Role of genetic factors and ethnicity on the multiplicity of Plasmodium falciparum infection in children with asymptomatic malaria in Yaoundé, Cameroon

Roman, Dongang Nana Rodrigue; Anne, Ngono Ngane Rosalie; Singh, Vineeta; Luther, Koanga Mogtomo Martin; Chantal, Ngonde Essome Marie; Albert, Mouelle Sone

doi:10.1016/j.heliyon.2018.e00760

Cited by 7 publications

(7 citation statements)

References 49 publications

(53 reference statements)

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“…For example, studies in Colombia and Cameroon found that there was a high probability of sampling-related parasites in different residents of the same and neighboring households [65,66]. Yet, there are also reports that have identified limited spatiotemporal correlation in parasite strains, consistent with local transmission networks being more stochastic in nature [67,68].…”

Section: Transmission Intensity Amentioning

confidence: 99%

“…It has been suggested that approximately 25% of the variation in individual susceptibility is due to host genetic factors [105,106]. Several genetic factors, including the sickle-cell trait, a-thalassemia, gucose-6-phosphate dehydrogenase deficiency, and having the O blood group, offer protection against infection, clinical symptoms, or severe disease [66,107]. An individual's attractiveness to mosquitoes has also been identified as a heritable trait, with those least attractive protected from malaria and those most attractive being most at risk [98,104].…”

Section: Human Geneticsmentioning

confidence: 99%

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Malaria Hotspots: Is There Epidemiological Evidence for Fine-Scale Spatial Targeting of Interventions?

Stresman

Bousema

Cook

2019

Trends in Parasitology

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As data at progressively granular spatial scales become available, the temptation is to target interventions to areas with higher malaria transmission -so-called hotspots -with the aim of reducing transmission in the wider community. This paper reviews literature to determine if hotspots are an intrinsic feature of malaria epidemiology and whether current evidence supports hotspot-targeted interventions. Hotspots are a consistent feature of malaria transmission at all endemicities. The smallest spatial unit capable of supporting transmission is the household, where peri-domestic transmission occurs. Whilst the value of focusing interventions to highburden areas is evident, there is currently limited evidence that local-scale hotspots fuel transmission. As boundaries are often uncertain, there is no conclusive evidence that hotspot-targeted interventions accelerate malaria elimination.

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Section: Transmission Intensity Amentioning

confidence: 99%

Section: Human Geneticsmentioning

confidence: 99%

Malaria Hotspots: Is There Epidemiological Evidence for Fine-Scale Spatial Targeting of Interventions?

Stresman

Bousema

Cook

2019

Trends in Parasitology

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“…In contrast, previous studies of the COI in African settings have found both higher average COI values in some regions and, in general, greater variability. For example, in Cameroon large mean COIs between 2.33 to 3.82 have been reported [61][62][63]. Conversely, in Ghana the mean COI has been reported to be between 1.13 and 1.91 in 2012-2013 [64].…”

Section: Discussionmentioning

confidence: 98%

coiaf: directly estimating complexity of infection with allele frequencies

Paschalidis

Watson

Aydemir

et al. 2022

Preprint

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In malaria, individuals are often infected with different parasite strains; the complexity of infection (COI) is defined as the number of genetically distinct parasite strains in an individual. Changes in the mean COI in a population have been shown to be informative of changes in transmission intensity with a number of probabilistic likelihood and Bayesian models now developed to estimate the COI. However, rapid, direct measures based on heterozygosity or FwS do not properly represent the COI. In this work, we present two new methods that use easily calculated measures to directly estimate the COI from allele frequency data. Using a simulation framework, we show that our methods are computationally efficient and comparably accurate to current methods in the literature. Through a sensitivity analysis, we characterize how the bias and accuracy of our two methods are impacted by the distribution of parasite densities and the assumed sequencing depth and number of sampled loci. We further estimate the COI globally from Plasmodium falciparum sequencing data using our developed methods and compare the results against the literature. We show significant differences in estimated COI globally between continents and a weak relationship between malaria prevalence and COI.Author summaryComputational models, used in conjunction with rapidly advancing sequencing technologies, are increasingly being used to help inform surveillance efforts and understand the epidemiological dynamics of malaria. One such important metric, the complexity of infection (COI), indirectly quantifies the level of transmission. Existing “gold-standard” COI measures rely on complex probabilistic likelihood and Bayesian models. As an alternative, we have developed the statistics and software package coiaf, which features two rapid, direct measures to estimate of the number of genetically distinct parasite strains in an individual (the COI). Our methods were evaluated using simulated data and subsequently compared to current “state-of-the-art” methods, yielding comparable results. Lastly, we examined the distribution of the COI in several locations across the world, identifying significant differences in COI between continents. coiaf, therefore, provides a new, promising framework for rapidly characterizing polyclonal infections.

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“…In countries with limited resources available for malaria control, identifying host genotypes that are associated with asymptomatic parasite carriage within the population can help in selecting the target population for certain control interventions. The influence of host genetics on malaria has been well studied over the past years; however, these studies mainly determine the influence on symptomatic malaria [ 46 ], with very few studies identifying how host genetics, particularly certain host gene polymorphisms, can influence asymptomatic P. falciparum parasite carriage [ 47 ]. This study was set out to determine whether some host factors that are known to protect people living in malaria-endemic settings from symptomatic malaria predispose them to harbor P. falciparum in asymptomatic infections.…”

Section: Discussionmentioning

confidence: 99%

Association of TNF-Alpha, MBL2, NOS2, and G6PD with Malaria Outcomes in People in Southern Ghana

et al. 2022

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Background. One major issue that has set back the gains of the numerous malaria control interventions that national malaria control programs have implemented is asymptomatic malaria. Certain host genetic factors are known to influence symptomatic malaria; however, not much is known about how host genetics influences the acquisition of asymptomatic malaria. Methods. Genomic DNA was extracted from whole blood collected from 60 symptomatic and 149 nonfebrile (asymptomatic, N = 109, and uninfected, N = 40) volunteers aged between 2 and 69 years from a high (Obom) and a low (Asutsuare) malaria transmission setting in Southern Ghana. Restriction fragment length polymorphism (RFLP) was used to determine polymorphisms at the MBL2 54, TNF-α 308, NOS2 954, and G6PD 202/376 gene loci. Results. Polymorphisms at the MBL2 54 and TNF-α 308 loci were significantly different amongst the three categories of volunteers in both Asutsuare (p = 0.006) and Obom p = 0.05 . In Asutsuare, a low malaria transmission area, the allele G has significantly higher odds (3.15) of supporting asymptomatic malaria as against symptomatic malaria. There were significantly higher odds of TNF-α genotype GA being associated with symptomatic malaria as against asymptomatic malaria in both sites, Obom p = 0.027 and Asutsuare p = 0.027 . The allele B of the G6PD gene was more prevalent in symptomatic rather than asymptomatic parasite-infected individuals in both Obom p = 0.001 and Asutsuare p = 0.003 . Conclusion. Individuals in Southern Ghana carrying the TNF-α 308 GA genotype are more likely to exhibit symptoms of malaria when infected with the malaria parasite as opposed to harboring an asymptomatic infection. Also, the B allele of the G6PD gene is likely to prevent a P. falciparum-infected person from exhibiting symptoms and thereby promote asymptomatic parasite carriage.

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Role of genetic factors and ethnicity on the multiplicity of Plasmodium falciparum infection in children with asymptomatic malaria in Yaoundé, Cameroon

Cited by 7 publications

References 49 publications

Malaria Hotspots: Is There Epidemiological Evidence for Fine-Scale Spatial Targeting of Interventions?

Malaria Hotspots: Is There Epidemiological Evidence for Fine-Scale Spatial Targeting of Interventions?

coiaf: directly estimating complexity of infection with allele frequencies

Association of TNF-Alpha, MBL2, NOS2, and G6PD with Malaria Outcomes in People in Southern Ghana

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