Helminths and the gut microbiota

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HelminthsAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths] and bacteria form a complex, interactive ecosystem involved in immunity

The gut and its inhabitants should be considered a complex ecosystem, not only involving bacteria but also parasitesAn organism that lives in or on another organism (its host) and benefits at the host’s expense. (The organisms used in helminthic therapy are, strictly speaking, not parasites, but mutualists, because they have a mutually beneficial symbiotic relationship with their hosts.), not just sitting together but interacting. (Prof Richard Grencis, Manchester University) [1]

It is like a three-legged stool - the microbes, worms and immune system regulate each other. The worms have been with us throughout our evolution and their presence, along with bacteria, in the ecosystem of the gut is important in the development of a functional immune system. (Prof Ian Roberts, Manchester University) [2]

Our findings show that murine intestinal helminth infection not only alters the intestinal bacterial communities but that intestinal bacteria contribute to the ability of helminth infection to attenuate allergic airway inflammation. (Zaiss, et al) [3]

Scientific papers and articles relating to helminthsAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths] and the gut microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably.

2019

• The Effect of Gut Microbiome Composition on Human Immune Responses: An Exploration of Interference by Helminth Infections -- Full text | PDF

• Infection with a small intestinal helminth, Heligmosomoides polygyrus bakeri, consistently alters microbial communities throughout the murine small and large intestine

This work provides conclusive evidence that intestinal helminthsAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths] can impact the mammalian intestinal microbiomeAll the microorganisms living in and on the body, or the genome of these microorganisms. "Microbiota" refers to the specific population of microorganisms living in a certain part of the body, such as the gut. These two terms are often used interchangeably., and indicates that helminthAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths]-induced changes can occur at regions distant from the site of parasiteAn organism that lives in or on another organism (its host) and benefits at the host’s expense. (The organisms used in helminthic therapy are, strictly speaking, not parasites, but mutualists, because they have a mutually beneficial symbiotic relationship with their hosts.) infection.

• The interplay of type 2 immunity, helminth infection and the microbiota in regulating metabolism -- Full text | PDF

• Helminth-microbiota cross-talk - a journey through the vertebrate digestive system

• Contribution of the Gut Microbiota in P28GST-Mediated Anti-Inflammatory Effects: Experimental and Clinical Insights -- Full text

• Helminths and microbiota — partners in arthritis prevention?

• Progress of research on the interplay between helminth and intestinal protozoa and gut microbiota

• Suppression of obesity by an intestinal helminth through interactions with intestinal microbiota -- PDF (Also reported by EurekAlert: Intestinal helminths boost fat burning: Japanese investigators show how)

HelminthsAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths] prevented weight gain in laboratory mice on a high-fat diet. They did this by boosting populations of bacteria - notably certain species of Bacillus and Escherichia - that produce compounds which trigger increased energy consumption.

• The Impact of Anthelmintic Treatment on Human Gut Microbiota Based on Cross-Sectional and Pre- and Postdeworming Comparisons in Western Kenya -- Full text | PDF

This study contributes to understanding of how microbial communities differ between individuals infected by soil-transmitted helminthsAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths] and those who are uninfected.

• Chinese liver fluke Clonorchis sinensis infection changes the gut microbiome and increases probiotic Lactobacillus in mice

• Cross-Domain and Viral Interactions in the Microbiome

In a very detailed “HelminthsAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths]” section (pages 26-35), this paper discusses evidence that host-associated microbes may impact helminth infection success, that helminth colonization may impact the diversity and composition of the gut microbiomeAll the microorganisms living in and on the body, or the genome of these microorganisms. "Microbiota" refers to the specific population of microorganisms living in a certain part of the body, such as the gut. These two terms are often used interchangeably., and that both can have impacts on immune function.

2018

• Mucosal Barrier and Th2 Immune Responses Are Enhanced by Dietary Inulin in Pigs Infected With Trichuris suis -- Full text | PDF

Trichuris suisThe porcine (pig) whipworm used in helminthic therapy and taken as microscopic eggs (TSO) in a drink every two weeks. and dietary inulin co-operatively mediate beneficial changes in microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. composition in pigs to enhance anti-inflammatory immune responses.

• A comprehensive analysis of the faecal microbiome and metabolome of Strongyloides stercoralis infected volunteers from a non-endemic area -- Full text | PDF

Monospecific, chronic infection with the helminthAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths], S. stercoralisThe roundworm that causes strongyloidiasis and is known as 'pinworm' in the UK and 'threadworm' in the US. Infection with S. stercoralis [https://www.ncbi.nlm.nih.gov/pubmed/30898993 can be fatal]., were found to be associated with global shifts in the composition of the human faecal microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably., as well as subtle changes in faecal metabolic profiles.

• The Intestinal Roundworm Ascaris suum Releases Antimicrobial Factors Which Interfere With Bacterial Growth and Biofilm Formation -- Full text | PDF

The helminthAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths], A. suum, uses a variety of factors with broad-spectrum antibacterial activity to affirm itself within its microbe-rich environment in the gut.

• Characteristics of the bacterial microbiome in association with common intestinal parasites in irritable bowel syndrome -- Full text | PDF

While this study focused on the parasitesAn organism that lives in or on another organism (its host) and benefits at the host’s expense. (The organisms used in helminthic therapy are, strictly speaking, not parasites, but mutualists, because they have a mutually beneficial symbiotic relationship with their hosts.), Dientamoeba fragilis and Blastocystis, rather than helminthsAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths], its conclusions are nevertheless interesting.

“Presence of parasitesAn organism that lives in or on another organism (its host) and benefits at the host’s expense. (The organisms used in helminthic therapy are, strictly speaking, not parasites, but mutualists, because they have a mutually beneficial symbiotic relationship with their hosts.) was associated to a rich and diverse microbiomeAll the microorganisms living in and on the body, or the genome of these microorganisms. "Microbiota" refers to the specific population of microorganisms living in a certain part of the body, such as the gut. These two terms are often used interchangeably. in healthy controls and individuals with unspecific GIGastroenterology is the branch of medicine concerned with disorders of the digestive system which includes all the organs of the gastrointestinal (GI) tract (alimentary canal) from mouth to anus. Physicians practicing in this field of medicine are called gastroenterologists or GI specialists. symptoms… Observations of parasiteAn organism that lives in or on another organism (its host) and benefits at the host’s expense. (The organisms used in helminthic therapy are, strictly speaking, not parasites, but mutualists, because they have a mutually beneficial symbiotic relationship with their hosts.) colonization being associated to healthy features of the gut microbiomeAll the microorganisms living in and on the body, or the genome of these microorganisms. "Microbiota" refers to the specific population of microorganisms living in a certain part of the body, such as the gut. These two terms are often used interchangeably. should differentiate our view of intestinal parasitesAn organism that lives in or on another organism (its host) and benefits at the host’s expense. (The organisms used in helminthic therapy are, strictly speaking, not parasites, but mutualists, because they have a mutually beneficial symbiotic relationship with their hosts.) beyond the focus on pathogenicity.”

• Classic Models for New Perspectives: Delving into Helminth–Microbiota–Immune System Interactions
• Helminth–Bacterial Interactions: Cause and Consequence
• Parasite-Microbiota Interactions With the Vertebrate Gut: Synthesis Through an Ecological Lens -- Full text | PDF

This is a good review of studies investigating the interactions of the intestinal microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably., gut parasitesAn organism that lives in or on another organism (its host) and benefits at the host’s expense. (The organisms used in helminthic therapy are, strictly speaking, not parasites, but mutualists, because they have a mutually beneficial symbiotic relationship with their hosts.) and their host, and how these interactions may affect the overall health of the host.

• The therapeutic prospect of crosstalk between prokaryotic and eukaryotic organisms in the human gut
• Associations between Gut Microbiota and Common Luminal Intestinal Parasites
• Manipulation of host and parasite microbiotas: Survival strategies during chronic nematode infection -- Full text | PDF

The eggs of T. muris that hatch in sterile conditions are free from bacteria.

T. muris maintains its own distinct microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably., comprising bacteria selected from the intestine of its host, regardless of the surrounding bacterial populations.

Infection with T. muris causes significant restructuring of the host cecal microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. and a reduction in total bacterial diversity.

T. muris-induced changes in the host microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. suppresses subsequent parasiteAn organism that lives in or on another organism (its host) and benefits at the host’s expense. (The organisms used in helminthic therapy are, strictly speaking, not parasites, but mutualists, because they have a mutually beneficial symbiotic relationship with their hosts.) egg hatching, consequently controlling parasiteAn organism that lives in or on another organism (its host) and benefits at the host’s expense. (The organisms used in helminthic therapy are, strictly speaking, not parasites, but mutualists, because they have a mutually beneficial symbiotic relationship with their hosts.) numbers in the infected host intestine independently of the host adaptive immune system.

• Differential human gut microbiome assemblages during soil-transmitted helminth infections in Indonesia and Liberia -- Full text | PDF
• The impact of a helminth-modified microbiome on host immunity

2017

• Infections by human gastrointestinal helminths are associated with changes in faecal microbiota diversity and composition
• Parasite-microbiota interactions potentially affect intestinal communities in wild mammals
• Reciprocal Interactions between Nematodes and Their Microbial Environments

Highlights findings concerning responses to bacterial stimuli, antimicrobial peptides and the reciprocal influences between nematodesA category of worms with slender, unsegmented, cylindrical bodies that include roundworms and threadworms. and their environmental bacteria. Also discussed are the microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. of nematodesA category of worms with slender, unsegmented, cylindrical bodies that include roundworms and threadworms. and alterations in the intestinal microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. of mammalian hosts by helminth infections.

• Enteric helminth-induced type-I interferon signalling protects against pulmonary virus infection through interaction with the microbiota
• Gut microbiota disturbance during helminth infection: can it affect cognition and behaviour of children? -- Full text | PDF

2016

• Modulation of IL-12 and IFNγ by probiotic supplementation promotes protection against Toxocara canis infection in mice

• Macrobiota - helminths as active participants and partners of the microbiota in host intestinal homeostasis -- Full text | PDF

• Helminth infection promotes colonization resistance via type 2 immunity -- Full Text | PDF

Helminth infection protects mice deficient in the Crohn’s disease susceptibility gene Nod2 from intestinal abnormalities by inhibiting colonization with an inflammatory Bacteroides species.

• Interactions between the intestinal microbiome and helminth parasites -- Full text | PDF

Discusses at length the interrelationships between intestinal helminthsAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths] and microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably., in both humans and mice, and highlights the fact that certain microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. species can determine the outcomes of helminth infection.
"... although intestinal helminthsAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths] are generally accepted to possess potent immuno-modulatory activity, it is unknown whether this capacity requires interactions with intestinal bacteria. We propose that this 'ménage à trois' situation is likely to have exerted a strong selective pressure on the development of our metabolic and immune systems."

2015

• Worming Their Way into the Picture: Microbiota Help Helminths Modulate Host Immunity -- Full text | PDF

HelminthsAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths] and bacterial microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. act in bi-directional synergy to modulate immune responses.

• Unraveling the Hygiene Hypothesis of helminthes and autoimmunity: origins, pathophysiology, and clinical applications -- Full text | PDF

HelminthsAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths] move the balance of the intestinal flora to favour “probioticMicroorganisms that are believed to provide health benefits when consumed.” microorganisms.

• Cohabitation in the Intestine: Interactions among Helminth Parasites, Bacterial Microbiota, and Host Immunity -- Full text | PDF

• The Intestinal Microbiota Contributes to the Ability of Helminths to Modulate Allergic Inflammation -- Full text | PDF

• Can Helminth Infection Reverse Microbial Dysbiosis?-- Full text | PDF

• Experimental hookworm infection and escalating gluten challenges are associated with increased microbial richness in celiac subjects -- Full text|PDF

"Notably, we observed a significant increase in microbial species richness over the course of the trial, which could represent a potential mechanism by which hookwormsA helminth that lives in the small intestine. Necator americanus (NA) is the only hookworm species used in helminthic therapy. Its microscopic larvae are applied periodically to the skin. can regulate gluten-induced inflammation and maintain intestinal immune homeostasis."

• Type 2 immunity-dependent reduction of segmented filamentous bacteria in mice infected with the helminthic parasite Nippostrongylus brasiliensis -- Full text | PDF

"Dynamic interactions between the host and gastrointestinal microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. play an important role for local and systemic immune homeostasis."

• Interactions between multiple helminths and the gut microbiota in wild rodents -- Full text | PDF

"In general, helminth presence is linked with high microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. diversity, which may confer health benefits to the host… The most pronounced helminthAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths]-microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. association was between the presence of tapewormsA helminth with a flat, ribbon-like, segmented body. Only the murine (rat) tapeworm, Hymenolepis diminuta, is used in helminthic therapy and this generally does not reach adulthood in humans so requires regular dosing of HDC. in the small intestine and increased S24-7 (Bacteroidetes) family in the stomach."

• Suppression of inflammation by helminths: a role for the gut microbiota? -- Full text | PDF

"In this article, we review recent progress in the elucidation of host-parasiteAn organism that lives in or on another organism (its host) and benefits at the host’s expense. (The organisms used in helminthic therapy are, strictly speaking, not parasites, but mutualists, because they have a mutually beneficial symbiotic relationship with their hosts.)-microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. interactions in both animal models of chronic inflammation and humans, and provide a working hypothesis of the role of the gut microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. in helminthAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths]-induced suppression of inflammation."

• The gut microbiome in the helminth infected host

• Helminths and the microbiota: parts of the hygiene hypothesis — Full text | PDF

• Chronic Trichuris muris Infection Decreases Diversity of the Intestinal Microbiota and Concomitantly Increases the Abundance of Lactobacilli -- Full text | PDF

• Alteration of the rat cecal microbiome during colonization with the helminth Hymenolepis diminuta -- Full text | PDF

Colonisation by Hymenolepis diminutaA murine (rat) tapeworm used in helminthic therapy that generally does not mature in humans and is taken as cysticerci (HDC) in a drink every 2 or 3 weeks. led to several changes in rat cecal microbiomeAll the microorganisms living in and on the body, or the genome of these microorganisms. "Microbiota" refers to the specific population of microorganisms living in a certain part of the body, such as the gut. These two terms are often used interchangeably. that were mostly within the Firmicutes phylum, involved about 20% of the total bacteria, and entailed a shift from Bacilli to Clostridia species.

• Chronic Trichuris muris Infection in C57BL/6 Mice Causes Significant Changes in Host Microbiota and Metabolome: Effects Reversed by Pathogen Clearance -- Full text | PDF

"... infection of T. muris causes a significant and substantial impact on intestinal microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. and digestive function of mice with affects in long term immune regulation."

2014

• Impact of experimental hookworm infection on the human gut microbiota -- Full text | PDF

HookwormA helminth that lives in the small intestine. Necator americanus (NA) is the only hookworm species used in helminthic therapy. Its microscopic larvae are applied periodically to the skin. infection produces a minor increase in microbial species richness, but has no detectable effect on community structure, diversity or relative abundance of individual bacterial species. (NB. Testing was done at only 8 weeks, so the worms were not yet fully engaged.)

• Virus-helminth coinfection reveals a microbiota-independent mechanism of immunomodulation -- Full text | PDF

“… helminthAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths]-induced immunomodulation occurs independently of changes in the microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. but is dependent on Ym1.”

• The microbiota and helminths: sharing the same niche in the human host

Discusses changes occurring in the microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. upon helminth infection and the underlying mechanisms leading to these changes.

• Helminth colonization is associated with increased diversity of the gut microbiota -- Full text | PDF

HelminthsAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths] may have an impact on the diversity, bacterial community structure and function of the gut microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably..

• Bacteria can mobilize nematode-trapping fungi to kill nematodes -- Full text | PDF

Some bacteria and nematodeA category of worms with slender, unsegmented, cylindrical bodies that include roundworms and threadworms.-trapping fungi form mutually beneficial relationships to victimise nematodesA category of worms with slender, unsegmented, cylindrical bodies that include roundworms and threadworms..

• Effect of Bifidobacterium animalis on mice infected with Strongyloides venezuelensis -- Full text | PDF

The bacterium, B. animalis, significantly decreased the S. venezuelensis worm burden and egg output.

2013

• A role for IL-22 in the relationship between intestinal helminths, gut microbiota and mucosal immunity -- Full text | PDF

"… by inducing an immune response that includes IL-22, intestinal helminthsAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths] may enhance the mucosal barrier function of the intestinal epithelium. This may restore the mucosal microbiotaThe specific population of microorganisms living in a certain part of the body, such as the gut. "Microbiome" refers to all the microorganisms living in and on the body, or the genome of these microorganisms. These two terms are often used interchangeably. populations from dysbiosis associated with colitis and improve intestinal homeostasis."

2012

• Alterations in the porcine colon microbiota induced by the gastrointestinal nematode Trichuris suis -- Full text | PDF
• Therapeutic helminth infection of macaques with idiopathic chronic diarrhea alters the inflammatory signature and mucosal microbiota of the colon -- Full text | PDF

WhipwormsA helminth with a tapering whiplike body that lives in the colon. In helminthic therapy, the microscopic eggs of either the human Trichuris trichiura (TTO) or pig Trichuris suis (TSO) are taken in a drink. can restore the balance of gut bacterial communities in sick monkeys.

2011

• Probiotics for the Control of Parasites: An Overview -- Full text | PDF

Some probioticMicroorganisms that are believed to provide health benefits when consumed. strains have been shown to be effective in controlling some species of parasiticAn organism that lives in or on another organism (its host) and benefits at the host’s expense. (The organisms used in helminthic therapy are, strictly speaking, not parasites, but mutualists, because they have a mutually beneficial symbiotic relationship with their hosts.) worm. NB. This study was not concerned with helminthsAn intestinal worm which grows large enough to be seen with the naked eye when mature but which is microscopic when administered in helminthic therapy. [https://en.wikipedia.org/wiki/Helminths Wikipedia:Helminths] used in therapy, but other types of parasiteAn organism that lives in or on another organism (its host) and benefits at the host’s expense. (The organisms used in helminthic therapy are, strictly speaking, not parasites, but mutualists, because they have a mutually beneficial symbiotic relationship with their hosts.).

• Changes in the mucosal barrier during acute and chronic Trichuris muris infection -- Full text | PDF

2010

• Alteration of the murine gut microbiota during infection with the parasitic helminth Heligmosomoides polygyrus -- Full text | PDF

Helminth infection shifts the composition of intestinal bacteria.

• Exploitation of the intestinal microflora by the parasitic nematode Trichuris muris -- Full text | PDF

• How the parasitic worm has turned

"It is like a three-legged stool - the microbes, worms and immune system regulate each other. The worms have been with us throughout our evolution and their presence, along with bacteria, in the ecosystem of the gut is important in the development of a functional immune system."