An American doctor who was stricken with the often fatal Ebola virus in Liberia has taken a "slight turn for the worse," said his Christian aid agency today.
Kent Brantly and another American missionary worker, Nancy Writebol, "are in stable but grave condition," said a statement from Samaritan's Purse, the US group for which Brantly worked.
"Dr Brantly took a slight turn for the worse overnight," it said.
The group did not elaborate further on Brantly's condition.
It said that when an experimental serum arrived in the capital, Monrovia yesterday, there was only enough for one person and Brantly had asked for it to be given to Writebol.
"Even as he battles to survive Ebola, this heroic doctor is still focused on the well-being of others," said the statement.
It also noted that Brantly, 33, had been given a unit of blood from a 14-year-old boy who survived Ebola because of his care.
"The young boy and his family wanted to be able to help the doctor who saved his life," it said.
US Centers for Disease Control and Prevention (CDC) chief Tom Frieden told reporters he was unaware of what kind of serum may have been given, but stressed that there is no known cure for Ebola.
"I don't know the details of what may have been given," he said on a conference call to discuss CDC's latest warning against non-essential travel to West Africa.
"We have reviewed the evidence of the treatments out there and we don't have any treatment that has proven effectiveness against Ebola disease," Frieden said.
He also said it was unclear whether getting blood from a recovered patient would be helpful.
"This was something that was done in the past for infectious diseases, but there are so many things we don't know about why someone may recover, which antibodies may be protective and which may be harmful," Frieden said.
"It is very difficult to know how to comment on that," he added.
The current outbreak of Ebola is the largest in history and has killed 729 people in Sierra Leone, Guinea, Nigeria and Liberia, the World Health Organization said.
