MADRID: Countries across the world scrambled to stem a deadly Ebola outbreak that UN officials warn is getting worse as New York’s main JFK airport prepared to screen travelers from epidemic-hit west Africa.

And in Madrid, the serious condition of a Spanish nurse, who was the first person to become infected with Ebola outside of Africa, showed signs of improving.

More than 4,000 people have died from Ebola in seven countries since the start of the year, according to the UN’s World Health Organization, and the disease appears to be outpacing efforts to fight it.

“The virus is far ahead of us and every day the situation gets worse,” the head of the UN’s emergency Ebola mission Anthony Banbury, told UN leaders after a tour of Liberia, Guinea and Sierra Leone, the nations worst affected by the epidemic.

At John F Kennedy International Airport in New York, passengers and crew arriving from the three countries at the center of the outbreak will have their temperatures taken and be screened for signs of illness and answer questions about possible exposure, the US Centers for Disease Control and Prevention (CDC) said.

“Exit screening might not find every person with Ebola, however, it does not have to be perfect to help reduce the spread of Ebola,” the CDC said in a statement. Four other major US airports are to start similar checks next week.

In Latin America, Peru and Uruguay have announced airport measures and Mexico and Nicaragua planned to tighten controls of migrants heading for US soil as an Ebola precaution.

Amid fears of a global contagion, two countries on Saturday ruled out suspect cases.

The Brazilian Health Ministry reported a Guinean man tested negative for Ebola.

And in Macedonia, tests showed that a British man who died displaying Ebola-like symptoms did not have the virus, officials said.

IMF chief Christine Lagarde on Saturday pleaded with people to remember that all of Africa has not been hit with the deadly Ebola epidemic, which remains relatively isolated in three countries.