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Microbes and Infection Jul 2011The generative mechanism(s) of predisposition to Ascaris infection are currently unknown. While many factors play a role in interindividual infection intensity, much... (Review)
Review
The generative mechanism(s) of predisposition to Ascaris infection are currently unknown. While many factors play a role in interindividual infection intensity, much focus has been placed on the host's immunological response to infection and the underlying genetics. The present review describes the research conducted that has examined various immunological parameters and genetic factors that may play a role in resistance to ascariasis. We also discuss the contribution that animal models have made to our understanding of resistance to the parasitic roundworm and their role in possible future work.
Topics: Animals; Antigens, Helminth; Ascariasis; Ascaris; Disease Susceptibility; Humans; Models, Animal
PubMed: 20934532
DOI: 10.1016/j.micinf.2010.09.013 -
Biomedicine & Pharmacotherapy =... Nov 2023Toosendanin (TSN), extracted from Melia. toosendan Sieb.et Zucc. and Melia. azedarach L., has been developed into an ascaris repellent in China. However, with the... (Review)
Review
Toosendanin (TSN), extracted from Melia. toosendan Sieb.et Zucc. and Melia. azedarach L., has been developed into an ascaris repellent in China. However, with the improvement of public health protection, the incidence of ascariasis has been reduced considerably, resulting in limited medical application of TSN. Therefore, it is questionable whether this old ascaris repellent can develop into a drug candidate. Modern studies have shown that TSN has strong pharmacological activities, including anti-tumor, anti-botulinum, anti-viral and anti-parasitic potentials. It also can regulate fat formation and improve inflammation. These researches indicate that TSN has great potential to be developed into a corresponding medical product. In order to better development and application of TSN, the availability, pharmacodynamics, pharmacokinetics and toxicology of TSN are summarized systematically. In addition, this review discusses shortcomings in the current researches and provides useful suggestions about how TSN developed into a drug candidate. Therefore, this paper illustrates the possibility of developing TSN as a medical product, aimed to provide directions for the clinical application and further research of TSN.
Topics: Animals; Humans; Ascaris; Drugs, Chinese Herbal; Neoplasms; China
PubMed: 37738795
DOI: 10.1016/j.biopha.2023.115541 -
PLoS Neglected Tropical Diseases Apr 2022It remains largely unknown where and how infections with soil-transmitted helminths (STHs; Ascaris, Trichuris, Necator and Ancylostoma) occur. We therefore aimed to...
BACKGROUND
It remains largely unknown where and how infections with soil-transmitted helminths (STHs; Ascaris, Trichuris, Necator and Ancylostoma) occur. We therefore aimed to identify possible sources of infection by assessing the environmental contamination in an STH-endemic area.
METHODS
We first performed a series of laboratory experiments designed to optimize a soil straining-flotation method to detect and quantify Ascaris and Trichuris eggs in soil, and to validate the diagnostic performance of the optimized method when followed by microscopy and qPCR. In a second phase, we applied this method to assess the level of STH contamination in 399 environmental samples collected from 10 school compounds, 50 households and 9 open markets in Jimma Town (Ethiopia). Subsequently, we explored associations between the environmental contamination and both the corresponding STH epidemiology at the level of the schools and the household characteristics. Finally, we assessed the knowledge, attitude and practice (KAP) towards STHs in school children.
PRINCIPAL FINDINGS
Our soil straining-flotation method has an analytical sensitivity of 50 eggs per 100 grams of soil and egg recovery rate of 36.0% (Ascaris) and 8.0% (Trichuris). The analysis of field samples with both microscopy and qPCR revealed the presence of 8 different helminth species of medical importance, including but not limited to the human STHs. There was a significant association between the environmental contamination and prevalence of any STH infections at the school level only. The KAP indicated a lack of knowledge and awareness of STHs.
CONCLUSIONS/SIGNIFICANCE
Our optimized straining-flotation method has a moderate diagnostic performance and revealed that life stages of helminths are ubiquitous in the environment, which might be due to the poor sanitary facilities at both the schools and the households, and a poor level of KAP towards STHs. Further research is required to gain more insights into the contribution of these life stages to transmission.
Topics: Animals; Ascaris; Ascaris lumbricoides; Child; Ethiopia; Feces; Helminthiasis; Helminths; Humans; Prevalence; Soil; Trichuris
PubMed: 35377880
DOI: 10.1371/journal.pntd.0010307 -
Scientific Reports Dec 2022The nematode parasite intestine absorbs nutrients, is involved in innate immunity, can metabolize xenobiotics and as we show here, is also a site of action of the...
The nematode parasite intestine absorbs nutrients, is involved in innate immunity, can metabolize xenobiotics and as we show here, is also a site of action of the anthelmintic, diethylcarbamazine. Diethylcarbamazine (DEC) is used to treat lymphatic filariasis and activates TRP-2, GON-2 & CED-11 TRP channels in Brugia malayi muscle cells producing spastic paralysis. DEC also has stimulatory effects on ascarid nematode parasites. Using PCR techniques, we detected, in Ascaris suum intestine, message for: Asu-trp-2, Asu-gon-2, Asu-ced-11, Asu-ocr-1, Asu-osm-9 and Asu-trpa-1. Comparison of amino-acid sequences of the TRP channels of B. malayi, and A. suum revealed noteworthy similarity, suggesting that the intestine of Ascaris will also be sensitive to DEC. We used Fluo-3AM as a Ca indicator and observed characteristic unsteady time-dependent increases in the Ca signal in the intestine in response to DEC. Application of La and the TRP channel inhibitors, 2-APB or SKF 96365, inhibited DEC mediated increases in intracellular Ca. These observations are important because they emphasize that the nematode intestine, in addition to muscle, is a site of action of DEC as well as other anthelmintics. DEC may also enhance the Ca toxicity effects of other anthelmintics acting on the intestine or, increase the effects of other anthelmintics that are metabolized and excreted by the nematode intestine.
Topics: Animals; Ascaris; Ascaris suum; Anthelmintics; Elephantiasis, Filarial; Brugia malayi
PubMed: 36494409
DOI: 10.1038/s41598-022-25648-7 -
PLoS Neglected Tropical Diseases May 2023Soil-transmitted helminth (STH) control programs currently lack evidence-based recommendations for cost-efficient survey designs for monitoring and evaluation. Here, we... (Clinical Trial)
Clinical Trial
A general framework to support cost-efficient fecal egg count methods and study design choices for large-scale STH deworming programs-monitoring of therapeutic drug efficacy as a case study.
BACKGROUND
Soil-transmitted helminth (STH) control programs currently lack evidence-based recommendations for cost-efficient survey designs for monitoring and evaluation. Here, we present a framework to provide evidence-based recommendations, using a case study of therapeutic drug efficacy monitoring based on the examination of helminth eggs in stool.
METHODS
We performed an in-depth analysis of the operational costs to process one stool sample for three diagnostic methods (Kato-Katz, Mini-FLOTAC and FECPAKG2). Next, we performed simulations to determine the probability of detecting a truly reduced therapeutic efficacy for different scenarios of STH species (Ascaris lumbricoides, Trichuris trichiura and hookworms), pre-treatment infection levels, survey design (screen and select (SS); screen, select and retest (SSR) and no selection (NS)) and number of subjects enrolled (100-5,000). Finally, we integrated the outcome of the cost assessment into the simulation study to estimate the total survey costs and determined the most cost-efficient survey design.
PRINCIPAL FINDINGS
Kato-Katz allowed for both the highest sample throughput and the lowest cost per test, while FECPAKG2 required both the most laboratory time and was the most expensive. Counting of eggs accounted for 23% (FECPAKG2) or ≥80% (Kato-Katz and Mini-FLOTAC) of the total time-to-result. NS survey designs in combination with Kato-Katz were the most cost-efficient to assess therapeutic drug efficacy in all scenarios of STH species and endemicity.
CONCLUSIONS/SIGNIFICANCE
We confirm that Kato-Katz is the fecal egg counting method of choice for monitoring therapeutic drug efficacy, but that the survey design currently recommended by WHO (SS) should be updated. Our generic framework, which captures laboratory time and material costs, can be used to further support cost-efficient choices for other important surveys informing STH control programs. In addition, it can be used to explore the value of alternative diagnostic techniques, like automated egg counting, which may further reduce operational costs.
TRIAL REGISTRATION
ClinicalTrials.gov NCT03465488.
Topics: Animals; Humans; Ascaris lumbricoides; Feces; Helminthiasis; Helminths; Sensitivity and Specificity; Soil; Trichuris
PubMed: 37196017
DOI: 10.1371/journal.pntd.0011071 -
Infectious Diseases of Poverty Mar 2022Achieving the elimination of soil-transmitted helminth (STH) infections requires a sufficient understanding of the current epidemiological status of STH endemicity. We...
BACKGROUND
Achieving the elimination of soil-transmitted helminth (STH) infections requires a sufficient understanding of the current epidemiological status of STH endemicity. We aimed to examine the status of STH in Myanmar - a country with the eighth highest STH prevalence in the world, 10 years after instigation of the national deworming programme.
METHODS
In August 2016 we screened for STH infections using Kato Katz (KK) microscopy and real-time PCR (qPCR) in schoolchildren from the Bago Region township of Phyu, a STH sentinel site in Myanmar. Ten schools were randomly selected, and one stool sample each from a total of 264 students was examined. Prevalence and intensity of infection were calculated for each STH.
RESULTS
High prevalence of STH was identified in the study area with 78.8% of the schoolchildren infected with at least one STH by qPCR, and 33.3% by KK. The most prevalent STH was Trichuris trichiura, diagnosed by both KK (26.1%) and qPCR (67.1%), followed by Ascaris lumbricoides (15.5% KK; 54.9% qPCR). No hookworm infections were identified by KK; however, the qPCR analysis showed a high prevalence of Ancylostoma sp. infection (29.6%) with few Necator americanus (1.1%) infections.
CONCLUSIONS
Despite bi-annual deworming of schoolchildren in the fourth-grade and below, STH prevalence remains stubbornly high. These results informed the expansion of the Myanmar National STH control programme to include all school-aged children by the Ministry of Health and Sports in 2017, however further expansion to the whole community should be considered along with improving sanitation and hygiene measures. This would be augmented by rigorous monitoring and evaluation, including national prevalence surveys.
Topics: Animals; Ascaris lumbricoides; Child; Cross-Sectional Studies; Humans; Myanmar; Prevalence; Soil
PubMed: 35272701
DOI: 10.1186/s40249-022-00952-6 -
ACS Chemical Neuroscience Sep 2021Neural circuit synaptic connectivities (the connectome) provide the anatomical foundation for our understanding of nematode nervous system function. However, other...
Neural circuit synaptic connectivities (the connectome) provide the anatomical foundation for our understanding of nematode nervous system function. However, other nonsynaptic routes of communication are known in invertebrates including extrasynaptic volume transmission (EVT), which enables short- and/or long-range communication in the absence of synaptic connections. Although EVT has been highlighted as a facet of neurosignaling, no experimental evidence identifies body cavity fluid (pseudocoelomic fluid; PCF) as a vehicle for either neuropeptide or biogenic amine transmission. In the parasitic nematode , FMRFamide-like peptides encoded on potently stimulate female reproductive organs but are expressed in cells that are anatomically distant from the reproductive organ, with no known synaptic connections to this tissue. Here we investigate nonsynaptic neuropeptide signaling in nematodes mediated by the body cavity fluid. Our data show that (i) PCF (As-PCF) contains a catalog of neuropeptides including FMRFamide-like peptides and neuropeptide-like proteins, (ii) the FMRFamide-like peptide As-FLP-18A dominates the As-PCF peptidome, (iii) As-PCF potently modulates nematode reproductive muscle function , mirroring the effects of synthetic FLP-18 peptides, (iv) As-PCF activates the FLP-18 receptors NPR-4 and -5, (v) As-PCF alters behavior, and (vi) FLP-18 and FLP-18 receptors display pan-phylum distribution in nematodes. This study provides the first direct experimental evidence to support an extrasynaptic volume route for neuropeptide transmission in nematodes. These data indicate nonsynaptic signaling within the nematode functional connectome and are particularly pertinent to receptor deorphanization approaches underpinning drug discovery programs for nematode pathogens.
Topics: Animals; Ascaris suum; Caenorhabditis elegans; FMRFamide; Female; Nematoda; Neuropeptides
PubMed: 34347433
DOI: 10.1021/acschemneuro.1c00281 -
Journal of Food Protection Jun 2000Published techniques for recovering parasites from fruit and vegetables are generally inadequate, with low and variable recovery efficiencies. Here we describe an...
Published techniques for recovering parasites from fruit and vegetables are generally inadequate, with low and variable recovery efficiencies. Here we describe an improved methodology for analyzing fruit and vegetables for Giardia cysts, Cryptosporidium oocysts, and Ascaris eggs. The method includes washing procedures, sonication, and, for Giardia and Cryptosporidium, immunomagnetic separation. Identification is by immunofluorescence (Giardia and Cryptosporidium) or brightfield microscopy (Ascaris). Recovery efficiencies from lettuce, Chinese leaves, and strawberries were found to be approximately 67% for Giardia, 42% for Cryptosporidium, and 72% for Ascaris. Recovery efficiencies from bean sprouts tended to be more variable and lower. This could be due to material removed with the parasites during the washing procedures, which, in turn, appeared related to the age of the bean sprouts. It is therefore recommended that fruit and vegetables should be as fresh as possible when analyzed for parasites.
Topics: Animals; Ascaris; Cryptosporidium; Food Parasitology; Fruit; Giardia; Immunomagnetic Separation; Parasite Egg Count; Vegetables
PubMed: 10852573
DOI: 10.4315/0362-028x-63.6.775 -
British Medical Journal Sep 1968
Topics: Ascaris; Eosinophilia; Humans; Pulmonary Eosinophilia
PubMed: 5667987
DOI: No ID Found -
The Science of the Total Environment May 2024Safe and hygienic management of human waste is essential in humanitarian settings. Urine-diverting dry toilets (UDDTs) can enable this management in some humanitarian...
Safe and hygienic management of human waste is essential in humanitarian settings. Urine-diverting dry toilets (UDDTs) can enable this management in some humanitarian emergency settings. A seeded, longitudinal environmental study was conducted in Hiloweyn refugee camp, Dollo Ado, Ethiopia, to measure Escherichia coli and Ascaris suum ova inactivation within closed UDDT vaults and to document environmental conditions (temperature, moisture content, and pH) that could influence inactivation. Hiloweyn camp represented an optimal location for a desiccation-based sanitation technology such as the UDDT. E. coli and Ascaris ova inactivation was observed in UDDTs under warm, dry, alkaline conditions at 6, 9, and 12 months of storage; UDDTs with samples containing <1000 E. coli/g total solids increased from 30 % to 95 % over 12 months, and a >2.8-log reduction in Ascaris ova viability was observed after 6 months. Additional laboratory-based studies were conducted to provide insights into the field study findings and study the impact of hydrated lime on E. coli and Ascaris ova inactivation. Results suggest that adding hydrated lime to elevate pH > 12 may increase inactivation and decrease storage time. Overall, UDDTs could contribute to the safe and hygienic management of human waste in comparable warm and dry humanitarian settings.
Topics: Animals; Humans; Escherichia coli; Bathroom Equipment; Ethiopia; Calcium Compounds; Ascaris; Oxides
PubMed: 38518820
DOI: 10.1016/j.scitotenv.2024.171838