4 Flooding of mosquito habitats can introduce RVFV into domestic animal populations by the production of vertically infected Aedes mosquitoes (Figure 1). Epizootic/epidemic cycles are driven by the subsequent elevation of various Culex mosquito populations, which serve http://www.selleckchem.com/products/Erlotinib-Hydrochloride.html as excellent secondary vectors if immature mosquito habitats remain flooded long enough.5 On the basis of this previous research, we have developed a monitoring and risk mapping system6,7 that uses a variety of satellite measurements including sea surface temperatures, outgoing longwave radiation, rainfall, and landscape ecology using the normalized difference vegetation index (NDVI). The measurements represent the total variety of climate and ecological drivers that would lead to conditions associated with the emergence of RVFV vectors resulting in episodic patterns of epizootics/epidemics through time.

These data are input into an RVF prediction system to map in a dynamic manner areas at potential risk for RVF activity.6 This system operates in near real-time to monitor RVF risk on a monthly basis and offers the opportunity to identify eco-climatic conditions associated with potential vector-borne disease outbreaks over large areas, and has been in operation for the last 10 years.7 The system predicted conditions likely to lead to an RVF outbreak in East Africa in September 2006, 3 months before confirmation of disease transmission by the end of November 2006 and human RVF cases mid-December 2006.

8 In this work we focus on the assessment of the predictions with regard to the clusters of outbreaks in East Africa (Kenya, Somalia, and Tanzania): September 2006�CMay 2007; Sudan: May 2007�CDecember 2007; and Southern Africa and Madagascar: September 2007�CMay 2008. The dates mentioned previously represent the time periods when elevated rainfall occurred at least 2 to 3 months before reported RVFV activity (Figure 2). In all of the regions examined except for Madagascar, most of the areas where RVF cases were reported received in excess of 200 mm of rainfall during the outbreak period with the highest excess rainfall occurring in East Africa with amounts up to +400 mm. Details of the setup and implementation of the monitoring and prediction system have been presented in previous works.3,6�C8 Figure 1.

Endemic (on left) and epidemic (on right) life cycles of Rift Valley fever involving close association between heavy rainfall conditions, vector Aedes and Culex mosquitoes, domestic animals, Entinostat and humans. The epidemic cycle is precipitated by excessive … Figure 2. Cumulative rainfall anomalies for (A) East Africa: September 2006�CMay 2008. (B) Sudan: May�CNovember 2007. (C) Southern Africa: September 2007�CMay 2008. (D) Madagascar: September 2007�CMay 2008. Except for Madagascar, all … RVF risk mapping prediction and assessments.