Relationship between entomological inoculation rate, Plasmodium falciparum prevalence rate, and incidence of malaria attack in rural Gabon

Élissa, Nohal; Migot-Nabias, Florence; Luty, Adrian J. F.; Renaut, A.; Touré, Fousseyni S.; Vaillant, Michel; Lawoko, M.; Yangari, Patrick; Mayombo, J.; Lékoulou, Faustin; Tshipamba, Paul; Moukagni, R.; Millet, Pascal; Deloron, Philippe

doi:10.1016/s0001-706x(02)00266-8

Cited by 44 publications

(48 citation statements)

References 16 publications

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“…The study was performed in Bakoumba in southeast Gabon near the border with the Republic of the Congo. In this region, malaria is highly endemic with peaks in transmission at the end of the rainy seasons (September to December and March to June) (56). A cross-sectional survey was conducted in May to June 2000 in a cohort of 641 asymptomatic children between the ages of 1 and 12 y.…”

Section: Methodsmentioning

confidence: 99%

Evidence of strain structure in Plasmodium falciparum var gene repertoires in children from Gabon, West Africa

Day

Artzy‐Randrup

Tiedje

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

100

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Existing theory on competition for hosts between pathogen strains has proposed that immune selection can lead to the maintenance of strain structure consisting of discrete, weakly overlapping antigenic repertoires. This prediction of strain theory has conceptual overlap with fundamental ideas in ecology on niche partitioning and limiting similarity between coexisting species in an ecosystem, which oppose the hypothesis of neutral coexistence. For Plasmodium falciparum, strain theory has been specifically proposed in relation to the major surface antigen of the blood stage, known as PfEMP1 and encoded by the multicopy multigene family known as the var genes. Deep sampling of the DBLα domain of var genes in the local population of Bakoumba, West Africa, was completed to define whether patterns of repertoire overlap support a role of immune selection under the opposing force of high outcrossing, a characteristic of areas of intense malaria transmission. Using a 454 high-throughput sequencing protocol, we report extremely high diversity of the DBLα domain and a large parasite population with DBLα repertoires structured into nonrandom patterns of overlap. Such population structure, significant for the high diversity of var genes that compose it at a local level, supports the existence of "strains" characterized by distinct var gene repertoires. Nonneutral, frequency-dependent competition would be at play and could underlie these patterns. With a computational experiment that simulates an intervention similar to mass drug administration, we argue that the observed repertoire structure matters for the antigenic var diversity of the parasite population remaining after intervention.Plasmodium falciparum | var genes | parasite diversity | strain structure | Gabon

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Section: Methodsmentioning

confidence: 99%

Evidence of strain structure in Plasmodium falciparum var gene repertoires in children from Gabon, West Africa

Day

Artzy‐Randrup

Tiedje

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

100

View full text Add to dashboard Cite

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“…During the rainy season, the entomologic inoculation rates in Bakoumba and Dienga are 0.83 and 0.91 infective bites/person/night, respectively. 15,35 The Hp levels were significantly negatively correlated with parasite density. This finding is consistent with a study performed in Tanzania, 10 although another study in The Gambia showed no association between parasite density and Hp levels.…”

Section: Discussionmentioning

confidence: 96%

“…Malaria is highly endemic with peaks of transmission at the end of the rainy seasons (September-December and March-June). 15 A cross-sectional survey was conducted in May-June in 2000 in a cohort of 641 asymptomatic children 1-12 years of age. This study was initially designed to investigate antibody properties in relation to erythrocyte polymorphisms.…”

Section: Methodsmentioning

confidence: 99%

Association of Haptoglobin Levels With Age, Parasite Density, and Haptoglobin Genotype in a Malaria-Endemic Area of Gabon

Fowkes

Imrie

Migot-Nabias

et al. 2006

The American Journal of Tropical Medicine and Hygiene

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Abstract. Haptoglobin (Hp) levels were investigated in relation to host genotype in a malaria-endemic area in Gabon. A cross-sectional study of 1-12-year-old children was conducted in the rainy season, a period of high malaria transmission, to examine this relationship. Variables that influenced Hp levels were Hp genotype, location, and age interacting with parasite density. At low parasite densities, there was a negative correlation between Hp levels and age. At higher densities, there was a positive correlation with age. This suggests that in the presence of greater parasiteinduced hemolysis, older children are capable of increased production of Hp. Sickle cell trait and ABO blood group was not associated with Hp levels in this population.

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“…As in most parts of the country, malaria is highly endemic and P. falciparum is predominantly due to Anopheles gambiae (80%), with an entomological infection rate of 100 infective bites per human per year [28]. Malaria seasonal peaks of transmission coincide with the rains, from February to June and from September to December [28].…”

Section: Study Sitementioning

confidence: 99%

Pfmdr1 gene polymorphism of Plasmodium falciparum isolates from asymptomatic individuals of Dienga, southeastern Gabon

Pegha-Moukandja¹,

Kouna²,

Maghendji-Nzdondo³

et al. 2018

J Parasitic Diseases

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Relationship between entomological inoculation rate, Plasmodium falciparum prevalence rate, and incidence of malaria attack in rural Gabon

Cited by 44 publications

References 16 publications

Evidence of strain structure in Plasmodium falciparum var gene repertoires in children from Gabon, West Africa

Evidence of strain structure in Plasmodium falciparum var gene repertoires in children from Gabon, West Africa

Association of Haptoglobin Levels With Age, Parasite Density, and Haptoglobin Genotype in a Malaria-Endemic Area of Gabon

Pfmdr1 gene polymorphism of Plasmodium falciparum isolates from asymptomatic individuals of Dienga, southeastern Gabon

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