The number of patients being monitored for Ebola has increased to 16 in Spain, as of Saturday, in the first outbreak outside of West Africa.

Two priests, who had been working in affected areas of West Africa and repatriated back to Spain when they became infected, allegedly caused the spread when a nurse who treated them became sick, Reuters reported.

Both priests died.

Since then, at least 15 others have been identified, and of those only the nurse, Teresa Romero, 44, has tested positive for the virus.

The Spanish government is under pressure to contain the outbreak, before it spreads to the rest of Europe.

The virus has killed more than 4,000 in West African countries including Liberia, Sierra Leone, Guinea, Nigeria and Senegal.

There has also been a report of an unrelated outbreak in the Democratic Republic of Congo.

In Spain, those who have been in contact with Romero, including a hairdresser, another nurse and a cleaner, were admitted to the isolation unit at the Carlos III hospital on Friday evening, Reuters reported.

None of those being monitored have shown symptoms except for Romero.

The nurse had admitted she may have touched her face with the gloves of her protective suit and thereby contracting the virus.

Ebola is spread through contact with bodily fluids, including sweat and blood. This has proved to be the reason for such an accelerated spread in West Africa -- where hot temperatures mean constantly sweating, added to contact through handshakes, hugs and holding hands or comforting a loved one.

Five days after Romero tested positive, which was days after she reported one of the symptoms of Ebola -- a fever -- Deputy Prime Minister Soraya Saenz de Santamaria was placed in charge of handling the health crisis.

The continuing spread has put the spotlight on treatments for the disease, and Romero is being treated with one agent used in an experimental drug, ZMapp, that was given to one of the priests. ZMapp was created by a San Diego company, and the initial supplies, which had never been tested on humans before, had mixed results. The initial supply of the drug has been exhausted, but the FDA has greenlighted an expediated track for the trials.