FIG 1.

Timeline of the immunizations and blood serum samplings performed in horses for the evaluation of the cross-protective immunity offered by the inactivated vaccine. The black syringes indicate the double primary vaccinations; the white syringe indicates the annual booster vaccination. Arrows depict the time points of blood serum samplings. Weeks in which these samplings were conducted are displayed above the arrows. The two black arrows marked with asterisks depict samplings performed 1 week prior to the initiation of the primary vaccinations of 2011 and 2012, respectively, in order to detect and select WNV-seronegative horses.