Search

Objective To determine if the prevalence of schistosomiasis in children aged 9- 12 years is associated with the prevalence in 5-8-year-olds and adults after preventive chemotherapy in schools or the community. Methods We combined data from four community-randomized, preventive chemotherapy trials in treatment-naive populations in Cote d'Ivoire, Kenya and the United Republic of Tanzania during 2010-2016 according to the number of praziquantel treatments and the delivery method. Schistosoma mansoni infection was sought on two slides prepared from each participant's first stool using the Kato-Katz technique. We assessed associations between S. mansoni prevalence in 9-12-year-olds and 5- 8-year-olds and adults in the community before and after treatment using Bayesian regression models. Findings Stool samples from 47 985 5-8-year-olds, 81 077 9-12-year-olds and 20 492 adults were analysed. We found associations between the prevalence in 9-12-year-olds and that in 5-8-year-olds and adults after preventive treatment, even when only school-age children were treated. When the prevalence in 9-12-year-olds was under 10%, the prevalence in 5-8-year-olds was consistently under 10%. When the prevalence in 9-12-year-olds was under 50%, the prevalence in adults after two or four rounds of preventive chemotherapy was 10%-15% lower than before chemotherapy. Post-chemotherapy age-group associations were consistent with pre-chemotherapy associations in this analysis and previous studies. Conclusion The prevalence of S. mansoni infection in 9-12-year-olds was associated with the prevalence in other age groups and could be used to guide community treatment decisions. Abstracts in [phrase omitted], Francais, [phrase omitted] and Espanol at the end of each article. [phrase omitted] Objectif Determiner si la prevalence de la schistosomiase chez les enfants de 9 a 12 ans est associee a celle observee chez les 5-8 ans et les adultes apres une chimiotherapie preventive au sein des ecoles ou de la communaute. Methodes Nous avons regroupe les donnees provenant de quatre essais randomises de chimiotherapie preventive menes en milieu communautaire aupres de populations n'ayant jamais ete traitees en Cote d'Ivoire, au Kenya et en Republique-Unie de Tanzanie entre 2010 et 2016, en fonction du nombre de traitements au praziquantel et du mode d'administration. Une infection a Schistosoma mansoni a ete recherchee sur deux lames preparees a partir des premieres selles de chaque participant, a l'aide de la technique de Kato-Katz. Nous avons employe des modeles de regression bayesienne qui nous ont permis d'identifier un rapport entre la prevalence de S. mansoni au sein de la communaute chez les 9-12 ans d'une part, et chez les 5-8 ans et les adultes de l'autre, avant et apres traitement. Resultats Les echantillons de selles de 47 985 enfants ages de 5 a 8 ans, 81 077 enfants de 9 a 12 ans et 20 492 adultes ont ete analyses. Nous avons constate qu'apres un traitement preventif, la prevalence chez les 9-12 ans ainsi que chez les 5-8 ans et les adultes etait liee, meme quand seuls les enfants d'age scolaire etaient traites. Lorsque la prevalence chez les 9-12 ans etait inferieure a 10%, celle chez les 5-8 ans etait systematiquement sous les 10%. Lorsque la prevalence chez les 9-12 ans etait inferieure a 50%, celle chez les adultes apres deux ou quatre traitements par chimiotherapie preventive etait 10 a 15% plus faible qu'avant toute chimiotherapie. Les liens par categorie d'age en post-chimiotherapie etaient coherents avec ceux en pre-chimiotherapie, tant dans la presente analyse que dans de precedentes etudes. Conclusion La prevalence de l'infection a S. mansoni chez les 9-12 ans etait associee a la prevalence dans d'autres categories d'age, ce qui pourrait servir a orienter les decisions de prise en charge au sein de la communaute. [phrase omitted] Objetivo Determinar si la prevalencia de la esquistosomiasis en ninos de 9 a 12 anos esta asociada con la prevalencia en ninos de 5 a 8 anos y adultos tras la quimioterapia preventiva en escuelas o en la comunidad. Metodos Se combinaron datos de cuatro ensayos aleatorizados a nivel comunitario de quimioterapia preventiva en poblaciones sin tratamiento en Costa de Marfil, Kenia y la Republica Unida de Tanzania entre 2010 y 2016 segun el numero de tratamientos con praziquantel y el metodo de administracion. La infeccion por Schistosoma mansoni se busco en dos laminillas preparadas a partir de las primeras heces de cada participante mediante la tecnica de Kato-Katz. Se evaluaron las asociaciones entre la prevalencia de S. mansoni en ninos de 9 a 12 anos y de 5 a 8 anos y adultos en la comunidad antes y despues del tratamiento mediante modelos de regresion bayesiana. Resultados Se analizaron muestras de heces de 47 985 ninos de 5 a 8 anos, 81 077 ninos de 9 a 12 anos y 20 492 adultos. Se encontraron asociaciones entre la prevalencia en ninos de 9 a 12 anos y la de ninos de 5 a 8 anos y adultos tras el tratamiento preventivo, incluso cuando solo se trato a ninos en edad escolar. Cuando la prevalencia en ninos de 9 a 12 anos era inferior al 10%, la prevalencia en ninos de 5 a 8 anos era siempre inferior al 10%. Cuando la prevalencia en ninos de 9 a 12 anos era inferior al 50%, la prevalencia en adultos despues de dos o cuatro ciclos de quimioterapia preventiva era entre un 10% y un 15% inferior que antes de la quimioterapia. Las asociaciones entre grupos de edad tras la quimioterapia fueron coherentes con las asociaciones previas a la quimioterapia en este analisis y en estudios anteriores. Conclusion La prevalencia de la infeccion por S. mansoni en ninos de 9 a 12 anos se asocio con la prevalencia en otros grupos de edad. Ademas, podria utilizarse para orientar las decisiones de tratamiento en la comunidad., Introduction Control programmes for schistosomiasis, the human disease caused by worms of the genus Schistosoma, focus on collecting and evaluating data from school-age children. (1) The use of school-age children [...]

Background: The standard diagnosis of Ascaris lumbricoides and other soil-transmitted helminth (STH) infections relies on the detection of worm eggs by copromicroscopy. However, this method is dependent on worm patency and shows only limited accuracy in low-intensity infection settings. We aimed to decipher the diagnostic accuracy of different antibodies using various Ascaris antigens in reference to copromicroscopy and quantitative PCR (qPCR), four months after national STH preventative chemotherapy among school children in western Kenya. Methodology: STH infection status of 390 school children was evaluated via copromicroscopy (Kato-Katz and mini-FLOTAC) and qPCR. In parallel, Ascaris-specific antibody profiles against larval and adult worm lysates, and adult worm excretory-secretory (ES) products were determined by enzyme-linked immunosorbent assay. Antibody cross-reactivity was evaluated using the closely related zoonotic roundworm species Toxocara cati and Toxocara canis. The diagnostic accuracy of each antibody was evaluated using receiver operating curve analysis and the correspondent area under the curve (AUC). Principal findings: Ascaris was the predominant helminth infection with an overall prevalence of 14.9% (58/390). The sensitivity of mini-FLOTAC and Kato-Katz for Ascaris diagnosis reached only 53.5% and 63.8%, respectively compared to qPCR. Although being more sensitive, qPCR values correlated with microscopic egg counts (R = -0.71, P<0.001), in contrast to antibody levels. Strikingly, IgG antibodies recognizing the ES products of adult Ascaris worms reliably diagnosed active Ascaris infection as determined by qPCR and microscopy, with IgG1 displaying the highest accuracy (AUC = 0.83, 95% CI: 0.75–0.91). Conclusion: IgG1 antibody responses against adult Ascaris-ES products hold a promising potential for complementing the standard fecal and molecular techniques employed for monitoring Ascaris infections. This is of particular importance in the context of deworming programs as the antibody diagnostic accuracy was independent of egg counts. Author summary: Ascaris lumbricoides is the most common human intestinal helminth globally, affecting a quarter of the world's population. Microscopic methods are used to diagnose and monitor Ascaris infections. However, these methods are unsatisfactory for diagnosing low-intensity infections, are prone to human error, their accuracy is greatly affected by the heterogeneous distribution of worm eggs and are limited to detecting only patent infections. qPCR offers an attractive alternative with regard to sensitivity and high-throughput capacity but is also limited by worm patency. Here, we compared the diagnostic accuracy of different antibodies using Ascaris antigen lysates as well as Ascaris excretory/secretory (ES) products using copromicroscopy and qPCR as reference. Our data show that IgG1 antibody responses directed against ES antigens of adult Ascaris worms, but not against the infective third-stage larval or adult worm extracts, reliably decipher between Ascaris-infected and Ascaris-negative participants independent of the microscopic egg counts. Our study is the first to report strong IgG1 responses directed against ES products of adult worms and their potential value as markers for an active Ascaris infection. Our results indicate the potential to develop an antibody-based Ascaris-immunoassay utilizing Ascaris-ES antigens to complement the monitoring of reinfections and transmission dynamics. [ABSTRACT FROM AUTHOR]

Background: Control and elimination of schistosomiasis is an arduous task, with current strategies proving inadequate to break transmission. Exploration of genetic approaches to interrupt Schistosoma mansoni transmission, the causative agent for human intestinal schistosomiasis in sub-Saharan Africa and South America, has led to genomic research of the snail vector hosts of the genus Biomphalaria. Few complete genomic resources exist, with African Biomphalaria species being particularly underrepresented despite this being where the majority of S. mansoni infections occur. Here we generate and annotate the first genome assembly of Biomphalaria sudanica sensu lato, a species responsible for S. mansoni transmission in lake and marsh habitats of the African Rift Valley. Supported by whole-genome diversity data among five inbred lines, we describe orthologs of immune-relevant gene regions in the South American vector B. glabrata and present a bioinformatic pipeline to identify candidate novel pathogen recognition receptors (PRRs). Results: De novo genome and transcriptome assembly of inbred B. sudanica originating from the shoreline of Lake Victoria (Kisumu, Kenya) resulted in a haploid genome size of ~ 944.2 Mb (6,728 fragments, N50 = 1.067 Mb), comprising 23,598 genes (BUSCO = 93.6% complete). The B. sudanica genome contains orthologues to all described immune genes/regions tied to protection against S. mansoni in B. glabrata, including the polymorphic transmembrane clusters (PTC1 and PTC2), RADres, and other loci. The B. sudanica PTC2 candidate immune genomic region contained many PRR-like genes across a much wider genomic region than has been shown in B. glabrata, as well as a large inversion between species. High levels of intra-species nucleotide diversity were seen in PTC2, as well as in regions linked to PTC1 and RADres orthologues. Immune related and putative PRR gene families were significantly over-represented in the sub-set of B. sudanica genes determined as hyperdiverse, including high extracellular diversity in transmembrane genes, which could be under pathogen-mediated balancing selection. However, no overall expansion in immunity related genes was seen in African compared to South American lineages. Conclusions: The B. sudanica genome and analyses presented here will facilitate future research in vector immune defense mechanisms against pathogens. This genomic/transcriptomic resource provides necessary data for the future development of molecular snail vector control/surveillance tools, facilitating schistosome transmission interruption mechanisms in Africa. [ABSTRACT FROM AUTHOR]