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Lancet (London, England) Jan 2018More than a quarter of the world's population is at risk of infection with the soil-transmitted helminths Ascaris lumbricoides, hookworm (Ancylostoma duodenale and... (Review)
Review
More than a quarter of the world's population is at risk of infection with the soil-transmitted helminths Ascaris lumbricoides, hookworm (Ancylostoma duodenale and Necator americanus), Trichuris trichiura, and Strongyloides stercoralis. Infected children and adults present with a range of medical and surgical conditions, and clinicians should consider the possibility of infection in individuals living in, or returning from, endemic regions. Although safe and effective drugs are donated free to endemic countries, only half of at-risk children received treatment in 2016. This Seminar describes the epidemiology, lifecycles, pathophysiology, clinical diagnosis, management, and public health control of soil-transmitted helminths. Previous work has questioned the effect of population-level deworming; however, it remains beyond doubt that treatment reduces the severe consequences of soil-transmitted helminthiasis. We highlight the need for refined diagnostic tools and effective control options to scale up public health interventions and improve clinical detection and management of these infections.
Topics: Anthelmintics; Helminthiasis; Humans; Public Health; Soil
PubMed: 28882382
DOI: 10.1016/S0140-6736(17)31930-X -
American Family Physician Mar 2004Intestinal parasites cause significant morbidity and mortality. Diseases caused by Enterobius vermicularis, Giardia lamblia, Ancylostoma duodenale, Necator americanus,... (Review)
Review
Intestinal parasites cause significant morbidity and mortality. Diseases caused by Enterobius vermicularis, Giardia lamblia, Ancylostoma duodenale, Necator americanus, and Entamoeba histolytica occur in the United States. E. vermicularis, or pinworm, causes irritation and sleep disturbances. Diagnosis can be made using the "cellophane tape test." Treatment includes mebendazole and household sanitation. Giardia causes nausea, vomiting, malabsorption, diarrhea, and weight loss. Stool ova and parasite studies are diagnostic. Treatment includes metronidazole. Sewage treatment, proper handwashing, and consumption of bottled water can be preventive. A. duodenale and N. americanus are hookworms that cause blood loss, anemia, pica, and wasting. Finding eggs in the feces is diagnostic. Treatments include albendazole, mebendazole, pyrantel pamoate, iron supplementation, and blood transfusion. Preventive measures include wearing shoes and treating sewage. E. histolytica can cause intestinal ulcerations, bloody diarrhea, weight loss, fever, gastrointestinal obstruction, and peritonitis. Amebas can cause abscesses in the liver that may rupture into the pleural space, peritoneum, or pericardium. Stool and serologic assays, biopsy, barium studies, and liver imaging have diagnostic merit. Therapy includes luminal and tissue amebicides to attack both life-cycle stages. Metronidazole, chloroquine, and aspiration are treatments for liver abscess. Careful sanitation and use of peeled foods and bottled water are preventive.
Topics: Adult; Amebicides; Ancylostoma; Animals; Child; Entamoeba histolytica; Entamoebiasis; Enterobiasis; Enterobius; Giardia lamblia; Giardiasis; Hookworm Infections; Humans; Intestinal Diseases, Parasitic; Necator americanus
PubMed: 15023017
DOI: No ID Found -
Parasitology Mar 2019Caenorhabditis elegans is a free-living nematode that resides in soil and typically feeds on bacteria. We postulate that haematophagic C. elegans could provide a model...
Caenorhabditis elegans is a free-living nematode that resides in soil and typically feeds on bacteria. We postulate that haematophagic C. elegans could provide a model to evaluate vaccine responses to intestinal proteins from hematophagous nematode parasites, such as Necator americanus. Human erythrocytes, fluorescently labelled with tetramethylrhodamine succinimidyl ester, demonstrated a stable bright emission and facilitated visualization of feeding events with fluorescent microscopy. C. elegans were observed feeding on erythrocytes and were shown to rupture red blood cells upon capture to release and ingest their contents. In addition, C. elegans survived equally on a diet of erythrocytes. There was no statistically significant difference in survival when compared with a diet of Escherichia coli OP50. The enzymes responsible for the digestion and detoxification of haem and haemoglobin, which are key components of the hookworm vaccine, were found in the C. elegans intestine. These findings support our postulate that free-living nematodes could provide a model for the assessment of neutralizing antibodies to current and future hematophagous parasite vaccine candidates.
Topics: Animals; Blood; Caenorhabditis elegans; Diet; Disease Models, Animal; Feeding Behavior; Microscopy, Fluorescence; Vaccines
PubMed: 30355366
DOI: 10.1017/S0031182018001518 -
The American Journal of Tropical... Sep 2016Historically, the diagnosis of soil-transmitted helminths (STHs) (e.g., Strongyloides stercoralis, Trichuris trichiura, Ancylostoma duodenale, Necator americanus, and... (Review)
Review
Historically, the diagnosis of soil-transmitted helminths (STHs) (e.g., Strongyloides stercoralis, Trichuris trichiura, Ancylostoma duodenale, Necator americanus, and Ascaris lumbricoides) has relied on often-insensitive microscopy techniques. Over the past several years, there has been an effort to use molecular diagnostics, particularly quantitative polymerase chain reaction (qPCR), to detect intestinal pathogens. While some platforms have been approved by regulatory bodies (e.g., Food and Drug Administration) to detect intestinal bacteria, viruses, and protozoa, there are no approved tests currently available for STH. Although studies comparing qPCR to microscopy methods for STH are imperfect, due in large part to a lack of a sufficient gold standard, they do show a significant increase in sensitivity and specificity of qPCR compared with microscopic techniques. These studies, as well as the advantages and disadvantages of using qPCR for STH diagnosis, are discussed. Guidelines for those designing future studies utilizing qPCR are proposed for optimizing results, as is the proposition for using standardized molecular diagnostics routinely for STH in clinical laboratories and for field-based studies when possible.
Topics: Helminthiasis; Humans; Molecular Diagnostic Techniques; Polymerase Chain Reaction; Sensitivity and Specificity; Soil
PubMed: 27481053
DOI: 10.4269/ajtmh.16-0266 -
Journal of Infection in Developing... Jan 2014The worldwide prevalence of geohelminths and their unique place in evolutionary biology have attracted research focus. These major soil-transmitted intestinal nematodes... (Review)
Review
The worldwide prevalence of geohelminths and their unique place in evolutionary biology have attracted research focus. These major soil-transmitted intestinal nematodes that cause human diseases are the nematode roundworm (Ascaris lumbricoides), the whipworm (Trichuris trichiura) and the two hookworms (Ancylostoma duodenale and Necator americanus), often collectively referred as geohelminths. Studies of geohelminthiasis in poorly nourished children in developing regions report that geohelminths contribute to stunted growth and cognitive impairment. Insights into immunology have shed light on the modulatory role of the parasite on the host immune system and have defined the role of T cells in controlling geohelminthic infection. Recent molecular biological techniques have created an opportunity to analyse the interaction between parasites and their hosts at the molecular level. This paper is a review of the recent literature that examined the prevalence of geohelminthiasis in developing countries, the association between geohelminths in relation to public health, parasitological/diagnostic features, and therapeutic and preventive aspects of these major soil-transmitted helminth (STH) pathogens in humans.
Topics: Ancylostomatoidea; Animals; Ascaris lumbricoides; Developing Countries; Developmental Disabilities; Helminthiasis; Humans; Intestinal Diseases; Intestinal Diseases, Parasitic; Prevalence; Trichuris
PubMed: 24423707
DOI: 10.3855/jidc.3183 -
Frontiers in Pediatrics 2019Gluten is known to be the main triggering factor for celiac disease (CeD), an immune-mediated disorder. CeD is therefore managed using a strict and lifelong gluten-free... (Review)
Review
Gluten is known to be the main triggering factor for celiac disease (CeD), an immune-mediated disorder. CeD is therefore managed using a strict and lifelong gluten-free diet (GFD), the only effective treatment available currently. However, the GFD is restrictive. Hence, efforts are being made to explore alternative therapies. Based on their mechanisms of action on various molecular targets involved in the pathogenesis of CeD, these therapies may be classified into one of the following five broad approaches. The first approach focuses on decreasing the immunogenic content of gluten, using strategies like genetically modified wheat, intra-intestinal gluten digestion using glutenases, microwave thermal treatment of hydrated wheat kernels, and gluten pretreatment with either bacterial/ fungal derived endopeptidases or microbial transglutaminase. The second approach involves sequestering gluten in the gut lumen before it is digested into immunogenic peptides and absorbed, using binder drugs like polymer p(HEMA-co-SS), single chain fragment variable (scFv), and anti- gluten antibody AGY. The third approach aims to prevent uptake of digested gluten through intestinal epithelial tight junctions, using a zonulin antagonist. The fourth approach involves tissue transglutaminase (tTG) inhibitors to prevent the enhancement of immunogenicity of digested gluten by the intestinal tTG enzyme. The fifth approach seeks to prevent downstream immune activation after uptake of gluten immunogenic peptides through the intestinal mucosal epithelial layer. Examples include HLA-DQ2 blockers that prevent presentation of gluten derived- antigens by dendritic cells to T cells, immune- tolerizing therapies like the vaccine Nexvax2 and TIMP-Glia, cathepsin inhibitors, immunosuppressants like corticosteroids, azathioprine etc., and anti-cytokine agents targeting TNF-α and interleukin-15. Apart from these approaches, research is being done to evaluate the effectiveness of probiotics/prebiotics, helminth therapy using , low FODMAP diet, and pancreatic enzyme supplementation in CeD symptom control; however, the mechanisms by which they play a beneficial role in CeD are yet to be clearly established. Overall, although many therapies being explored are still in the pre-clinical phase, some like the zonulin antagonist, immune tolerizing therapies and glutenases have reached phase II/III clinical trials. While these potential options appear exciting, currently they may at best be used to supplement rather than supplant the GFD.
PubMed: 31157194
DOI: 10.3389/fped.2019.00193 -
Cellular and Molecular Gastroenterology... 2019Celiac Disease (CeD) is defined as a chronic small intestinal immune-mediated enteropathy that is precipitated by exposure to dietary gluten in genetically predisposed... (Review)
Review
Celiac Disease (CeD) is defined as a chronic small intestinal immune-mediated enteropathy that is precipitated by exposure to dietary gluten in genetically predisposed individuals. CeD is one of the most common autoimmune disorders affecting around 1% of the population worldwide. Currently, the only acceptable treatment for CeD is strict, lifelong adherence to a gluten-free diet (GFD) which can often present a challenging task. A GFD alone is not sufficient to control symptoms and prevent mucosal damage that can result from unintentional gluten exposure. Moreover, long-term complications can occur in many patients. Consequently, there is an unmet need for non-dietary therapies for the management of CeD. Such therapies could serve as an adjunct to the GFD but eventually may replace it. This review will focus on and discuss non-dietary therapies currently in clinical development for the management of CeD. METHODOLOGY: We searched clinicaltrials.gov and PubMed to extract articles about celiac disease. We used keywords including, but not limited to, "celiac disease," "non-dietary," "therapeutics," "pathophysiology," "Endopeptidases," "tight junction modulators," "vaccine," and "Nexvax2". We focused mainly on articles that conducted pathophysiologic and therapeutic research in human trials.
Topics: Celiac Disease; Clinical Trials as Topic; Combined Modality Therapy; Diet, Gluten-Free; Genetic Predisposition to Disease; Humans; Treatment Outcome
PubMed: 31146067
DOI: 10.1016/j.jcmgh.2019.04.017 -
Frontiers in Immunology 2022
Topics: Animals; Antibodies, Helminth; Helminths
PubMed: 35359963
DOI: 10.3389/fimmu.2022.877707