-
Journal of Helminthology Jan 2020Glutathione S-transferases (GSTs) are a detoxifying enzyme family that is essential for parasite blood-feeding and survival, and represent potential targets for hookworm...
Glutathione S-transferases (GSTs) are a detoxifying enzyme family that is essential for parasite blood-feeding and survival, and represent potential targets for hookworm vaccine development. Multiple GST-encoding complementary DNAs (cDNAs) have been cloned from Ancylostoma caninum and Necator americanus, but there are no reports about the cloning of this enzyme from Ancylostoma ceylanicum, the animal-derived zoonotic hookworm. To study the molecular nature and tissue localization of GST of A. ceylanicum (Ace-GST), we designed primers based on the GST gene sequence of A. ceylanicum in GenBank, amplified the Ace-GST cDNA by reverse transcription polymerase chain reaction, and analysed its homology and genetic evolution relationship. The amplified product was cloned into the pET-32a vector and transformed into Escherichia coli BL21 (DE3) for expression. To prepare anti-GST polyclonal antibodies, the recombinant protein was purified and used to immunize Kunming mice. The level of immunoglobulin G (IgG) antibody in the serum of immunized mice was detected by indirect enzyme-linked immunosorbent assay, and the Ace-GST localization in adult worm was determined using the immunofluorescence method. The results showed that the full-length cDNA encoding Ace-GST was 468 bp, which had the highest homology with Ac-GST-1 (60.1%) and clustered into one branch (v-class) with Ac-GST-1 and Na-GST-1 in a phylogenetic tree. Mice immunized with recombinant Ace-GST showed specific IgG antibody response. Immunolocalization revealed that natural Ace-GST is mainly located in the epidermis, muscle and intestine of the adult. These results may lay a foundation for further studies on the biological function of Ace-GST.
Topics: Ancylostoma; Ancylostomiasis; Animals; Antibodies, Helminth; Antigens, Helminth; Cloning, Molecular; DNA, Helminth; Escherichia coli; Glutathione Transferase; Immunohistochemistry; Phylogeny; Recombinant Proteins; Transformation, Bacterial
PubMed: 31959266
DOI: 10.1017/S0022149X20000012 -
The American Journal of Tropical... Jul 2020Hookworm infections are classified as the most impactful of the human soil-transmitted helminth (STH) infections, causing a disease burden of ∼4 million...
Hookworm infections are classified as the most impactful of the human soil-transmitted helminth (STH) infections, causing a disease burden of ∼4 million disability-adjusted life years, with a global prevalence of 406-480 million infections. Until a decade ago, epidemiological surveys largely assumed and as the relevant human hookworm species implicated as contributing to iron-deficiency anemia. This assumption was based on the indistinguishable morphology of the spp. eggs in stool and the absence of awareness of a third zoonotic hookworm species, . The expanded use of molecular diagnostic assays for differentiating hookworm species infections during STH surveys has now implicated , a predominant hookworm of dogs in Asia, as the second most common hookworm species infecting humans in Southeast Asia and the Pacific. Despite this, with the exception of sporadic case reports, there is a paucity of data available on the impact of this emerging zoonosis on human health at a population level. This situation also challenges the current paradigm, necessitating a One Health approach to hookworm control in populations in which this zoonosis is endemic. Here, we have summarized the available research studies and case reports on human infections in Southeast Asia and the Pacific after 2013 using a systematic review approach. We summarized eight research articles and five clinical case studies, highlighting the importance of future in-depth investigation of zoonotic infections using sensitive and cost-effective diagnostic tools.
Topics: Ancylostoma; Ancylostomiasis; Animals; Asia, Southeastern; Dog Diseases; Dogs; Feces; Humans; Neglected Diseases; One Health; Pacific Islands; Parasite Egg Count; Zoonoses
PubMed: 32342850
DOI: 10.4269/ajtmh.20-0060 -
Scientific Reports May 2019Hookworms are one of the most prevalent and important parasites, infecting ~500 million people worldwide. Hookworm disease is among the leading causes of iron-deficiency...
Hookworms are one of the most prevalent and important parasites, infecting ~500 million people worldwide. Hookworm disease is among the leading causes of iron-deficiency anemia in the developing world and is associated with significant growth stunting and malnutrition. In humans, hookworms appear to impair memory and other forms of cognition, although definitive data are hard to come by. Here we study the impact of a human hookworm parasite, Ancylostoma ceylanicum, on cognition in hamsters in a controlled laboratory setting. We developed tests that measure long-term memory in hamsters. We find that hookworm-infected hamsters were fully capable of detecting a novel object. However, hookworm-infected hamsters were impaired in detecting a displaced object. Defects could be discerned at even at low levels of infection, whereas at higher levels of infection, hamsters were statistically unable to distinguish between displaced and non-displaced objects. These spatial memory deficiencies could not be attributed to defects in infected hamster mobility or to lack of interest. We also found that hookworm infection resulted in reproducible reductions in diversity and changes in specific taxanomic groups in the hamster gut microbiome. These data demonstrate that human hookworm infection in a laboratory mammal results in a specific, rapid, acute, and measurable deficit in spatial memory, and we speculate that gut alterations could play some role in these cognitive deficits. Our findings highlight the importance of hookworm elimination and suggest that finer tuned spatial memory studies be carried out in humans.
Topics: Ancylostoma; Ancylostomiasis; Animals; Cognition; Cricetinae; Disease Models, Animal; Female; Gastrointestinal Microbiome; Humans; Male; Memory, Long-Term
PubMed: 31133690
DOI: 10.1038/s41598-019-44301-4 -
Acta Tropica Jan 2015The occurrence and spatial distribution of intestinal helminth infection in children is fairly well understood. However, knowledge on how helminth infections govern...
Multiparasitism and intensity of helminth infections in relation to symptoms and nutritional status among children: a cross-sectional study in southern Lao People's Democratic Republic.
The occurrence and spatial distribution of intestinal helminth infection in children is fairly well understood. However, knowledge on how helminth infections govern intestinal morbidity is scarce. We conducted a cross-sectional study to assess and quantify the relationship between single and multiple species helminth infection with clinical and self-reported morbidity indicators and nutritional status in Champasack province, southern Lao People's Democratic Republic (Lao PDR). A random sample of 1313 children, aged 6 months to 12 years, from villages in nine rural districts were enrolled and examined for helminth infection using duplicate Kato-Katz thick smears. Morbidity was assessed by self-reported symptoms, coupled with clinical examination and appraisal of nutritional status and anaemia. Bivariate and multivariate logistic regression was employed to study associations between helminth infection and morbidity indicators and anaemia. We found considerable morbidity among the surveyed children, including hepatomegaly (13.7%), pale conjunctiva (13.2%) and abdominal pain (10.4%). Anaemia was recorded in 60.4% of the children, whilst signs of stunting and low body mass index (BMI) were observed in 49.8% and 33.3% of the surveyed children, respectively. Hookworm and Opisthorchis viverrini were the predominant helminth species with prevalences of 51.0% and 43.3%, respectively. The prevalence of Schistosoma mekongi in the surveyed children was 5.6%. Multiple species helminth infections were recorded in 40.4% of the study cohort. Morbidity was associated with specific helminth species infection (e.g. S. mekongi with hepatomegaly; adjusted odds ratio (aOR): 9.49, 95% confidence interval (CI): 2.07-43.51) and multiparasitism (e.g. two or more helminth species with abdominal pain; aOR: 2.40, 95% CI: 1.46-3.93). Anaemia was associated with hookworm infection (aOR: 1.64, 95% CI: 1.16-2.34) and multiparasitism (aOR: 1.64, 95% CI: 1.18-2.29). Low BMI was associated with O. viverrini infection (aOR: 1.68, 95% CI: 1.14-2.49) and multiparasitism (aOR: 1.42, 95% CI: 1.01-2.00). The multiple strong associations reported here between helminth infections (single or multiple species) and intestinal morbidity among children in rural parts of southern Lao PDR call for concerted efforts to control helminth infections, which in turn might improve children's health and development.
Topics: Ancylostomatoidea; Ancylostomiasis; Anemia; Animals; Child; Child, Preschool; Coinfection; Cross-Sectional Studies; Feces; Female; Gastrointestinal Hemorrhage; Helminthiasis; Helminths; Hookworm Infections; Humans; Infant; Intestinal Diseases, Parasitic; Laos; Logistic Models; Male; Nutritional Status; Opisthorchiasis; Opisthorchis; Prevalence; Rural Population; Schistosomiasis; Surveys and Questionnaires; Thinness
PubMed: 25291046
DOI: 10.1016/j.actatropica.2014.09.015 -
BioMed Research International 2018To develop a -shift method for detection of dog-derived and three sets of primers were designed based on three SNPs (ITS71, ITS197, and ITS296) of their internal...
To develop a -shift method for detection of dog-derived and three sets of primers were designed based on three SNPs (ITS71, ITS197, and ITS296) of their internal transcribed spacer 1 (ITS1) sequences. The detection effect of the -shift was assessed through the stability, sensitivity, accuracy test, and clinical detection. The results showed that these three sets of primers could distinguish accurately between and . The coefficient of variation in their values on the three SNPs was 0.09% and 0.15% (ITS71), 0.18% and 0.14% (ITS197), and 0.13% and 0.07% (ITS296), respectively. The lowest detectable concentration of standard plasmids for and was 5.33 × 10 ng/L and 5.03 × 10 ng/L. The -shift results of ten DNA samples from the dog-derived hookworms were consistent with their known species. In the clinical detection of 50 fecal samples from stray dogs, the positive rate of hookworm detected by -shift (42%) was significantly higher than that by microscopic examination (34%), and the former can identify the species. It is concluded that the -shift method is rapid, specific, sensitive, and suitable for the clinical detection and zoonotic risk assessment of the dog-derived hookworm.
Topics: Ancylostoma; Ancylostomiasis; Animals; DNA, Helminth; Dog Diseases; Dogs; Polymorphism, Single Nucleotide
PubMed: 29862291
DOI: 10.1155/2018/7617094 -
Mayo Clinic Proceedings Oct 2015
Topics: Adult; Ancylostoma; Ancylostomiasis; Anemia, Iron-Deficiency; Animals; Anthelmintics; Female; Humans; Iron Compounds; Pruritus; Treatment Outcome
PubMed: 26434973
DOI: 10.1016/j.mayocp.2015.07.028 -
PLoS Neglected Tropical Diseases May 2018The soil-transmitted nematodes (STNs) or helminths (hookworms, whipworms, large roundworms) infect the intestines of ~1.5 billion of the poorest peoples and are leading...
In vivo and in vitro studies of Cry5B and nicotinic acetylcholine receptor agonist anthelmintics reveal a powerful and unique combination therapy against intestinal nematode parasites.
BACKGROUND
The soil-transmitted nematodes (STNs) or helminths (hookworms, whipworms, large roundworms) infect the intestines of ~1.5 billion of the poorest peoples and are leading causes of morbidity worldwide. Only one class of anthelmintic or anti-nematode drugs, the benzimidazoles, is currently used in mass drug administrations, which is a dangerous situation. New anti-nematode drugs are urgently needed. Bacillus thuringiensis crystal protein Cry5B is a powerful, promising new candidate. Drug combinations, when properly made, are ideal for treating infectious diseases. Although there are some clinical trials using drug combinations against STNs, little quantitative and systemic work has been performed to define the characteristics of these combinations in vivo.
METHODOLOGY/PRINCIPAL FINDINGS
Working with the hookworm Ancylostoma ceylanicum-hamster infection system, we establish a laboratory paradigm for studying anti-nematode combinations in vivo using Cry5B and the nicotinic acetylcholine receptor (nAChR) agonists tribendimidine and pyrantel pamoate. We demonstrate that Cry5B strongly synergizes in vivo with both tribendimidine and pyrantel at specific dose ratios against hookworm infections. For example, whereas 1 mg/kg Cry5B and 1 mg/kg tribendimidine individually resulted in only a 0%-6% reduction in hookworm burdens, the combination of the two resulted in a 41% reduction (P = 0.020). Furthermore, when mixed at synergistic ratios, these combinations eradicate hookworm infections at doses where the individual doses do not. Using cyathostomin nematode parasites of horses, we find based on inhibitory concentration 50% values that a strongylid parasite population doubly resistant to nAChR agonists and benzimidazoles is more susceptible or "hypersusceptible" to Cry5B than a cyathostomin population not resistant to nAChR agonists, consistent with previous Caenhorhabditis elegans results.
CONCLUSIONS/SIGNIFICANCE
Our study provides a powerful means by which anthelmintic combination therapies can be examined in vivo in the laboratory. In addition, we demonstrate that Cry5B and nAChR agonists have excellent combinatorial properties-Cry5B combined with nAChR agonists gives rise to potent cures that are predicted to be recalcitrant to the development of parasite resistance. These drug combinations highlight bright spots in new anthelmintic development for human and veterinary animal intestinal nematode infections.
Topics: Ancylostoma; Ancylostomiasis; Animals; Anthelmintics; Bacillus thuringiensis Toxins; Bacterial Proteins; Cricetinae; Drug Therapy, Combination; Endotoxins; Female; Hemolysin Proteins; Horse Diseases; Horses; Humans; Intestinal Diseases, Parasitic; Male; Mesocricetus; Nicotinic Antagonists; Receptors, Nicotinic
PubMed: 29775454
DOI: 10.1371/journal.pntd.0006506 -
Parasites & Vectors Dec 2019The canine hookworm, Ancylostoma caninum is the most prevalent and important intestinal nematode parasite of dogs in the USA. Hookworms are typically well controlled by...
BACKGROUND
The canine hookworm, Ancylostoma caninum is the most prevalent and important intestinal nematode parasite of dogs in the USA. Hookworms are typically well controlled by treatment with all commonly used anthelmintics that are approved for this use in dogs. However, in the past few years, cases of recurrent/persistent canine hookworm infections appear to have dramatically increased, suggesting that anthelmintic resistance (AR) may have evolved in this parasite. These cases are highly overrepresented by greyhounds, but multiple other breeds are also represented. The aim of this study was to characterize several of these suspected resistant isolates using in vitro, genetic and clinical testing to determine if these cases represent true anthelmintic resistance in A. caninum.
METHODS
Fecal samples containing hookworm eggs from three cases of persistent hookworm infections; one from a greyhound, one from a miniature schnauzer and one from a hound-mix, were received by our laboratory. These were then used to establish infections in laboratory dogs and to perform egg hatch assays (EHA) and larval development assays (LDA) for detecting resistance to benzimidazoles and macrocyclic lactones, respectively. Additional EHA and LDA were performed on eggs recovered from the laboratory-induced infections. Fecal egg count reduction tests were performed to detect resistance to pyrantel. Deep amplicon sequencing assays were developed to measure the frequency of non-synonymous single nucleotide polymorphisms (SNP) at codons 167, 198 and 200 of the A. caninum isotype-1 β-tubulin gene.
RESULTS
Resistance ratios for the three A. caninum isolates tested ranged from 6.0 to > 100 and 5.5 to 69.8 for the EHA and LDA, respectively. Following treatment with pyrantel, reduction in faecal egg counts was negative or 0%. Deep amplicon sequencing of the isotype-1 β-tubulin gene identified a high frequency of resistance-associated SNPs at codon 167 in all three resistant isolates and in two additional clinical cases.
CONCLUSIONS
These data conclusively demonstrate multiple anthelmintic resistance in multiple independent isolates of A. caninum, strongly suggesting that this is an emerging problem in the USA. Furthermore, evidence suggest that these resistant hookworms originate from racing greyhound farms and kennels, though additional research is needed to confirm this.
Topics: Ancylostoma; Ancylostomiasis; Animals; Anthelmintics; Breeding; Dog Diseases; Dogs; Drug Resistance, Multiple; Feces; Parasite Egg Count; Polymorphism, Single Nucleotide; Pyrantel; United States
PubMed: 31818311
DOI: 10.1186/s13071-019-3828-6 -
PLoS Neglected Tropical Diseases Sep 2015The implementation of soil-transmitted helminth (STH) treatment programmes occurs in varied environmental, social and economic contexts. Programme impact will be...
BACKGROUND
The implementation of soil-transmitted helminth (STH) treatment programmes occurs in varied environmental, social and economic contexts. Programme impact will be influenced by factors that affect the reduction in the prevalence and intensity of infections following treatment, as well as the subsequent rate of reinfection. To better understand the heterogeneity of programme impact and its underlying reasons, we investigated the influence of contextual factors on reduction in STH infection as part of the national school based deworming (SBD) programme in Kenya.
MATERIALS AND METHODS
Data on the prevalence and intensity of infection were collected within the monitoring and evaluation component of the SBD programme at baseline and after delivery of two annual treatment rounds in 153 schools in western Kenya. Using a framework that considers STH epidemiology and transmission dynamics, capacity to deliver treatment, operational feasibility and financial capacity, data were assembled at both school and district (county) levels. Geographic heterogeneity of programme impact was assessed by descriptive and spatial analyses. Factors associated with absolute reductions of Ascaris lumbricoides and hookworm infection prevalence and intensity were identified using mixed effects linear regression modelling adjusting for baseline infection levels.
PRINCIPAL FINDINGS
The reduction in prevalence and intensity of A. lumbricoides and hookworms varied significantly by county and within counties by school. Multivariable analysis of factors associated with programme impact showed that absolute A. lumbricoides reductions varied by environmental conditions and access to improved sanitation at schools or within the community. Larger reduction in prevalence and intensity of hookworms were found in schools located within areas with higher community level access to improved sanitation and within counties with higher economic and health service delivery indicator scores.
CONCLUSIONS
The study identifies factors associated with the impact of school-based deworming and in particular highlights how access to water, sanitation and hygiene and environmental conditions influence the impact of deworming programmes.
Topics: Ancylostomiasis; Animals; Antinematodal Agents; Ascariasis; Delivery of Health Care; Humans; Kenya; Neglected Diseases; Nematode Infections; Prevalence; Program Evaluation; Public Health; School Health Services; Socioeconomic Factors; Trichuriasis; Water
PubMed: 26421808
DOI: 10.1371/journal.pntd.0004108 -
Enfermedades Infecciosas Y... May 2019Infections caused by Strongyloides stercoralis and other soil-transmitted worms such as hookworms (Necator americanus and Ancylostoma duodenale) represent a major...
Infections caused by Strongyloides stercoralis and other soil-transmitted worms such as hookworms (Necator americanus and Ancylostoma duodenale) represent a major problem worldwide, especially in developing areas. They are difficult to suspect clinically since they produce non-specific and often overlapping signs and symptoms. Likewise, their long prepatent periods hamper the detection of parasitic structures. Microscopic diagnosis is still the most commonly used tool in healthcare laboratories but it is still far from being the ideal technique to detect these infections due to its low sensitivity. In addition, these nematodes have strong morphologic similarities and consequently microbiological diagnosis remains a challenge. Serology has made progress in the diagnosis of S. stercoralis infection but this option is not yet available for hookworms. Molecular biology techniques have been shown to slightly increase this lack of sensitivity, but as with other parasitic infections, they are not currently available for use in clinical microbiology laboratories. Supplement information: This article is part of a supplement entitled «SEIMC External Quality Control Programme. Year 2016», which is sponsored by Roche, Vircell Microbiologists, Abbott Molecular and Francisco Soria Melguizo, S.A. © 2019 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosasy Microbiología Clínica. All rights reserved.
Topics: Ancylostomiasis; Animals; Helminthiasis; Humans; Necator americanus; Necatoriasis; Soil; Strongyloides stercoralis; Strongyloidiasis
PubMed: 31138419
DOI: 10.1016/S0213-005X(19)30178-8