Fig. 2

Associations between infectious burden and AD covered by this review. Single-taxon infections are listed in the left column, while combinations of pathogenic taxa that may occur in multi-taxon infections are listed in the right. The infectious burden hypothesis assumes that the combined activity of multiple pathogens contributes to the development of the disease. Most studies on infection and AD have used a limited set of diagnostic tests and could, therefore only examine the contributions of individual taxa. This review highlights the need to use multi-species diagnostic tests in such studies