Figure 2From: Estimating front-wave velocity of infectious diseases: a simple, efficient method applied to bluetongueFrench municipalities with at least one clinical case of BT reported in 2007-2008 ( n = 10 994). Blank areas are areas where no or incomplete clinical cases were reported. Paris is represented by a star. Four periods were defined based on the ecology of Culicoides and BTV transmission rate: 1 July - 31 August, 1 September - 31 October, 1 November - 31 December, and 1 March - 30 June.Back to article page