The Greater Wax Moth Galleria mellonella as an Alternative Model Host for Human Pathogens

Abstract

Pathogenic infections are the cause of millions of deaths all over the world. Limitations in the use of mammalian models and requirements for novel strategies to counter resistant bugs have led to the emergence of insects as alternative models. Insects are widely used as feasible and convenient model systems to evaluate pathogenesis of numerous human pathogens. The fruit fly Drosophila melanogaster is by far the most intensively used model system to evaluate infection and developmental biology of the host in varying detail. However, the lepidopteran greater wax moth, Galleria mellonella is attracting increasing attention as an improved model system for several pathogens having medical significance. Among the advantages provided by insects (e.g. low rearing costs, dsRNA-mediated gene silencing, convenient injection feasibility, and ethically acceptable animal model) it is of particular importance that Galleria can be reared at mammalian physiological temperatures i.e. 37°C to which human pathogens are adapted and which are essential for synthesis of many virulence/pathogenicity factors. This chapter focuses on the validity and limits of using the Galleria model and the outcome of recent studies in which it has been used (1) as a surrogate host to study pathogenesis and virulence factors of prominent bacterial and fungal human pathogens, (2) as a whole-animal high-throughput system for testing pathogen mutant libraries, and (3) as a reliable and more “simple” organism than vertebrates to elucidate the complex molecular mechanisms of microbial pathogenesis in human-like fatal infections of the brainstem.