15 research outputs found
<i>Schistosoma haematobium</i> effects on <i>Plasmodium falciparum</i> infection modified by soil-transmitted helminths in school-age children living in rural areas of Gabon
<div><p>Background</p><p>Malaria burden remains high in the sub-Saharan region where helminths are prevalent and where children are often infected with both types of parasites. Although the effect of helminths on malaria infection is evident, the impact of these co-infections is not clearly elucidated yet and the scarce findings are conflicting. In this study, we investigated the effect of schistosomiasis, considering soil-transmitted helminths (STH), on prevalence and incidence of <i>Plasmodium falciparum</i> infection.</p><p>Methodology</p><p>This longitudinal survey was conducted in school-age children living in two rural communities in the vicinity of Lambaréné, Gabon. Thick blood smear light microscopy, urine filtration and the Kato-Katz technique were performed to detect malaria parasites, <i>S</i>. <i>haematobium</i> eggs and, STH eggs, respectively. <i>P</i>. <i>falciparum</i> carriage was assessed at inclusion, and incidence of malaria and time to the first malaria event were recorded in correlation with Schistosoma carriage status. Stratified multivariate analysis using generalized linear model was used to assess the risk of plasmodium infection considering interaction with STH, and survival analysis to assess time to malaria.</p><p>Main findings</p><p>The overall prevalence on subject enrolment was 30%, 23% and 9% for <i>S</i>. <i>haematobium</i>, <i>P</i>. <i>falciparum</i> infections and co-infection with both parasites, respectively. Our results showed that schistosomiasis in children tends to increase the risk of plasmodium infection but a combined effect with <i>Trichuris trichiura</i> or hookworm infection clearly increase the risk (aOR = 3.9 [<sub>95%</sub>CI: 1.7–9.2]). The incidence of malaria over time was 0.51[<sub>95%</sub>CI: 0.45–0.57] per person-year and was higher in the Schistosoma-infected group compared to the non-infected group (0.61 <i>vs</i> 0.43, <i>p</i> = 0.02), with a significant delay of time-to first-malaria event only in children aged from 6 to 10-years-old infected with <i>Schistosoma haematobium</i>.</p><p>Conclusions</p><p>Our results suggest that STH enhance the risk for <i>P</i>. <i>falciparum</i> infection in schistosomiasis-positive children, and when infected, that schistosomiasis enhances susceptibility to developing malaria in young children but not in older children.</p></div
Potential risk factors including <i>S</i>. <i>haematobium</i> infection associated with <i>P</i>. <i>falciparum</i> infection among the 739 participants seen at baseline.
<p>Potential risk factors including <i>S</i>. <i>haematobium</i> infection associated with <i>P</i>. <i>falciparum</i> infection among the 739 participants seen at baseline.</p
Malaria risk and malaria incidence among the 584 participants according to Schistosoma status and other risk factors.
<p>Malaria risk and malaria incidence among the 584 participants according to Schistosoma status and other risk factors.</p
Distribution of <i>P</i>. <i>falciparum</i> and <i>S</i>. <i>haematobium</i> infections among the 739 participants seen at baseline.
<p>Distribution of <i>P</i>. <i>falciparum</i> and <i>S</i>. <i>haematobium</i> infections among the 739 participants seen at baseline.</p
Depicts estimates of time to malaria after 52 weeks of follow-up.
<p>Depicted in the vertical axis the proportion of children who did not experience malaria and in the horizontal axis, the follow-up time in months. In red, children in <i>S</i>. <i>haematobium</i> non-infected group and in blue children in <i>S</i>. <i>haematobium</i> infected group. 2A) Kaplan Meier curve for time-to-first malaria case for overall study population. 2B) Kaplan Meier curve for time-to-first malaria case for children aged from 6 to 10 years old. 2C) Kaplan Meier curve for time-to-first malaria case for children aged from 11 to 16 years old.</p
Characteristics of study groups considered for longitudinal analysis regarding Schistosoma status (N = 586).
<p>Characteristics of study groups considered for longitudinal analysis regarding Schistosoma status (N = 586).</p
Flow chart of the participants during the study course.
<p>The inclusion phase is shown as a solid line and the follow-up phase is shown as a broken line.</p
Sensitivity, specificity, positive and negative predictive values of the <i>Loa loa</i> qPCR, in-house ELISA and Ll-SXP-1-RDT to detect loiasis defined by either a positive life-time history of eyeworm assessed by the RAPLOA questionnaire and/or detectable microfilaremia.
Sensitivity, specificity, positive and negative predictive values of the Loa loa qPCR, in-house ELISA and Ll-SXP-1-RDT to detect loiasis defined by either a positive life-time history of eyeworm assessed by the RAPLOA questionnaire and/or detectable microfilaremia.</p
The PCR settings for the <i>Loa loa</i> qPCR and <i>Mansonella</i> real-time FRET assay.
The PCR settings for the Loa loa qPCR and Mansonella real-time FRET assay.</p
A) An overview of ELISA seropositivity and arbitrary units (AU) as well as B) Ll-SXP-1-RDT positivity and absolute intensity of Reader Units (RU) by loiasis subgroups.
*Arbitrary Antibody Units, ** Interquartile range, *** Wilcoxon-rank sum test comparing median AU or RU. ‡Participants were defined by microfilaremia density as low (1–7,999 mf/mL), high (8,000–19,999 mf/mL) and hyper-microfilaremic (≥20,000 mf/mL).</p