A British doctor working on the frontline of the fight against Ebola says situation on the ground in Sierra Leone is "quite shocking".

Dr Stacey Mearns has been working in the isolation unit at the Connaught Hospital in Freetown, and as a technical adviser to the relief effort.

In the first instalment of a video diary for the BBC, she says her three weeks in Sierra Leone have been "intense, challenging and exhausting".

She describes the situation as a "complex humanitarian crisis", and says: "The level of human suffering is really quite moving and harrowing."