In teleost species, IL-34 is reported to be involved in viral, bacterial and parasite infections, such as infection of grass carp (Ctenopharyngodon idella) with Flavobacterium columnare and spring viremia of carp virus [35], Vibrio anguillarum infection in large yellow croaker (Larimichthys crocea), parasitic infection of gilthead sea bream (Sparus aurata) with Enteromyxum leei, and grouper (Epinephelus coioides) infected with Cryptocaryon irritans [54]. Here, IL34 is linked to biological process involved in symbiotic interaction.