Figure 2.

Viremia titers in vaccinated or mock vaccinated sheep upon RVFV challenge. Viremia was determined by direct virus titration of individual whole blood samples recovered from days 1–12 post-infection. Lysed blood samples (see “Materials and methods” section) were incubated for 6 days in Vero cells seeded in multi-well 96 plates. End point titers were estimated by the Reed and Muench method [25] based on observation of cytopathic effect upon cell staining.