A bug's life: Delving into the challenges of helminth microbiome studies.
The body of vertebrates is inhabited by trillions of microorganisms, i.e. viruses, archaea, bacteria and unicellular eukaryotes, together referred to as the ‘microbiota’. Similarly, vertebrates also host a plethora of parasitic worms (the ‘macrobiota’), some of which share their environment with the microbiota inhabiting the gastrointestinal tract [1]. Complex interactions between the helminths and the gut microbiota have been associated with establishment of parasite infection, disease manifestations, and host immune-modulation [2, 3]. Remarkably, not only enteric helminths alter the 26 gut microbiome composition [4], but also the infection with blood flukes of the genus Schistosoma has be…
Baseline Gut Microbiota Composition Is Associated With Schistosoma mansoni Infection Burden in Rodent Models
In spite of growing evidence supporting the occurrence of complex interactions between Schistosoma and gut bacteria in mice and humans, no data is yet available on whether worm-mediated changes in microbiota composition are dependent on the baseline gut microbial profile of the vertebrate host. In addition, the impact of such changes on the susceptibility to, and pathophysiology of, schistosomiasis remains largely unexplored. In this study, mice colonized with gut microbial populations from a human donor (HMA mice), as well as microbiota-wild type (WT) animals, were infected with Schistosoma mansoni, and alterations of their gut microbial profiles at 50 days post-infection were compared to …
Helminths, hosts, and their microbiota: new avenues for managing gastrointestinal helminthiases in ruminants
Evidence is emerging of complex interactions occurring between gastrointestinal (GI) parasites of ruminants and the resident gut flora, with likely implications for the pathophysiology of worm infection and disease. Similarly, recent data point toward the occurrence of a GI nematode (GIN)-specific microbiota, with potential roles in worm fundamental physiology and reproduction. Parasite-microbiota relationships might represent potential targets for the development of novel parasiticides.In this article, we review current knowledge of the role(s) that host- and helminth-associated microbiota play in ruminant host-parasite relationships, and outline potential avenues for the control of GIN of…
Helminth Microbiota Profiling Using Bacterial 16S rRNA Gene Amplicon Sequencing: From Sampling to Sequence Data Mining
Symbiont microbial communities play important roles in animal biology and are thus considered integral components of metazoan organisms, including parasitic worms (helminths). Nevertheless, the study of helminth microbiomes has thus far been largely overlooked, and symbiotic relationships between helminths and their microbiomes have been only investigated in selected parasitic worms. Over the past decade, advances in next-generation sequencing technologies, coupled with their increased affordability, have spurred investigations of helminth-associated microbial communities aiming at enhancing current understanding of their fundamental biology and physiology, as well as of host-microbe intera…
Molecular mechanisms of hookworm disease: stealth, virulence, and vaccines.
Hookworms produce a vast repertoire of structurally and functionally diverse molecules that mediate their long-term survival and pathogenesis within a human host. Many of these molecules are secreted by the parasite, after which they interact with critical components of host biology, including processes that are key to host survival. The most important of these interactions is the hookworm's interruption of nutrient acquisition by the host through its ingestion and digestion of host blood. This results in iron deficiency and eventually the microcytic hypochromic anemia or iron deficiency anemia that is the clinical hallmark of hookworm infection. Other molecular mechanisms of hookworm infec…
Classic Models for New Perspectives: Delving into Helminth–Microbiota–Immune System Interactions
Whilst a wealth of data indicate that infections by gastrointestinal helminths are accompanied by significant alterations in the composition of the vertebrate gut flora, little is known of the immune-molecular mechanisms that regulate host-parasite-microbiota interactions. 'Traditional' experimental models of gastrointestinal helminthiases, in which the role(s) of each of the components of this triad can be tested, provide an opportunity to advance research in this area. In this article, we propose the Echinostoma caproni-mouse system as a potentially useful tool for studies of the role of the host gut microbiota in preventing pathology and inducing parasite clearance via interleukin (IL)-2…
Gut-microbiota-derived extracellular vesicles: Overlooked mediators in host–helminth interactions?
Helminth infections impact the composition of the mammalian gut microbiota; however, the mechanisms underpinning these interactions are, thus far, unknown. In this article, we propose that microbiota-derived extracellular vesicles might represent key players in host-helminth-microbiome crosstalk, and outline future directions to elucidate their role(s) in host-parasite relationships.