Drivers of Rift Valley fever epidemics, Madagascar by Lancelot, R, Béral, M, Rakotoharinome, V, Andriamandimby, S, Héraud, J, Coste, C, Apolloni, A, Squarzoni-Diaw, C, de La Rocque, S, Formenty, P, Bouyer, J, Wint, G, Cardinale, E