PARASITIC INFECTIONS IN GERM-FREE ANIMALS

The association of vertebrate hosts with the indigenous microbiota and its effect on the response to infections has long been a subject of s cientific curiosity. From the first theory supported by Louis Pasteur that life would be impossible in the absence of associated microorgani sms to the development of germfree mammals for research, a lot was lea rned about how the normal microbiota influences the environment in whi ch pathogens may find themselves. In the present review, we attempt to summarize the more recent results from our group and others on the in fluence of the normal microbiota on the outcome of parasitic infection s. Our results and those of others point to a complex relationship bet ween the mammalian system and its indigenous microbiota, leading to gr eater resistance to some infections and enhanced susceptibility to oth ers.