Figure A1. Figure A1. Systeme Probatoire pour l'Observation de la Terre vegetation sensor 1 km normalized difference vegetation index (NDVI) anomaly images of the Arabian Peninsula region during June 2000 (A) and June 2005 (B). Data are the percentage deviation from the long-term mean calculated for the period January 1999–June 2005 in NDVI units. A value of zero indicates that current values are identical to the 1998–2005 mean. Rift Valley fever virus was isolated in the Al Qunfuda, Asir, and Jazir areas in Saudi Arabia and in Wadi Mawr in Yemen between August and September 2000 (panel A). Positive anomalies in June 2005 are of higher magnitude than in June 2000. Satellite rainfall estimates were blended with rain-gauge data where available for April 2000 (C) and April 2005 (D). More widespread rainfall occurred in April 2005 compared with April 2000, which suggests prime conditions for vector breeding and prevalence in 2005.