(Reuters) - A Spanish nurse who is the first person to contract Ebola outside of Africa may have touched her face with the gloves of her protective suit while caring for a priest who died of the disease, a doctor treating her said on Wednesday.

The nurse, Teresa Romero, was being treated for the deadly infection at a Madrid hospital while Spanish officials launched an investigation into how she was able to contract Ebola despite strict protocols for handling contagious patients.

The virus, which the World Health Organization said had killed 3,879 people by Oct. 5 in West Africa since March in the largest outbreak of the disease on record, causes haemorrhagic fever and is spread through direct contact with body fluids from an infected person.

A Liberian man who was the first person diagnosed with Ebola in the United States died in a hospital isolation ward on Wednesday and the U.S. government ordered extra screenings at five major airports.

The WHO said it saw no evidence of the disease being brought under control in Liberia, Sierra Leone and Guinea, with neighbouring countries being told to prepare for the disease to spread across their borders.

Britain said it was sending extra troops, aircraft and a naval vessel to Sierra Leone to help stem the spread. The deployment will see 750 military personnel help set up treatment centres and a training facility. Three helicopters and a 100-bed naval hospital will also be sent to the region.

INTERNET DISCOVERY

While Romero is the only confirmed Ebola case in Spain aside from two priests who contracted the disease in Africa and died, more than 50 other people who may have had contact with the virus in the country are being monitored, including primary health care and hospital staff, European officials said.

"She has talked to me about the gloves, she touched her face with the gloves. That's what she remembers and what she has told me three times," German Ramirez, one of the doctors at Carlos III hospital where the nurse is being treated, told reporters.

The nurse took leave from work immediately after Spanish missionary Manuel Garcia died on Sept. 25. Wearing a full protective suit, she had entered the priest's room once while he was alive and once after his death to clean the room.

"I believe the error was made when taking off the suit," she told Spain's El Pais newspaper in a telephone interview published on Wednesday. "I see that as the most critical moment, when something could have happened. But I'm not sure."

Health worker union officials said Romero alerted hospital staff three times to say she had a fever and a rash, but because her temperature had not gone above 38.6 degrees Celsius the hospital did not see her as a risk.

Romero found out she had the disease by looking at the news on the Internet on her phone while she was waiting for the result of her test, she told Cuatro television station in a telephone interview.

"I asked the doctor for the result and he didn't answer in a very clear way and that's when I started to suspect," adding she then looked at her phone to find there was a positive case of Ebola in Spain.

Health authorities on Thursday put down the dog, a labrador-type breed called Excalibur, who lived with the nurse and her husband in a suburban Madrid flat, saying it posed a biological risk and there was evidence dogs could carry the virus.

The dog was taken out of the apartment block in a police-protected van with the windows blacked out and a driver in a protective suit while around 30 animal rights activists shouted "Murderers!".

The childless couple are two of six people under observation in the sealed-off sixth floor of the hospital in Madrid. The rest of the people, including other nurses who cared for the infected priests, have initially tested negative for Ebola, health authorities said.

Other people being monitored include two hairdressers who waxed the nurse as part of a beauty treatment, media reports said.

CALLS FOR CALM

Spanish Prime Minister Mariano Rajoy defended his country's health authorities and urged people not to panic.

"We have to keep calm. It is extremely unlikely that this will turn into an outbreak affecting many people," he said.

Rajoy said he had created a committee to oversee co-ordination between the regional Madrid government, the central government and European institutions. He said Spain was in constant contact with the European Union and the World Health Organization.

"Let the professionals do their work," he said. "The Spanish health system is one of the best in the world."

He said the investigation into how the infection had occurred was a priority and was still under way.

Two experts from the Stockholm-based European Centre for Disease Prevention and Control (ECDC), which monitors disease in the region, have gone to Spain to help with the investigation, a spokesman for the European Commission said.

The spokesman said Spanish authorities had told the EU it was not clear at this stage how the infection had occurred, but it may have been due to "possible relaxation" of protocols for handling the corpse or for the disposal of medical waste.

The Commission's health security committee gathered representatives from all EU states, the ECDC and from the World Health Organisation's European regional headquarters to discuss the situation on Wednesday.

The WHO's Europe director Zsuzsanna Jakab told Reuters in an interview on Tuesday it was "unavoidable" that Europe would see more cases of Ebola within its borders because of busy travel links with Guinea, Liberia and Sierra Leone.

She stressed, however, that the continent was well prepared for handling Ebola virus disease, and said she did not expect to see any widespread outbreaks in European countries.

A new World Bank assessment of the potential impact of the epidemic estimated that if it spread wider from the three states into neighbouring larger economies, the two-year regional financial impact could reach $32.6 billion by the end of 2015.

(AP) — An American photojournalist who contracted Ebola while working in Liberia is expected to arrive Monday in Nebraska where he will be treated for the virus that has ravaged West Africa.

Ashoka Mukpo, 33, will be the second Ebola patient to be treated at the Nebraska Medical Center's specialized isolation unit. Mukpo was working in Liberia as a freelance cameraman for NBC News when he became ill last week.

NBC reported Sunday evening that Mukpo had started his journey to the U.S. for treatment and that he would arrive Monday morning. Mukpo's family said Friday he would be treated in Omaha. Hospital officials said they expected an Ebola patient to arrive Monday, but declined to provide a name.

Mukpo is the fifth American to return to the United States for treatment since the start of the latest Ebola outbreak, which the World Health Organization estimates has killed more than 3,400 people.

The hospital's biocontainment unit was created in 2005 specifically to handle this kind of illness, said Dr. Phil Smith, who oversees the unit.

"We are ready, willing and able to care for this patient," Smith said. "We consider it our duty to give these American citizens the best possible care we can."

Mukpo's father, Dr. Mitchell Levy, told NBC Sunday that his son was "counting the minutes" until he could leave Liberia but that he was not feeling that ill Sunday. Levy said the family was travelling from Rhode Island to Nebraska.

Doctors at the isolation unit — the largest of four nationwide — will evaluate Mukpo before determining how to treat him. They said they will apply the lessons learned while treating American aid worker Rick Sacra in September. Sacra was successfully treated in the Nebraska unit and was allowed to return to his home in Massachusetts after three weeks, on Sept. 25.

Sacra received an experimental Tekmira Pharmaceuticals drug called TKM-Ebola, as well as two blood transfusions from another American aid worker who recovered from Ebola at an Atlanta hospital. The transfusions are believed to help a patient fight off the virus because the survivor's blood carries antibodies for the disease. Sacra also received supportive care, including IV fluids and aggressive electrolyte management.

In Dallas, another man who recently traveled to the U.S. from Liberia was listed in critical condition Sunday. Thomas Eric Duncan has been hospitalized at Texas Health Presbyterian Hospital since Sept. 28. Dr. Tom Frieden, director of the federal Centers for Disease Control and Prevention, said he was aware that Duncan's health had "taken a turn for the worse," but he declined to describe Duncan's condition further.

The virus that causes Ebola is not airborne and can only be spread through direct contact with the bodily fluids — blood, sweat, vomit, feces, urine, saliva or semen — of an infected person who is showing symptoms.

Duncan arrived in Dallas on Sept. 20 and fell ill a few days later. Officials say 10 people definitely had close contact with Duncan and a further 38 may have been around him when he was showing symptoms of the disease.

Before he was admitted to the hospital, Duncan stayed with Louise Troh, her 13-year-old son and two nephews in their northeast Dallas apartment. The family has been kept in isolation in an undisclosed location since Friday and a hazardous materials crew has twice decontaminated their home. No one in the family has developed Ebola symptoms.

On Sunday, Troh told The Associated Press that she was afraid the crew might damage or destroy some irreplaceable keepsakes that she was forced to leave at the apartment, including photographs and recordings of her daughter, a singer, who died in childbirth.

"If they throw out her picture, her recordings, I'll be hurt. Her live CD's in there. That's all I have to show her children in the future. I don't want to miss it," she said in a phone interview.