Dataset Information

Patterns of malaria indices across three consecutive seasons in children in a highly endemic area of West Africa: a three times-repeated cross-sectional study.

ABSTRACT:

Objectives

To study the manifestations of Plasmodium infection, and its relations with the malaria disease, especially when comparing dry and rainy seasons in a hyperendemic area of West Africa.

Methods

The study was carried out in an area where malaria transmission is high, showing important seasonal variations. One thousand children, representing the total child population (1-12 year old), were observed transversally at the end of three consecutive seasons (dry/rainy/dry). The usual indicators, such as parasite density, splenomegaly, anaemia, or febrile disease were recorded and analysed.

Results

The prevalence of Plasmodium falciparum was high in all age groups and seasons, constantly around 60%. The high transmission season (rainy) showed higher rates of anaemia and spleen enlargement and, in the youngest children only, higher parasite densities. There were also differences between the two dry seasons: in the first one, there was a higher rate of fever than in the second one (p < 0.001). Low parasite density (<2,000 p/?l) was never associated with fever during any season, raising some concern with regard to the usefulness of parasite detection. The possible origins of fever are discussed, together with the potential usefulness of analyzing these indices on a population sample, at a time when fever incidence rises and malaria is one potential cause among others. The distinction to be made between the Plasmodium infection and the malaria disease is highlighted.

Conclusions

These data confirm previous hypotheses of a strong difference in malaria infection and disease between dry and rainy seasons. The most relevant seasonal indicator was not mainly parasite rate and density but anaemia, spleen enlargement, prevalence and possible origin of fever.

Recommendations

In any situation (i.e. fever or not) and especially during the dry season, one must consider that detection of parasites in the blood is only evidence of a Plasmodium infection and not necessarily of a malaria disease. In such a situation, it seems suitable to obtain, through national malaria teams, a well-defined situation of transmission and prevalence of Plasmodium infection following zones and seasons, in order to adapt control strategies. For researchers, a systematic management of data separately for dry and rainy season appears mandatory.

SUBMITTER: Ardiet DL

PROVIDER: S-EPMC4082285 | biostudies-literature | 2014 May

REPOSITORIES: biostudies-literature

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Publications

Patterns of malaria indices across three consecutive seasons in children in a highly endemic area of West Africa: a three times-repeated cross-sectional study.

Ardiet Denis-Luc DL Graz Bertrand B Szeless Thomas T Mauris Anne A Falquet Jacques J Doumbo Ogobara K OK Dolo Amagana A Guindo Ousmane O Sissoko Mahamadou S MS Konaré Moussa M Motamed Sandrine S Rougemont André C AC

Malaria journal 20140528

<h4>Objectives</h4>To study the manifestations of Plasmodium infection, and its relations with the malaria disease, especially when comparing dry and rainy seasons in a hyperendemic area of West Africa.<h4>Methods</h4>The study was carried out in an area where malaria transmission is high, showing important seasonal variations. One thousand children, representing the total child population (1-12 year old), were observed transversally at the end of three consecutive seasons (dry/rainy/dry). The u ...[more]

PMID: 24885107

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Project description:UnlabelledIt is well known that rhizosphere microbiomes differ from those of surrounding soil, and yet we know little about how these root-associated microbial communities change through the growing season and between seasons. We analyzed the response of soil bacteria to roots of the common annual grass Avena fatua over two growing seasons using high-throughput sequencing of 16S rRNA genes. Over the two periods of growth, the rhizosphere bacterial communities followed consistent successional patterns as plants grew, although the starting communities were distinct. Succession in the rhizosphere was characterized by a significant decrease in both taxonomic and phylogenetic diversity relative to background soil communities, driven by reductions in both richness and evenness of the bacterial communities. Plant roots selectively stimulated the relative abundance of Alphaproteobacteria, Betaproteobacteria, and Bacteroidetes but reduced the abundance of Acidobacteria, Actinobacteria, and Firmicutes. Taxa that increased in relative abundance in the rhizosphere soil displayed phylogenetic clustering, suggesting some conservation and an evolutionary basis for the response of complex soil bacterial communities to the presence of plant roots. The reproducibility of rhizosphere succession and the apparent phylogenetic conservation of rhizosphere competence traits suggest adaptation of the indigenous bacterial community to this common grass over the many decades of its presence.ImportanceWe document the successional patterns of rhizosphere bacterial communities associated with a "wild" annual grass, Avena fatua, which is commonly a dominant plant in Mediterranean-type annual grasslands around the world; the plant was grown in its grassland soil. Most studies documenting rhizosphere microbiomes address "domesticated" plants growing in soils to which they are introduced. Rhizosphere bacterial communities exhibited a pattern of temporal succession that was consistent and repeatable over two growing seasons. There are few studies assessing the reproducibility over multiple seasons. Through the growing season, the rhizosphere community became progressively less diverse, likely reflecting root homogenization of soil microniches. Phylogenetic clustering of the rhizosphere dynamic taxa suggests evolutionary adaptation to Avena roots. The reproducibility of rhizosphere succession and the apparent phylogenetic conservation of rhizosphere competence traits suggest adaptation of the indigenous bacterial community to this common grass over the many decades of its presence.

Dataset Information

Patterns of malaria indices across three consecutive seasons in children in a highly endemic area of West Africa: a three times-repeated cross-sectional study.

Objectives

Methods

Results

Conclusions

Recommendations

Publications

Patterns of malaria indices across three consecutive seasons in children in a highly endemic area of West Africa: a three times-repeated cross-sectional study.

Similar Datasets

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