A Spanish hospital has released five patients who had been under observation in an isolation ward after having been in contact with a nurse who was infected with Ebola, a government health committee announced on Thursday.

Nurse Teresa Romero, 44, was the first person to catch the disease outside West Africa in the current outbreak which has killed thousands in Liberia, Sierra Leone and Guinea. She was cleared of the deadly virus by doctors at Madrid's Carlos III hospital this week but not discharged.

The patients who have passed the 21-day quarantine needed to rule out contagion are a doctor, a health center cleaning woman, two hairdressers and a friend of Romero, hospital sources said.

The Ebola virus, which is spread through direct contact with bodily fluids of an infected person, came to Spain when the government repatriated two priests who had caught the disease in Liberia and Sierra Leone.

Romero treated both priests, who later died.

Her infection in a high-security ward caused recriminations in Spain, with health workers saying hospitals were not prepared to cope with an Ebola outbreak and that staff had not received adequate training and equipment.

Ten other people who had contact with Romero remain in isolation in Madrid's Carlos III hospital, including her husband, though none have shown symptoms.

Another 68 people considered to be at low risk of having caught the disease are staying inside their homes and checking their temperature several times a day.