It is notable that VEGF appears to be able to act as growth factor for not only vascular endothelial cells but also epithelial cells in mouse models.21 Moreover, the absence of EGFR-expressing CD163+ macrophages in the tongue mucosa of bluetongue virus-infected or healthy sheep clearly indicates that the expression of this receptor is not the result of generic viral infection but may be unique to ORFV infection. This evidence concerns the gene CD163 and viral infectious disease.