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Seasonal Dynamics of Malaria in Pregnancy in West Africa: Evidence for Carriage of Infections Acquired Before Pregnancy Until First Contact with Antenatal Care.

ABSTRACT: In malaria-endemic areas, Plasmodium falciparum prevalence is often high in young women because of 1) low use of insecticide-treated nets before their first pregnancy and 2) acquired immunity, meaning infections are asymptomatic and thus untreated. Consequently, a common source of malaria in pregnancy (MiP) may be infected women becoming pregnant, rather than pregnant women becoming infected. In this study, prevalence of infection was determined by microscopy at first antenatal care (ANC) visit in primigravidae and secundigravidae in Ghana, Burkina Faso, Mali, and The Gambia, four countries with strong seasonal variations in transmission. Duration of pregnancy spent in the rainy season and other risk factors for infection were evaluated using multivariable Poisson regression. We found that the overall prevalence of malaria at first ANC was generally high and increased with time spent pregnant during the rainy season: prevalence among those with the longest exposure was 59.7% in Ghana, 56.7% in Burkina Faso, 42.2% in Mali, and 16.8% in Gambia. However, the prevalence was substantial even among women whose entire pregnancy before first ANC had occurred in the dry season: 41.3%, 34.4%, 11.5%, and 7.8%, respectively, in the four countries. In multivariable analysis, risk of infection was also higher among primigravidae, younger women, and those of lower socioeconomic status, independent of seasonality. High prevalence among women without exposure to high transmission during their pregnancy suggests that part of the MiP burden results from long-duration infections, including those acquired preconception. Prevention of malaria before pregnancy is needed to reduce the MiP burden.

SUBMITTER: Berry I

PROVIDER: S-EPMC5929207 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature

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Seasonal Dynamics of Malaria in Pregnancy in West Africa: Evidence for Carriage of Infections Acquired Before Pregnancy Until First Contact with Antenatal Care.

Berry Isha I Walker Patrick P Tagbor Harry H Bojang Kalifa K Coulibaly Sheick Oumar SO Kayentao Kassoum K Williams John J Oduro Abraham A Milligan Paul P Chandramohan Daniel D Greenwood Brian B Cairns Matthew M

The American journal of tropical medicine and hygiene 20171130 2

In malaria-endemic areas, <i>Plasmodium falciparum</i> prevalence is often high in young women because of 1) low use of insecticide-treated nets before their first pregnancy and 2) acquired immunity, meaning infections are asymptomatic and thus untreated. Consequently, a common source of malaria in pregnancy (MiP) may be infected women becoming pregnant, rather than pregnant women becoming infected. In this study, prevalence of infection was determined by microscopy at first antenatal care (ANC) ...[more]

PMID: 29210351

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Project description:BackgroundAnaemia is a major cause of morbidity and mortality for children in Africa. The plasma protein haptoglobin (Hp) binds avidly to free haemoglobin released following malaria-induced haemolysis. Haptoglobin polymorphisms result in proteins with altered haemoglobin-binding capacity and different antioxidant, iron-recycling, and immune functions. Previous studies examined the importance of haptoglobin polymorphism in malaria and iron homeostasis, but it is unknown whether haptoglobin genotype might be a risk factor for anaemia in children in a malaria-endemic area.Methods and findingsA cohort of 780 rural Gambian children aged 2-6 y was surveyed at the start and end of the malaria season. Samples were taken to assess haemoglobin (Hb) concentration, iron status (ferritin, zinc protoporphyrin, transferrin saturation, and soluble transferrin receptor concentration), haptoglobin concentration, alpha-1-antichymotrypsin (a measure of inflammation), and malaria parasites on blood film. We extracted DNA and genotyped for haptoglobin, sickle cell, and glucose-6-phosphate (G6PD) deficiency. Mean Hb levels fell over the malaria season. Children with the haptoglobin 2-2 genotype (17%) had a greater mean drop in Hb level over the malaria season (an 8.9 g/l drop; confidence interval [CI] 5.7, 12.1) compared to other children (a 5.1 g/l drop; CI 3.8, 6.4). In multivariate regression analysis, controlling for baseline Hb level, age group, village, malaria parasites on blood film, iron status, haptoglobin concentration, and G6PD deficiency, haptoglobin genotype predicted Hb level at the end of the malaria season (p = 0.0009, coefficient = -4.2). Iron status was not influenced by haptoglobin genotype.ConclusionsThe finding that haptoglobin 2-2 genotype is a risk factor for anaemia in children in a malaria-endemic area may reflect the reduced ability of the Hp2-2 polymer to scavenge free haemoglobin-iron following malaria-induced haemolysis. The magnitude of the effect of haptoglobin genotype (4 g/l Hb difference, p = 0.0009) was comparable to that of G6PD deficiency or HbAS (3 g/l difference, p = 0.03; and 2 g/l difference, p = 0.68, respectively).

Project description:Despite contributing to the large disease burden in West Africa, little is known about the genomic epidemiology of Streptococcus pneumoniae which cause meningitis among children under 5 years old in the region. We analysed whole-genome sequencing data from 185 S. pneumoniae isolates recovered from suspected paediatric meningitis cases as part of the World Health Organization (WHO) invasive bacterial diseases surveillance from 2010 to 2016. The phylogeny was reconstructed, accessory genome similarity was computed and antimicrobial-resistance patterns were inferred from the genome data and compared to phenotypic resistance from disc diffusion. We studied the changes in the distribution of serotypes pre- and post-pneumococcal conjugate vaccine (PCV) introduction in the Central and Western sub-regions separately. The overall distribution of non-vaccine, PCV7 (4, 6B, 9V, 14, 18C, 19F and 23F) and additional PCV13 serotypes (1, 3, 5, 6A, 19A and 7F) did not change significantly before and after PCV introduction in the Central region (Fisher's test P value 0.27) despite an increase in the proportion of non-vaccine serotypes to 40 % (n=6) in the post-PCV introduction period compared to 21.9 % (n=14). In the Western sub-region, PCV13 serotypes were more dominant among isolates from The Gambia following the introduction of PCV7, 81 % (n=17), compared to the pre-PCV period in neighbouring Senegal, 51 % (n=27). The phylogeny illustrated the diversity of strains associated with paediatric meningitis in West Africa and highlighted the existence of phylogeographical clustering, with isolates from the same sub-region clustering and sharing similar accessory genome content. Antibiotic-resistance genotypes known to confer resistance to penicillin, chloramphenicol, co-trimoxazole and tetracycline were detected across all sub-regions. However, there was no discernible trend linking the presence of resistance genotypes with the vaccine introduction period or whether the strain was a vaccine or non-vaccine serotype. Resistance genotypes appeared to be conserved within selected sub-clades of the phylogenetic tree, suggesting clonal inheritance. Our data underscore the need for continued surveillance on the emergence of non-vaccine serotypes as well as chloramphenicol and penicillin resistance, as these antibiotics are likely still being used for empirical treatment in low-resource settings. This article contains data hosted by Microreact.

Project description:INTRODUCTION:Africa harbours a high burden of pneumococcal disease, with associated high mortality rates. Despite 34 countries introducing the pneumococcal conjugate vaccine, which reduces the risk of pneumococcal carriage (a prerequisite for disease) of some of the most pathogenic pneumococcal serotypes, it remains uncertain whether they will achieve the sustained direct or indirect protection necessary to reduce pneumococcal carriage to levels sufficient to interrupt transmission and disease. We will therefore summarise the available data on the impact of the pneumococcal conjugate vaccine in reducing vaccine serotype carriage and pneumococcal pneumonia in Africa between 2000 and 2019. METHODS AND ANALYSIS:Using a predetermined search strategy, we will conduct a comprehensive search of PubMed, MEDLINE database, the Excerpta Medica Database, the ISI Web of Science (Science Citation Index), Scopus and the African Index Medicus to identify published studies reporting the prevalence of Streptococcus pneumoniae carriage (vaccine type and non-vaccine type), incidence rates of pneumococcal pneumonia and mortality among children, adults and HIV-infected (all-ages) pre-pneumococcal conjugate vaccine (PCV) and post-PCV introduction (published between 1st January 2000 and 31st December 2019) in African countries that have introduced PCVs (PCV7/PCV10/PCV13) in their routine national immunisation programme. The studies retained and data extracted will be assessed for bias using prevalidated tools and checklists. Heterogeneity across studies will be assessed using the ?2 test on Cochrane Q statistic. A random effect meta-analysis will be used to estimate the overall prevalence of pneumococcal carriage and incidence of pneumococcal pneumonia across studies with similar characteristics. Results will be reported in compliance with the Meta-Analysis Of Observational Studies in Epidemiology guidelines. The protocol has been prepared in accordance to the 2015 guidelines on Preferred Reporting Items for Systematic Reviews and Meta-Analyses. ETHICS AND DISSEMINATION:This systematic review will not require ethical approval as we will be using already published data. The final manuscript will be submitted for publication in a peer-reviewed journal and presented at conferences. PROSPERO REGISTRATION NUMBER:CRD42019130976.

Project description:BackgroundEvidence of the association between early antenatal care (ANC) and receiving at least three doses of sulphadoxine-pyrimethamine (IPTp3+) during pregnancy is limited. It's also unclear whether the association between early ANC and IPTp3+ is modified by planned pregnancy status.ObjectivesOur primary aim was to assess the relationship between early ANC and IPTp3+ and to assess whether this relationship is modified by a woman's planned pregnancy status. We also estimated IPTp3+ coverage across Sub-Saharan African countries.MethodsData on 77 183 mothers with a live birth in the past two years were analyzed using multiple indicator cluster surveys (MICSs) from 17 Sub-Saharan African countries conducted between 2013 and 2019. We used modified Poisson regression with a robust variance to assess the association between early ANC and IPTp3+, while adjusting for country, clustering, stratification and sample weights. Effect modification by planned pregnancy status was assessed on the additive and multiplicative scales. We used meta-analytic techniques to pool prevalent estimates of IPTp3+ across all countries.FindingsIPTp3+ overall coverage was 22.1% (95% CI: 17.0%, 27.1%), and ranged from 2.9% (95% CI: 1.3%, 4.4%) in São Tomé and Príncipe to 51.7% (95% CI: 49.2%, 54.1%) in Ghana. IPTp3+ coverage was 30% higher among mothers who had early ANC compared to those who did not have early ANC [adjusted prevalence ratio (aPR): 1.30, 95% CI: 1.23,1.36]. There was evidence of effect modification on the additive [relative excess risk due to interaction (RERI): 0.08, 95% CI: 0.0002, 0.15] and multiplicative (aPR: 1.10, 95% CI: 1.01, 1.20) scales.ConclusionsIPTp3+ coverage was low across many of the countries in Sub-Saharan Africa. Women who had early ANC were more likely to receive IPTp3+. Women whose pregnancies were unplanned were less likely to receive IPTp3+, but our effect modification analysis showed that early ANC among such women can increase IPTp3+ coverage.

Project description:Since 2000, substantial progress has been made in reducing malaria worldwide. However, some countries in West Africa remain a hotspot for malaria with all age groups at risk. Asymptomatic carriers of Plasmodium spp. are important sources of infections for malaria vectors and thus contribute to the anchoring of the disease in favourable eco-epidemiological settings. The objective of this study was to assess the asymptomatic malaria case rates in Korhogo and Kaedi, two urban areas in northern Côte d'Ivoire and southern Mauritania, respectively.Cross-sectional surveys were carried out during the rainy season in 2014 and the dry season in 2015 in both settings. During each season, 728 households were randomly selected and a household-based questionnaire was implemented to collect demographic and epidemiological data, including of malaria preventive methods used in communities. Finger-prick blood samples were obtained for biological examination using microscopy and rapid diagnostic tests (RDTs).Overall, 2672 households and 15?858 consenting participants were surveyed. Plasmodium spp. infection was confirmed in 12.4% (n?=?832) and 0.3% (n?=?22) of the assessed individuals in Korhogo and Kaedi, respectively. In Korhogo, the prevalence of asymptomatic malaria was 10.5% (95% CI: 9.7-11.2) as determined by microscopy and 9.3% (95% CI: 8.6-10.0%) when assessed by RDT. In Kaedi, asymptomatic malaria prevalence was 0.2% (95% CI: 0.1-0.4%) according to microscopy, while all RDTs performed were negative (n?=?8372). In Korhogo, asymptomatic malaria infection was significantly associated with age and season, with higher risk within the 5-14 years-old, and during the rainy season. In Kaedi, the risk of asymptomatic malaria infection was associated with season only (higher during the dry season; crude OR (cOR): 6.37, 95% CI: 1.87-21.63). P. falciparum was the predominant species identified in both study sites representing 99.2% (n?=?825) in Korhogo and 59.1% (n?=?13) in Kaedi. Gametocytes were observed only in Korhogo and only during the rainy season at 1.3% (95% CI: 0.7-2.4%).Our findings show a low prevalence of clinical malaria episodes with a significant proportion of asymptomatic carriers in both urban areas. National policies for malaria infections are focused on treatment of symptomatic cases. Malaria control strategies should be designed for monitoring and managing malaria infections in asymptomatic carriers. Additional measures, including indoor residual spraying, effective use of long-lasting insecticidal nets is strongly needed to reduce the number of Plasmodium spp. infections in Korhogo and Kaedi.

Dataset Information

Seasonal Dynamics of Malaria in Pregnancy in West Africa: Evidence for Carriage of Infections Acquired Before Pregnancy Until First Contact with Antenatal Care.

Publications

Seasonal Dynamics of Malaria in Pregnancy in West Africa: Evidence for Carriage of Infections Acquired Before Pregnancy Until First Contact with Antenatal Care.

Similar Datasets

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