New Perspectives on Galleria mellonella Larvae as a Host Model Using Riemerella anatipestifer as a Proof of Concept.

larvae have been used as a host model to study interactions between pathogens and hosts for several years. However, whether the model is useful to interrogate infection biology remained unknown. This study aimed to exploit the potential of larvae and reveal their limitations as a host model for infection. larvae were shown to be effective for virulence evaluations of different strains. Furthermore, the virulent strain CH-1 had a stronger ability to proliferate than the attenuated strain ATCC 11845 in both larvae and ducklings. Unconventionally it was shown that larvae cannot be used to evaluate the efficacy of antimicrobials and their combinations. Additionally, it was shown that certain virulence factors, such as OmpA (B739_0861), B739_1208, B739_1343, and Wza (B739_1124), were specific only for ducklings, suggesting that larvae must be cautiously used to identify virulence factors of Evaluation of heme uptake-related virulence genes, such as and , required preincubating the strains with hemoglobin before infection of larvae since cannot obtain a heme source from larvae. In conclusion, this study revealed the applicability and limitations of as a model with which to study the pathogen-host interaction, particularly in the context of infection.