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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although the ABO blood group of the human host has been reported to influence malarial infection, there have been few clinical observations on this effect. A hospital-based, comparative study was therefore performed to investigate the relationship between blood-group type and severe disease i nPlasmodium falciparum malaria. Overall, 243 cases of malaria (163 uncomplicated and 80 severe) and 65 patients with severe, non-malarial infections were studied. In terms of ABO-blood-group composition, the patients with severe malaria were significantly different from the patients with the uncomplicated disease (P<0.001) and also from a population control described previously (P<0.0001). The patients with uncomplicated malaria or severe but non-malarial disease were, however, similar to the population control. The cases of severe malaria were significantly less likely to be of blood group O (P=0.0003), and significantly more likely to be of group AB (P<0.0001), than the patients with nonsevere malaria. It appears that individuals who are of blood-group O are relatively resistant to the severe disease caused by P. falciparum infection.
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PMID:ABO-blood-group types and protection against severe, Plasmodium falciparum malaria. 1581 30

We compared the serological phenotypic frequencies of ABO, MNSs, and Duffy in 417 blood donors and 309 malaria patients from four Brazilian Amazon areas. Our results suggest no correlation between ABO phenotype and malaria infection in all areas studied. We observed significant correlation between the S +s +, S +s -, and S -s + phenotypes and malaria infection in three areas. Some of the Duffy phenotypes showed significant correlation between donors and malaria patients in different areas. These data are an additional contribution to the establishment of differential host susceptibility to malaria.
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PMID:Frequencies of ABO, MNSs, and Duffy phenotypes among blood donors and malaria patients from four Brazilian Amazon areas. 1703 27

The main objective was to investigate the effects of ABO/Rh blood groups, haemoglobin genotype and G-6-P-D enzyme activity on malaria. The study was carried out in Buea, South West Province, Cameroon. Subjects consulting at health care facilities in Buea were randomly recruited into the study. A total of 121 febrile patients 1-60 years old comprised the study subjects. Thin and thick blood films were prepared for malaria parasite detection. G-6-P-D enzyme activity was assayed using the met-haemoglobin reduction test. Determination of haemoglobin genotypes was by a rapid screening method alongside electrophoresis. Malaria positive patients were treated. The highest malaria prevalence of 74.5 % was in Group O individuals and the lowest of 58.6% in group B individuals. Mean parasite density (Log(10)(-1)/ul blood) in the various blood groups was not significantly different. Individuals with G-6-P-D deficiency had a significantly lower malaria prevalence (47.5%) when compared with active individuals. Mean parasite density in enzyme deficient and active individuals was 3.7(SD+/- 3.9) and 4.4(SD +/-5.0) respectively and the difference was significant (p < 0.05). Malaria prevalence was lower (57.5%) in HbS individuals when compared with HbAA (74.6%) and HbSS (60%) but parasite density was not significantly different. Our results suggest that individuals with blood group O who have the HbAA genotype and show G-6-P-D enzyme activity may be more susceptible to malaria. Information on the influence of these genetic factors on malaria would be useful in the better management of the disease in the study area.
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PMID:Effects of ABO/Rh blood groups, G-6-P-D enzyme activity and haemoglobin genotypes on malaria parasitaemia and parasite density. 1729 25

In the century since the discovery of the ABO blood groups, numerous associations between ABO groups and disease have been noted. However, the selection pressures defining the ABO distributions remain uncertain. We review published information on Plasmodium falciparum infection and ABO blood groups. DNA sequence information dates the emergence and development of the group O allele to a period of evolution before human migration out of Africa, concomitant with P falciparum's activity. The current geographic distribution of group O is also consistent with a selection pressure by P falciparum in favor of group O individuals in malaria-endemic regions. We critically review clinical reports of ABO and P falciparum infection, documenting a correlation between disease severity and ABO group. Finally, we review published data on the pathogenesis of P falciparum infection, and propose a biologic model to summarize the role of ABO blood groups in cytoadherence biology. Such ABO-related mechanisms also point to a new hypothesis to account for selection of the Le(a-b-) phenotype. Taken together, a broad range of available evidence suggests that the origin, distribution, and relative proportion of ABO blood groups in humans may have been directly influenced by selective genetic pressure from P falciparum infection.
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PMID:The ABO blood group system and Plasmodium falciparum malaria. 1750 54

Malaria has been a major selective force on the human population, and several erythrocyte polymorphisms have evolved that confer resistance to severe malaria. Plasmodium falciparum rosetting, a parasite virulence phenotype associated with severe malaria, is reduced in blood group O erythrocytes compared with groups A, B, and AB, but the contribution of the ABO blood group system to protection against severe malaria has received little attention. We hypothesized that blood group O may confer resistance to severe falciparum malaria through the mechanism of reduced rosetting. In a matched case-control study of 567 Malian children, we found that group O was present in only 21% of severe malaria cases compared with 44-45% of uncomplicated malaria controls and healthy controls. Group O was associated with a 66% reduction in the odds of developing severe malaria compared with the non-O blood groups (odds ratio 0.34, 95% confidence interval 0.19-0.61, P < 0.0005, severe cases versus uncomplicated malaria controls). In the same sample set, P. falciparum rosetting was reduced in parasite isolates from group O children compared with isolates from the non-O blood groups (P = 0.003, Kruskal-Wallis test). Statistical analysis indicated a significant interaction between host ABO blood group and parasite rosette frequency that supports the hypothesis that the protective effect of group O operates through the mechanism of reduced P. falciparum rosetting. This work provides insights into malaria pathogenesis and suggests that the selective pressure imposed by malaria may contribute to the variable global distribution of ABO blood groups in the human population.
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PMID:Blood group O protects against severe Plasmodium falciparum malaria through the mechanism of reduced rosetting. 1795 77

There is growing epidemiological and molecular evidence that ABO blood group affects host susceptibility to severe Plasmodium falciparum infection. The high frequency of common ABO alleles means that even modest differences in susceptibility could have a significant impact on the health of people living in malaria endemic regions. We performed an association study, the first to utilize key molecular genetic variation underlying the ABO system, genotyping >9000 individuals across three African populations. Using population- and family-based tests, we demonstrated that alleles producing functional ABO enzymes are associated with greater risk of severe malaria phenotypes (particularly malarial anemia) in comparison with the frameshift deletion underlying blood group O: case-control allelic odds ratio (OR), 1.2; 95% confidence interval (CI), 1.09-1.32; P = 0.0003; family-studies allelic OR, 1.19; 95% CI, 1.08-1.32; P = 0.001; pooled across all studies allelic OR, 1.18; 95% CI, 1.11-1.26; P = 2 x 10(-7). We found suggestive evidence of a parent-of-origin effect at the ABO locus by analyzing the family trios. Non-O haplotypes inherited from mothers, but not fathers, are significantly associated with severe malaria (likelihood ratio test of Weinberg, P = 0.046). Finally, we used HapMap data to demonstrate a region of low F(ST) (-0.001) between the three main HapMap population groups across the ABO locus, an outlier in the empirical distribution of F(ST) across chromosome 9 (approximately 99.5-99.9th centile). This low F(ST) region may be a signal of long-standing balancing selection at the ABO locus, caused by multiple infectious pathogens including P. falciparum.
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PMID:Common variation in the ABO glycosyltransferase is associated with susceptibility to severe Plasmodium falciparum malaria. 1800 41

Host susceptibility to Plasmodium falciparum infection is central for improved understanding of malaria in human populations. Red blood cell (RBC) polymorphisms have been proposed as factors associated with malaria infection or its severity, although no systematic appraisal of ABO phenotypes and malaria risk has been undertaken. This analysis summarises epidemiological, clinical and immunological evidence on the nature of ABO histo-blood antigens and their interaction with malaria in terms of population genetics, infection risk, severe malaria and placental malaria. In non-pregnant subjects, a meta-analysis showed no conclusive evidence associating ABO phenotypes with risk of uncomplicated malaria. There was stronger evidence that ABO phenotype modulates severity of P. falciparum malaria, with group A associated with severe disease and blood group O with milder disease. Among pregnant subjects, group O was associated with increased risk of placental malaria in primigravidae and reduced risk in multigravidae. The biological basis for ABO-related susceptibility to malaria is reviewed. Several mechanisms relate to these associations including affinity for Anopheles gambiae; shared ABO antigens with P. falciparum; impairment of merozoite penetration of RBCs; and cytoadherence, endothelial activation and rosetting. ABO phenotypic associations with malaria are related to its pathogenesis and improved understanding of these interactions is required for understanding the glycobiology of malaria infection.
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PMID:ABO blood group phenotypes and Plasmodium falciparum malaria: unlocking a pivotal mechanism. 1806 95

While circulating levels of soluble Intercellular Adhesion Molecule 1 (sICAM-1) have been associated with diverse conditions including myocardial infarction, stroke, malaria, and diabetes, comprehensive analysis of the common genetic determinants of sICAM-1 is not available. In a genome-wide association study conducted among 6,578 participants in the Women's Genome Health Study, we find that three SNPs at the ICAM1 (19p13.2) locus (rs1799969, rs5498 and rs281437) are non-redundantly associated with plasma sICAM-1 concentrations at a genome-wide significance level (P<5x10(-8)), thus extending prior results from linkage and candidate gene studies. We also find that a single SNP (rs507666, P = 5.1x10(-29)) at the ABO (9q34.2) locus is highly correlated with sICAM-1 concentrations. The novel association at the ABO locus provides evidence for a previously unknown regulatory role of histo-blood group antigens in inflammatory adhesion processes.
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PMID:Novel association of ABO histo-blood group antigen with soluble ICAM-1: results of a genome-wide association study of 6,578 women. 1860 67

A cross-sectional study was conducted in Gadarif Hospital in eastern Sudan to determine the prevalence, and evaluate the risk factors, of placental malaria. Two hundred and thirty-six delivering women were enrolled in the study. Socio-demographic characteristics were gathered through questionnaires. Maternal hemoglobin was measured, ABO blood groups were determined, and placental histological examinations for malaria were performed. The birth weight of the newborn was also recorded. The mean (SD) maternal age was 25.5 (6.0) yr and the mean (SD) hemoglobin was 9.8 (0.9) g/dl. Placental histology showed acute malaria infections in 13 (5.5%) and chronic infections in 5 (2.1%) women; 28 (11.9%) of the placentas revealed past infection and 190 (80.5%) indicated no infection. Lack of prenatal care was significantly associated with placental infections (OR = 12.0, 95% CI = 2.3-16.2; P = 0.003). There was no significant association between placental malaria infections and maternal age, parity, and blood group. Thirty-two (13.5%) of these pregnancy outcomes resulted in low birthweight babies. There was, however, no significant association between placental malaria and low birth weight (OR = 2.0, 95% CI = 0.4-4.1; P = 0.1). Thus, placental malaria infections affect pregnant women in this area of eastern Sudan regardless of their age or parity. Prenatal care should be encouraged to reduce malaria in the area. Much more research regarding malaria and pregnancy is needed.
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PMID:Placental malaria and lack of prenatal care in an area of unstable malaria transmission in eastern Sudan. 1964 7

We investigated the ABO genotypes and heterogeneity of the O alleles in Plasmodium falciparum-infected and non-infected individuals from the Brazilian Amazon region. Sample collection took place from May 2003 to August 2005, from P. falciparum malaria patients from four endemic regions of the Brazilian Amazon. The control group consisted of donors from four blood banks in the same areas. DNA was extracted using the Easy-DNA(TM) extraction kit. ABO genotyping was performed using PCR/RFLP. There was a high frequency of ABO*O01O01. ABO*AO01 was the second most frequent genotype, and the third most frequent genotype was ABO*BO01. There were low frequencies of the ABO*O01O02, ABO*AA, ABO*AB, ABO*BB, and ABO*O02O02 genotypes. We analyzed the alleles of the O phenotype; the O(1variant) allele was the most frequent, both in malaria and non-malaria groups; consequently, the homozygous genotype O(1)(v)O(1)(v) was the most frequently observed. There was no evidence of the homozygous O(2) allele. Significant differences were not detected in the frequency of individuals with the various alleles in the comparison of the malaria patients and the general population (blood donors).
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PMID:Frequency of ABO blood group system polymorphisms in Plasmodium falciparum malaria patients and blood donors from the Brazilian Amazon region. 2067 33


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