their loved ones to the distant capital in search of better medical care, unknowingly spreading what ultimately was discovered to be Ebola, one of the world's most deadly diseases.

Ebola, a hemorrhagic fever that can cause its victims to bleed from the ears and nose, had never before been seen in this part of West Africa where medical clinics are few and far between. The disease has turned up in at least two other countries — Liberia and Sierra Leone — and 539 deaths have been attributed to the outbreak that is now the largest on record.

The key to halting Ebola is isolating the sick, but fear and panic have sent some patients into hiding, complicating efforts to stop its spread. Ebola has reached the capitals of all three countries, and the World Health Organization reported 44 new cases including 21 deaths on Friday.
There has been "a gross misjudgment across the board in gauging the severity and scale of damage the current Ebola outbreak can unleash," the aid group Plan International warned earlier this month.
"There are no cases from outside Africa to date. The threat of it spreading though is very much there," said Dr. Unni Krishnan, head of disaster preparedness and response for the aid group.
Preachers are calling for divine intervention, and panicked residents in remote areas have on multiple occasions attacked the very health workers sent to help them. In one town in Sierra Leone, residents partially burned down a treatment center over fears that the drugs given to victims were actually causing the disease.

Activists are trying to spread awareness in the countryside where literacy is low, even through a song penned about Ebola.

"It has no cure, but it can be prevented; let us fight it together. Let's protect ourselves, our families and our nation," sings the chorus.
"Do not touch people with the signs of Ebola," sings musician and activist Juli Endee. "Don't eat bush meat. Don't play with monkey and baboons. Plums that bats have bitten or half-eaten, don't eat them."
Guinea first notified WHO about the emergence of Ebola in March and soon after cases were reported in neighboring Liberia. Two months later there were hopes that the outbreak was waning, but then people began falling ill in Sierra Leone.
Doctors Without Borders says it fears the number of patients now being treated in Sierra Leone could be "just the tip of the iceberg." Nearly 40 were reported in a single village in the country's east.

"We're under massive time pressure: The longer it takes to find and follow up with people who have come in contact with sick people, the more difficult it will be to control the outbreak," said Anja Wolz, emergency coordinator for the group, also referred to by its French name Medecins Sans Frontieres.
This Ebola virus is a new strain and did not spread to West Africa from previous outbreaks in Uganda and Congo, researchers say. Many believe it is linked to the human consumption of bats carrying the virus. Many of those who have fallen ill in the current outbreak are family members of victims and the health workers who treated them.

There is no cure and no vaccine for Ebola, and those who have survived managed to do so only by receiving rehydration and other supportive treatment. Ebola's high fatality rate means many of those brought to health clinics have been merely kept as comfortable as possible in quarantine as they await death. As a result, some families have been afraid to take sick loved ones to the clinics.

"Let this warning go out: Anyone found or reported to be holding suspected Ebola cases in homes or prayer houses can be prosecuted under the law of Liberia," President Ellen Johnson Sirleaf stated recently.

Liberian President Ellen Johnson Sirleaf
Her comments came just days after Sierra Leone issued a similar warning, saying some patients had discharged themselves from the hospital and had gone into hiding.
At the airport in Guinea's capital, departing passengers must undergo temperature screening, and those with a fever are pulled aside for further evaluation. Still, the stigma of Ebola follows Guineans well outside the region.
"The police treated us like we were aliens. They said they didn't want us in their country because of the disease affecting Guinea," says Tafsir Sow, a businessman who was briefly detained at the airport in Casablanca, Morocco before continuing on to Paris. "I had tears in my eyes."
Still, WHO health officials are hopeful they will be able to get the situation under control in the next several weeks. A recent conference in the capital of Ghana brought together health authorities from across the affected areas, and the countries agreed on a common approach to fight Ebola.
"When you have it spread, of course it's moving in the wrong direction," said Dr. Keiji Fukuda, WHO's assistant director-general for health security and environment. "You want to see the number of infections going down. So we really have to redouble our efforts. But saying that it's out of control makes it sound like there are no solutions. This is a virus for which there are very clear solutions."
___
Associated Press writers John Heilprin in Geneva; Boubacar Diallo in Conakry, Guinea; Clarence Roy-Macaulay in Freetown, Sierra Leone; Jonathan Paye-Layleh in Monrovia, Liberia and Francis Kokutse in Accra, Ghana contributed to this report.

Ebola 'out of control' in West Africa

Ebola virus explained in 60 seconds