The results described above show that BTV-1 infection of BHK cells occurs via a clathrin-independent entry mechanism that shares certain characteristics with macropinocytosis. Macropinosomes can fuse with lysosomes or recycle their contents back to the extracellular space, most likely via early-and recycling-endosomes [32, 59, 60] . Therefore, we investigated whether BTV-1 was delivered to these compartments during entry. BTV-1 was internalised for 15, 30, 60, 90 and 120 minutes before the cells were fixed and processed for confocal microscopy using PM10 (anti-VP5) to detect internalised virus. Early-and recyclingendosomes were labelled by incubating the cells with Alexa-568 labelled transferrin during the final 15 minutes of virus uptake (i.e. for 15 minutes before the cells were fixed). Alternatively, other cells were double labelled for virus (as above) and LAMP-1 (a marker for late-endosomes and lysosomes) using Mab 4A1. Figure 8 , shows representative cells from these experiments. After 15 or 30 minutes of virus uptake, little or no virus colocalisation with transferrin was observed (Fig. 8A-F) . Similarly, at the other times investigated, virus co-localisation with transferrin was not observed (data not shown). These results show that during the first 2 h of entry, BTV-1 does not appear to enter early-or recycling-endosomes, supporting the conclusion that CME is not required for BTV-1 infection. Similarly, at 15 minutes postuptake, virus was not co-localised with LAMP-1 (data not shown). In contrast, at 0.5 h and 2 h post-entry BTV-1 was observed co-localised with LAMP -1 ( Fig. 8G-L) . At 0.5 and 2 h post uptake, ,34% and ,54% of the virus was judged to be colocalised with LAMP-1. These results are consistent with an uptake mechanism that delivers BTV-1 to LAMP-1 positive compartments (late-endosomes/lysosomes) without the need to first pass through early-endosomes.