Nasal secretion of interferon-alpha (IFN-α), c-c motif chemokine ligand 2 (CCL2), CCL3, CCL5, CCL11, secretory cluster of differentiation 14 (sCD14), interferon-gamma (IFN-γ), and interleukin 10 (IL-10) is detectable in nasal secretions of non-immune horses following viral infection (15, 16, 28, 29), but only anti-inflammatory IL-10 and the T cell chemokine CCL5 are secreted in immune horses (15, 16). This evidence concerns the gene IL10 and viral infectious disease.