Last week the World Health Organization (WHO) warned the number of Ebola cases could hit 21,000 by early November unless efforts to curb the outbreak are ramped up. I recently participated in a Senate committee hearing on the global challenge and public health threat of the Ebola crisis in West Africa and what our country can and is doing to help. In this edition of "From the Mailbag" I answer a question about the threat of Ebola.