Macropinocytosis is actin dependent and is increasingly recognised as an important cell entry route for a number of viruses [36] . Macropinocytosis is also dependent on the amiloridesensitive Na + /H + exchangers [36] and is inhibited by 5-(N-ethyl-N-isopropyl)-amiloride (EIPA). EIPA has previously been shown to inhibit macropinocytosis without affecting other endocytic pathways such as CME [58] . Figure 5 shows representative cells and that EIPA effectively inhibited uptake of dextran (Fig. 5I) and BTV-1 (Fig. 5G) . Virtually all of the drug treated cells showed no uptake of dextran or virus (n.300 cells counted for each ligand). In contrast, EIPA did not inhibit uptake of transferrin (Fig. 5H ) as virtually all cells showed transferrin uptake; (n.300 cells counted). These results also suggest that BTV-1 entry may be mediated by macropinocytosis or a macropinocytosis-like mechanism. In addition, as EIPA blocked uptake of BTV-1 but not transferrin, these observations strengthen our conclusion that BTV-1 entry is not mediated by the clathrin pathway.