The human malaria parasite Plasmodium falciparum is globally widespread, but its prevalence varies significantly between and even within countries. Most population genetic studies in P. falciparum focus on regions of high transmission where parasite populations are large and genetically diverse, such as sub-Saharan Africa. Understanding population dynamics in low transmission settings, however, is of particular importance as these are often where drug resistance first evolves. Here, we use the Pacific Coast of Colombia and Ecuador as a model for understanding the population structure and evolution of Plasmodium parasites in small populations harboring less genetic diversity. The combination of low transmission and a high proportion of monoclonal infections means there are few outcrossing events and clonal lineages persist for long periods of time. Yet despite this, the population is evolutionarily labile and has successfully adapted to changes in drug regime. Using newly sequenced whole genomes, we measure relatedness between 166 parasites, calculated as identity by descent (IBD), and find 17 distinct but highly related clonal lineages, six of which have persisted in the region for at least a decade. This inbred population structure is captured in more detail with IBD than other common population structure analyses like PCA, ADMIXTURE, and distance-based trees. We additionally use patterns of intra-chromosomal IBD and an analysis of haplotypic variation to explore past selection events in the region. Two genes associated with chloroquine resistance, crt and aat1, show evidence of hard selective sweeps, while selection appears soft and/or incomplete at three other key resistance loci (dhps, mdr1, and dhfr). Overall, this work highlights the strength of IBD analyses for studying parasite population structure and resistance evolution in regions of low transmission, and emphasizes that drug resistance can evolve and spread in small populations, as will occur in any region nearing malaria elimination.

Intestinal parasitic infections (IPIs) are a public health challenge in developing countries such as Colombia, causing anaemia and delayed growth and development in children. We aimed to estimate the geographical and prevalence trend of IPIs in the last 30 years in school and preschool children in Colombia. Methods: We conducted a systematic review and meta-analysis. We identified potential manuscripts through PubMed, EMBASE, Web of Science, LILACS, Scielo and Google Scholar on the IPIs prevalence in school and preschool children in Colombia. Articles included in the qualitative analysis were published between 1990 and 2020 in English or Spanish and met the inclusion criteria. Subsequently, a random-effects meta-analysis, a meta-regression and a trend analysis were performed. Results: We identified 2292 articles; 109 were included in the qualitative review, and 79 articles were included in the meta-analysis. The estimated IPI prevalence was 55% (95% CI: 48-63). By age group, the prevalence in preschool children was 37% (95% CI: 26-49) and 66% (95% CI: 52-78) in schoolchildren. The prevalence by region was heterogeneous, with the Amazon being the highest (69%) and the Santanderes the lowest (28%). In the last 20 years, the prevalence of helminthiasis has decreased (from 64.66% in 1990-1995 to 22.09% in 2016-2020). Conclusion:The prevalence of IPIs is high (>30%) in three of the seven regions in Colombia. Biannual administration of mass deworming in schoolchildren is recommended in the Amazon region. Public policies aiming to control IPIs should be reinforced. Further prevalence studies should include Cesar, Guaviare, Vichada and Vaupés, where the epidemiology of IPIs is unknown. Sustainable Development Goals: Good health and wellbeing, clean water and sanitation, sustainable cities and communities.

Objetivo Explicar las barreras para la eliminación de la malaria en Guapi (Cauca, Colombia), según la percepción de la comunidad.Método Se realizó un estudio cualitativo descriptivo de tipo exploratorio en Guapi, de octubre a noviembre de 2016, a través del análisis de contenido de grupos focales de ocho mujeres voluntarias y de análisis inductivo e interpretativo.Resultados Basadas en las respuestas de las voluntarias, se construyeron tres categorías, de las cuales se originaron cinco subcategorías relacionadas con barreras (tema) para la eliminación de la malaria que incluyen determinantes sociales del municipio tales como las barreras ambientales, culturales y de atención en salud. Todas ellas requieren de la intervención integral por parte de las diferentes dependencias del Estado, con la inclusión de las características propias de la comunidad guapireña.Conclusión Se identificó que la falta de planeación e infraestructura deficiente en el municipio obstaculiza no solo la eliminación de la malaria sino también la de otras enfermedades transmisibles. El desarrollo de actividades económicas como la minería, las prácticas de automedicación, la poca adherencia a las medidas de prevención por parte de la comunidad, la falta de contratación de profesionales y microscopistas y el difícil acceso a los servicios de salud constituyen las principales barreras para la eliminación de la malaria en este municipio de la región pacífica colombiana.

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