Evaluation of greater wax moth (Galleria mellonella) larvae as an alternate host to study the virulence of Vibrio harveyi

Abstract

This study evaluated the suitability of Galleria mellonella larvae as an alternative model for investigating the virulence of Vibrio harveyi, a significant fish pathogen in marine aquaculture. Traditional vertebrate models for studying aquatic pathogens are costly, raise ethical concerns, and are subject to regulatory restrictions. In contrast, G. mellonella larvae offer advantages such as low cost, minimal infrastructure requirements, rapid infection cycles, and greater ethical acceptability. Larvae were injected with V. harveyi suspensions, supernatants, or heat-killed bacteria, and survival rates were monitored. No mortality was observed in control groups or larvae injected with heat-killed bacteria, confirming that viable bacteria are necessary for pathogenic effects. Survival rates of larvae inoculated with bacterial supernatants at $1 \times 10^9$ cfu/mL were strain-dependent but relatively high, with a range of $86.67-93.33\%$ at 168 h. The strain FR-5 exhibited no apparent pathogenicity in larvae. These findings suggest that G. mellonella may not be a reliable alternate host for studying V. harveyi infections, underlining the need to validate the suitability of alternate hosts in the study of the virulence of specific pathogenic species.