Moreover, infection studies of catfish (Ictalurus punctatus) and Japanese flounder (Paralichthys olivaceus) using fur deletion mutants of E. ictaluri and P. fluorescens, respectively, show that these genetically engineered pathogens could be useful tools in the development of immersion-oral vaccines for the fish industry (Wang et al., 2009; Santander et al., 2012). The gene discussed is FURIN; the disease is infection.