The Prevalence of Parasite Infestation and House Dust Mite Sensitization in Gabonese Schoolchildren

Biggelaar, Anita H. J. van den; Lopuhaä, Christa E.; Ree, Ronald van; Zee, Jaring S. van der; Jans, Judith; Hoek, Anita M. van den; Migombet, B.; Borrmann, Steffen; Luckner, Doris; Kremsner, Peter G.; Yazdanbakhsh, Maria

doi:10.1159/000049519

Cited by 108 publications

(94 citation statements)

References 21 publications

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“…One may therefore argue that observed effects of albendazole strike a good balance between efficacy, safety, and compliance, taking into account the possible protective effects of helminths against atopic diseases (20,21,27,29,46). If, however, a substantial worm reduction in a population is desired, a single dose of albendazole is insufficiently effective.…”

Section: Discussionmentioning

confidence: 99%

“…This study (registered at ClinicalTrials.gov under registration number NCT01192802) was designed as a single-center, randomized, controlled, assessor-blinded clinical trial to compare the efficacy and safety of an albendazole single-dose with a two-or three-dose regimen in school-age children residing in an In this region, soil-transmitted helminths (5,16,19), malaria, and schistosomiasis (19,21,(27)(28)(29) are endemic. Approximately 3,000 inhabitants reside in these villages, and houses typically have poor sanitation.…”

Section: Methodsmentioning

confidence: 99%

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Randomized, Controlled, Assessor-Blind Clinical Trial To Assess the Efficacy of Single- versus Repeated-Dose Albendazole To Treat Ascaris lumbricoides, Trichuris trichiura, and Hookworm Infection

Adegnika

Zinsou

Issifou

et al. 2014

Antimicrob Agents Chemother

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In many regions where soil-transmitted helminth infections are endemic, single-dose albendazole is used in mass drug administration programs to control infections. There are little data on the efficacy of the standard single-dose administration compared to that of alternative regimens. We conducted a randomized, controlled, assessor-blinded clinical trial to determine the efficacies of standard and extended albendazole treatment against soil-transmitted helminth infection in Gabon. A total of 175 children were included. Adequate cure rates and egg reduction rates above 85% were found with a single dose of albendazole for Ascaris infection, 85% (95% confidence interval [CI], 73, 96) and 93.8% (CI, 87.6, 100), respectively, while two doses were necessary for hookworm infestation (92% [CI, 78, 100] and 92% [CI, 78, 100], respectively). However, while a 3-day regimen was not sufficient to cure Trichuris (cure rate, 83% [CI, 73, 93]), this regimen reduced the number of eggs up to 90.6% (CI, 83.1, 100). The rate ratios of two-and three-dose regimens compared to a single-dose treatment were 1.7 (CI, 1.1, 2.5) and 2.1 (CI, 1.5, 2.9) for Trichuris and 1.7 (CI, 1.0, 2.9) and 1.7 (CI, 1.0, 2.9) for hookworm. Albendazole was safe and well tolerated in all regimens. A singledose albendazole treatment considerably reduces Ascaris infection but has only a moderate effect on hookworm and Trichuris infections. The single-dose option may still be the preferred regimen because it balances efficacy, safety, and compliance during mass drug administration, keeping in mind that asymptomatic low-level helminth carriage may also have beneficial effects. (This study has been registered at ClinicalTrials.gov under registration number NCT01192802.) S oil-transmitted helminths affect more than two billion people worldwide (1, 2). They are widely endemic in the tropics and are prevalent mostly in preschool and school-age children (3, 4) as well as in pregnant women (5). Infections are related to poor sanitation and hygiene and classified as neglected tropical diseases (6). These infections are responsible for significant morbidity, which includes anemia (7,8), stunting (9), and iron and vitamin A deficiencies (10-13). Additionally, helminth infections have the capacity to reduce the host immune response to vaccines as well as to environmental and parasitic antigens (14-16). The consequences of such hyporesponsiveness may explain changes in host susceptibility to commonly encountered pathogens, as reported recently (17)(18)(19). However, helminths may have beneficial effects as well, such as dampening of excessive inflammatory responses against other pathogens or environmental antigens (14, 20,21). Nevertheless, it is commonly accepted that the risks of helminth infection outweigh the benefits, and several public health interventions are in place to control soil-transmitted helminths.Albendazole is frequently used in mass drug administration (MDA) campaigns as a principal control tool for intestinal helminth infections (2,(22)(23)(24). Howeve...

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Randomized, Controlled, Assessor-Blind Clinical Trial To Assess the Efficacy of Single- versus Repeated-Dose Albendazole To Treat Ascaris lumbricoides, Trichuris trichiura, and Hookworm Infection

Adegnika

Zinsou

Issifou

et al. 2014

Antimicrob Agents Chemother

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“…Despite type 2 responses being considered necessary for the development of allergies, the presence of schistosome infections in humans may reduce allergic responses in infected populations (6). Thus, Schistosoma hematobium-infected school children in Gabon had a lower prevalence of skin reactivity to house dust mites than those free of this infection (7). Therefore, the chronic down-regulation of the immune system during helminth infection evokes a regulatory environment that may impart protection from allergies (8).…”

Section: Helminth Infection Protects Mice From Anaphylaxis Via Il-10-mentioning

confidence: 99%

Helminth Infection Protects Mice from Anaphylaxis via IL-10-Producing B Cells

Mangan

Fallon

Smith³

et al. 2004

The Journal of Immunology

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Modulation of the immune system by infection with helminth parasites, including schistosomes, is proposed to reduce the levels of allergic responses in infected individuals. In this study we investigated whether experimental infection with Schistosoma mansoni could alter the susceptibility of mice to an extreme allergic response, anaphylaxis. We formally demonstrate that S. mansoni infection protects mice from an experimental model of systemic fatal anaphylaxis. The worm stage of infection is shown to mediate this protective effect. In vivo depletion studies demonstrated an imperative role for B cells and IL-10 in worm-mediated protection. Furthermore, worm infection of mice increases the frequency of IL-10-producing B cells compared with that in uninfected mice. However, transfer of B cells from worm-infected mice or in vitro worm-modulated B cells to sensitized recipients exacerbated anaphylaxis, which was attributed to the presence of elevated levels of IL-4-producing B cells. Worm-modulated, IL-10-producing B cells from IL-4-deficient, but not IL-5-, IL-9- or IL-13-deficient, mice conferred complete resistance to anaphylaxis when transferred to naive mice. Therefore, we have dissected a novel immunomodulatory mechanism induced by S. mansoni worms that is dependent on an IL-10-producing B cell population that can protect against allergic hypersensitivity. These data support a role for helminth immune modulation in the hygiene hypothesis and further illustrate the delicate balance between parasite induction of protective regulatory (IL-10) responses and detrimental (IL-4) allergic responses.

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“…Another study showed an inverse correlation between Schistosoma mansoni infection and positive responses to aeroallergens in skin prick tests (3). In Gabon, school children infected with Schistosoma haematobium had a lower prevalence of skin reactivity to house dust mites than noninfected children (32). The mechanism involved in asthma modulation is currently being clarified, using a murine model.…”

mentioning

confidence: 99%

Schistosoma mansoni Antigens Modulate Experimental Allergic Asthma in a Murine Model: a Major Role for CD4 ⁺ CD25 ⁺ Foxp3 ⁺ T Cells Independent of Interleukin-10

et al. 2009

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In areas where schistosomiasis is endemic, a negative correlation is observed between atopy and helminth infection, associated with a low prevalence of asthma. We investigated whether Schistosoma mansoni infection or injection of parasite eggs can modulate airway allergic inflammation in mice, examining the mechanisms of such regulation. We infected BALB/c mice with 30 S. mansoni cercariae or intraperitoneally injected 2,500 schistosome eggs, and experimental asthma was induced by ovalbumin (OVA). The number of eosinophils in bronchoalveolar lavage fluid was higher in the asthmatic group than in asthmatic mice infected with S. mansoni or treated with parasite eggs. Reduced Th2 cytokine production, characterized by lower levels of interleukin-4 (IL-4), IL-5, and immunoglobulin E, was observed in both S. mansoni-treated groups compared to the asthmatic group. There was a reduction in the number of inflammatory cells in lungs of S. mansoni-infected and egg-treated mice, demonstrating that both S. mansoni infection and the egg treatment modulated the lung inflammatory response to OVA. Only allergic animals that were treated with parasite eggs had increased numbers of CD4 ؉ CD25 ؉ Foxp3 ؉ T cells and increased levels of IL-10 and decreased production of CCL2, CCL3, and CCL5 in the lungs compared to the asthmatic group. Neutralization of IL-10 receptor or depletion of CD25 ؉ T cells in vivo confirmed the critical role of CD4 ؉ CD25 ؉ Foxp3 ؉ regulatory T cells in experimental asthma modulation independent of IL-10.The prevalence of allergic diseases such as asthma has increased markedly over the past few decades (5). The immune response to allergens is characterized by eosinophilic inflammation of the airways, airway hyperreactivity, and immunoglobulin E (IgE) production by B cells (39). The immune etiology of asthma is complex. Genetic and immunological analyses of atopic individuals have revealed that Th2 cytokines are usually associated with allergies (23, 25). Furthermore, Th2 cells which produce interleukin-4 (IL-4), IL-5, and IL-13 mediate the inflammatory reaction in the lung. Production of IL-5 increases differentiation, recruitment, and survival of eosinophils and therefore plays an important role in the development of pulmonary eosinophilia during allergic disorders (26). Moreover, IL-13 is important for IgE production, mucus hyperplasia, and eosinophilia (34). The levels of these cytokines are higher in allergic patients and play a direct role in the inflammatory response.It has been suggested that people in developing countries suffer less from allergic disease than those who live in industrialized countries because the former are frequently exposed to bacteria and helminth infections associated with poverty and lack of basic sanitary conditions (21). Both helminth infections and allergic diseases are associated with Th2 cytokines and high levels of IgE and eosinophilia. Though they appear to have similar immune responses, a negative correlation between helminth infection and allergic disease has been obse...

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The Prevalence of Parasite Infestation and House Dust Mite Sensitization in Gabonese Schoolchildren

Cited by 108 publications

References 21 publications

Randomized, Controlled, Assessor-Blind Clinical Trial To Assess the Efficacy of Single- versus Repeated-Dose Albendazole To Treat Ascaris lumbricoides, Trichuris trichiura, and Hookworm Infection

Randomized, Controlled, Assessor-Blind Clinical Trial To Assess the Efficacy of Single- versus Repeated-Dose Albendazole To Treat Ascaris lumbricoides, Trichuris trichiura, and Hookworm Infection

Helminth Infection Protects Mice from Anaphylaxis via IL-10-Producing B Cells

Schistosoma mansoni Antigens Modulate Experimental Allergic Asthma in a Murine Model: a Major Role for CD4 ⁺ CD25 ⁺ Foxp3 ⁺ T Cells Independent of Interleukin-10

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The Prevalence of Parasite Infestation and House Dust Mite Sensitization in Gabonese Schoolchildren

Cited by 108 publications

References 21 publications

Randomized, Controlled, Assessor-Blind Clinical Trial To Assess the Efficacy of Single- versus Repeated-Dose Albendazole To Treat Ascaris lumbricoides, Trichuris trichiura, and Hookworm Infection

Randomized, Controlled, Assessor-Blind Clinical Trial To Assess the Efficacy of Single- versus Repeated-Dose Albendazole To Treat Ascaris lumbricoides, Trichuris trichiura, and Hookworm Infection

Helminth Infection Protects Mice from Anaphylaxis via IL-10-Producing B Cells

Schistosoma mansoni Antigens Modulate Experimental Allergic Asthma in a Murine Model: a Major Role for CD4 + CD25 + Foxp3 + T Cells Independent of Interleukin-10

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Schistosoma mansoni Antigens Modulate Experimental Allergic Asthma in a Murine Model: a Major Role for CD4 ⁺ CD25 ⁺ Foxp3 ⁺ T Cells Independent of Interleukin-10