Fish tlr5 was also strongly up-regulated in some tissues of E. coioides and in the Tibetan highland fish (Gymnocypris przewalskii) in response to infection with the ciliates C. irritans [24,60] and I. multifiliis [61] respectively, although, as far as we know, no particular role for this receptor in parasite recognition has been reported. This evidence concerns the gene TLR5 and infection.