Bill Gates 'optimistic' about Ebola response

Microsoft founder Bill Gates has said he is "optimistic" about increasing the treatment capacity for Ebola in West Africa.

The billionaire philanthropist welcomed promises by UK and US governments to send "very substantial resources" to affected countries.

The Gates Foundation has also committed $50m to help step up efforts to tackle the deadly virus.

He told the BBC's Laura Trevelyan: "It's knowing what has to be done... we have got to get medical personnel in there."