This chapter aims to provide insights into current knowledge and gaps in our understanding of the influence that trace metals in the environment have on the pathogenesis of infectious diseases. By reducing immune function, trace metal deficiencies may substantially contribute to the global burden of diarrhea, pneumonia, and malaria. Improved methods and biomarkers for assessing the risks of trace metals deficiencies and toxicities are required. Human activities may be contributing to trace metal deficiency in soils and plants, which is a risk factor for infectious diseases in many countries, by exacerbating the preponderance of cereals and cash crops that reduce food diversity and micronutrient intake. Adaptive strategies are needed to reverse these trends. The microbiomes of the body are in the frontline for exposure to metals and crucial in moderating the outcome of host–parasite interactions. Anthropogenic activities have led to increased toxic metal exposure, and effects on human hosts need clarification. Metal toxicities can also impair the immune system and hence increase the susceptibility to infectious pathogens. Climate change affects metal speciation and the build-up of trace elements in the human food chain, with as yet unknown outcomes on infectious disease. Food processing and the use of metallic nanomaterials can alter human exposure to metals in ways that can influence the host–pathogen competition for metals. The effects of metals on human health may also be mediated through modification of the epigenome, conferring drug resistance on pathogenic bacteria and enhancing/reducing human tolerance to infectious parasites. The emerging metals cerium, gadolinium, lanthanum, and yttrium constitute another driver of change in metal exposure and may potentially modulate the immune system with unknown consequences for human health.
© 2015 Massachusetts Institute of Technology and the Frankfurt Institute for Advanced Studies.