Using climate data to map the potential distribution of Culicoides imicola (Diptera: Ceratopogonidae) in Europe.

Culicoides imicola, a vector of bluetongue virus and African horse sickness virus, is principally Afro-Asian in distribution, but has recently been found in parts of Europe. A logistic regression model based on climate data (temperature, saturation deficit, rainfall and altitude) and the published distribution of C. imicola in Iberia was developed and then applied to other countries in Europe, to identify locations where C. imicola could become established. The model identified three temperature variables as significant determinants of the distribution of C. imicola in Iberia (minimum of the monthly minimum temperatures, maximum of the monthly maximum temperatures and number of months per year with a mean temperature > or = 12.5 degrees C). The model indicated that under current conditions, the distribution of C. imicola in Spain, Greece and Italy could be extended and the vector could potentially invade parts of Albania, Yugoslavia, Bosnia and Croatia. To simulate the effect of global warming, temperature values in the model were increased by 2 degrees C. Under these conditions, the potential spread of C. imicola in Europe would be even more extensive.