In this study, six isolates (H1 to H6) were obtained from a shrimp hatchery in Rio Grande do
Norte (Natal-Area, Brazil),which had been confrontedwith disease outbreaks in 2009. The aimwas to characterize
the virulence of these isolates, both in vitro (virulence factor production) and in vivo (virulence towards gnotobiotic
brine shrimp, Artemia franciscana, larvae) and to compare these characteristics to those of the most
virulent pathogen in the brine shrimp model described to date, Vibrio campbellii LMG 21363.