Parasite Versus Host: Pathology and Disease
Eric S. Loker, Bruce V. Hofkin in Parasitology, 2015
The apparent link between infection with certain parasites and a reduction in the severity of certain medical conditions has given rise to what seems oxymoronic: helminth therapy. This is the deliberate infection of patients with specific intestinal nematodes to alleviate symptoms of certain clinical conditions. To date, most research and treatment has focused on the hookworm Necator americanus and especially on the pig whipworm, Trichuris suis (Figure 5.20). Both of these species have shown promise in the treatment of a wide range of autoimmune and allergic conditions, including inflammatory bowel disease, multiple sclerosis, asthma, eczema, and hay fever. In fact, although not exactly commonplace and although perhaps not for the squeamish, the use of T suis to combat inflammatory bowel disorders is now viewed by some as an acceptable treatment option.
Parasite Versus Host: Pathology and Disease
Eric S. Loker, Bruce V. Hofkin in Parasitology, 2023
The apparent link between infection with certain parasites and a reduction in the severity of certain medical conditions has given rise to what seems oxymoronic—helminth therapy: the deliberate infection of patients with specific intestinal nematodes to alleviate symptoms of certain clinical conditions. To date, most research and treatment has focused on the hookworm Necator americanus and especially on the pig whipworm, Trichuris suis (Figure 5.26). Although the logic of helminth therapy may make sense, clinical trials have provided mixed results. In some cases, individuals have clearly benefited, seeing reducing symptomology for conditions such as inflammatory bowel disease, multiple sclerosis, eczema and hay fever. And although there is a general trend in these trials toward some patient improvement, the data supporting the deliberate infection of individuals to treat medical conditions has not been overly compelling.
The Helminths
Donald L. Price in Procedure Manual for the Diagnosis of Intestinal Parasites, 2017
Hookworm eggs in human feces may represent either Ancylostoma sp. or Necator americanus. Differentiation must be made from adult or filariform juvenile stage. The filariform stage is obtained for identification by culturing the eggs or juvenile worms (Melvin and Brooke, 1982; Ash and Orihel, 1987). When hookworm eggs are delayed in moving through the intestine, they may develop to the juvenile stage. Some juvenile worms may emerge in feces before it is passed so, in addition to eggs, occasionally juvenile nematodes of hookworms are seen in the fecal specimen. The juvenile stages of Strongyloides stercoralis also may be present in fecal specimens where hookworm eggs are present. In such cases, the juveniles must be positively identified (see Plates 12 and 35). Hookworm eggs are differentiated from Temidens deminutus eggs only on the basis of size.
Dynamics of the bacterial gut microbiota during controlled human infection with Necator americanus larvae
Published in Gut Microbes, 2020
Q. R. Ducarmon, M. A. Hoogerwerf, J. J. Janse, A. R. Geelen, J. P. R. Koopman, R. D. Zwittink, J. J. Goeman, E. J. Kuijper, M. Roestenberg
Helminths such as hookworms can have beneficial effects on auto-immune diseases1,2 such as celiac disease,3,4 but also cause eosinophilic gastroenteritis, anemia and protein loss and are therefore responsible for a high burden of disease in low- and middle-income countries.5 As a part of the human gut microbiome in developing countries with a high rate of hookworm infections, hookworms can exert evolutionary pressure on the bacterial gut ecosystem through intestinal motility, mucin glycosylation, mucus secretion, epithelial damage and worm products.6 For example, several helminths and their products have been shown to increase permeability of monolayers in cell culture.7,8 In addition, worm products can have direct antibacterial activity, thereby having the potential to directly alter the bacterial gut microbiota.9,10 However, the complex interplay between hookworms such as Necator americanus and the bacterial microbiota is largely unknown.
Investigational drug therapies for coeliac disease – where to from here?
Published in Expert Opinion on Investigational Drugs, 2018
James Haridy, Diana Lewis, Evan D. Newnham
The ‘hygiene hypothesis’ postulates the rise in autoimmune and immune-mediated diseases in developed countries is in part related to the reduction in infectious disease exposure, particularly in childhood [52]. Epidemiologic studies suggest that a major factor includes the dramatic reduction in helminth infections [53]. Animal and human models have demonstrated reduced autoantigen-specific responses and attenuated response in both autoimmune liver disease and IBD [54–56]. An initial Phase 2 double-blinded placebo-controlled study of 20 patients infected with necator americanus for 21 weeks did not improve histological or patient-reported outcomes [57]. Immunological data this study was encouraging, displaying suppression of intestinal inflammatory cytokine production and possibly modulating T-helper cell responses [58]. This led to a second non-blinded nor placebo-controlled 52-week study of 12 of the same subjects with lower levels of gluten challenge. The study noted a paradoxical decline in mean TG2 IgA titers upon exposure to 3g of gluten daily, and there was no alteration in villous height to crypt depth ratio in those exposed to 1g gluten daily. Patient-reported outcomes were not significantly improved [59]. It is difficult to draw sufficient conclusions based on current data. However, a further Phase 2 trial is currently underway with necator americanus on a larger sample population.
Prevalence and associated risk factors of intestinal parasitic infections in Kurdistan province, northwest Iran
Published in Cogent Medicine, 2018
Fares Bahrami, Ali Haghighi, Ghasem Zamini, Mohammad Bagher Khadem-Erfan, Eznolla Azargashb
In developing countries, intestinal parasitic infections (IPIs) are the most common infections (Sayyari, Imanzadeh, Bagheri Yazdi, Karami, & Yaghoobi, 2005). If IPIs are not recognized and treated appropriately, they can result in significant morbidity and mortality (Gilles & Hoffman, 2002). IPIs can be caused by protozoan organisms or helminths. The most common intestinal pathogenic parasites include: Giardia intestinalis, Entamoeba histolytica/E. dispar, Cryptosporidium spp., microsporidia, Cyclospora cayetanenensis, Ascaris lumbricoides, Ancylostoma duodenale, Blastocystis sp. Necator americanus, Hymenolepis nana, Taenia saginata, and Trichuris trichiura (Haque, 2007; Horton, 2003).
Related Knowledge Centers
- Ancylostoma Duodenale
- Cheek
- Helminthiasis
- Hookworm
- Parasitism
- Parasitic Worm
- Necatoriasis
- Hookworm Infection
- Trichuris Suis
- Helminthic Therapy