MbCD treated cells were also infected with BTV-1 (m.o.i. = 1) for 1 h in the presence of the drug (see methods). Mock-treated cells were infected in parallel. After washing the cells to remove excess virus and drug, infection was continued for a further 11 h. At the end of infection, the cells were processed for confocal microscopy using NS2 to detect infected cells. Figure 3C shows that pre-treatment of cells with MbCD did not inhibit infection when compared to mock-treated cells. These results show that the cell entry mechanism used by BTV-1 to infect BHK cells does not require cholesterol and is, therefore unlikely to be mediated by caveolae or other lipid-raft mediated endocytic pathways.