(A) Schematic representation of the Rift Valley fever virus genome. The antigenomic sense RNA and the encoded open reading frames (blue box) are represented. For the ambisense S segment, the genome and its open reading frame are represented (below). (B) Schematic diagram of the mRNA transcribed from the segment M of Rift Valley fever virus. (A color version of this figure is available online at www.vetres.org.)