Investigating Vibrio harveyi Infections in Siganus rivulatus and Rhabdosargus haffara from the Red Sea, Hurghada, Egypt

This study investigated the prevalence of Vibrio harveyi infections in two marine fish species, Siganus rivulatus and Rhabdosargus haffara. The overall infection rate among the sampled fish was 11.23%. A significantly higher prevalence was observed in R. haffara (64.52%) compared to S. rivulatus (35.48%). These findings identify V. harveyi as a notable pathogen impacting both species, with R. haffara showing greater susceptibility. The identification of V. harveyi was conducted through morpho-chemical tests and experimental infection trials demonstrated its pathogenicity in both species with greater pathogenicity to R. haffara (70% mortality rate) in comparison with S. rivulatus (50% mortality rate). The histopathological examination of specimens from infected S. rivulatus revealed distinct changes in the tissue structure of the liver and kidney. The antimicrobial sensitivity test revealed that V. harveyi was highly sensitive to chloramphenicol, with additional sensitivity observed for tetracycline, ciprofloxacin, and ofloxacin. This underscores the critical need for monitoring and managing Vibrio infections to safeguard marine fish health and support sustainability in aquaculture industry.