Background: Partial protective immunity to schistosomiasis develops over time, following repeated praziquantel treatment. Moreover, animals develop protective immunity after repeated immunisation with irradiated cercariae. Here, we evaluated development of natural immunity through consecutive exposure-treatment cycles with Schistosoma mansoni (Sm) in healthy, Schistosoma-naïve participants using single-sex controlled human Sm infection.
View Article and Find Full Text PDFLancet Glob Health
November 2024
Background: Vaccine immunogenicity and effectiveness vary geographically. Chronic immunomodulating parasitic infections including schistosomes and malaria have been hypothesised to be mediators of geographical variations.
Methods: We compared vaccine-specific immune responses between three Ugandan settings (schistosome-endemic rural, malaria-endemic rural, and urban) and did causal mediation analysis to assess the role of Schistosoma mansoni and malaria exposure in observed differences.
Background: Immune responses induced by several important vaccines differ between populations, with reduced responses in low-income and rural settings compared with high-income and urban settings. BCG immunisation boosts immune responses to some unrelated vaccines in high-income populations. We aimed to test the hypothesis that BCG revaccination can enhance responses to unrelated vaccines in Ugandan schoolchildren.
View Article and Find Full Text PDFLancet Glob Health
November 2024
Background: Several important vaccines differ in immunogenicity and efficacy between populations. We hypothesised that malaria suppresses responses to unrelated vaccines and that this effect can be reversed-at least partially-by monthly malaria intermittent preventive treatment (IPT) in high-transmission settings.
Methods: We conducted an individually randomised, double-blind, placebo-controlled trial of the effect of malaria IPT with dihydroartemisinin-piperaquine on vaccine responses among schoolchildren aged 9-17 years in Jinja district, Uganda.
Lancet Glob Health
November 2024
Background: Vaccine responses differ between populations and are often impaired in rural and low-income settings. The reasons for this are not fully understood, but observational data suggest that the immunomodulating effects of parasitic helminths might contribute. We hypothesised that Schistosoma mansoni infection suppresses responses to unrelated vaccines, and that suppression could be reversed-at least in part-by intensive praziquantel administration.
View Article and Find Full Text PDFInt J Infect Dis
December 2024
Objectives: Despite evidence of praziquantel's (PZQ) safety for treating schistosomiasis in pregnancy, many countries withhold treatment. Only two randomized controlled trials have investigated PZQ in pregnancy, none involving Schistosoma haematobium.
Methods: Pregnant women during the second trimester in Lambaréné (Gabon) were screened for S.
Infection with Schistosoma haematobium causes urogenital disease associated with organ disfunction, bleeding, pain, and higher susceptibility to infections and cancer. Timely and accurate diagnosis is crucial for prompt and appropriate treatment as well as surveillance efforts, and the use of plasma biomarkers offers important advantages over parasitological examination of urine, including increased sensitivity and the possibility to use the same specimen for multiple investigations. The present study aims to evaluate the diagnostic performance of different plasma biomarkers in endemic populations from Burkina Faso, West Africa.
View Article and Find Full Text PDFFront Immunol
September 2024
A laboratory-based lateral flow (LF) test that utilizes up-converting reporter particles (UCP) for ultrasensitive quantification of circulating anodic antigen (CAA) in urine is a well-accepted test to identify active infection. However, this UCP-LF CAA test requires sample pre-treatment steps not compatible with field applications. Flow, a new low-cost disposable, allows integration of large-volume pre-concentration of urine analytes and LF detection into a single field-deployable device.
View Article and Find Full Text PDFBackground: Reasons for the high prevalence of Kaposi sarcoma-associated herpesvirus (KSHV) in sub-Saharan Africa, and risk factors leading to viral reactivation and shedding, remain largely undefined. Preliminary studies have suggested that schistosome infection, which has been associated with impaired viral control, is associated with KSHV. In this study we sought to determine the relationship between active or infection and KSHV shedding.
View Article and Find Full Text PDFPLoS Negl Trop Dis
April 2024
Introduction: Schistosomiasis is a parasitic infection highly prevalent in sub-Saharan Africa (SSA) with Madagascar being among the countries with highest burden of the disease worldwide. Despite WHO recommendations, suggesting treatment of pregnant women after the first trimester, this group is still excluded from Mass Drug Administration programs. Our study, had the objective to measure the prevalence of schistosome infection among pregnant women in Madagascar in order to inform public health policies for treatment in this vulnerable population.
View Article and Find Full Text PDFOver 240 million people are infected with schistosomiasis. Detecting eggs in stool using Kato-Katz thick smears (Kato-Katzs) is highly specific but lacks sensitivity. The urine-based point-of-care circulating cathodic antigen test (POC-CCA) has higher sensitivity, but issues include specificity, discrepancy between batches and interpretation of trace results.
View Article and Find Full Text PDFControl of schistosomiasis depends on a single drug, praziquantel, with variable cure rates, high reinfection rates, and risk of drug resistance. A vaccine could transform schistosomiasis control. Preclinical data show that vaccine development is possible, but conventional vaccine efficacy trials require high incidence, long-term follow-up, and large sample size.
View Article and Find Full Text PDFSchistosomiasis is a disease caused by parasitic flatworms of the Schistosoma spp., and is increasingly recognized to alter the immune system, and the potential to respond to vaccines. The impact of endemic infections on protective immunity is critical to inform vaccination strategies globally.
View Article and Find Full Text PDFSchistosomiasis is a major neglected tropical disease (NTD) affecting both humans and animals. The morbidity and mortality inflicted upon livestock in the Afrotropical region has been largely overlooked, in part due to a lack of validated sensitive and specific tests, which do not require specialist training or equipment to deliver and interpret. As stressed within the recent WHO NTD 2021-2030 Roadmap and Revised Guideline for schistosomiasis, inexpensive, non-invasive, and sensitive diagnostic tests for livestock-use would also facilitate both prevalence mapping and appropriate intervention programmes.
View Article and Find Full Text PDFUnlabelled: The impact of endemic infections on protective immunity is critical to inform vaccination strategies. In this study, we assessed the influence of infection on host responses in a Ugandan fishing cohort given a Hepatitis B (HepB) vaccine. Concentrations of schistosome-specific circulating anodic antigen (CAA) pre-vaccination showed a significant bimodal distribution associated with HepB titers, which were lower in individuals with high CAA.
View Article and Find Full Text PDFPLoS Negl Trop Dis
December 2022
Background: Most studies assessing praziquantel (PZQ) efficacy have used relatively insensitive diagnostic methods, thereby overestimating cure rate (CR) and intensity reduction rate (IRR). To determine accurately PZQ efficacy, we employed more sensitive DNA and circulating antigen detection methods.
Methodology: A sub-analysis was performed based on a previously published trial conducted in children from Côte d'Ivoire with a confirmed Schistosoma mansoni infection, who were randomly assigned to a standard (single dose of PZQ) or intense treatment group (4 repeated doses of PZQ at 2-week intervals).
Background: Female genital schistosomiasis (FGS) occurs when eggs are deposited in reproductive tissue. Female genital schistosomiasis in the cervical mucosa is associated with increased vascularity. If FGS is associated with the presence of hemoglobin in cervicovaginal lavage (CVL), the use of urinary reagent strips to detect hemoglobin in CVL could supplement FGS diagnosis.
View Article and Find Full Text PDFSchistosomes infect over 200 million people worldwide, but few studies have characterized the effects of Schistosoma mansoni infection and effective treatment on the lower gastrointestinal mucosa. In this prospective cohort study, we compared the clinical findings on sigmoidoscopy and laboratory measures in Tanzanian adults with and without S. mansoni infection at baseline and 6 months after praziquantel treatment.
View Article and Find Full Text PDFTrop Med Infect Dis
October 2022
Background: Knowing the prevalence of schistosomiasis is key to informing programmes to control and eliminate the disease as a public health problem. It is also important to understand the impact of infection on child growth and development in order to allocate appropriate resources and effort to the control of the disease.
Methods: We conducted a survey to estimate the prevalence of schistosomiasis among school aged children in villages along the Albert-Nile shore line in the district of Pakwach, North Western Uganda.
Am J Trop Med Hyg
April 2022
The increasing number of refugees coming from or passing through Schistosoma-endemic areas and arriving in Europe highlights the importance of screening for schistosomiasis on arrival, and focuses attention on the choice of diagnostic test. We evaluate the diagnostic performance of circulating anodic antigen (CAA) detection in 92 asymptomatic refugees from Eritrea. Results were compared with already-available stool microscopy, serology, and urine point-of-care circulating cathodic antigen (POC-CCA) data.
View Article and Find Full Text PDFTrials
November 2021
Background: Mass drug administration (MDA) of praziquantel is one of the main control measures against human schistosomiasis. Although there are claims for including pregnant women, infants and children under the age of 5 years in high-endemic regions in MDA campaigns, they are usually not treated without a diagnosis. Diagnostic tools identifying infections at the primary health care centre (PHCC) level could therefore help to integrate these vulnerable groups into control programmes.
View Article and Find Full Text PDF