Insects as models for studying the virulence of fungal pathogens of humans

Abstract

Insects represent one of the most successful groups of animals, exploiting almost all niches on Earth, except the seas, and accounting for at least 1 million species and 10 individuals (Vilmos & Kurucz, 1998). Insects diverged from vertebrates approximately 500 million years ago and despite this early divergence, have maintained an immune response with strong structural and functional similarities to the innate immune response of mammals (Vilmos & Kurucz, 1998; Salzet, 2001). Insects rely exclusively upon an immune system analogous to the innate immune response of mammals and consequently have become extremely valuable as models for studying vertebrate innate immune responses to many pathogenic micro-organsims. There are obvious ethical concerns with using mammalian models for in vivo testing of microbial pathogens, many of which can be removed by employing invertebrate models. Invertebrates, such as insects, do not have a well-developed nervous system and consequently do not experience pain in the same manner as mammals. Although invertebrate models would not be the only source of in vivo testing, they have the potential to substantially reduce the number of mammals sacrificed. In addition using invertebrates as models to study the pathogenicity of microbes yields faster results.