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Lack of associations of α(+) - thalassemia with the risk of Plasmodium falciparum and Plasmodium vivax infection and disease in a cohort of children aged 3-21 months from Papua New Guinea

Rosanas-Urgell, A. and Senn, N. and Rarau, P. and Aponte, J. J. and Reeder, J. C. and Siba, P. M. and Michon, P. and Mueller, I.. (2012) Lack of associations of α(+) - thalassemia with the risk of Plasmodium falciparum and Plasmodium vivax infection and disease in a cohort of children aged 3-21 months from Papua New Guinea. International journal for parasitology, Vol. 42, H. 12. pp. 1107-1113.

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Official URL: http://edoc.unibas.ch/dok/A6094256

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Abstract

Despite consistent evidence of a protective effect of alpha(+)-thalassemia against severe Plasmodium falciparum disease, the mechanisms underlying this protection remain unknown. An increase in risk of Plasmodium vivax malaria in early childhood resulting in a cross-species protection against severe P. falciparum malaria has been proposed as a possible mechanism in Melanesian children. The association of alpha(+)-thalassemia genotypes with a risk of P. falciparum and P. vivax infection and uncomplicated illness was reassessed in a cohort of 1,112 Papua New Guinean children, followed from 3-21 months of age. Three hundred and eighty-nine (35.0%) children were homozygous for a(+)-thalassemia (-a/-a), 506 (45.5%) heterozygous (aa/-a) and 217 (19.5%) homozygous for the wild-type allele. No significant differences in the incidence of P. falciparum (Pf) or P. vivax (Pv) malaria were observed between alpha(+)-thalassemia homozygote (Pf: Incidence rate ratio (IRR) = 1.13, CI(95) (0.82,1.56), P = 0.45, Pv: IRR = 1.15, CI(95) (0.9881.56), P = 0.31), heterozygote (Pf: IRR = 0.98, CI(95) (0.71,1.34), P = 0.93, Pv: IRR = 1.14, CI(95) (0.88,1.48), P =0.33) and wild-type children. The prevalence of infection with either species did not differ between alpha(+)-thalassemia genotypes, although densities of P. vivax (but not of P. falciparum) infections were significantly higher in alpha(+)-thalassemia homozygote and heterozygote children. An excessive risk of moderate-to-severe anemia (hemoglobin (Hb) > 8 g/dl) was observed in alpha(+)-thalassemia homozygote children (IRR = 1.54, CI(95)(1.12, 2.11), P = 0.008). This study therefore failed to confirm an increased risk of P. vivax or P. falciparum malaria in very young, alpha(+)-thalassemic children without significant levels of acquired immunity. This confirms the lack of protection by alpha(+)-thalassemia against uncomplicated P. falciparum and challenges the hypothesis of immunological cross-protection between P. falciparum and P. vivax as a mechanism underlying alpha(+)-thalassemia protection against severe P. falciparum disease in Melanesian children
Faculties and Departments:09 Associated Institutions > Swiss Tropical and Public Health Institute (Swiss TPH) > Department of Epidemiology and Public Health (EPH) > Health Interventions
UniBasel Contributors:Senn, Nicolas
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
Publisher:Elsevier
ISSN:0020-7519
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:16 Aug 2013 07:34
Deposited On:16 Aug 2013 07:28

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