A longitudinal study of malaria infection, morbidity and antibody titres in infants of a rural community in Ghana

Akanmori, Bartholomew D.; Afari, Edwin; Sakatoku, H.; Nkrumah, Francis

doi:10.1016/0035-9203(95)90107-8

Cited by 14 publications

(13 citation statements)

References 7 publications

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“…There are presently no specific quantities of malaria antibodies that correlate with clinical protection [73] and therefore it is not possible to state whether or not the antibody concentrations in the cord blood were enough to offer protection to the infants born to study participants. Children with particularly high levels of antibodies at birth can remain antibody positive (in the absence of active immunization by infection) up to 11 months but in Ghana the median duration of maternal antibodies to a crude P. falciparum schizont extract was 14 weeks [74].…”

Section: Discussionmentioning

confidence: 99%

Effect of IPTp on Plasmodium falciparum antibody levels among pregnant women and their babies in a sub-urban coastal area in Ghana

Stephens

Kyei-Baafour

Dickson

et al. 2017

Malar J

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BackgroundWomen exposed to Plasmodium infection develop antibodies and become semi-immune. This immunity is suppressed during pregnancy making both the pregnant woman and the foetus vulnerable to the adverse effects of malaria, particularly by Plasmodium falciparum. Intermittent preventive treatment of malaria in pregnancy (IPTp) with Sulfadoxine–pyrimethamine (SP) tablets is one of the current interventions to mitigate the effects of malaria on both the pregnant woman and the unborn child. The extent to which IPTp may interfere with the acquisition of protective immunity against pregnancy-associated malaria (PAM) is undefined in Ghana.MethodsThree-hundred-and-twenty pregnant women were randomly enrolled at the antenatal clinic (ANC) in Madina, Accra. Venous blood samples were obtained at first ANC registration and at 4-week intervals (post-IPTp administration). Placental and cord blood samples were obtained at delivery and the infants were followed monthly for 6 months after birth. Anti-IgG and IgM antibodies against a crude antigen preparation and the glutamate-rich protein (GLURP) of P. falciparum were quantified by the enzyme-linked immunosorbent assay (ELISA).ResultsThere was a general decline in the trend of mean concentrations of all the antibodies from enrolment to delivery. The levels of antibodies in cord blood and placenta were well correlated. Children did not show clinical signs of malaria at 6 months after birth.ConclusionsIgG against both crude antigen and GLURP were present in placenta and cord blood and it is therefore concluded that there is a trend of declining antibody from enrolment to delivery and IPTp-SP may have reduced malaria exposure, however, this does not impact on the transfer of antibodies to the foetus in utero. The levels of maternal and cord blood antibodies at delivery showed no adverse implications on malaria among the children at 6 months. However, the quantum and quality of the antibody transferred needs further investigation to ensure that the infants are protected from severe episodes of malaria.

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Section: Discussionmentioning

confidence: 99%

Effect of IPTp on Plasmodium falciparum antibody levels among pregnant women and their babies in a sub-urban coastal area in Ghana

Stephens

Kyei-Baafour

Dickson

et al. 2017

Malar J

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“…In particular, prime-boost strategies designed to elicit antibodies and especially T cell responses associated with protection are moving to immunogenicity and efficacy studies in endemic populations. A long-term goal of these studies is to establish antibody and T cell assays at sites in Southern Ghana that might be used for clinical trials[51,52]. To achieve this there were two aims.…”

Section: Discussionmentioning

confidence: 99%

Measuring naturally acquired immune responses to candidate malaria vaccine antigens in Ghanaian adults

Dodoo

Hollingdale

Anum

et al. 2011

Malar J

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BackgroundTo prepare field sites for malaria vaccine trials, it is important to determine baseline antibody and T cell responses to candidate malaria vaccine antigens. Assessing T cell responses is especially challenging, given genetic restriction, low responses observed in endemic areas, their variability over time, potential suppression by parasitaemia and the intrinsic variability of the assays.MethodsIn Part A of this study, antibody titres were measured in adults from urban and rural communities in Ghana to recombinant Plasmodium falciparum CSP, SSP2/TRAP, LSA1, EXP1, MSP1, MSP3 and EBA175 by ELISA, and to sporozoites and infected erythrocytes by IFA. Positive ELISA responses were determined using two methods. T cell responses to defined CD8 or CD4 T cell epitopes from CSP, SSP2/TRAP, LSA1 and EXP1 were measured by ex vivo IFN-γ ELISpot assays using HLA-matched Class I- and DR-restricted synthetic peptides. In Part B, the reproducibility of the ELISpot assay to CSP and AMA1 was measured by repeating assays of individual samples using peptide pools and low, medium or high stringency criteria for defining positive responses, and by comparing samples collected two weeks apart.ResultsIn Part A, positive antibody responses varied widely from 17%-100%, according to the antigen and statistical method, with blood stage antigens showing more frequent and higher magnitude responses. ELISA titres were higher in rural subjects, while IFA titres and the frequencies and magnitudes of ex vivo ELISpot activities were similar in both communities. DR-restricted peptides showed stronger responses than Class I-restricted peptides. In Part B, the most stringent statistical criteria gave the fewest, and the least stringent the most positive responses, with reproducibility slightly higher using the least stringent method when assays were repeated. Results varied significantly between the two-week time-points for many participants.ConclusionsAll participants were positive for at least one malaria protein by ELISA, with results dependent on the criteria for positivity. Likewise, ELISpot responses varied among participants, but were relatively reproducible by the three methods tested, especially the least stringent, when assays were repeated. However, results often differed between samples taken two weeks apart, indicating significant biological variability over short intervals.

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“…Relative to the cohort with noncritical Hb, we also hypothesized that severe anemia would be associated with parasitemia, higher parasite density, more febrile illness, and residence proximal to perennial breeding sites of anopheline mosquitoes. Owing to natural decline, by 6 months of maternally transferred protection, 3 and the greater vulnerability to infection that malnutrition, low birth weight, and stunting impart, we further expected that severe anemia might be more prevalent at the lower end of the 6-24-month range studied and would be associated with higher rates of parasitemia, greater parasite densities, more febrile illness, female sex, and low body weight for age.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of severe anemia and its association with malaria in young children of the Kassena-Nankana District of northern Ghana.

Owusu‐Agyei¹,

Fryauff²,

Chandramohan³

et al. 2002

Am J Trop Med Hyg

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Abstract. Severe anemia is thought to be the principal underlying cause of malaria death in areas of intense seasonal malaria transmission such as the Kassena-Nankana District of northern Ghana. Factors associated with severe anemia in young children, 6-24 months old, were elucidated by analyzing results of 2 malaria-associated anemia surveys (1996, 2000), separated by 4 years, but conducted in the same community and at the same seasonal time point. Age-adjusted comparison confirmed that the proportion of severely anemic children and overall mean hemoglobin (Hb) levels in the November 2000 sample were significantly improved over those of the 1996 sample (17.5 versus 26.4%, P ‫ס‬ 0.03; Hb 7.5 versus 6.9 g/dL, P ‫ס‬ 0.002). Weight-for-age Z-scores also indicated a significant improvement in the 2000 sample (−1.93 versus −2.20, P < 0.05). Independently, each survey identified statistically significant associations between severe anemia and age, parasite rate, fever, and sex. Relative to children with Hb Ն 6.0 g/dL, those with severe anemia (Hb < 6.0 g/dL) were older, more frequently parasitemic (odds ratio [OR], 1.60; 95% confidence interval [CI], 1.08-2.35), more often febrile (OR, 2.44; 95% CI, 1.71-3.48), and predominantly male (OR, 1.50; 95% CI, 1.05-2.13). An association was identified in both surveys between severe anemia and residence in the northern part of the district, but no clear link was observed in relation to irrigation. Blood transfusions, a likely surrogate index of severe anemia in young children, followed a distinct seasonal pattern. Evidence suggests that dramatic peaks and troughs of severe anemia are regular and possibly predictable events that may be used to gauge the health and survival of young children in this area.

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A longitudinal study of malaria infection, morbidity and antibody titres in infants of a rural community in Ghana

Cited by 14 publications

References 7 publications

Effect of IPTp on Plasmodium falciparum antibody levels among pregnant women and their babies in a sub-urban coastal area in Ghana

Effect of IPTp on Plasmodium falciparum antibody levels among pregnant women and their babies in a sub-urban coastal area in Ghana

Measuring naturally acquired immune responses to candidate malaria vaccine antigens in Ghanaian adults

Characteristics of severe anemia and its association with malaria in young children of the Kassena-Nankana District of northern Ghana.

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