Studies in cholera-free temperate or cold regions are scarce but all have underlined the absence of ctx+ isolates in environmental strains (Zo et al., 2009; Schuster et al., 2011; Haley et al., 2012) whereas toxigenic strains were mainly detected in outbreak contexts (Tobin-D'Angelo et al., 2008; Haley et al., 2014). The gene discussed is CYP27A1; the disease is vibrio infectious disease.