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Peter Burney – 1st expert on this subject based on the ideXlab platform

  • Ascaris atopy and exercise induced bronchoconstriction in rural and urban south african children
    The Journal of Allergy and Clinical Immunology, 2010
    Co-Authors: James Calvert, Peter Burney


    Background Populations with endemic parasitosis have high levels of IgE but low levels of allergic disease. We investigated the association between infection with the parasite Ascaris allergic sensitization, and exercise-induced bronchospasm (EIB). Objective We sought to investigate the effect of Ascaris infection on bronchial hyperreactivity, skin testing, and specific IgE levels. Methods A cross-sectional prevalence survey was conducted in urban and rural South African children to measure levels of EIB. A sample of children was enrolled in a nested case-control study for further investigation based on response to exercise. Analyses used weighted logistic regression. Results Geometric mean total IgE levels were higher in Ascaris –infected subjects (infected subjects: 451 IU (95% CI, 356-572) vs uninfected subjects: 344 IU (95% CI, 271-437), P  = .04), and high levels of total IgE were positively associated with detection of specific IgE to the aeroallergens tested, but there was no significant association between Ascaris infection and titers of specific IgE. Ascaris infection was associated with a decreased risk of a positive skin test response (odds ratio, 0.63; 95% CI, 0.42–0.94; P = .03) but an increased risk of EIB (odds ratio, 1.62; 95% CI, 1.23-2.11; P = .001). Conclusion In areas of high parasite endemicity, Ascaris might induce an inflammatory response in the lungs independent of its effect on IgE production. This could explain some of the contradictory findings seen in studies examining the association between geohelminth infection, atopy, and asthma.

Stefan M Geiger – 2nd expert on this subject based on the ideXlab platform

  • cellular responses and cytokine profiles in Ascaris lumbricoides and trichuris trichiura infected patients
    Parasite Immunology, 2002
    Co-Authors: Stefan M Geiger, Cristiano Lara Massara, Jeffrey M Bethony, Peter T Soboslay, Omar Dos Santos Carvalho, Rodrigo Correaoliveira


    Abstract The impact of intestinal helminth infection, i.e. Ascaris lumbricoides and Trichuris trichiura, on cellular responsiveness and cytokine production was investigated in young adults. Ascaris-specific cellular responsiveness was higher in parasite-free endemic controls than in patients infected with T. trichiura, or A. lumbricoides, or patients co-infected with both parasites. Also, mitogen-induced tumour necrosis factor (TNF)-alpha, interleukin (IL)-12 and interferon (IFN)-gamma secretion by peripheral blood mononuclear cells (PBMC) was higher in negative endemic controls than in infected individuals. Ascaris antigen-specific production of TNF-alpha, IL-12 and IFN-gamma was low in singly Ascaris as well as in co-infected patients, whereas secretion of IL-10 and IL-13 was elevated and similarly high in all patient groups. The detection of Trichuris-specific and Ascaris-specific IgG4 revealed significantly higher serum antibody levels in Trichuris or Ascaris patients when compared to endemic controls (P < 0.05), whereas parasite-specific IgE antibody levels were similarly high in infected individuals and in endemic controls. In summary, chronically infected Ascaris and Trichuris patients with a high parasite load presented reduced cellular reactivity and lower type 1 TNF-alpha, IFN-gamma and IL-12 responses when compared with endemic controls, whereas type 2 IL-10 and IL-13 productions were similar in all groups from the endemic area. The former may support parasite persistence, whereas substantial type 2 cytokine release may promote protective immunity, suggesting an adaptation of the host to control the parasite burden while minimizing immune-mediated host self-damage.

Jan L L Kimpen – 3rd expert on this subject based on the ideXlab platform

  • respiratory atopic disease Ascaris immunoglobulin e and tuberculin testing in urban south african children
    Clinical & Experimental Allergy, 2006
    Co-Authors: Charles C Obihara, Nulda Beyers, M O Hoekstra, John E Fincham, Ben J Marais, Carl Lombard, L A Dini, Jan L L Kimpen


    Background Epidemiological relation of intestinal helminth infection and atopic disease, both associated with a T-helper (Th) 2 immune response, is controversial, as it has been reported that helminth infection may either suppress or pre-dispose to atopic disease. This relation has not been tested in an area with a high burden of Mycobacterium tuberculosis (MTB) infection, a known Th1-stimulating infection.

    Objective To study the association of intestinal helminth infection and atopic disease in a community where helminth infection is endemic and MTB infection is high.

    Methods Three-hundred and fifty-nine randomly selected children aged 6–14 years from a poor urban suburb were tested with allergy questionnaire, skin prick test (SPT) to common aeroallergens, Ascaris-specific IgE (Ascaris-sIgE), fecal examination for pathogenic intestinal helminths and tuberculin skin testing (TST). Histamine bronchoprovocation was tested in the group of children aged 10 years and older. Results were corrected for demographic variables, socioeconomic status, parental allergy, environmental tobacco smoke (ETS) exposure in the household, recent anthelminthic treatment and for clustering in the sampling unit.

    Results Ascaris-sIgE was elevated in 48% of children, Ascaris eggs were found in 15% and TST was positive in 53%. Children with elevated Ascaris-sIgE had significantly increased risk of positive SPT to aeroallergens, particularly house dust mite, atopic asthma (ever and recent), atopic rhinitis (ever and recent) and increased atopy-related bronchial hyper-responsiveness. In children with negative TST (<10 mm), elevated Ascaris-sIgE was associated with significantly increased risk of atopic symptoms (adjusted odds ratio (ORadj) 6.5; 95% confidence interval (CI) 1.9–22.4), whereas in those with positive TST (10 mm) this association disappeared (ORadj 0.96; 95% CI 0.4–2.8).

    Conclusions These results suggest that immune response to Ascaris (Ascaris-sIgE) may be a risk factor of atopic disease in populations exposed to mild Ascaris infection and that MTB infection may be protective against this risk, probably by stimulation of anti-inflammatory networks.