Medical staff working with Medecins sans Frontieres (MSF) put on their protective gear before entering an isolation area at the MSF Ebola treatment centre in Kailahun

Medical staff working with Medecins sans Frontieres (MSF) put on their protective gear before entering an isolation area at the MSF Ebola treatment centre in Kailahun July 20, 2014. Sierra Leone now has the highest number of Ebola cases, at 454, surpassing neighbouring Guinea where the outbreak originated in February. Picture taken July 20, 2014. REUTERS/Tommy Trenchard (SIERRA LEONE – Tags: HEALTH) – RTR40DKX