A second health worker in Texas has tested positive for Ebola, according to state officials.
The unnamed member of staff reported they had a fever on Tuesday and was immediately isolated at Texas Health Presbyterian Hospital.
"Health officials have interviewed the latest patient to quickly identify any contacts or potential exposures, and those people will be monitored," a statement from the Texas Department of State Health Services said.
"The type of monitoring depends on the nature of their interactions and the potential they were exposed to the virus."
The US President Barack Obama is holding a conference with major world leaders to discuss the outbreak, which he says the world is not doing enough about.
Mr Obama said he plans to pressure some countries into taking firmer action to slow the spread of the disease.
His comments came as it was revealed that the United States is establishing a rapid-reaction team to help hospitals whenever a case of Ebola is discovered.
UN worker dies
It comes after a United Nations employee, infected with Ebola while working in West Africa, died in a German hospital yesterday.
The aid worker was taken to Germany after contracting the disease in Liberia and was being treated in hospital in Leipzig.
He was the third patient to be taken to the country and arrived five days ago. One of the others has been released from hospital and the other is still receiving treatment.
In a statement the hospital said: "The patient sick with Ebola fever died during the night in St Georg Clinic in Leipzig. Despite intensive medical measures and maximum efforts by the medical team, the 56-year-old UN employee succumbed to the serious infectious disease."
The man had tested positive for Ebola on October 6th and was put into a special isolation unit when he arrived in Germany three days later.
The latest Ebola outbreak has so far killed more than 4,000 people, mainly in Sierra Leone, Guinea and Liberia.
The World Health Organisation (WHO) has called it the "most severe acute health emergency in modern times".
The death in Germany comes as the UK began screening passengers for the virus at airports.
The WHO has given this backdrop to the current outbreak:
