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Acta Dermato-venereologica Jul 2019Cutaneous larva migrans is a dermatitis, typically acquired in warm tropical or sub-tropical countries, caused by migration of the larvae of nematodes (hookworm; mainly... (Review)
Review
Cutaneous larva migrans is a dermatitis, typically acquired in warm tropical or sub-tropical countries, caused by migration of the larvae of nematodes (hookworm; mainly Ancylostoma braziliense and, occasionally, Ancylostoma caninum or Uncinaria stenocephala), which are parasitic on animals such as cats and dogs, into the patient's skin. The larvae penetrate the skin after contact with infected soil and cause a typical creeping eruption. Patients with cutaneous larva migrans seen in Europe have usually acquired the disease following a stay in a tropical or sub-tropical area. How-ever, some cases of cutaneous larval migrans are acquired in Europe. We report here 5 autochthonous cases in France and give an overview of European autochthonous cases.
Topics: Adult; Ancylostoma; Animals; Antinematodal Agents; Disease Transmission, Infectious; Female; France; Humans; Infant; Ivermectin; Larva Migrans; Male; Middle Aged; Remission Induction; Skin; Treatment Outcome; Young Adult
PubMed: 31073620
DOI: 10.2340/00015555-3217 -
PLoS Neglected Tropical Diseases Dec 2017Necator americanus, a haematophagous hookworm parasite, infects ~10% of the world's population and is considered to be a significant public health risk. Its lifecycle...
Necator americanus, a haematophagous hookworm parasite, infects ~10% of the world's population and is considered to be a significant public health risk. Its lifecycle has distinct stages, permitting its successful transit from the skin via the lungs (L3) to the intestinal tract (L4 maturing to adult). It has been hypothesised that the L3 larval sheath, which is shed during percutaneous infection (exsheathment), diverts the immune system to allow successful infection and reinfection in endemic areas. However, the physicochemical properties of the L3 larval cuticle and sheath, which are in direct contact with the skin and its immune defences, are unknown. In the present study, we controlled exsheathment, to characterise the sheath and underlying cuticle surfaces in situ, using atomic force microscopy (AFM) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). AFM revealed previously unseen surface area enhancing nano-annuli exclusive to the sheath surface and confirmed greater adhesion forces exist between cationic surfaces and the sheath, when compared to the emergent L3 cuticle. Furthermore, ToF-SIMS elucidated different chemistries between the surfaces of the cuticle and sheath which could be of biological significance. For example, the phosphatidylglycerol rich cuticle surface may support the onward migration of a lubricated infective stage, while the anionic and potentially immunologically active heparan sulphate rich deposited sheath could result in the diversion of immune defences to an inanimate antigenic nidus. We propose that our initial studies into the surface analysis of this hookworm provides a timely insight into the physicochemical properties of a globally important human pathogen at its infective stage and anticipate that the development and application of this analytical methodology will support translation of these findings into a biological context.
Topics: Animals; Antigens, Helminth; Larva; Mass Spectrometry; Multivariate Analysis; Necator americanus
PubMed: 29216182
DOI: 10.1371/journal.pntd.0005971 -
The Lancet. Microbe Dec 2023Vaccine development against hookworm is hampered by the absence of the development of protective immunity in populations repeatedly exposed to hookworm, limiting... (Randomized Controlled Trial)
Randomized Controlled Trial
Protective efficacy of short-term infection with Necator americanus hookworm larvae in healthy volunteers in the Netherlands: a single-centre, placebo-controlled, randomised, controlled, phase 1 trial.
BACKGROUND
Vaccine development against hookworm is hampered by the absence of the development of protective immunity in populations repeatedly exposed to hookworm, limiting identification of mechanisms of protective immunity and new vaccine targets. Immunisation with attenuated larvae has proven effective in dogs and partial immunity has been achieved using an irradiated larvae model in healthy volunteers. We aimed to investigate the protective efficacy of immunisation with short-term larval infection against hookworm challenge.
METHODS
We did a single-centre, placebo-controlled, randomised, controlled, phase 1 trial at Leiden University Medical Center (Leiden, Netherlands). Healthy volunteers (aged 18-45 years) were recruited using advertisements on social media and in publicly accessible areas. Volunteers were randomly assigned (2:1) to receive three short-term infections with 50 infectious Necator americanus third-stage filariform larvae (50L3) or placebo. Infection was abrogated with a 3-day course of albendazole 400 mg, 2 weeks after each exposure. Subsequently all volunteers were challenged with two doses of 50L3 at a 2-week interval. The primary endpoint was egg load (geometric mean per g faeces) measured weekly between weeks 12 and 16 after first challenge, assessed in the per-protocol population, which included all randomly assigned volunteers with available data on egg counts at week 12-16 after challenge. This study is registered with ClinicalTrials.gov, NCT03702530.
FINDINGS
Between Nov 8 and Dec 14, 2018, 26 volunteers were screened, of whom 23 enrolled in the trial. The first immunisation was conducted on Dec 18, 2018. 23 volunteers were randomly assigned (15 to the intervention group and eight to the placebo group). Egg load after challenge was lower in the intervention group than the placebo group (geometric mean 571 eggs per g [range 372-992] vs 873 eggs per g [268-1484]); however, this difference was not statistically significant (p=0·10). Five volunteers in the intervention group developed a severe skin rash, which was associated with 40% reduction in egg counts after challenge (geometric mean 742 eggs per g [range 268-1484] vs 441 eggs per g [range 380-520] after challenge; p=0·0025) and associated with higher peak IgG1 titres.
INTERPRETATION
To our knowledge, this is the first study to describe a protective effect of short-term exposure to hookworm larvae and show an association with skin response, eosinophilic response, and IgG1. These findings could inform future hookworm vaccine development.
FUNDING
Dioraphte Foundation.
Topics: Humans; Animals; Dogs; Necator americanus; Healthy Volunteers; Netherlands; Hookworm Infections; Immunoglobulin G; Larva
PubMed: 38042152
DOI: 10.1016/S2666-5247(23)00218-5 -
Acta Tropica May 2017It is estimated that over a billion people are infected with soil-transmitted helminths (STHs) globally with majority occurring in tropical and subtropical regions of... (Review)
Review
It is estimated that over a billion people are infected with soil-transmitted helminths (STHs) globally with majority occurring in tropical and subtropical regions of the world. The roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura), and hookworms (Ancylostoma duodenale and Necator americanus) are the main species infecting people. These infections are mostly gained through exposure to faecally contaminated water, soil or contaminated food and with an increase in the risk of infections due to wastewater and sludge reuse in agriculture. Different methods have been developed for the detection and quantification of STHs eggs in environmental samples. However, there is a lack of a universally accepted technique which creates a challenge for comparative assessments of helminths egg concentrations both in different samples matrices as well as between locations. This review presents a comparison of reported methodologies for the detection of STHs eggs, an assessment of the relative performance of available detection methods and a discussion of new emerging techniques that could be applied for detection and quantification. It is based on a literature search using PubMed and Science Direct considering all geographical locations. Original research articles were selected based on their methodology and results sections. Methods reported in these articles were grouped into conventional, molecular and emerging techniques, the main steps in each method were then compared and discussed. The inclusion of a dissociation step aimed at detaching helminth eggs from particulate matter was found to improve the recovery of eggs. Additionally the selection and application of flotation solutions that take into account the relative densities of the eggs of different species of STHs also results in higher egg recovery. Generally the use of conventional methods was shown to be laborious and time consuming and prone to human error. The alternate use of nucleic acid-based techniques has improved the sensitivity of detection and made species specific identification possible. However, these nucleic acid based methods are expensive and less suitable in regions with limited resources and skill. The loop mediated isothermal amplification method shows promise for application in these settings due to its simplicity and use of basic equipment. In addition, the development of imaging soft-ware for the detection and quantification of STHs shows promise to further reduce human error associated with the analysis of environmental samples. It may be concluded that there is a need to comparatively assess the performance of different methods to determine their applicability in different settings as well as for use with different sample matrices (wastewater, sludge, compost, soil, vegetables etc.).
Topics: Ancylostoma; Animals; Ascaris lumbricoides; Feces; Helminthiasis; Helminths; Humans; Necator americanus; Soil; Trichuris; Wastewater
PubMed: 28214519
DOI: 10.1016/j.actatropica.2017.02.014 -
Parasites & Vectors Sep 2020An accurate understanding of the geographical distributions of both soil-transmitted helminths (STHs; Ascaris lumbricoides, Trichuris trichiura, and the hookworms...
BACKGROUND
An accurate understanding of the geographical distributions of both soil-transmitted helminths (STHs; Ascaris lumbricoides, Trichuris trichiura, and the hookworms Necator americanus and Ancylostoma duodenale) and schistosomes (SCH; Schistosoma mansoni and S. haematobium) is pivotal to be able to effectively design and implement mass drug administration (MDA) programmes. The objective of this study was to provide up-to-date data on the distribution of both STH and SCH in Ethiopia to inform the design of the national control program and to be able to efficiently achieve the 75% MDA coverage target set by the WHO.
METHODS
Between 2013 and 2015, we assessed the distributions of STH and SCH infections in a nationwide survey covering 153,238 school-aged children (aged 5-15 years), from 625 woredas (districts), representing all nine Regional States and two City Administrations of Ethiopia. Nationwide disease maps were developed at the woreda level to enable recommendations on the design of the national MDA programme.
RESULTS
The prevalence of any STH infection across the study population was 21.7%, with A. lumbricoides (12.8%) being the most prevalent STH, followed by hookworms (7.6%) and T. trichiura (5.9%). The prevalence for any SCH was 4.0% in areas where both SCH species were evaluated. Schistosoma mansoni was the most prevalent SCH (3.5 vs 0.3%). STHs were more prevalent in southwest Ethiopia, whereas SCH was found mostly in the west and northeast of the country. The prevalence of moderate-to-heavy intensity infections was 2.0% for STHs and 1.6% for SCH. For STH, a total of 251 woredas were classified as moderately (n = 178) or highly endemic (n = 73), and therefore qualify for an annual and biannual MDA program, respectively. For SCH, 67 woredas were classified as endemic and 8 as highly endemic, and hence they require every two years and annual MDA programme, respectively.
CONCLUSIONS
The results confirm that Ethiopia is endemic for both STHs and SCH, posing a significant public health problem. Following the WHO recommendations on mass drug administration, 18 and 14 million school-aged children are in need of MDA for STHs and SCH, respectively, based on the number of SACs that live on the eligible geographical areas.
Topics: Adolescent; Ancylostomatoidea; Animals; Anthelmintics; Ascaris lumbricoides; Child; Child, Preschool; Cross-Sectional Studies; Epidemiological Monitoring; Ethiopia; Female; Helminthiasis; Helminths; Humans; Male; Mass Drug Administration; Prevalence; Schistosoma haematobium; Schistosoma mansoni; Schistosomiasis; Schistosomiasis mansoni; Schools; Soil; Trichuris
PubMed: 32873333
DOI: 10.1186/s13071-020-04317-6 -
Philosophical Transactions of the Royal... Aug 2015Multiple recent investigations have highlighted the promise of helminth-based therapies for the treatment of inflammatory disorders of the intestinal tract of humans,... (Review)
Review
Multiple recent investigations have highlighted the promise of helminth-based therapies for the treatment of inflammatory disorders of the intestinal tract of humans, including inflammatory bowel disease and coeliac disease. However, the mechanisms by which helminths regulate immune responses, leading to the amelioration of symptoms of chronic inflammation are unknown. Given the pivotal roles of the intestinal microbiota in the pathogenesis of these disorders, it has been hypothesized that helminth-induced modifications of the gut commensal flora may be responsible for the therapeutic properties of gastrointestinal parasites. In this article, we review recent progress in the elucidation of host-parasite-microbiota interactions in both animal models of chronic inflammation and humans, and provide a working hypothesis of the role of the gut microbiota in helminth-induced suppression of inflammation.
Topics: Ancylostomatoidea; Animals; Celiac Disease; Disease Models, Animal; Gastrointestinal Microbiome; Helminths; Host-Parasite Interactions; Humans; Immunosuppression Therapy; Inflammation; Inflammatory Bowel Diseases; Trichuris
PubMed: 26150662
DOI: 10.1098/rstb.2014.0296 -
Scientific Reports Jan 2023Accurate diagnosis by precise identification of causative agents is essential for the effectiveness of any control interventions. Despite high zoonotic potential,...
Accurate diagnosis by precise identification of causative agents is essential for the effectiveness of any control interventions. Despite high zoonotic potential, available literature on hookworms in Bangladesh is still scarce and nonspecific. The objective of this study was to determine the occurrence of hookworms in public locations across northeastern Bangladesh (Sylhet metropolitan area) using integrated parasitological and molecular assays. A total of 130 samples (80 soil and 50 environmental canine feces) were collected and examined using modified flotation technique and formalin-ether sedimentation methods. Modified plate culture was used to isolate larvae. The identification was made based on morphometric features and confirmed by amplifying the ITS region of the nuclear rDNA. Overall, 66.2% (86/130) of examined samples were positive for hookworms infection. Characteristic eggs (61-68 × 29-37 μm) and/or larvae of hookworms were observed in 73.8% (59/80) soils and 54.0% (27/50) environmental fecal samples. Rhabditiform larvae (0.48-0.54 × 0.04-0.07 mm) were observed in cultured samples. Genetic analysis of rDNA sequences revealed the presence of Ancylostoma caninum and Ancylostoma ceylanicum. In this study, hookworms' contamination of the public environment was substantial. To the best of our knowledge, this is the first molecular proof of A. caninum and A. ceylanicum observed in urban public environment in Bangladesh.
Topics: Animals; Dogs; Ancylostomatoidea; Bangladesh; Hookworm Infections; Ancylostoma; Feces; DNA, Ribosomal; Soil; Larva; Dog Diseases
PubMed: 36599848
DOI: 10.1038/s41598-022-26813-8 -
British Medical Journal Nov 1964
Topics: Ancylostomatoidea; Ancylostomiasis; Anemia; Anemia, Hypochromic; Animals; Anthelmintics; Hookworm Infections; Humans; Iron; Tropical Medicine
PubMed: 14204532
DOI: No ID Found -
Current Opinion in Genetics &... Oct 1996Hookworms cause severe anemia and malnutrition in developing countries of the tropics, with an estimated one billion people infected worldwide. An in vitro system that... (Comparative Study)
Comparative Study Review
Hookworms cause severe anemia and malnutrition in developing countries of the tropics, with an estimated one billion people infected worldwide. An in vitro system that models the early events of infection has provided new information about the linkage between the infectious process and the parasite's developmental biology. The cloning and expression of Ancylostoma secreted protein, ASP 1 - a secreted molecule associated with these developmental processes - is an example of how this system allows us to dissect the infectious process at the molecular level.
Topics: Amino Acid Sequence; Ancylostoma; Ancylostomiasis; Animals; Helminth Proteins; Humans; Kinetics; Larva; Molecular Sequence Data; Sequence Homology, Amino Acid
PubMed: 8939719
DOI: 10.1016/s0959-437x(96)80092-x -
PloS One 2021IgE characterizes the humoral response of allergic sensitization but less is known about what modulates its function and why some patients present clinical symptoms for... (Observational Study)
Observational Study
BACKGROUND
IgE characterizes the humoral response of allergic sensitization but less is known about what modulates its function and why some patients present clinical symptoms for a given IgE level and others do not. An IgE response also occurs during helminth diseases, independently of allergic symptoms. This response could be a model of non-functional IgE.
OBJECTIVE
To study the IgE response against environmental allergens induced during natural helminth infection.
METHODS
In 28 non allergic subjects from the periphery of Ho Chi Minh city with (H+, n = 18) and without helminth infection (H-, n = 10), we measured IgE and IgG4 against several components of Dermatophagoïdes pteronyssinus (Dpt) and Ascaris (a marker of immunization against nematodes), and determined the IgE component sensitization profile using microarray ISAC biochips. The functional ability of IgE to induce degranulation of cultured mast cells was evaluated in the presence of Dpt.
RESULTS
Non allergic H+ subjects exhibited higher levels of IgE against Dpt compared to H- subjects. Dpt IgE were not functional in vitro and did not recognize usual Dpt major allergens. IgE recognized other component allergens that belong to different protein families, and most were glycosylated. Depletion of IgE recognizing carbohydrate cross-reactive determinant (CCD) did not induce a reduction in Dpt IgE. The Dpt IgG4 were not significantly different.
CONCLUSION
Helminth infections induced IgE against allergens such as Dpt and molecular components that belong to different sources as well as against CCD (such as β-1,2-xylose and/or ⍺-1,3-fucose substituted N-glycans). Dpt IgE were not able to induce degranulation of mast cells and were not explained by sensitization to usual major allergens or N-glycans.
Topics: Adolescent; Adult; Aged; Allergens; Ancylostomatoidea; Animals; Antigens, Dermatophagoides; Ascaris; Case-Control Studies; Cells, Cultured; Cross Reactions; Dermatophagoides pteronyssinus; Female; Healthy Volunteers; Humans; Immunoglobulin E; Male; Mast Cells; Middle Aged; Nematode Infections; Primary Cell Culture; Vietnam; Young Adult
PubMed: 34197505
DOI: 10.1371/journal.pone.0253887