Figure 1: Predicted mechanisms of helminth-bacterial interactions.

The mechanisms by which helminth infection results in altered intestinal bacterial communities are many and include indirect and direct interactions. Indirect effects result from helminth-induced type two immune response in the mammalian host. This response has been shown to alter intestinal bacterial communities via a number of mechanisms including; i) increased production of SPRR2A and Relmβ proteins that exert antimicrobial activity against gram-positive and gram-negative bacterial spp, respectively and ii) increased and altered production of mucins. It is also likely that type 2 cytokine mediated “weep and sweep’ response, characterised by increased intestinal motility and secretions, impacts microbial communities along the entire intestinal tract. A direct impact of helminth on bacterial communities is likely to occur through multiple mechanisms including, but not restricted to, helminth-induced modulation of bacterial gene expression, the production of shared metabolites and/or toxic metabolic by-products, or competition for essential nutrients. Nutrients could be derived from the host diet, the helminth or bacteria and include; i) macronutrients such as carbohydrates (CHO), lipids and proteins, ii) micronutrients (minerals and vitamins). “Created with BioRender.com”.