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Objectives: In low malaria transmission areas, the elimination of the disease has been hampered partly by the existence of a reservoir of subpatent Plasmodium falciparum infections within communities. This reservoir, often undetected, serves as a source of parasites and contributes to ongoing transmission and clinical malaria cases., Methods: This study, spanning a period of 9 years from June 2014 to December 2022, examined individual variations and long-term subpatent P. falciparum carriage in two matched cohorts of 44 individuals each living in Dielmo village in the Sudanian area of Senegal. Biannual blood samples, collected in June/July and December of each year, underwent P. falciparum diagnosis by quantitative polymerase chain reaction. QGIS and R analytical tools were used to map infections, assess the occurrence and clustering of subpatent and clinical P. falciparum infections, and determine the risk of infection in the vicinity of asymptomatic P. falciparum carriers., Results: The point frequency and long-term P. falciparum carriage were significantly higher among the quantitative polymerase chain reaction (qPCR) positive cohort compared to the negative cohort across the 16 cross-sectional surveys analyzed in this study (19.76% vs 10.99%, P-value <0.001). Asymptomatic carriage events in qPCR-positive group were 18.86 ± 1.72% and significantly greater (P-value = 0.001) than in the qPCR-negative group (11.32 ± 1.32%). The relative risk of P. falciparum infection or clinical malaria calculated with a 95% confidence interval significantly increased in the vicinity of infected individuals and was 1.44 (P-value = 0.53) and 2.64 (P-value = 0.04) when at least one individual in the direct (household) or indirect (block of households) vicinity is infected, respectively. The risk increased to 3.64 (P-value <0.001) if at least 1/5 of individuals in the indirect vicinity were P. falciparum-infected., Conclusions: The study provides a detailed qualitative and quantitative analysis of the asymptomatic P. falciparum reservoir and its temporal and spatial dynamics within two subgroups of P. falciparum-infected and non-infected individuals in Dielmo village. It identified high-risk populations known as "hotpops" and hotspots that could be targeted by innovative interventions to accelerate the elimination of malaria in Dielmo village., Competing Interests: Declarations of competing interest The authors have declared that no competing interests exist., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Peanuts and peanut products are significant revenue sources for smallholder farmers in the Senegalese peanut basin. However, microbial contamination during production and storage can greatly affect market access for producers. Peanut products have emerged as possible sources of foodborne illness, encouraging discussions on international standards for peanuts. In this study, we interviewed 198 households throughout the Senegalese peanut basin to assess current production practices, storage methods, and producers' prior knowledge of microbial contamination using a 162-question survey. A member of each household orally completed the survey with a trained enumerator and the results were compared to microbiological results obtained from peanut samples collected at the time of the interview using linear regression and an analysis of variance model. Samples were collected from stored peanuts at each household; peanuts were shelled and total Enterobacteriaceae, coliform, and yeast and mold populations were enumerated. Of the 198 samples analyzed, 13.0% and 13.6% were greater than the upper detection limits for Enterobacteriaceae and coliforms, respectively. A total of 21.2% of samples were above the detection limit for yeast and mold populations. Only 22.7% and 18.7% of producers were aware of pathogenic bacteria or aflatoxins, respectively; there were no significant differences in observed microbial populations between household who took preventative measures against microbial contamination and those who did not. Additionally, four households reported washing their kitchen utensils before using them to eat and 60.1% reported always washing their hands before eating. Enumerators were asked to report peanut storage container type and if the containers were stored off the ground at the time of collection. While the interaction between storage container type and if the container was stored off the ground was significant for Enterobacteriaceae and coliforms, it was not significant for yeast and mold. Additionally, when storage container type and if peanuts were stored off the ground were included in the regression model, these methods were predictive of contamination levels for Enterobacteriaceae and coliforms. To our knowledge, this is the first study to analyze the relationship among Enterobacteriaceae, coliforms, and yeast and mold contamination and producer knowledge of Senegalese peanuts. These results provide preliminary data to inform future studies to determine pathogen prevalence and impactful preventative measures to minimize microbial contamination of peanuts produced in Senegal., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Mass drug administration (MDA) with azithromycin is a cornerstone of the trachoma elimination strategy. Although the global prevalence of active trachoma has declined considerably, prevalence persists or even increases in some communities and districts. To increase understanding of MDA impact, we investigated the prevalence of active trachoma and ocular C. trachomatis prevalence, organism load, and circulating strains at baseline and one-year post-MDA in The Gambia and Senegal., Methods: Pre- and one-year post-MDA, children aged 0-9 years were examined for clinical signs of trachoma in six Gambian and 12 Senegalese villages. Ocular swabs from each child's right conjunctiva were tested for evidence of ocular C. trachomatis infection and organism load (ompA copy number), and ompA and multi-locus sequence typing (MLST) was performed., Results: A total of 1171 children were examined at baseline and follow-up in The Gambia. Active trachoma prevalence decreased from 23.9% to 17.7%, whereas ocular C. trachomatis prevalence increased from 3.0% to 3.8%. In Senegal, 1613 and 1771 children were examined at baseline and follow-up, respectively. Active trachoma prevalence decreased from 14.9% to 8.0%, whereas ocular C. trachomatis prevalence increased from 1.8% to 3.6%. Higher organism load was associated with having active trachoma and severe inflammation. Sequence typing demonstrated that all Senegalese samples were genovar A, whereas Gambian samples were a mix of genovars A and B. MLST provided evidence of clustering at village and household levels and demonstrated differences of strain variant frequencies in Senegal, indicative of an "outbreak". MLST, including partial ompA typing, provided greater discriminatory power than complete ompA typing., Conclusions: We found that one round of MDA led to an overall decline in active trachoma prevalence but no impact on ocular C. trachomatis infection, with heterogeneity observed between villages studied. This could not be explained by MDA coverage or number of different circulating strains pre- and post-MDA. The poor correlation between active trachoma and infection prevalence supports the need for further work on alternative indicators to clinical signs for diagnosing ocular C. trachomatis infection. MLST typing has potential molecular epidemiology utility, including better understanding of transmission dynamics, although relationship to whole-genome sequence variability requires further exploration.

Background: The clinical signs of active trachoma are often present in the absence of ocular Chlamydia trachomatis infection in low prevalence and mass treated settings. Treatment decisions are currently based on the prevalence of clinical signs, and this may result in the unnecessary distribution of mass antibiotic treatment. We aimed to evaluate the diagnostic accuracy of a prototype point-of-care (POC) test, developed for field diagnosis of ocular C. trachomatis, in low prevalence settings of The Gambia and Senegal., Methodology/principal Findings: Three studies were conducted, two in The Gambia and one in Senegal. Children under the age of 10 years were screened for the clinical signs of trachoma. Two ocular swabs were taken from the right eye. The first swab was tested by the POC test in the field and the result independently graded by two readers. The second swab was tested for the presence of C. trachomatis by Amplicor Polymerase Chain Reaction. In Senegal, measurements of humidity and temperature in the field were taken. A total of 3734 children were screened, 950 in the first and 1171 in the second Gambian study, and 1613 in Senegal. The sensitivity of the prototype POC test ranged between 33.3-67.9%, the specificity between 92.4-99.0%, the positive predictive value between 4.3-21.0%, and the negative predictive value between 98.0-99.8%. The rate of false-positives increased markedly at temperatures above 31.4°C and relative humidities below 11.4%., Conclusions/significance: In its present format, this prototype POC test is not suitable for field diagnosis of ocular C. trachomatis as its specificity decreases in hot and dry conditions: the environment in which trachoma is predominantly found. In the absence of a suitable test for infection, trachoma diagnosis remains dependent on clinical signs. Under current WHO recommendations, this is likely resulting in the continued mass treatment of non-infected communities.