Madrid's Barajas international airport activated emergency measures on Thursday after a passenger arriving on an Air France flight was suspected of possibly having Ebola, a spokeswoman for airports operator Aena said.

Spain's health ministry confirmed that an Ebola emergency protocol had been set in motion but declined to give details.

Aena and Air France said in separate statements that a passenger on Air France 1300 from Lagos via Paris had started shaking during the flight. Air France said the other passengers disembarked from the plane, which will now be disinfected. The return flight has been cancelled.

Spain's government has stepped up its response to suspected Ebola cases in the wake of a health scare when a nurse in Madrid became the first person outside Africa to become infected with the deadly disease in the current outbreak.

The nurse, Teresa Romero, was diagnosed with the virus last week and is still seriously ill but stable. She had cared for two infected priests repatriated from West Africa and who later died.

Spanish authorities said on Thursday that a person who had been in contact with Romero and was being monitored remotely for signs of the disease would be hospitalized, after developing a fever, one of the symptoms of Ebola.

The person was one of 68 considered to have a low risk of catching Ebola, and who have to check their temperature regularly from home.

Another 15 people, including Romero's husband, are still under observation for signs of Ebola in Madrid's Carlos III hospital where she is also being treated, but have shown no symptoms.