China
Africa
Explore chapters and articles related to this topic
The Ecology of Parasitism
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Consider the mammalian intestine which harbors hoards of bacteria (estimated as 1013 bacteria in humans) comprised of hundreds of strains and species, along with commensal fungi. The parasitic nematode Trichuris muris lives in the cecum and large intestine of mice, also among swarms of bacteria. It has become a commonly studied model for parasite–microbiome interactions (Figure 6.3). These interactions include direct and indirect effects, the latter often mediated by the host’s immune system. One example of a direct effect is that hatching of the characteristic eggs of this species depends not only on elevated temperatures found in the host’s gut but also on physical contact between the polar plugs found on each end of the egg, and gut microbes.
Mucosal responses to helminth infections
Published in Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald, Principles of Mucosal Immunology, 2020
William Gause, Richard Grencis
Trichinella spiralis is a cosmopolitan and unusual parasite of mammals that infects the host as an L1 larval stage found in striated muscle (infected meat normally) and invades the epithelium of the small intestine. The value of this model in mice is that it generates a very robust immune response in the intestine with rapid clearance of the parasites. Trichuris muris is a natural parasite of the mouse, lives embedded within the epithelium of the large intestine, and is an excellent model for human whipworm infection (the second most prevalent human STH, T. trichiura), which occupies the same intestinal niche. This model can also be manipulated in the laboratory to induce strong host protective immunity or chronic infection. The use of this array of model systems has generated the current view of host immunity to this group of mucosal pathogens in addition to identifying novel aspects of mucosal immune responses.
The Influence of Hormones on Infectious and Parasitic Disease
Published in Istvan Berczi, Pituitary Function and Immunity, 2019
Short-term treatment with cortisone acetate prevented the expulsion of Trichuris muris, and allowed the establishment and survival of an adult worm population in mice for at least 70 days. Serum taken from tolerant mice transferred passive immunity to naive mice, but cells transferred from such donors were ineffective. Cells from immune mice caused a significant reduction in worm numbers, when given on the same day as a secondary infection. It was suggested that corticosteroid treatment deleted an accessory cell population, which led to tolerization of immunocompetent T cells.40
Worm expulsion is independent of alterations in composition of the colonic bacteria that occur during experimental Hymenolepis diminuta-infection in mice
Published in Gut Microbes, 2020
Adam Shute, Arthur Wang, Timothy S. Jayme, Marc Strous, Kathy D. McCoy, Andre G. Buret, Derek M. McKay
It is intuitive to accept that helminths residing in the intestine would affect bacteria in this niche; a postulate reinforced by culture-independent sequencing of the small-subunit ribosomal RNA gene (16S) revealing order/family level shifts in bacterial abundance and diversity in helminth-infected humans, rodents and other mammals.2 Acknowledging parasite-host specificity, infection with helminth parasites often results in contraction of Bacteroidetes and expansion of Firmicutes in the hosts’ colon.3 While reports using 16S rRNA sequence analysis describe alterations in the gut microbiome of helminth-infected individuals, the functional consequences of such shifts on the helminth-bacteria relationship and enteric homeostasis remain incompletely understood. Ova hatching and establishment of the whipworm Trichuris muris in the mouse require the presence of commensal bacteria.4 Similarly, it appears that gut bacteria are essential for the nematode Heligmosomoides polygyrus to thrive.5 The protection against airway inflammation evoked by H. polygyrus was attributed to the short-chain fatty acid (SCFA) acetate, produced by the gut microbiota.6
Characterization of Trichuris muris secreted proteins and extracellular vesicles provides new insights into host–parasite communication
Published in Journal of Extracellular Vesicles, 2018
Ramon M. Eichenberger, Md Hasanuzzaman Talukder, Matthew A. Field, Phurpa Wangchuk, Paul Giacomin, Alex Loukas, Javier Sotillo
Infection with Trichuris spp. occurs after ingestion of infective eggs, which hatch in the caecum of the host. Larvae penetrate the mucosal tissue, where they moult to become adult worms and reside for the rest of their lives. Owing to the difficulty in obtaining parasite material to study whipworm infections, particularly adult worms, the rodent whipworm, Trichuris muris, has been extensively used as a tractable model of human trichuriasis [3–5]. In addition to parasitologists, immunologists have also benefited from the study of T. muris infections, and a significant amount of basic immunology research has been conducted using this model (reviewed by [6]). For instance, the role of IL-13 in resistance to nematode infections was elucidated using T. muris [7].