MADRID (AFP) - The condition of a Spanish nurse infected with the deadly Ebola virus has improved and she is talking, a medical source said on Saturday.

The nurse, Teresa Romero, "is quite a bit better than yesterday. Her condition improved in the night. She is conscious and talks from time to time when she is in a good mood," the source told AFP.

Her condition "is serious but is improving", the source said.

Doctors in Madrid started treating Romero with the experimental Ebola treatment ZMapp late on Friday, the source added.

There is still no vaccine or widely available treatment for Ebola, but ZMapp is one of several drugs that have been fast-tracked for development.

Romero was on Oct 6 the first person diagnosed as having caught the deadly haemorrhagic fever outside of Africa.

She is thought to have contracted the disease in late September in a Madrid hospital while caring for a Spanish missionary who was repatriated after he became infected with Ebola in Africa.