First US Ebola case Thomas Duncan 'critical'

The first person to be diagnosed with Ebola within the US has deteriorated from a serious to a critical condition, doctors in Texas say.

Thomas Duncan, who caught the virus in his native Liberia, is being treated at a Dallas hospital in isolation.

Four other occupants of the flat where he lived are being kept in isolation.

Some 3,431 people have died in West Africa in the worst Ebola outbreak yet.

Laura Westbrook reports.