Ethnic differences in the prevalence of splenomegaly and malaria in The Gambia

Bm, Greenwood; Groenendaal, Floris; Bradley, A. K.; Greenwood, A.M.; Shenton, Fiona C.; Tulloch, S.; Hayes, Richard

doi:10.1080/00034983.1987.11812130

Cited by 58 publications

(45 citation statements)

References 10 publications

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“…First, we assumed that ethnic differences in the response to P. falciparum malaria between sites are small, although such differences are known to occur in sub-Saharan Africa. 37,38 Although our model showed satisfactory overall fits to the various datasets across a wide range of transmission intensities, a somewhat poorer fit was observed with the Navrongo data. A likely explanation for this relatively poor fit to this more recently collected dataset is that we assumed that the impact of anti-malaria treatment was negligible.…”

Section: Discussionmentioning

confidence: 73%

A Model for Natural Immunity to Asexual Blood Stages of Plasmodium Falciparum Malaria in Endemic Areas

Maire

Smith

Ross

et al. 2006

The American Journal of Tropical Medicine and Hygiene

161

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Abstract. Most mathematical models for acquired immunity to Plasmodium falciparum consider effects of immunity on duration of infection and infectiousness, but do not consider the most evident effect of immunity, which is to reduce parasite densities. Few attempts have been made to fit such models to field data. We propose a stochastic simulation model to predict the distributions of P. falciparum parasite densities in endemic areas, in which acquired immunity acts by reducing parasite densities. We have fitted this model to age-specific prevalence and geometric mean densities from settings in Ghana, Nigeria, and Tanzania. The model appears to reproduce reasonably well the parasitologic patterns seen in malariologic surveys in endemic areas and is appropriate for predicting the impact of interventions such as vaccination in the context of continual exposure to P. falciparum.

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Section: Discussionmentioning

confidence: 73%

A Model for Natural Immunity to Asexual Blood Stages of Plasmodium Falciparum Malaria in Endemic Areas

Maire

Smith

Ross

et al. 2006

The American Journal of Tropical Medicine and Hygiene

161

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“…Moreover, Troye-Blomberg et al (34) reported that the production of interleukin 4 by activated human cells is associated with elevated levels of antibodies to malaria antigens. The hypothesis of a stronger activation of the immune system in the Fulani is also suggested by the higher frequency in this ethnic group of the hyperreactive malarial splenomegaly syndrome (22,23).…”

Section: Discussionmentioning

confidence: 86%

Different response toPlasmodium falciparummalaria in West African sympatric ethnic groups

Modiano

Petrarca

Sirima

et al. 1996

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

230

199

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The comparison of malaria indicators among populations that have different genetic backgrounds and are uniformly exposed to the same parasite strains is one approach to the study of human heterogeneities in the response to the infection. We report the results of comparative surveys on three sympatric West African ethnic groups, Fulani, Mossi, and Rimaibé, living in the same conditions of hyperendemic transmission in a Sudan savanna area northeast of Ouagadougou, Burkina Faso. The Mossi and Rimaibé are Sudanese negroid populations with a long tradition of sedentary farming, while the Fulani are nomadic pastoralists, partly settled and characterized by non-negroid features of possible caucasoid origin. Parasitological, clinical, and immunological investigations showed consistent interethnic differences in Plasmodium falciparum infection rates, malaria morbidity, and prevalence and levels of antibodies to various P. falciparum antigens. The data point to a remarkably similar response to malaria in the Mossi and Rimaibé, while the Fulani are clearly less parasitized, less affected by the disease, and more responsive to all antigens tested. No difference in the use of malaria protective measures was demonstrated that could account for these findings, and sociocultural or environmental factors do not seem to be involved. Known genetic factors of resistance to malaria did not show higher frequencies in the Fulani. The differences in the immune response were not explained by the entomological observations, which indicated substantially uniform exposure to infective bites. The available data support the existence of unknown genetic factors, possibly related to humoral immune responses, determining interethnic differences in the susceptibility to malaria.The ability to resist Plasmodium falciparum malaria is an important adaptive trait of human populations living in endemic areas. The detection of significant differences in the expression of this trait and the identification of the factors involved should improve the understanding of the hostparasite relationship and might lead to advances in control strategies (1). The importance of this research area is emphasized by the recent finding that particular HLA class I and class II alleles are associated with resistance to severe malaria (2) and by the complexities faced in the design of an effective vaccine against P. falciparum (3).The study of human heterogeneities in the response to malaria can be approached at the population level by comparing either groups with similar genetic backgrounds exposed to different disease selective pressures (4)-e.g., the same population distributed over endemic and non-endemic zones-or groups with different genetic backgrounds exposed to similar parasite inoculation rates-e.g., different ethnic groups living together in an endemic zone. The interethnic comparison has been only rarely pursued (5-8), presumably deterred by the high number of possible confounding factors due to sociocultural differences. Following a preliminary survey ...

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“…4 Although the sample size and power of the current study are greater, its ethnic composition is different. Differences in allele frequencies and in LD at this and other loci exist between ethnic groups in the Gambia: [21][22][23][24] accordingly ethnic variation in allele frequency and differences in LD between the TNFÀ308A allele and a putative causal allele or alleles within HAP3 may have produced a weaker association.…”

Section: Discussionmentioning

confidence: 99%

Genetic variation at the TNF locus and the risk of severe sequelae of ocular Chlamydia trachomatis infection in Gambians

et al. 2007

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Tumor necrosis factor (TNF) is thought to be a key mediator of the inflammatory and fibrotic response to Chlamydia trachomatis (Ct) infection. A large matched-pair case-control study investigated putative functional single nucleotide polymorphisms (SNPs) across the major histocompatibility complex (MHC) class III region, including TNF and its immediate neighbors nuclear factor of k light polypeptide gene enhancer in B cells (IkBL), inhibitor like 1 and lymphotoxin alpha (LTA) in relation to the risk of scarring sequelae of ocular Ct infection. Haplotype and linkage disequilibrium analysis demonstrated two haplotypes, differing at position TNF-308, conferring an increased risk of trichiasis. The TNF-308A allele, and its bearing haplotype, correlated with increased TNF production in lymphocyte cultures stimulated with chlamydial elementary body antigen. Thus TNF-308A may determine directly, or be a marker of a high TNF producer phenotype associated with increased risk of sequelae of chlamydial infection. Multivariate analysis provided evidence for the presence of additional risk-associated variants near the TNF locus.

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Ethnic differences in the prevalence of splenomegaly and malaria in The Gambia

Cited by 58 publications

References 10 publications

A Model for Natural Immunity to Asexual Blood Stages of Plasmodium Falciparum Malaria in Endemic Areas

A Model for Natural Immunity to Asexual Blood Stages of Plasmodium Falciparum Malaria in Endemic Areas

Different response toPlasmodium falciparummalaria in West African sympatric ethnic groups

Genetic variation at the TNF locus and the risk of severe sequelae of ocular Chlamydia trachomatis infection in Gambians

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