DNA of Dientamoeba fragilis detected within surface-sterilized eggs of Enterobius vermicularis. Exp Parasitol

Laboratory of Parasitology, Department of Microbiology and Infection Control, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark. Electronic address: .
Experimental Parasitology (Impact Factor: 1.64). 10/2012; 133(1). DOI: 10.1016/j.exppara.2012.10.009
Source: PubMed


With no evidence of a cyst stage, the mode of transmission of Dientamoeba fragilis, an intestinal protozoon of common occurrence and suggested pathogenicity, is incompletely known. Numerous studies have suggested that eggs of intestinal nematodes, primarily Enterobius vermicularis (pinworm), can serve as vectors for D. fragilis, although attempts to culture D. fragilis from pinworm eggs have been unsuccessful and data from epidemiological studies on D. fragilis/pinworm co-infection have been conflicting. The aim of this study was to investigate whether we could detect D. fragilis DNA from pinworm eggs collected from routine diagnostic samples (cellophane tape) and surface-sterilised by hypochlorite. DNA was extracted from individual eggs and tested by PCR using D. fragilis- and E. vermicularis-specific primers; amplicons were sequenced for confirmation. In cellophane tape samples from 64 patients with unknown D. fragilis status we detected D. fragilis DNA in 12/238 (5%) eggs, and in a patient known to harbour D. fragilis we detected D. fragilis DNA in 39/99 (39%) eggs. The finding of D. fragilis DNA within eggs of E. vermicularis strongly supports the hypothesis of D. fragilis-transmission by pinworm and has implications for antimicrobial intervention as well as control and public health measures.

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Available from: Dennis Röser, Mar 03, 2015
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    • "As the ingestion of a small number of E. vermicularis eggs can cause infection, the fact that those children who had the most eggs on their hands did not wash their hands before eating , means that the potential for infection is great, and that hand washing promotion in these communities could have an impact on infection levels in children. In addition E. vermicularis eggs have recently been identified as vectors for Dientamoeba fragilis (Ogren et al., 2013; Roser et al., 2013), a gastrointestinal parasite that has been suggested to be pathogenic. Therefore by decreasing infection of E. vermicularis, disease, such as chronic diarrhoea, fatigue, and stunted development in children, caused by D. fragilis will also be decreased. "
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    ABSTRACT: Enterobius vermicularis is a helminth that is difficult to control, is found globally, especially in crowded conditions, and can be transmitted from person to person by contaminated hands. A newly developed method for the quantification of helminth eggs on hands was tested among schoolchildren in a rural South African region to look at the role hands play in helminth infection, and to determine the risk factors for hand contamination. The study found 16.6% of participants' hands positive for helminth eggs, with E. vermicularis most commonly identified. Egg concentrations on hands ranged from 0-57 eggs/2 hands. Gender, toilet type used at home, and not reporting to wash hands with soap before eating were all associated with the presence of eggs on hands. The study highlights the need to improve sanitation facilities, and promote handwashing with soap in schools to prevent transmission of E. vermicularis. Copyright © 2015. Published by Elsevier B.V.
    Acta tropica 07/2015; 150. DOI:10.1016/j.actatropica.2015.07.001 · 2.27 Impact Factor
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    • "Les protozooses cavitaires ne génèrent pas d'HE; le cas du parasitisme à Dientamoeba fragilis, souvent retrouvé associé à cette anomalie hématologique , serait expliqué par la fréquente association avec l'oxyurose [15]. Cette coïnfection serait elle-même favorisée par une transmission transovarienne de D. fragilis par Enterobius vermicularis [16]. Une HE est par contre observée lors de certaines protozooses systémiques rares, comme la sarcocystose [17]. "
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    ABSTRACT: Hypereosinophilia (HE) is defined by an increase of more than 0.5 G/L eosinophils in circulating blood. This haematological abnormality may have multiple etiologies but the majority of them correspond to a secondary HE known as “allergic HE”, encountered frequently in helminth infections. Indeed, during an aggression caused by helminths, cytokines called “alarmins” are secreted and they lead to an overproduction of IL-5, IL-13 and IL-4, which are accountable for HE and increase of type E immunoglobulin. High level of eosinophils evolving over a long period may lead to tissue damage in relation to the activation of these cells, leading to severe clinical manifestations. Exploring an HE requires anamnestic, epidemiological, and clinical data to orientate the diagnosis and also to target the panel of laboratory tests. Optical techniques remain the first line of investigation, because these tests can quickly lead to the definitive diagnosis, if performed by experienced operators. Immunodiagnostics of helminth infections present a major contribution in special situations, but these techniques are complementary to conventional optical investigations and are often difficult to explore.
    Revue Francophone des Laboratoires 04/2014; 2014(462):87–94. DOI:10.1016/S1773-035X(14)72482-7
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    • "Dientamoeba fragilis is an intestinal parasite of unsettled clinical significance and possibly transmitted by pinworm (Johnson et al., 2004; Röser et al., 2013a; Stensvold et al., 2007a). We have recently shown that 43% of approximately 22,000 faecal DNAs from patients with intestinal symptoms tested positive for D. fragilis by real-time PCR in our clinical microbiology laboratory, with a range in positive proportion from 10% to 70% depending on age group (Röser et al., 2013b). "
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    ABSTRACT: Dientamoeba fragilis is a common intestinal parasite of unsettled clinical significance. Differences in clinical outcome of parasitic infections may reflect parasite genetic diversity, and so tools to study intra-genetic diversity that could potentially reflect differences in clinical phenotypes are warranted. Here, we show that genetic analysis of three D. fragilis housekeeping genes enables clear distinction between the two known genotypes, but that integration of housekeeping genes in multi-locus sequencing tools for D. fragilis may have limited epidemiological and clinical value due to no further added genetic resolution.
    Infection Genetics and Evolution 05/2013; 18:284-286. · 3.02 Impact Factor
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