Texas Ebola patient now in critical condition

The first person to be diagnosed with the deadly Ebola virus on US soil is now in a critical condition, health officials said today, having previously described him as seriously ill.

"Mr. Duncan is in critical condition," the Texas hospital treating Thomas Eric Duncan, who traveled from Liberia to Texas in late September, said in a brief statement.

The update came as US authorities said none of the individuals believed to have had exposure to Duncan, including nine deemed to be at high risk, had shown any signs of Ebola infection.

"We are confident that none of those with definite contact had any symptoms related to Ebola, none of them had fever," said Tom Frieden, the director of the US Centers for Disease Control and Prevention (CDC).

The nine people deemed at high risk would be monitored closely, Frieden said.

"We will be looking very closely particularly at the nine individuals in the coming days, understanding that the peak period after exposure is about eight to nine days but can be as long as 21 days," he said.

Duncan was initially sent home when he first sought medical care, leaving a four-day span when he was sick and contagious while in contact with others, sparking concern over how many others may have been exposed.