Post-hunter-gatherer era microbes’ role in chronic inflammatory diseases and implications for infectious diseases

Abstract

This article discusses a variant of the altered microbiota hypothesis, the leading hypothesis to explain the increase in allergic/autoimmune/inflammatory diseases with westernization. Instead of emphasizing the microbes that are missing/reduced due to westernization, this article focuses on those that are relatively novel. Environmental microbes encountered in association with a pre-agricultural lifestyle would presumably be the most coevolved with the human immune system, and thus they would be less likely to promote debilitating chronic disease. Post-hunter-gatherer era microbes (PHM) are microbes that are encountered more frequently and/or at higher levels since humans ceased to live as nomadic hunter-gatherers. Research will be discussed that suggests that some PHM suppress/dysregulate the immune system, potentially causing chronic inflammatory diseases and increased vulnerability to severe infections. PHM colonization or infection, hypersensitivity reactions and associated chronic stress could significantly impact multiple diseases. Exploration of this hypothesis might generate insights into pathogenic mechanisms and improved treatment approaches.