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hookworm, ascaris lumbricoides infection and polyparasitism associated with poor cognitive performance in brazilian schoolchildren.to investigate the relationship between hookworm and ascaris lumbricoides infection and performance on three subsets of the wechsler intelligence scale for children - third edition (wisc-iii) (digit span, arithmetic and coding) and raven colored progressive matrices.200818627581
binding of excreted and/or secreted products of adult hookworms to human nk cells in necator americanus-infected individuals from brazil.the impact of the interaction between excreted and/or secreted (es) necator americanus products and nk cells from necator-infected individuals was analyzed. we investigated the binding of es products to nk cells, the expression of nk cell receptors (cd56, cd159a/nkg2a, cd314/nkg2d, cd335/nkp46, and klrf1/nkp80), the frequency of gamma interferon (ifn-gamma)-producing nk cells after whole-blood in vitro stimulation, and the capacity of n. americanus es products to induce nk cell chemotaxis. in co ...200818838519
improved insights into the transcriptomes of the human hookworm necator americanus--fundamental and biotechnological implications.hookworms of humans are blood-feeding parasitic nematodes of major socio-economic significance in a wide range of countries. they cause a neglected tropical disease (ntd) called "hookworm disease" (=necatoriasis and/or ancylostomiasis). necator americanus is the most widely distributed hookworm of humans and is a leading cause of iron deficiency anaemia, which can cause physical and mental retardation and deaths in children as well as adverse maternal-foetal outcomes. currently, there is a signi ...200918977428
spatial heterogeneity of parasite co-infection: determinants and geostatistical prediction at regional scales.multiple parasite infections are widespread in the developing world and understanding their geographical distribution is important for spatial targeting of differing intervention packages. we investigated the spatial epidemiology of mono- and co-infection with helminth parasites in east africa and developed a geostatistical model to predict infection risk. the data used for the analysis were taken from standardised school surveys of schistosoma mansoni and hookworm (ancylostoma duodenale/necator ...200919073189
geohelminth infection and re-infection after chemotherapy among slum-dwelling children in durban, south africa.the prevalences and intensities of ascaris lumbricoides, trichuris trichiura and hookworm (probably necator americanus) infection were measured in the young children (aged 2-10 years) living in 10 urban slums in durban, south africa. re-infection was assessed at 4-6 and 12 months post-treatment. the baseline prevalences of a. lumbricoides and t. trichiura were 81.7%-96.3% and 54.5%-86.2%, respectively, and the corresponding geometric mean intensities were 960 and 91 eggs/g faeces. most (85%) of ...200919341539
an enzymatically inactivated hemoglobinase from necator americanus induces neutralizing antibodies against multiple hookworm species and protects dogs against heterologous hookworm infection.hookworms digest hemoglobin from erythrocytes via a proteolytic cascade that begins with the aspartic protease, apr-1. ac-apr-1 from the dog hookworm, ancylostoma caninum, protects dogs against hookworm infection via antibodies that neutralize enzymatic activity and interrupt blood-feeding. toward developing a human hookworm vaccine, we expressed both wild-type (na-apr-1(wt)) and mutant (na-apr-1(mut)-mutagenesis of the catalytic aspartic acids) forms of na-apr-1 from the human hookworm, necator ...200919380510
coinfections with schistosoma haematobium, necator americanus, and entamoeba histolytica/entamoeba dispar in children: chemokine and cytokine responses and changes after antiparasite treatment.the effect of polyparasite infections on cytokine and chemokine responses as well as the effect of antiparasite treatment was studied in children without parasite infection (the g0 group), in children singly infected with schistosoma haematobium (the g1 group), and in children multiply infected with s. haematobium/schistosoma mansoni, entamoeba histolytica/entamoeba dispar, and necator americanus (the g3+ group). linear regression analysis disclosed a significant risk for coinfection with hookwo ...200919392635
case of creeping disease treated with ivermectin.we report a case of creeping disease treated successfully with ivermectin. a 46-year-old man presented with a 1-month history of pruriginous linear erythema on his right thigh after a visit to indonesia. although he had no history of eating raw fish or meat, he walked along the river and in the jungle without wearing shoes. creeping disease caused by animal hookworm was strongly suspected. the presence of parasite larvae was not confirmed in biopsied skin specimens. in enzyme-linked immunosorben ...200919284451
[relevance of helminths in the prevention and healing of immune diseases].the incidence of immune diseases has had a steady significant increase in the industrialized countries since the end of the last century. epidemiological data suggest that prevention of exposure to helminths may be one of the factors promoting the rise in these diseases. animal models of immune diseases support this concept by showing that these parasites can prevent and reverse developed diseases. helminths strongly modulate the host's immune system inducing regulatory immune cells and pathways ...200919418721
proteolytic degradation of hemoglobin in the intestine of the human hookworm necator americanus.blood-feeding parasites use mechanistically distinct proteases to digest hemoglobin (hb), often as multienzyme cooperative cascades. we investigated the roles played by 3 distinct proteases from adults of the human hookworm necator americanus. the aspartic protease na-apr-1 and the cysteine protease na-cp-3 were expressed in catalytically active form in yeast, and the metalloprotease na-mep-1 was expressed in catalytically active form in baculovirus. antibodies to all 3 proteases were used to im ...200919434933
identification of the nuclear receptor daf-12 as a therapeutic target in parasitic nematodes.nematode parasitism is a worldwide health problem resulting in malnutrition and morbidity in over 1 billion people. the molecular mechanisms governing infection are poorly understood. here, we report that an evolutionarily conserved nuclear hormone receptor signaling pathway governs development of the stage 3 infective larvae (il3) in several nematode parasites, including strongyloides stercoralis, ancylostoma spp., and necator americanus. as in the free-living caenorhabditis elegans, steroid ho ...200919497877
systems metabolic effects of a necator americanus infection in syrian hamster.hookworms (ancylostoma duodenale and necator americanus) are blood-feeding intestinal nematodes that infect approximately 700 million people worldwide. to further our understanding of the systems metabolic response of the mammalian host to hookworm infection, we employed a metabolic profiling strategy involving the combination of (1)h nmr spectroscopic analysis of urine and serum and multivariate data analysis techniques to investigate the biochemical consequences of a n. americanus infection in ...200919810771
immunologic profiles of persons recruited for a randomized, placebo-controlled clinical trial of hookworm infection.data from epidemiologic studies suggest that hookworm infections, in establishing an immunologic phenotype conducive to parasite survival, may protect against the development of allergic disease. we describe immunologic findings from a clinical study designed to investigate the safety of iatrogenic hookworm infection in participants with allergic rhinitis. the low, relatively safe level of hookworm infection used in this study was immunogenic, inducing eosinophilia and a significant specific igg ...200919861631
antigen-driven basophil activation is indicative of early necator americanus infection in ige-seronegative patients.parasitic worms induce a strong, polarized t(h)2-type immune response. the kinetics of gastrointestinal nematode-induced t(h)2-type responses, especially in the context of primary infection, have been extensively studied in experimental infection models but not in human subjects.200919800679
dose-response assay templates for in vitro assessment of resistance to benzimidazole and nicotinic acetylcholine receptor agonist drugs in human hookworms.with the implementation of mass drug administration programs for the control of human hookworms, there is a need to monitor for the emergence of drug resistance. we have therefore examined in vitro assays for monitoring sensitivity to benzimidazoles (egg hatch assay) and nicotinic acetylcholine receptor agonist drugs (motility and morphology assays), with a view to developing tools for monitoring drug sensitivity in the field. we have performed assays with necator americanus and ancylostoma ceyl ...200919556583
an update on the use of helminths to treat crohn's and other autoimmunune diseases.this review updates our previous one (reddy and fried, parasitol research 100: 921-927, 2007) on crohn's disease and helminths. the review considers the most recent literature on trichuris suis therapy and crohn's and the significant literature on the use of necator americanus larvae to treat crohn's and other autoimmune disorders. the pros and cons of helminth therapy as related to autoimmune disorders are discussed in the review. we also discuss the relationship of the bacterium campylobacter ...200919050918
anthelmintic activity of cyclotides: in vitro studies with canine and human hookworms.hookworm infection is a leading cause of maternal and child morbidity in countries of the tropics and subtropics, as well as being an important parasite in companion-animal medicine. the cyclotides are a novel family of cyclic cystine knot containing peptides from plants that have been shown to possess anthelmintic activity against haemonchus contortus and trichostrongylus colubriformis, two important gastrointestinal nematodes of sheep. in the current study we demonstrated the in vitro effects ...200919059189
necator americanus infection: a possible cause of altered dendritic cell differentiation and eosinophil profile in chronically infected individuals.hookworms survive for several years (5 to 7 years) in the host lumen, inducing a robust but largely ineffective immune response. among the most striking aspects of the immune response to hookworm (as with many other helminths) is the ablation of parasite-specific t cell proliferative response (hyporesponsiveness). while the role of the adaptive immune response in human helminth infection has been well investigated, the role of the innate immune responses (e.g., dendritic cells and eosinophils) h ...200919308259
metabolic alterations in the hamster co-infected with schistosoma japonicum and necator americanus.co-infection with hookworm and schistosomes is a common phenomenon in sub-saharan africa, as well as in parts of south america and southeast asia. as a first step towards understanding the metabolic response of a hookworm-schistosome co-infection in humans, we investigated the metabolic consequences of co-infection in an animal model, using a nuclear magnetic resonance (nmr)-based metabolic profiling technique, combined with multivariate statistical analysis. urine and serum samples were obtaine ...201019951707
nutritional status, body composition, and intestinal parasitism among the mbyá-guaraní communities of misiones, argentina.indigenous communities in argentina represent socially and economically neglected populations. they are living in extreme poverty and environmental degradation conditions. new information about health status and socio-environmental features is urgently needed to be applied in future sanitary policies. present study describes the nutritional status, body composition, and intestinal parasitism among mbyá-guaraní children from three communities in the misiones province. anthropometric parameters we ...201019642206
human helminth co-infection: no evidence of common genetic control of hookworm and schistosoma mansoni infection intensity in a brazilian community.strong statistical associations between soil-transmitted helminths and schistosomes are frequently observed in co-endemic human populations, although the underlying explanations remain poorly understood. this study investigates the contribution of host genetics and domestic environment to hookworm and schistosoma mansoni infection intensity and evaluates the role of genetic and non-genetic factors in co-variation of infection intensity. detailed genealogical information allowed assignment of 130 ...201019699204
copro-molecular identification of infections with hookworm eggs in rural lao pdr.the prevalence of hookworm eggs in fecal samples, by modified cellophane thick-smear technique, was found to be 30.0% (61/203 samples) in lahanam village, savannakhet province, lao pdr. the hookworm eggs were morphologically heterogeneous, so that identification was confirmed by copro-pcr with specific primers for hookworms and trichostrongylus spp.; 12 samples were positive for necator americanus, 19 for ancylostoma spp., with one mixed infection of both. sequencing of the ancylostoma spp. copr ...201020673938
massively parallel sequencing and analysis of the necator americanus transcriptome.the blood-feeding hookworm necator americanus infects hundreds of millions of people worldwide. in order to elucidate fundamental molecular biological aspects of this hookworm, the transcriptome of the adult stage of necator americanus was explored using next-generation sequencing and bioinformatic analyses.201020485481
hyperendemic h. pylori and tapeworm infections in a u.s.-mexico border population.a higher incidence of infectious disease has been documented in u.s. regions bordering mexico compared with non-border areas. we assessed the prevalence of important gastrointestinal infections in ciudad juarez, mexico, and el paso, texas, the largest binational community along the u.s.-mexico border.201020433039
alterations in the expression level of a putative aspartic protease in the development of angiostrongylus cantonensis.aspartic proteases are a family of proteinases with catalytic aspartate residues in the active site. these enzymes have been reported to initialize the degradation of host hemoglobin in blood-feeding helminths. after identifying an expressed sequence tag representing an aspartic protease from an angiostrongylus cantonensis young adult dataset, this sequence was found to encode a protein with a predicted molecular mass of 46 kda. it also showed good homologies to aspartic proteases from caenorhab ...201019945419
neutralizing antibodies to the hookworm hemoglobinase na-apr-1: implications for a multivalent vaccine against hookworm infection and schistosomiasis.the aspartic protease of necator americanus, na-apr-1, is a vaccine antigen that induces antibodies that neutralize hemoglobin proteolysis in the gut of the worm. to define the epitopes recognized by these antibodies, monoclonal antibodies (mabs) were raised and assessed for neutralizing activity. three immunoglobulin (ig) g1 mabs bound to the intestine of n. americanus and inhibited na-apr-1 enzymatic activity. overlapping fragments of na-apr-1 were expressed, and one (apr-1/5b) was recognized ...201020367477
a case of severe anemia by necator americanus infection in korea.this report describes clinical and parasitological findings of an 82-yr-old female patient who lived in a local rural village and suffered from severe chronic anemia for several years. she was transferred to the national police hospital in seoul for management of severe dyspnea and dizziness. at admission, she showed symptoms or signs of severe anemia. gastroduodenoscopy observed hyperemic mucosa of the duodenum and discovered numerous moving roundworms on the mucosa. endoscopy isolated seven of ...201021165298
hookworm (necator americanus) larval enzymes disrupt human vascular endothelium.knowledge of the molecular mechanisms used by necator americanus larvae to penetrate the human skin and the vasculature would aid the development of effective vaccines against this important pathogen. in this work, the impact of n. americanus exsheathing fluid (ef) and excretory/secretory products (es) on the endothelial barrier was examined using human umbilical vein endothelial cells (huvec). cellular responses were assessed by investigating molecular changes at cell-cell junctions and by dete ...201020810819
experimental hookworm infection: a randomized placebo-controlled trial in asthma.epidemiological studies suggest that hookworm infection protects against asthma, and therefore that hookworm infection may have a direct or an indirect therapeutic potential in this disease. we now report the first clinical trial of experimental hookworm infection in people with allergic asthma.201020030661
crystallization and preliminary x-ray analysis of na-saa-2 from the human hookworm parasite necator americanus.human hookworms are among the most pathogenic soil-transmitted helminths. these parasitic nematodes have co-evolved with the host and are able to maintain a high worm burden for decades without killing the human host. however, it is possible to develop vaccines against laboratory-challenge hookworm infections using either irradiated third-state infective larvae (l3) or enzymes from the adult parasites. in an effort to control hookworm infection globally, the human hookworm vaccine initiative, a ...201020124715
molecular cloning, biochemical characterization, and partial protective immunity of the heme-binding glutathione s-transferases from the human hookworm necator americanus.hookworm glutathione s-transferases (gsts) are critical for parasite blood feeding and survival and represent potential targets for vaccination. three cdnas, each encoding a full-length gst protein from the human hookworm necator americanus (and designated na-gst-1, na-gst-2, and na-gst-3, respectively) were isolated from cdna based on their sequence similarity to ac-gst-1, a gst from the dog hookworm ancylostoma caninum. the open reading frames of the three n. americanus gsts each contain 206 a ...201020145100
potency testing for the experimental na-gst-1 hookworm vaccine.over the next decade, a new generation of vaccines will target the neglected tropical diseases (ntds). the goal of most ntd vaccines will be to reduce the morbidity and decrease the chronic debilitating nature of these often-forgotten infections – outcomes that are hard to measure in the traditional potency testing paradigm. the absence of measurable correlates of protection, a lack of permissive animal models for lethal infection, and a lack of clinical indications that do not include th ...201020923271
the effect of tribendimidine and its metabolites against necator americanus in golden hamsters and nippostrongylus braziliensis in rats.the antinematode effect of tribendimidine (tbd) and its metabolites has been studied. a total of 107 hamsters were each infected with 250 necator americanus third stage infective larvae (nal3) for 25 days. in the first test, 75 hamsters were divided equally into 15 groups for determination of ed(50) and ed(90.) among them, five groups were treated orally with tbd or its metabolite, p-(1-dimethylamino ethylimino)aniline (aminoamidine, deacylated amidantel, bay d 9216, dadt), at single doses of 1, ...201020155372
advances in metabolic profiling of experimental nematode and trematode infections.metabonomics, which is the combination of metabolic profiling of biological samples using spectroscopic methods, together with multivariate data analysis, is a powerful approach for biomarker recovery. moreover, metabonomics holds promise to enhance our understanding of host-parasite interactions at the metabolic level, and therefore provides a framework for discovery of novel targets for diagnostics, drugs and vaccines. in this review, we summarise progress made to date with metabolic profiling ...201020627148
developing vaccines to combat hookworm infection and intestinal schistosomiasis.hookworm infection and schistosomiasis rank among the most important health problems in developing countries. both cause anaemia and malnutrition, and schistosomiasis also results in substantial intestinal, liver and genitourinary pathology. in sub-saharan africa and brazil, co-infections with the hookworm, necator americanus, and the intestinal schistosome, schistosoma mansoni, are common. the development of vaccines for these infections could substantially reduce the global disability associat ...201020948553
short report: human trichostrongylus colubriformis infection in a rural village in laos.in lahanam village, savannakhet province, laos, 125 of 253 villagers (49.4%) were found by fecal examination to harbor hookworm eggs. the eggs were heterogeneous in morphology and size, suggesting infections of mixed nematode species. to confirm the hookworm egg species, on a voluntary basis, 46 hookworm egg-positive participants were treated with albendazole, and post-treatment adult worms were collected from purged fecal samples. the common human hookworm was found in only 3 participants; 1 ca ...201121212201
incidence and risk factors of hookworm infection in a rural community of central thailand.a cohort study to identify incidence and risk factors of hookworm infection was conducted in a rural community, central thailand from november 2005 to february 2007. stool specimens were examined for hookworm eggs using wet preparation, kato thick smear, and water-ethyl acetate sedimentation technique. the incidence rate of hookworm infection was 7.5/100 person-years. the independent risk factors for acquiring hookworm infection were barefoot walking (incidence rate ratio [irr] = 4.2, 95% confid ...201121460016
assessment of the anthelmintic efficacy of albendazole in school children in seven countries where soil-transmitted helminths are endemic.the three major soil-transmitted helminths (sth) ascaris lumbricoides, trichuris trichiura and necator americanus/ancylostoma duodenale are among the most widespread parasites worldwide. despite the global expansion of preventive anthelmintic treatment, standard operating procedures to monitor anthelmintic drug efficacy are lacking. the objective of this study, therefore, was to define the efficacy of a single 400 milligram dose of albendazole (alb) against these three sth using a standardized p ...201121468309
[one case with mixed infection of giardia lamblia, clonorchis sinensis, and necator americanus]. 201121972592
Necator americanus and helminth co-infections: further down-modulation of hookworm-specific type 1 immune responses.Helminth co-infection in humans is common in tropical regions of the world where transmission of soil-transmitted helminths such as Ascaris lumbricoides, Trichuris trichiura, and the hookworms Necator americanus and Ancylostoma duodenale as well as other helminths such as Schistosoma mansoni often occur simultaneously.201121909439
[Aetiology of intestinal parasites in a sample of students from Mozambique].The purpose of this survey is to assess the prevalence of intestinal parasites in a population of Mozambican students. Ninety five faecal samples were collected at the three schools in Marrere, Mozambique, for a period of about one week. Observations of fresh and Giemsa-stained samples were performed at the laboratory of the Geral de Marrere Hospital; observation after concentration (FEA) was performed later at the Microbiology Laboratory of the S. Maria Nuova Hospital (Reggio Emilia, Italy). Th ...201122037436
a history of hookworm vaccine development.the human hookworms necator americanus and ancylostoma duodenale remain among the most common infections of humans in areas of rural poverty in the developing regions of the world, with an estimated 1 billion people infected with one or more of these parasites. herein, we review the nearly 100 years of research, development, animal testing, and fieldwork that have led to our current progress in recombinant hookworm vaccines. we begin with the identification of hookworm at the start of the 20th c ...201122064562
structure of a two-cap-domain protein from the human hookworm parasite necator americanus.major proteins secreted by the infective larval stage hookworms upon host entry include ancylostoma secreted proteins (asps), which are characterized by one or two cap (cysteine-rich secretory protein/antigen 5/pathogenesis related-1) domains. the cap domain has been reported in diverse phylogenetically unrelated proteins, but has no confirmed function. the first structure of a two-cap-domain protein, na-asp-1, from the major human hookworm parasite necator americanus was refined to a resolution ...201121543848
the effect of egg embryonation on field-use of a hookworm benzimidazole-sensitivity egg hatch assay in yunnan province, people's republic of china.current efforts to control human soil-transmitted helminths (sths) involve the periodic mass administration of benzimidazole drugs to school aged children and other at- risk groups. given that high levels of resistance to these drugs have developed in roundworms of livestock, there is a need to monitor drug efficacy in human sths. the current study aimed to evaluate an in vitro egg hatch assay for measuring the sensitivity of human hookworms to benzimidazole drugs in an isolated field setting in ...201121738805
prevention of soil-transmitted helminth infection.soil-transmitted helminths (sths) form one of the most important groups of infectious agents and are the cause of serious global health problems. the most important sths are roundworms (ascaris lumbricoides), whipworms (trichuris trichiura) and hookworms (necator americanus or ancylostoma duodenale); on a global level, more than a billion people have been infected by at least one species of this group of pathogens. this review explores the general concepts of transmission dynamics and the enviro ...201121731306
suppression of inflammatory immune responses in celiac disease by experimental hookworm infection.we present immunological data from two clinical trials where the effect of experimental human hookworm (necator americanus) infection on the pathology of celiac disease was evaluated. we found that basal production of interferon- (ifn-)γ and interleukin- (il-)17a from duodenal biopsy culture was suppressed in hookworm-infected participants compared to uninfected controls. increased levels of cd4+cd25+foxp3+ cells in the circulation and mucosa are associated with active celiac disease. we show th ...201121949691
is anthelmintic resistance a concern for the control of human soil-transmitted helminths?the major human soil-transmitted helminths (sth), ascaris lumbricoides, hookworms (necator americanus and ancylostoma duodenale) and trichuris trichiura have a marked impact on human health in many parts of the world. current efforts to control these parasites rely predominantly on periodic mass administration of anthelmintic drugs to school age children and other at-risk groups. after many years of use of these same drugs for controlling roundworms in livestock, high levels of resistance have d ...201124533260
effect of hookworm infection on wheat challenge in celiac disease--a randomised double-blinded placebo controlled trial.the association between hygiene and prevalence of autoimmune disease has been attributed in part to enteric helminth infection. a pilot study of experimental infection with the hookworm necator americanus was undertaken among a group of otherwise healthy people with celiac disease to test the potential of the helminth to suppress the immunopathology induced by gluten.201121408161
high throughput multiplex pcr and probe-based detection with luminex beads for seven intestinal parasites.polymerase chain reaction (pcr) assays for intestinal parasites are increasingly being used on fecal dna samples for enhanced specificity and sensitivity of detection. comparison of these tests against microscopy and copro-antigen detection has been favorable, and substitution of pcr-based assays for the ova and parasite stool examination is a foreseeable goal for the near future. one challenge is the diverse list of protozoan and helminth parasites. several existing real-time pcr assays for the ...201121292910
a pentaplex real-time polymerase chain reaction assay for detection of four species of soil-transmitted helminths.soil-transmitted helminth infections remain a major public health burden in low- and middle-income countries. the traditional diagnosis by microscopic examination of fecal samples is insensitive and time-consuming. in this study, a pentaplex real-time polymerase chain reaction (pcr) was evaluated for the simultaneous detection of ancylostoma, necator americanus, ascaris lumbricoides, and strongyloides stercoralis. the results were compared with those obtained by conventional parasitological diag ...201121292911
bugs as drugs, part two: worms, leeches, scorpions, snails, ticks, centipedes, and spiders.in this second of a two-part series analyzing the evidence for the use of organisms as medicine, the use of a number of different "bugs" (worms, leeches, snails, ticks, centipedes, and spiders) is detailed. several live organisms are used as treatments: leeches for plastic surgery and osteoarthritis and the helminths trichuris suis and necator americanus for inflammatory bowel disease. leech saliva is the source of a number of anticoagulants, including the antithrombin agent hirudin and its synt ...201121438646
proteases in blood-feeding nematodes and their potential as vaccine candidates.parasitic nematodes express and secrete a variety of proteases which they use for many purposes including the penetration of host tissues, digestion of host protein for nutrients, evasion of host immune responses and for internal processes such as tissue catabolism and apoptosis. for these broad reasons they have been examined as possible parasite control targets. blood-feeding nematodes such as the barber-pole worm haemonchus contortus that infect sheep and goats and the hookworms, ancylostoma ...201121660664
in vitro and in vivo efficacy of monepantel (aad 1566) against laboratory models of human intestinal nematode infections.few effective drugs are available for soil-transmitted helminthiases and drug resistance is of concern. in the present work, we tested the efficacy of the veterinary drug monepantel, a potential drug development candidate compared to standard drugs in vitro and in parasite-rodent models of relevance to human soil-transmitted helminthiases.201122216366
hookworm virulence factors: making the most of the host.hookworm disease from necator americanus and ancylostoma duodenale affects approximately 700 million people, with n. americanus being the predominant species. unlike other pathogens (e.g., bacterial infections), where "virulence" is described in regards to acute pathogenesis and case-fatality, hookworms are well-evolved, multicellular parasites that establish long-term infections in their human hosts with a subtle and chronic, but insidious, pathogenesis, usually in the form of iron deficiency a ...201223006854
[investigation on spread and hazards of human parasites in qushui village, suixi county, zhanjiang city].to understand the transmission of human parasites in qushui village, yangqing town, suixi county, zhanjing city, guangdong province.201223236799
real-time pcr demonstrates ancylostoma duodenale is a key factor in the etiology of severe anemia and iron deficiency in malawian pre-school children.hookworm infections are an important cause of (severe) anemia and iron deficiency in children in the tropics. type of hookworm species (ancylostoma duodenale or necator americanus) and infection load are considered associated with disease burden, although these parameters are rarely assessed due to limitations of currently used diagnostic methods. using multiplex real-time pcr, we evaluated hookworm species-specific prevalence, infection load and their contribution towards severe anemia and iron ...201222514750
overt gastrointestinal bleeding because of hookworm infection.hookworm infection is a relatively common cause of anemia in endemic areas. the most common hookworm species are ancylostoma duodenale and necator americanus. in this report we present a case of overt gastrointestinal bleeding because of hookworm infection. capsule endoscopy revealed many hookworms in the lumen of proximal jejunum where active bleeding was seen. the patient was successfully treated with albendazole.201222449530
application of a real-time pcr method for detecting and monitoring hookworm necator americanus infections in southern china.to develop a quantitative pcr method for detecting hookworm infection and quantification.201223593570
peptide-based subunit vaccine against hookworm infection.hookworms infect more people than hiv and malaria combined, predominantly in third world countries. treatment of infection with chemotherapy can have limited efficacy and re-infections after treatment are common. heavy infection often leads to debilitating diseases. all these factors suggest an urgent need for development of vaccine. in an attempt to develop a vaccine targeting the major human hookworm, necator americanus, a b-cell peptide epitope was chosen from the apical enzyme in the hemoglo ...201223056500
molecular identification of human hookworm infections in economically disadvantaged communities in peninsular malaysia.species identification of human hookworm infections among eight communities in rural areas of peninsular malaysia was determined during 2009-2011. fecal samples were examined by microscopy and subsequently, the internal transcribed spacer 2 and 28s ribosomal rna region of necator americanus and ancylostoma spp. were sequenced. overall, 9.1% (58 of 634) were identified positive by microscopy for hookworm infection, and 47 (81.0%) of 58 were successfully amplified and sequenced. sequence compariso ...201222556084
soil-transmitted helminthiasis in laos: a community-wide cross-sectional study of humans and dogs in a mass drug administration environment.we conducted a community cross-sectional survey of soil-transmitted helminthiasis in humans and dogs in four provinces in northern laos. we collected and tested human and dog fecal samples and analyzed results against sociodemographic data. the prevalence of ascaris lumbricoides, trichuris trichiura, hookworm, and strongyloides stercoralis was 26.1% (95% confidence interval [ci] = 23.7-28.4%), 41.5% (95% ci = 38.8-44.1%), 46.3% (95% ci = 43.3-49.0%), and 8.9% (95% ci = 7.4-10.4%), respectively. ...201222492147
Acquired hookworm immunity in the golden hamster (Mesocricetus auratus) elicited by living Necator americanus third-stage infective larvae.The aim of the study is to demonstrate and understand the acquired immunity in golden hamsters (Mesocricetus auratus) elicited by primary Necator americanus infective third-stage larvae (L3) infection. Hamsters infected with 150 L3 for 1, 2, 3, 6 and 10weeks, were challenged with the same number of L3 and sacrificed 25days post challenge. The primarily infected hamsters exhibited 99-100% protection against subsequent L3 challenge compared to un-infected naive hamsters. The acquired immunity was ...201222024448
Non-dietary therapeutic clinical trials in coeliac disease.Coeliac disease is a permanent immunological intolerance to gluten proteins in genetically predisposed individuals. The only management is life-long strict adherence to a gluten-free diet. Unfortunately, compliance with gluten-free diet is very difficult in practice due to the widespread presence of gluten in Western diets. For this reason, about 50% of coeliacs following a gluten-free diet continue to suffer from symptoms and present with autoantibodies and/or villous atrophy while on a gluten- ...201222153524
rapid detection and identification of human hookworm infections through high resolution melting (hrm) analysis.hookworm infections are still endemic in low and middle income tropical countries with greater impact on the socioeconomic and public health of the bottom billion of the world's poorest people. in this study, a real-time polymerase chain reaction (pcr) coupled with high resolution melting-curve (hrm) analysis was evaluated for an accurate, rapid and sensitive tool for species identification focusing on the five human hookworm species.201222844538
epidemiological and genetic data supporting the transmission of ancylostoma ceylanicum among human and domestic animals.currently, information on species-specific hookworm infection is unavailable in malaysia and is restricted worldwide due to limited application of molecular diagnostic tools. given the importance of accurate identification of hookworms, this study was conducted as part of an ongoing molecular epidemiological investigation aimed at providing the first documented data on species-specific hookworm infection, associated risk factors and the role of domestic animals as reservoirs for hookworm infecti ...201222347515
sequence conservation in the ancylostoma secreted protein-2 of necator americanus (na-asp-2) from hookworm infected individuals in thailand.the ancylostoma secreted protein-2 of necator americanus (na-asp-2) was one of the promising vaccine candidates against the most prevalent human hookworm species as adverse vaccine reaction has compromised further human vaccine trials. to elucidate the gene structure and the extent of sequence diversity, we determined the complete nucleotide sequence of the na-asp-2 gene of individual larvae from 32 infected subjects living in 3 different endemic areas of thailand. sequence analysis revealed tha ...201222964044
malaria and helminthic co-infection among hiv-positive pregnant women: prevalence and effects of antiretroviral therapy.the impact of malaria on anemia and the interplay with helminths underline the importance of addressing the interactions between hiv/aids, malaria and intestinal helminth infections in pregnancy. the aim of this study was to determine the prevalence of malaria-helminth dual infections among hiv positive pregnant mothers after 12 months of art. a cross sectional study was conducted on intestinal helminths and malaria dual infections among hiv-positive pregnant women attending antenatal health cen ...201222940013
determining soil-transmitted helminth infection status and physical fitness of school-aged children.soil-transmitted helminth (sth) infections are common. indeed, more than 1 billion people are affected, mainly in the developing world where poverty prevails and hygiene behavior, water supply, and sanitation are often deficient. ascaris lumbricoides, trichuris trichiura, and the two hookworm species, ancylostoma duodenale and necator americanus, are the most prevalent sths. the estimated global burden due to hookworm disease, ascariasis, and trichuriasis is 22.1, 10.5, and 6.4 million disabilit ...201222951972
fusion of na-asp-2 with human immunoglobulin fcγ abrogates histamine release from basophils sensitized with anti-na-asp-2 ige.na-asp-2 is a major protein secreted by infective third-stage larvae (l3) of the human hookworm necator americanus upon host entry. it was chosen as a lead vaccine candidate for its ability to elicit protective immune responses. however, clinical development of this antigen as a recombinant vaccine was halted because it caused allergic reactions among some of human volunteers previously infected with n. americanus. to prevent ige-mediated allergic reactions induced by na-asp-2 but keep its immun ...201222651670
generalized urticaria induced by the na-asp-2 hookworm vaccine: implications for the development of vaccines against helminths.necator americanus ancylostoma-secreted protein 2 (na-asp-2) is secreted by infective hookworm larvae on entry into human hosts. vaccination of laboratory animals with recombinant na-asp-2 provides significant protection against challenge infections. in endemic areas antibodies to na-asp-2 are associated with reduced risk of heavy n americanus infections.201222633322
helminth therapy (worms) for allergic rhinitis.allergic rhinitis is a disorder of the nasal membranes and surrounding tissues, and a worldwide cause of illness and disability. helminths are complex tissue-dwelling or lumen-dwelling organisms that inhabit larger organisms and are frequently asymptomatic. helminths modulate the natural immune responses of their human hosts, and may prevent or cure immune-mediated or allergic diseases (e.g. allergic rhinitis) in the host. non-randomised studies support this hypothesis.201222513973
where are we on worms?there is something about living in an industrialized country that dramatically increases the risk of acquiring inflammatory bowel disease (ibd). loss of routine exposure to parasitic worms (helminths), due to modern highly hygienic life styles, likely contributes to this risk. this article reviews current understanding on how helminths influence intestinal inflammation and mucosal immune responses.201223079675
modelling the ecological niche of hookworm in brazil based on climate.the distribution of hookworm in schistosomiasis-endemic areas in brazil was mapped based on climate suitability. known biological requirements of hookworm were fitted to data in a monthly long-term normal climate grid (18 x 18 km) using geographical information systems. hookworm risk models were produced using the growing degree day (gdd) water budget (wb) concept. a moisture-adjusted model (ma-gdd) was developed based on accumulation of monthly temperatures above a base temperature of 15 °c (be ...201223032277
two crystal forms of a helix-rich fatty acid- and retinol-binding protein, na-far-1, from the parasitic nematode necator americanus.na-far-1 is an unusual α-helix-rich fatty acid- and retinol-binding protein from necator americanus, a blood-feeding intestinal parasitic nematode of humans. it belongs to the far protein family, which is unique to nematodes; no structural information is available to date for far proteins from parasites. crystals were obtained with two different morphologies that corresponded to different space groups. crystal form 1 exhibited space group p432 (unit-cell parameters a = b = c = 120.80 å, α = β = ...201222750878
expression, purification, and molecular analysis of the necator americanus glutathione s-transferase 1 (na-gst-1): a production process developed for a lead candidate recombinant hookworm vaccine antigen.the enzyme necator americanus glutathione s-transferase 1 (na-gst-1) belongs to a unique nu class of gsts and is a lead candidate antigen in a bivalent human hookworm vaccine. here we describe the expression of na-gst-1 in the yeast pichia pastoris at the 20 l manufacturing scale and its purification process performed by three chromatographic steps, comprised of a q sepharose xl anion exchange column, followed by a butyl sepharose hp hydrophobic affinity column and a superdex 75 size-exclusion c ...201222503665
advances in vaccines against neglected tropical diseases: enhancing physical stability of a recombinant hookworm vaccine through biophysical and formulation studies.a bivalent recombinant vaccine for human hookworm disease is under development. one of the lead candidate antigens in the vaccine is a glutathione s-transferase cloned from the hookworm necator americanus (na-gst-1) which is expressed in the yeast pichia pastoris. based on preliminary studies demonstrating that the recombinant protein was not stable in an acetate buffer at ph 6, we undertook an extensive stability analysis of the molecule. to improve and optimize stability we complemented tradit ...201222495115
changed gluten immunity in celiac disease by necator americanus provides new insights into autoimmunity.we recently completed clinical trials in people with diet-treated celiac disease who were purposefully infected with the ubiquitous human hookworm, necator americanus. hookworm infection elicited not only parasite-specific immunity but also modified the host's immune response to gluten. after infection, mucosal il-1β and il-22 responses were enhanced, but ifnγ and il-17a levels and circulating regulatory t cells following gluten challenge were suppressed, and the adaptive response to gluten acqu ...201323291460
parasitic infections and immune function: effect of helminth infections in a malaria endemic area.according to the hygiene hypothesis, reduced exposure to infections could explain the rise of atopic diseases in high-income countries. helminths are hypothesised to alter the host's immune response in order to avoid elimination and, as a consequence, also reduce the host responsiveness to potential allergens. to elucidate the effect of current helminth infections on immune responsiveness in humans, we measured cytokine production in a rural ghanaian population in an area with multiple endemic p ...201322999162
hookworm infection among school age children in kintampo north municipality, ghana: nutritional risk factors and response to albendazole treatment.children (n = 812) 6-11 years of age attending 16 schools in the kintampo north municipality of ghana were screened for participation in a study on hookworm infection, nutrition, and response to albendazole. the prevalence of necator americanus hookworm infection (n = 286) was 39.1%, and significant predictors of infection included age, malaria parasitemia, lack of health care, school area, levels of antibodies against hookworm, and low consumption of animal foods. the cure rate after a single d ...201323836564
prerequisites for the pharmaceutical industry to develop and commercialise helminths and helminth-derived product therapy.during the past 10 years, immunologists, epidemiologists and parasitologists have made many new exciting discoveries in the field of helminth-mediated immune regulation. in addition, many animal experiments have shown that certain helminths or products derived from helminths can protect mice from developing allergic or autoimmune disease. some clinical trials utilising trichuris suis or necator americanus for the treatment of allergic disorders and inflammatory bowel disease have been conducted. ...201323291462
translatability of helminth therapy in inflammatory bowel diseases.modern hygienic lifestyles are associated with the emergence of inflammatory bowel disease (ibd) which now afflicts millions of people in highly-developed countries. meticulous hygiene interrupts conduits of transmission required for ubiquitous exposure to parasitic worms (helminths). we proposed that loss of exposure to helminths permits development of ibd. early clinical trials suggested that exposure to helminths such as trichuris suis or necator americanus can improve ibd. over the last seve ...201323178819
effects of treatment on ige responses against parasite allergen-like proteins and immunity to reinfection in childhood schistosome and hookworm coinfections.naturally occurring human immunity to both schistosomiasis and hookworm infection has been associated with ige responses against parasite allergen-like proteins. since the two helminths frequently coinfect the same individuals, there is growing advocacy for their concurrent treatment. however, both helminths are known to exert strong immunomodulatory effects; therefore, coinfected individuals could have immune responses different from those characteristically seen in monoinfected individuals. in ...201323071136
structure of monomeric na-gst-3, a glutathione s-transferase from the major human hookworm parasite necator americanus.necator americanus is the major cause of human hookworm infection, which is a global cause of anemia in the developing world. ongoing efforts to control hookworm infection include the identification of candidate vaccine antigens as well as potential therapeutic targets from the infective l3 larval stages and adult stages of the parasite. one promising family of proteins are the adult-stage-secreted cytosolic glutathione s-transferases (gsts). nematode gsts facilitate the inactivation and degrada ...201323908024
timps of parasitic helminths - a large-scale analysis of high-throughput sequence datasets.tissue inhibitors of metalloproteases (timps) are a multifunctional family of proteins that orchestrate extracellular matrix turnover, tissue remodelling and other cellular processes. in parasitic helminths, such as hookworms, timps have been proposed to play key roles in the host-parasite interplay, including invasion of and establishment in the vertebrate animal hosts. currently, knowledge of helminth timps is limited to a small number of studies on canine hookworms, whereas no information is ...201323721526
discrimination of gastrointestinal nematode eggs from crude fecal egg preparations by inhibitor-resistant conventional and real-time pcr.diagnosis of gastrointestinal nematodes relies predominantly on coproscopic methods such as flotation, kato-katz, mcmaster or flotac. although flotac allows accurate quantification, many nematode eggs can only be differentiated to genus or family level. several molecular diagnostic tools discriminating closely related species suffer from high costs for dna isolation from feces and limited sensitivity since most kits use only small amounts of feces (<1 g). a direct pcr from crude egg preparations ...201323620739
soil-transmitted helminth infection in south america: a systematic review and geostatistical meta-analysis.the four common soil-transmitted helminth species-ascaris lumbricoides, trichuris trichiura, and the two hookworm species ancylostoma duodenale and necator americanus-are endemic in south america, but their distribution, infection prevalence, and regional burden are poorly understood. we aimed to estimate the risk and number of people infected with a lumbricoides, t trichiura, and hookworm across south america.201323562238
a novel, multi-parallel, real-time polymerase chain reaction approach for eight gastrointestinal parasites provides improved diagnostic capabilities to resource-limited at-risk populations.diagnosis of gastrointestinal parasites has traditionally relied on stool microscopy, which has low diagnostic sensitivity and specificity. we have developed a novel, rapid, high-throughput quantitative multi-parallel real-time polymerase chain reaction (qpcr) platform. species-specific primers/probes were used for eight common gastrointestinal parasite pathogens: ascaris lumbricoides, necator americanus, ancylostoma duodenale, giardia lamblia, cryptosporidium spp., entamoeba histolytica, trichu ...201323509117
relationship between carotid intima media thickness and helminth infections on flores island, indonesia.to examine the association between helminth infections and atherosclerosis.201323365679
evaluation of real-time pcr for strongyloides stercoralis and hookworm as diagnostic tool in asymptomatic schoolchildren in cambodia.diagnosis of soil-transmitted helminths such as strongyloides stercoralis and hookworms (ancylostoma duodenale and necator americanus) is challenging due to irregular larval and egg output in infected individuals and insensitive conventional diagnostic procedures. sensitive novel real-time pcr assays have been developed. our study aimed to evaluate the real-time pcr assays as a diagnostic tool for detection of strongyloides spp. and hookworms in a random stool sample of 218 asymptomatic schoolch ...201323298731
parasitic diseases of the pleura.parasitic infections are prevalent in certain parts of the world and may cause pleural involvement, which often goes unrecognized. common parasites involving the pleura include entamoeba histolytica, echinococcus granulosus and paragonimus westermani. amebiasis can cause empyema with "anchovy sauce" pus, reactive pleural effusions and bronchopleural fistula with hydropneumothorax. echinococcosis may result in pleural thickening, pneumothorax, secondary pleural hydatidosis and pleural effusions. ...201322990049
new vaccines for neglected parasitic diseases and dengue.neglected tropical diseases (ntds) are a significant source of morbidity and socioeconomic burden among the world's poor. virtually all of the 2.4 billion people who live on less than $2 per d, more than a third of the world's population, are at risk for these debilitating ntds. although chemotherapeutic measures exist for many of these pathogens, they are not sustainable countermeasures on their own because of rates of reinfection, risk of drug resistance, and inconsistent maintenance of drug t ...201323578479
molecular detection of ancylostoma duodenale, ancylostoma ceylanicum, and necator americanus in humans in northeastern and southern thailand.the 2 principal species of hookworms infecting humans are necator americanus and ancylostoma duodenale. case studies on zoonotic hookworm infections with ancylostoma ceylanicum and/or ancylostoma caninum are known mainly from asian countries. of these 2 zoonotic species, only a. ceylanicum can develop to adulthood in humans. in the present study, we report a molecular-based survey of human hookworm infections present in southern and northeastern thailand. thirty larval hookworm samples were obta ...201324516284
molecular and biological diagnostic tests for monitoring benzimidazole resistance in human soil-transmitted helminths.in endemic countries with soil-transmitted helminths mass drug administration with albendazole or mebendazole are being implemented as a control strategy. however, it is well known in veterinary helminths that the use of the same benzimidazole drugs can place selection on the β-tubulin gene, leading to resistance. given the concern that resistance could arise in human soil-transmitted helminths, there is an urgent need to develop accurate diagnostic tools for monitoring resistance. in this study ...201323458960
an extensive comparison of the effect of anthelmintic classes on diverse nematodes.soil-transmitted helminths are parasitic nematodes that inhabit the human intestine. these parasites, which include two hookworm species, ancylostomaduodenale and necator americanus, the whipworm trichuristrichiura, and the large roundworm ascarislumbricoides, infect upwards of two billion people and are a major cause of disease burden in children and pregnant women. the challenge with treating these diseases is that poverty, safety, and inefficient public health policy have marginalized drug de ...201323869246
genetic characterization of selected parasites from people with histories of gastrointestinal disorders using a mutation scanning-coupled approach.a sscp analysis and targeted sequencing approach was used for the genetic characterization of some major pathogens from a cohort of 227 people with histories of gastrointestinal disorders. genomic dnas from fecal samples were subjected to pcr-amplification of regions in the glycoprotein (gp60) or triose phosphate isomerase (tpi) gene, or the second internal transcribed spacer of nuclear ribosomal dna (its-2). cryptosporidium, giardia, and strongylid nematodes were detected in 94, 132 and 12 samp ...201323592267
activity of oxantel pamoate monotherapy and combination chemotherapy against trichuris muris and hookworms: revival of an old drug.it is widely recognized that only a handful of drugs are available against soil-transmitted helminthiasis, all of which are characterized by a low efficacy against trichuris trichiura, when administered as single doses. the re-evaluation of old, forgotten drugs is a promising strategy to identify alternative anthelminthic drug candidates or drug combinations.201323556013
neglected tropical diseases of oceania: review of their prevalence, distribution, and opportunities for control.among oceania's population of 35 million people, the greatest number living in poverty currently live in papua new guinea (png), fiji, vanuatu, and the solomon islands. these impoverished populations are at high risk for selected ntds, including necator americanus hookworm infection, strongyloidiasis, lymphatic filariasis (lf), balantidiasis, yaws, trachoma, leprosy, and scabies, in addition to outbreaks of dengue and other arboviral infections including japanese encephalitis virus infection. pn ...201323383349
lipid core peptide targeting the cathepsin d hemoglobinase of schistosoma mansoni as a component of a schistosomiasis vaccine.the self-adjuvanting lipid core peptide (lcp) system offers a safe alternative vaccine delivery strategy, eliminating the need for additional adjuvants such as cpg alum. in this study, we adopted the lcp as a scaffold for an epitope located on the surface of the cathepsin d hemoglobinase (sm-catd) of the human blood fluke schistosoma mansoni. sm-catd plays a pivotal role in digestion of the fluke's bloodmeal and has been shown to be efficacious as a subunit vaccine in a murine model of human sch ...201324231271
impact of helminth diagnostic test performance on estimation of risk factors and outcomes in hiv-positive adults.traditional methods using microscopy for the detection of helminth infections have limited sensitivity. polymerase chain reaction (pcr) assays enhance detection of helminths, particularly low burden infections. however, differences in test performance may modify the ability to detect associations between helminth infection, risk factors, and sequelae. we compared these associations using microscopy and pcr.201324324729
update on the mapping of prevalence and intensity of infection for soil-transmitted helminth infections in latin america and the caribbean: a call for action.it is estimated that in latin america and the caribbean (lac) at least 13.9 million preschool age and 35.4 million school age children are at risk of infections by soil-transmitted helminths (sth): ascaris lumbricoides, trichuris trichiura and hookworms (necator americanus and ancylostoma duodenale). although infections caused by this group of parasites are associated with chronic deleterious effects on nutrition and growth, iron and vitamin a status and cognitive development in children, few co ...201324069476
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