Multiclonal asymptomatic Plasmodium falciparum infections predict a reduced risk of malaria disease in a Tanzanian population
| Autor: | Sándor Bereczky, Anna Färnert, Lea Faraja, Fredrik Granath, Ingegerd Rooth, Scott Montgomery, Anne Liljander |
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| Rok vydání: | 2006 |
| Předmět: |
Adult
Male Adolescent Genotype Immunology Population Plasmodium falciparum Protozoan Proteins Antigens Protozoan Disease Microbiology Asymptomatic Tanzania Antimalarials Hemoglobins parasitic diseases medicine Animals Humans Longitudinal Studies Merozoite surface protein Malaria Falciparum education Child Genotyping Aged Aged 80 and over education.field_of_study biology Infant Middle Aged biology.organism_classification medicine.disease Virology Circumsporozoite protein Infectious Diseases Cross-Sectional Studies Child Preschool Female medicine.symptom Morbidity Malaria |
| Zdroj: | Microbes and infection. 9(1) |
| ISSN: | 1286-4579 |
| Popis: | Protective immunity to malaria is acquired after repeated exposure to the polymorphic Plasmodium falciparum parasite. Whether the number of concurrent antigenically diverse clones in asymptomatic infections predicts the risk of subsequent clinical malaria needs further understanding. We assessed the diversity of P. falciparum infections by merozoite surface protein 2 genotyping in a longitudinal population based study in Tanzania. The number of clones was highest in children 6-10 years and in individuals with long time to previous anti-malarial treatment. Individual exposure, analysed by circumsporozoite protein antibody levels, was associated with parasite prevalence but not with the number of clones. The risk of subsequent clinical malaria in children free of acute disease or recent treatment was, compared to one clone, reduced in individuals with multiclonal infections or without detectable parasites, with the lowest hazard ratio 0.28 (95% confidence interval 0.10-0.78 Cox regression) for 2-3 clones. The number of clones was not associated with haemoglobin levels. A reduced risk of malaria in asymptomatic individuals with multiclonal persistent P. falciparum infections suggests that controlled maintenance of diverse infections is important for clinical protection in continuously exposed individuals, and needs to be considered in the design and evaluation of new malaria control strategies. |
| Databáze: | OpenAIRE |
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