Plasmodium falciparum, anaemia and cognitive and educational performance among school children in an area of moderate malaria transmission: baseline results of a cluster randomized trial on the coast of Kenya

Current Status of Malaria Control and Elimination in Africa: Epidemiology, Diagnosis, Treatment, Progress and Challenges

The African continent carries the greatest malaria burden in the world. Falciparum malaria especially has long been the leading cause of death in Africa. Climate, economic factors, geographical location, human intervention and unstable security are factors influencing malaria transmission. Due to repeated infections and early interventions, the proportion of clinically atypical malaria or asymptomatic plasmodium carriers has increased significantly, which easily lead to misdiagnosis and missed diagnosis. African countries have made certain progress in malaria control and elimination, including rapid diagnosis of malaria, promotion of mosquito nets and insecticides, intermittent prophylactic treatment in high-risk groups, artemisinin based combination therapies, and the development of vaccines. Between 2000 and 2022, there has been a 40% decrease in malaria incidence and a 60% reduction in mortality rate in the WHO African Region. However, many challenges are emerging in the fight against malaria in Africa, such as climate change, poverty, substandard health services and coverage, increased outdoor transmission and the emergence of new vectors, and the growing threat of resistance to antimalarial drugs and insecticides. Joint prevention and treatment, identifying molecular determinants of resistance, new drug development, expanding seasonal malaria chemo-prevention intervention population, and promoting the vaccination of RTS, S/AS01 and R21/Matrix-M may help to solve the dilemma. China's experience in eliminating malaria is conducive to Africa's malaria prevention and control, and China-Africa cooperation needs to be constantly deepened and advanced. Our review aims to help the global public develop a comprehensive understanding of malaria in Africa, thereby contributing to malaria control and elimination.

Combating malaria in Kenya through collaborative population health education: a systematic review and pilot case study

BACKGROUND

Malaria continues to be a public health problem in Kenya, with an estimated 37.2 million people at high risk of the disease. The disease burden is compounded by inequalities in health service availability, housing, socioeconomic conditions, and access to education.

OBJECTIVES

We aimed to determine the status of community-based, health education interventions. Based on the findings, to develop an educational module for medical students to combat malaria in Kenya.

METHODS

A systematic review was conducted to identify different educational interventions, their successes and limitations, and legal challenges leading to low uptake and adherence to malaria prevention interventions from 2000-2023. Consequently, a 6-week online educational pilot was conducted with healthcare students from Kenya, Japan, the UK, and Cyprus.

RESULTS

Despite developing a national malaria strategy and monitoring and evaluation strategies, Kenya has not been able to meet the incidence reduction targets set by the World Health Organisation, underscoring the need for more work in identifying the barriers to implementing strategies and optimising the distribution of public health interventions. Student teams proposed innovative solutions, including two-tier malaria control strategies, maternal malaria clinical education, community awareness through schools and NGOs, and a 10-year health system strengthening and immunisation plan.

CONCLUSIONS

Public education regarding prevention strategies and increasing their adoption remains a key challenge in combating malaria in Kenya. In this regard, digital tools can facilitate international collaborative health education and exchange of best practices, allowing students and faculty to engage across boundaries and prepare them to be future-ready physicians connected to the global community.

Attributable risk factors for asymptomatic malaria and anaemia and their association with cognitive and psychomotor functions in schoolchildren of north-eastern Tanzania

In Africa, children aged 5 to 15 years (school age) comprises more than 50% (>339 million) of the under 19 years population, and are highly burdened by malaria and anaemia that impair cognitive development. For the prospects of improving health in African citizens, understanding malaria and its relation to anaemia in school-aged children, it is crucial to inform targeted interventions for malaria control and accelerate elimination efforts as part of improved school health policy. We conducted a study to determine the risk factors for asymptomatic malaria and their association to anaemia. We explored the prevalence of antimalarial drug resistance as well as the association of asymptomatic malaria infection and anaemia on cognitive and psychomotor functions in school-aged children living in high endemic areas. This study was a comprehensive baseline survey, within the scope of a randomised, controlled trial on the effectiveness and safety of antimalarial drugs in preventing malaria and its related morbidity in schoolchildren. We enrolled 1,587 schoolchildren from 7 primary schools located in Muheza, north-eastern Tanzania. Finger-pricked blood samples were collected for estimation of malaria parasitaemia using a microscope, haemoglobin concentration using a haemoglobinometer, and markers of drug resistance processed from dried blood spots (DBS). Psychomotor and Cognitive functions were assessed using a ‘20 metre Shuttle run’ and a test of everyday attention for children (TEA-Ch), respectively. The prevalence of asymptomatic malaria parasitaemia, anaemia and stunting was 26.4%, 49.8%, and 21.0%, respectively with marked variation across schools. In multivariate models, asymptomatic malaria parasitaemia attributed to 61% of anaemia with a respective population attribution fraction of 16%. Stunting, not sleeping under a bednet and illiterate parent or guardian were other factors attributing to 7%, 9%, and 5% of anaemia in the study population, respectively. Factors such as age group (10–15 years), not sleeping under a bednet, low socioeconomic status, parents’ or guardians’ with a low level of education, children overcrowding in a household, and fewer rooms in a household were significantly attributed to higher malaria infection. There was no significant association between malaria infection or anaemia and performance on tests of cognitive function (sustained attention) or psychomotor function (VO2 max). However, a history of malaria in the past one month was significantly associated with decreased cognitive scores (aOR = -4.1, 95% CI -7.7–0.6, p = 0.02). Furthermore, stunted children had significantly lower VO2max scores (aOR = -1.9, 95% CI -3.0–0.8, p = 0.001). Regarding the antimalarial drug resistance markers, the most prevalent Pfmdr1 86-184-1034-1042-1246 haplotypes were the NFSND in 47% (n = 88) and the NYSND in 52% (n = 98). The wild type Pfcrt haplotypes (codons 72–76, CVMNK) were found in 99.1% (n = 219) of the samples. Malaria, stunting and parents’ or guardians’ illiteracy were the key attributable factors for anaemia in schoolchildren. Given malaria infection in schoolchildren is mostly asymptomatic; an addition of interventional programmes such as intermittent preventive treatment of malaria in schoolchildren (IPTsc) would probably act as a potential solution while calling for an improvement in the current tools such as bednet use, school food programme, and community-based (customised) health education with an emphasis on nutrition and malaria control.

Iron Status, Anemia, and Iron Interventions and Their Associations with Cognitive and Academic Performance in Adolescents: A Systematic Review

In adolescents, iron-deficiency anemia is the leading cause of disability-adjusted life years lost. The World Health Organization recommends delivering iron supplementation through school-based platforms, requiring partnerships with the education sector. This anemia-reduction intervention is valued for the perceived benefits of improved learning and school performance. This article aims to systematically review the available evidence on the relationship between iron status and anemia and impacts of iron interventions on cognitive and academic performance in adolescents. Fifty studies were included: n = 26 cross-sectional and n = 24 iron-containing interventions. Our review suggests that iron status and anemia may be associated with academic performance in some contexts and that iron supplementation during adolescence may improve school performance, attention, and concentration. However, nearly all supplementation trials were judged to have moderate or high risk of bias. We did not find evidence suggesting that iron status and anemia influenced or were associated with attention, intelligence, nor memory in adolescents. Further, iron supplementation did not improve memory and recall or intelligence. Overall, more high-quality research is needed to guide programmers and policy makers to understand the relationships between anemia and educational performance and the potential impacts of iron interventions, which effectively reduce anemia, on adolescents’ learning and school performance.

Comparative effect of dihydroartemisinin-piperaquine and artemether-lumefantrine on gametocyte clearance and haemoglobin recovery in children with uncomplicated Plasmodium falciparum malaria in Africa: a systematic review and meta-analysis of randomized control trials

BACKGROUND

Plasmodium falciparum gametocytaemia has been associated with anaemia. The aim of this review was to synthesize available evidence on the comparative effect of dihydroartemisinin-piperaquine (DHA-PQ) and artemether-lumefantrine (AL) on gametocyte clearance and haemoglobin recovery in children with uncomplicated P. falciparum malaria in Africa.

METHODS

A systematic literature search was undertaken to identify relevant articles from online databases. The search was performed from August 2020 to 30 April 2021. Extracted data from eligible studies were pooled as risk ratios with 95% confidence intervals (CI).

RESULTS

Gametocyte carriage was reduced in both treatment groups, with no significant difference found between the groups. However, on days 28 and 42, a significant increase in serum haemoglobin level from baseline was observed in the DHA-PQ group (standardized mean difference 0.15, 95% CI 0.05-0.26; participants=2715; studies=4; I²⁼32%, high quality of evidence) compared with the AL group (mean difference 0.35, 95% CI 0.12-0.59; participants=1434; studies=3; I²=35%, high quality of evidence).

CONCLUSION

DHA-PQ had a greater impact on haemoglobin recovery than AL on days 28 and 42; this difference was significant.

Prevalence and associated risk factors of asymptomatic malaria and anaemia among school-aged children in Dara Mallo and Uba Debretsehay districts: results from baseline cluster randomized trial

Background

Despite the growing evidence that malaria and anaemia are two interlinked health problems of school-aged children (SAC) in developing countries, there is scarce information about malaria among SAC in Ethiopia. Moreover, anaemia-related studies were more concentrated in easily accessible areas. This study aimed to assess the prevalence of malaria and anaemia and corresponding risk factors among SAC in Dara Mallo and Uba Debretshay districts, in hard to reach areas, so as to inform appropriate integrated interventions for both diseases.

Methods

This study was part of baseline data collected for a cluster-randomized trial registered in Pan African Clinical Trials Registry (PACTR202001837195738). Data were collected from 2167 SAC and their households through face-to-face interview; malaria was diagnosed by using rapid diagnostic test (RDT); haemoglobin concentration was determined using hemoCue hb 301 and adjusted for altitude to determine anaemic status; helminth infections were determined by using kato-katz, and anthropometric measurements were made to determine nutritional status of children. Generalized mixed effects logistic regression model was used to assess the association between predictor variables and malaria and anaemia using school as a random variable.

Results

The overall prevalence of malaria was 1.62% (95% CI 1.15–2.27%) (35/2167). Of the 35 children positive for malaria, 20 (57.14%), 3 (8.57%) and 12 (34.29%) were due to Plasmodium falciparum, Plasmodium vivax and mixed infections of P. falciparum and P. vivax, respectively. Malaria was significantly lower among children from literate household head (Adjusted OR  =  0.38; 95% CI 0.15–0.95) and residence house located at an altitude range above 1100 masl (AOR  =  0.40; 95% CI 0.17–0.94). The prevalence of anaemia was 22.00% (95% CI 20.3–23.8%) (477/2167) and was significantly reduced by eating legumes, nuts or seed group of food in their 24-h dietary diversity recall (AOR  =  0.64; 95% CI 0.41–0.99).

Conclusions

The prevalence of malaria was low and unevenly distributed per school while the overall prevalence of anaemia was moderate. It is important to implement integrated interventions targeting both malaria and anaemia, with special emphasis given to children from illiterate households and living at an altitude below 1100 masl. The micronutrient content of locally grown legumes should be further investigated to recommend specific interventions to overcome anaemia.

Prevalence, Parasite Density and Determinants of Falciparum Malaria Among Febrile Children in Some Peri-Urban Communities in Southwestern Nigeria: A Cross-Sectional Study

Background

Malaria remains a serious public health problem worldwide, particularly in tropical and subtropical regions, including Nigeria. This study investigates the prevalence, parasite density and determinants of malaria among symptomatic children in some peri-urban communities in southwestern Nigeria.

Methods

This was a randomized cross-sectional and hospital-based study. The standard method of microscopy was employed. Thick and thin films were prepared and viewed under a light microscope to identify and quantify malaria parasites. A well-structured and pre-tested questionnaire was used to obtain the subject’s information on the demographic, socio-economic and environmental variables.

Results

A total of 380 (71.7%) participants were infected with Plasmodium falciparum with a mean parasite density of 1857.11 parasite/µL of blood. Malaria prevalence and mean parasite density were significantly higher among male compared to their female counterparts [80.3% vs 61.4% and 2026.46 vs 1619.63 parasite/µL of blood]. Similarly, age group ≤5 years had the highest malaria prevalence (92.2%) and mean parasite density (2031.66 parasite/µL of blood) than other age groups (AOR 2.281, 95% CI: 1.187–4.384, P < 0.05). The multivariate logistic analysis showed that malaria disease is significantly associated with having mother with no formal education (AOR 12.235, 95% CI: 3.253–46.021, P < 0.05), having well and river as a major source of household water supply (AOR 13.810, 95% CI: 3.012–63.314, P < 0.05 vs AOR 5.639, 95% CI: 1.455–21.853, P < 0.05) and presence of stagnant water around home (AOR 5.22, 95% CI: 2.921–9.332, P < 0.05). Furthermore, protective factors observed include ownership of mosquito bed net (AOR 0.474, 95% CI: 0.223–1.008, P < 0.05) and distance of home to hospital (AOR 0.279, 95% CI: 0.158–0.493, P < 0.05).

Conclusion

Malaria remains a serious public health problem in the study area. Adopting integrated malaria control measures including educating parents on malaria prevention and control strategies, distributing mosquito bed nets, and establishing larvae source management program is highly imperative.

Prevalence of malaria parasitaemia in school-aged children and pregnant women in endemic settings of sub-Saharan Africa: A systematic review and meta-analysis

Despite increased malaria control efforts, school-aged children (5–14 years) have higher a malaria prevalence compared to children under-five. In high-transmission settings, up to 70% of school-aged children harbour malaria parasitaemia and therefore contribute significantly to the reservoir for transmission. A systematic review was performed to explore the correlation between the malaria parasite carriage in pregnant women and school-aged children living in similar endemic settings of sub Saharan Africa to inform strategies to improve targeted malaria control.

In order to obtain data on malaria prevalence in pregnant women and school-aged children living in the same endemic setting, we searched the Malaria in Pregnancy Library, PubMed, Cochrane library and Web of Science in December 2018. We fit a fixed effect model to obtain a pooled risk ratio (PRR) of malaria in school-aged children versus pregnant women and used Poisson regression to estimate risk ratios in school-aged children for every increase in prevalence in pregnant women. We used data from six (out of 1096) sources that included 10 data points. There was a strong linear relation between the prevalence of malaria infection in pregnant women and school-aged children (r = 0·93, p < 0·0001). School-aged children were nearly twice at risk to carry parasites compared to pregnant women (RR = 1.95, 95% CI: 1·69–2.25, p < 0.01). Poisson regression showed that a 1% increase in prevalence of malaria infection in pregnant women was significantly associated with increase in risk in school-aged children by 4%.

Malaria infection prevalence in school-aged children is strongly correlated with the prevalence in pregnant women living in the same community, and may be considered as alternative indicators to track temporal and spatial trends in malaria transmission intensity. Chemoprevention strategies targeting school-aged children should be explored to reduce malaria burden and transmission in school-aged children and its potential impact on communities.

Effectiveness and safety of intermittent preventive treatment for malaria using either dihydroartemisinin-piperaquine or artesunate-amodiaquine in reducing malaria related morbidities and improving cognitive ability in school-aged children in Tanzania: A study protocol for a controlled randomised trial

BACKGROUND

In high transmission settings, up to 70% of school-aged children harbour malaria parasites without showing any clinical symptoms. Thus, epidemiologically, school aged children act as a substantial reservoir for malaria transmission. Asymptomatic Plasmodium infections induce inflammation leading to iron deficiency anaemia. Consequently, anaemia retards child growth, predisposes children to other diseases and reduces cognitive potential that could lead to poor academic performance. School aged children become increasingly more vulnerable as compared to those aged less than five years due to delayed acquisition of protective immunity. None of the existing Intermittent Preventive Treatment (IPT) strategies is targeting school-aged children. Here, we describe the study protocol of a clinical trial conducted in north-eastern Tanzania to expand the IPT by assessing the effectiveness and safety of two antimalarial drugs, Dihydroartemisinin-Piperaquine (DP) and Artesunate-Amodiaquine (ASAQ) in preventing malaria related morbidities in school-aged children (IPTsc) living in a high endemic area.

METHODS/DESIGN

The trial is a phase IIIb, individual randomized, open label, controlled trial enrolling school children aged 5-15 years, who receive either DP or ASAQ or control (no drug), using a "balanced block design" with the "standard of care" arm as reference. The interventional treatments are given three times a year for the first year. A second non-interventional year will assess possible rebound effects. Sample size was estimated to 1602 school children (534 per group) from selected primary schools in an area with high malaria endemicity. Thick and thin blood smears (to measure malaria parasitaemia using microscope) were obtained prior to treatment at baseline, and will be obtained again at month 12 and 20 from all participants. Haemoglobin concentration using a haemoglobinometer (HemoCue AB, Sweden) will be measured four monthly. Finger-prick blood (dried bloodspot-DBS) prepared on Whatman 3 M filter paper, will be used for sub-microscopic malaria parasite detection usingPCR, detect markers of drug resistance (using next generation sequencing (NGS) technology), and malaria serological assays (using enzyme-linked immunosorbent assay, ELISA). To determine the benefit of IPTsc on cognitive and psychomotor ability test of everyday attention for children (TEA-Ch) and a '20 m Shuttle run' respectively, will be conducted at baseline, month 12 and 20. The primary endpoints are change in mean haemoglobin from baseline concentration and reduction in clinical malaria incidence at month 12 and 20 of follow up. Mixed design methods are used to assess the acceptability, cost-effectiveness and feasibility of IPTsc as part of a more comprehensive school children health package. Statistical analysis will be in the form of multilevel modelling, owing to repeated measurements and clustering effect of participants.

DISCUSSION

Malaria intervention using IPTsc strategy may be integrated in the existing national school health programme. However, there is limited systematic evidence to assess the effectiveness and operational feasibility of this approach. School-aged children are easily accessible in most endemic malaria settings. The evidence from this study will guide the implementation of the strategy to provide complementary approach to reduce malaria related morbidity, anaemia and contribute to the overall burden reduction.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT03640403, registered on Aug 21, 2018, prospectively registered.Url https://www.clinicaltrials.gov/ct2/show/NCT03640403?term=NCT03640403&rank=1.

Efficacy of Nutrition and WASH/Malaria Educational Community-Based Interventions in Reducing Anemia in Preschool Children from Bengo, Angola: Study Protocol of a Randomized Controlled Trial

Angola reports one of the highest infant mortality rates in the world, and anemia represents one of its important causes. Recent studies, in under-five children from the Bengo province of Angola, described high prevalence’s, suggesting malaria, undernutrition and urogenital schistosomiasis as important contributors for the occurrence and spatial variations of anemia. Educational community-based interventions, either in Nutrition and Water, Sanitation, Hygiene and Malaria are recommended to correct anemia. Herein, we designed a cluster-randomized controlled trial to study the efficacy of two educational-plus-therapeutic interventions in the reduction of anemia: one in nutrition and the other in WASH/Malaria. Socioeconomic, nutritional, anthropometric, parasitological and biochemical data will be collected from all willing-to-participate children, aging under four and resident in the Health Research Center of Angola study area. Considering the multifactorial causes of this condition, determining the efficacy of both interventions might help documenting weaknesses and opportunities for planning integrated strategies to reduce anemia.

The protective effectiveness of control interventions for malaria prevention: a systematic review of the literature

Background: Thanks to a considerable increase in funding, malaria control interventions (MCI) whose efficacy had been demonstrated by controlled trials have been largely scaled up during the last decade. Nevertheless, it was not systematically investigated whether this efficacy had been preserved once deployed on the field. Therefore, we sought the literature to assess the disparities between efficacy and effectiveness and the effort to measure the protective effectiveness (PE) of MCI.

Methods: The PubMed database was searched for references with keywords related to malaria, to control interventions for prevention and to study designs that allow for the measure of the PE against parasitemia or against clinical outcomes.

Results: Our search retrieved 1423 references, and 162 articles were included in the review. Publications were scarce before the year 2000 but dramatically increased afterwards. Bed nets was the MCI most studied (82.1%). The study design most used was a cross-sectional study (65.4%). Two thirds (67.3%) were conducted at the district level or below, and the majority (56.8%) included only children even if the MCI didn’t target only children. Not all studies demonstrated a significant PE from exposure to MCI: 60.6% of studies evaluating bed nets, 50.0% of those evaluating indoor residual spraying, and 4/8 showed an added PE of using both interventions as compared with one only; this proportion was 62.5% for intermittent preventive treatment of pregnant women, and 20.0% for domestic use of insecticides.

Conclusions: This review identified numerous local findings of low, non-significant PE –or even the absence of a protective effect provided by these MCIs. The identification of such failures in the effectiveness of MCIs advocates for the investigation of the causes of the problem found. Ideal evaluations of the PE of MCIs should incorporate both a large representativeness and an evaluation of the PE stratified by subpopulations.

Malaria and macronutrient deficiency as correlates of anemia in young children: a systematic review of observational studies

BACKGROUND

Anemia is a leading cause of pediatric mortality and impaired development and is highly prevalent in young children in sub-Saharan Africa. Populations most affected by anemia also often are at high risk for malaria and macronutrient deficiency, conditions that may exacerbate anemia. Due to its multifactorial etiology, anemia presents a significant global health challenge, and successful interventions targeting anemia require a greater understanding of the relative and interacting contributions of malaria and undernutrition.

OBJECTIVES

The aim of this study was to assess the associations of malaria and undernutrition, indicated by stunting and wasting, with anemia in young children using a systematic review of observational studies.

METHODS

Searches were conducted in MEDLINE and Scopus. Articles were screened and reviewed for inclusion by two reviewers. Studies published after 1990 that measured anemia, Plasmodium falciparum malaria, and stunting or wasting in children aged 5 years or under were included.

FINDINGS

Of 620 articles reviewed, 15 studies from 9 countries in sub-Saharan Africa were included. Statistical approaches and anemia measurement varied widely, so synthesis was qualitative. Thirteen studies found that malaria infection was associated with anemia or lowered hemoglobin; in these studies, malaria accounted for more of the variation in anemia than nutritional status. In contrast, only 7 of the 13 studies investigating stunting and 3 of the 6 studies investigating wasting as correlates of anemia observed statistically significant associations at α = 0.05. The role of nutrition in anemia may differ by country.

CONCLUSIONS

Observational epidemiologic studies consistently demonstrate that malaria is an important correlate of anemia in young children; however, the roles of stunting and wasting and interactions between malaria and nutrition require further investigation. Based on the current evidence, these findings suggest that global health strategies to reduce the burden of anemia should prioritize malaria prevention and support research on alternative causes of anemia that reflect local conditions.

[Asymptomatic Parasitemia in under five, school age children and households self-medication, Lubumbashi, Democratic Republic of Congo]

INTRODUCTION

Long neglected, asymptomatic malaria is currently recognized as a potential threat and obstacle to malaria control. In DR Congo, the prevalence of this parasite is poorly documented. This study aims to determine the prevalence of asymptomatic parasitaemia in children less than 5 years of age as well as in those aged over five years for what concerns ongoing mass control interventions (LLINs).

METHODS

This is a cross-sectional study conducted among school age children, children less than 5 years of age living in the household of Lubumbashi. Schools, students and children less than 5 years of age were selected randomly. Thick and thin blood smears and rapid tests were performed and read.

RESULTS

Out of 350 examined students, 43 (12, 3%), IC 95% (9, 14-16, 04) had positive thick smear. Only plasmodium falciparum was identified in all the 43 cases. 314 households (90.5%) declared that they had administered anti-malarial drugs to their children to treat fever at home. More than one-third of households (39.9%) declared that they had administered antipyretics to their children to relieve fever, 19.7% administered quinine and only less than 2% artemether-lumefantrine. Considering the use of the TDR technique, the prevalence of asymptomatic parasitaemia was 3%, IC 95% (from 2.075 to 4.44), but if we consider microscopy as the gold standard, the prevalence was 1.9%, IC 95% (from 1.13 to 3.01).

CONCLUSION

Asymptomatic malaria is not without health consequences, so it is important to conduct such investigations to detect new malaria device programmes.

Elevated prevalence of malnutrition and malaria among school-aged children and adolescents in war-ravaged South Sudan

Emerging as a sovereign state from decades of civil war, the Republic of South Sudan now faces poverty, a lack of health care infrastructure, a high burden of infectious diseases and a widespread food insecurity. School-aged children and youth, in particular, represent a high-risk demographic for malnutrition and infectious diseases. We screened 109 school-aged children and youth for nutritional status and malaria antigenaemia in Akuak Rak, South Sudan, and found a large proportion of underweight (77/109 = 73%) and prevalent malaria (44/109 = 40%). There was no significant association between malnutrition and malaria. This study represents one of the few published reports on child and youth nutritional status and malaria prevalence in South Sudan since its independence. The implementation of nutrition and malaria screening combined with evidence-based interventions in schools could help target this high burden vulnerable group.

Malaria eradication and economic outcomes in sub-Saharan Africa: Evidence from Uganda

This study evaluates the economic consequences of a 1959-1960 malaria eradication campaign in southwestern Uganda. The effort constitutes a rare, large-scale, and well-documented attempt to eliminate malaria in sub-Saharan Africa and produced an immediate disease reduction. We use this quasi-experimental health shock to identify long-term changes in educational and economic outcomes. Comparing the treatment district to a similar synthetic control, we find malaria eradication raised educational attainment by about a half year for both males and females, increased primary school completion among females and generated an almost 40% rise in the likelihood of male wage employment.

The High Burden of Malaria in Primary School Children in Southern Malawi

Malaria among school children has received increased attention recently, yet there remain few detailed data on the health and educational burden of malaria, especially in southern Africa. This paper reports a survey among school children in 50 schools in Zomba District, Malawi. Children were assessed for Plasmodium infection, anemia, and nutritional status and took a battery of age-appropriate tests of attention, literacy, and numeracy. Overall, 60.0% of children were infected with Plasmodium falciparum, 32.4% were anemic and 32.4% reported sleeping under a mosquito net the previous night. Patterns of P. falciparum infection and anemia varied markedly by school. In multivariable analysis, higher odds of P. falciparum infection were associated with younger age and being stunted, whereas lower odds were associated with reported net use, higher parental education, and socioeconomic status. The odds of anemia were significantly associated with P. falciparum infection, with a dose-response relationship between density of infection and odds of anemia. No clear relationship was observed between health status and cognitive and educational outcomes. The high burden of malaria highlights the need to tackle malaria among school children.

Investigating the Pathogenesis of Severe Malaria: A Multidisciplinary and Cross-Geographical Approach

More than a century after the discovery of Plasmodium spp. parasites, the pathogenesis of severe malaria is still not well understood. The majority of malaria cases are caused by Plasmodium falciparum and Plasmodium vivax, which differ in virulence, red blood cell tropism, cytoadhesion of infected erythrocytes, and dormant liver hypnozoite stages. Cerebral malaria coma is one of the most severe manifestations of P. falciparum infection. Insights into its complex pathophysiology are emerging through a combination of autopsy, neuroimaging, parasite binding, and endothelial characterizations. Nevertheless, important questions remain regarding why some patients develop life-threatening conditions while the majority of P. falciparum-infected individuals do not, and why clinical presentations differ between children and adults. For P. vivax, there is renewed recognition of severe malaria, but an understanding of the factors influencing disease severity is limited and remains an important research topic. Shedding light on the underlying disease mechanisms will be necessary to implement effective diagnostic tools for identifying and classifying severe malaria syndromes and developing new therapeutic approaches for severe disease. This review highlights progress and outstanding questions in severe malaria pathophysiology and summarizes key areas of pathogenesis research within the International Centers of Excellence for Malaria Research program.

Effect of deworming on school-aged children's physical fitness, cognition and clinical parameters in a malaria-helminth co-endemic area of Côte d'Ivoire

Background

Malaria and helminth infections are thought to negatively affect children’s nutritional status and to impair their physical and cognitive development. Yet, the current evidence-base is weak. The purpose of this study was to determine the effect of deworming against soil-transmitted helminthiasis and schistosomiasis on children’s physical fitness, cognition and clinical parameters in a malaria-helminth co-endemic setting of Côte d’Ivoire.

Methods

We designed an intervention study with a 5-month follow-up among schoolchildren aged 5–14 years from Niablé, eastern Côte d’Ivoire. In late 2012, a baseline cross-sectional survey was conducted. Finger-prick blood, stool and urine samples were subjected to standardised, quality-controlled techniques for the diagnosis of Plasmodium spp., Schistosoma spp., soil-transmitted helminths and intestinal protozoa infections. Haemoglobin level was determined and anthropometric measurements were taken for appraisal of anaemia and nutritional status. Children underwent memory (digit span) and attention (code transmission) cognitive testing, and their physical fitness and strength were determined (20 m shuttle run, standing broad jump and grip strength test). All children were treated with albendazole (against soil-transmitted helminthiasis) and praziquantel (against schistosomiasis) after the baseline cross-sectional survey and again 2 months later. Five months after the initial deworming, the same battery of clinical, cognitive and physical fitness tests was performed on the same children.

Results

Lower scores in strength tests were significantly associated with children with harbouring nutritional deficiencies. Surprisingly, boys infected with Schistosoma mansoni achieved longer jumping distances than their non-infected counterparts. Light-intensity infection with S. mansoni was associated with slightly better aerobic capacity. Deworming showed no effect on haemoglobin levels and anaemia, but children with moderate- to heavy-intensity Schistosoma infection at baseline gained weight more pronouncedly than non-infected children. Interestingly, children with soil-transmitted helminth or Schistosoma infection at baseline performed significantly better in the sustained attention test than their non-infected counterparts at the 5-month follow-up.

Conclusions

This study revealed conflicting results regarding clinical parameters and cognitive behaviour of children after two rounds of deworming. We speculate that potential beneficial effects of deworming are likely to be undermined in areas where malaria is co-endemic and nutritional deficiencies are widespread.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2334-14-411) contains supplementary material, which is available to authorized users.

Infection and co-infection with helminths and Plasmodium among school children in Côte d'Ivoire: results from a National Cross-Sectional Survey

BACKGROUND

Helminth infection and malaria remain major causes of ill-health in the tropics and subtropics. There are several shared risk factors (e.g., poverty), and hence, helminth infection and malaria overlap geographically and temporally. However, the extent and consequences of helminth-Plasmodium co-infection at different spatial scales are poorly understood.

METHODOLOGY

This study was conducted in 92 schools across Côte d'Ivoire during the dry season, from November 2011 to February 2012. School children provided blood samples for detection of Plasmodium infection, stool samples for diagnosis of soil-transmitted helminth (STH) and Schistosoma mansoni infections, and urine samples for appraisal of Schistosoma haematobium infection. A questionnaire was administered to obtain demographic, socioeconomic, and behavioral data. Multinomial regression models were utilized to determine risk factors for STH-Plasmodium and Schistosoma-Plasmodium co-infection.

PRINCIPAL FINDINGS

Complete parasitological and questionnaire data were available for 5,104 children aged 5-16 years. 26.2% of the children were infected with any helminth species, whilst the prevalence of Plasmodium infection was 63.3%. STH-Plasmodium co-infection was detected in 13.5% and Schistosoma-Plasmodium in 5.6% of the children. Multinomial regression analysis revealed that boys, children aged 10 years and above, and activities involving close contact to water were significantly and positively associated with STH-Plasmodium co-infection. Boys, wells as source of drinking water, and water contact were significantly and positively associated with Schistosoma-Plasmodium co-infection. Access to latrines, deworming, higher socioeconomic status, and living in urban settings were negatively associated with STH-Plasmodium co-infection; whilst use of deworming drugs and access to modern latrines were negatively associated with Schistosoma-Plasmodium co-infection.

CONCLUSIONS/SIGNIFICANCE

More than 60% of the school children surveyed were infected with Plasmodium across Côte d'Ivoire, and about one out of six had a helminth-Plasmodium co-infection. Our findings provide a rationale to combine control interventions that simultaneously aim at helminthiases and malaria.

Prevalence of Plasmodium falciparum Parasitaemia and Its Correlation with Haematological Parameters among HIV-Positive Individuals in Nigeria

Malaria and HIV are the two most important health challenges of our time. Haematologic abnormalities are features in Plasmodium falciparum infection, and anaemia is a well-known outcome. The prevalence and haematological impact of P. falciparum parasitaemia were determined among HIV-infected individuals in Nigeria. Parasite detection was carried out using microscopy and Polymerase Chain Reaction (PCR). Haemoglobin concentration was determined using an automated machine while CD4+ T-cells count was analyzed using flow cytometer. Thirty-seven (18.5%) out of the 200 HIV individuals enrolled had malaria parasites detected in their blood. All the positive cases were detected by PCR while only 20 (10%) were detected by thick blood microscopy. The mean haemoglobin concentration and packed cell volume (PCV) of HIV individuals with malaria parasitaemia were lower compared to those without malaria parasitaemia but the difference was not statistically significant. Also no significant difference was observed in malaria positivity in respect to sex and mean CD4+ cell count. The study highlights the effects of P. falciparum parasitaemia on the haematologic and immune components of HIV individuals.

Impact of intermittent screening and treatment for malaria among school children in Kenya: a cluster randomised trial

BACKGROUND

Improving the health of school-aged children can yield substantial benefits for cognitive development and educational achievement. However, there is limited experimental evidence of the benefits of alternative school-based malaria interventions or how the impacts of interventions vary according to intensity of malaria transmission. We investigated the effect of intermittent screening and treatment (IST) for malaria on the health and education of school children in an area of low to moderate malaria transmission.

METHODS AND FINDINGS

A cluster randomised trial was implemented with 5,233 children in 101 government primary schools on the south coast of Kenya in 2010-2012. The intervention was delivered to children randomly selected from classes 1 and 5 who were followed up for 24 months. Once a school term, children were screened by public health workers using malaria rapid diagnostic tests (RDTs), and children (with or without malaria symptoms) found to be RDT-positive were treated with a six dose regimen of artemether-lumefantrine (AL). Given the nature of the intervention, the trial was not blinded. The primary outcomes were anaemia and sustained attention. Secondary outcomes were malaria parasitaemia and educational achievement. Data were analysed on an intention-to-treat basis. During the intervention period, an average of 88.3% children in intervention schools were screened at each round, of whom 17.5% were RDT-positive. 80.3% of children in the control and 80.2% in the intervention group were followed-up at 24 months. No impact of the malaria IST intervention was observed for prevalence of anaemia at either 12 or 24 months (adjusted risk ratio [Adj.RR]: 1.03, 95% CI 0.93-1.13, p = 0.621 and Adj.RR: 1.00, 95% CI 0.90-1.11, p = 0.953) respectively, or on prevalence of P. falciparum infection or scores of classroom attention. No effect of IST was observed on educational achievement in the older class, but an apparent negative effect was seen on spelling scores in the younger class at 9 and 24 months and on arithmetic scores at 24 months.

CONCLUSION

In this setting in Kenya, IST as implemented in this study is not effective in improving the health or education of school children. Possible reasons for the absence of an impact are the marked geographical heterogeneity in transmission, the rapid rate of reinfection following AL treatment, the variable reliability of RDTs, and the relative contribution of malaria to the aetiology of anaemia in this setting.

TRIAL REGISTRATION

www.ClinicalTrials.gov NCT00878007.

Do price subsidies on artemisinin combination therapy for malaria increase household use? Evidence from a repeated cross-sectional study in remote regions of Tanzania

Background

The Affordable Medicines Facility-malaria (AMFm) is a pilot program that uses price subsidies to increase access to Artemisinin Combination Therapies (ACTs), currently the most effective malaria treatment. Recent evidence suggests that availability and affordability of ACTs in retail sector drug shops (where many people treat malaria) has increased under the AMFm, but it is unclear whether household level ACT use has increased.

Methods and Findings

Household surveys were conducted in two remote regions of Tanzania (Mtwara and Rukwa) in three waves: March 2011, December 2011 and March 2012, corresponding to 3, 13 and 16 months into the AMFm implementation respectively. Information about suspected malaria episodes including treatment location and medications taken was collected. Respondents were also asked about antimalarial preferences and perceptions about the availability of these medications. Significant increases in ACT use, preference and perceived availability were found between Rounds 1 and 3 though not for all measures between Rounds 1 and 2. ACT use among suspected malaria episodes was 51.1% in March 2011 and increased by 10.9 percentage points by Round 3 (p = .017). The greatest increase was among retail sector patients, where ACT use increased from 31% in Round 1 to 49% in Round 2 (p = .037) and to 61% (p<.0001) by Round 3. The fraction of suspected malaria episodes treated in the retail sector increased from 30.2% in Round 1 to 46.7% in Round 3 (p = .0009), mostly due to a decrease in patients who sought no treatment at all. No significant changes in public sector treatment seeking were found.

Conclusions

The AMFm has led to significant increases in ACT use for suspected malaria, especially in the retail sector. No evidence is found supporting the concerns that the AMFm would crowd out public sector treatment or neglect patients in remote areas and from low SES groups.

Asymptomatic Plasmodium infection and cognition among primary schoolchildren in a high malaria transmission setting in Uganda

Asymptomatic parasitemia is common among schoolchildren living in areas of high malaria transmission, yet little is known about its effect on cognitive function in these settings. To investigate associations between asymptomatic parasitemia, anemia, and cognition among primary schoolchildren living in a high malaria transmission setting, we studied 740 children enrolled in a clinical trial in Tororo, Uganda. Parasitemia, measured by thick blood smears, was present in 30% of the children. Infected children had lower test scores for abstract reasoning (adjusted mean difference [AMD] -0.6, 95% confidence interval [CI] -1.01 to -0.21) and sustained attention (AMD -1.6 95% CI -2.40 to -0.81) compared with uninfected children. There was also evidence for a dose-response relationship between parasite density and scores for sustained attention. No associations were observed between anemia and either test of cognition. Schoolchildren in high transmission settings may experience cognitive benefits, from interventions aimed at reducing the prevalence of asymptomatic parasitemia.

Challenges for consent and community engagement in the conduct of cluster randomized trial among school children in low income settings: experiences from Kenya

Background

There are a number of practical and ethical issues raised in school-based health research, particularly those related to obtaining consent from parents and assent from children. One approach to developing, strengthening, and supporting appropriate consent and assent processes is through community engagement. To date, much of the literature on community engagement in biomedical research has concentrated on community- or hospital-based research, with little documentation, if any, of community engagement in school-based health research. In this paper we discuss our experiences of consent, assent and community engagement in implementing a large school-based cluster randomized trial in rural Kenya.

Methods

Data collected as part of a qualitative study investigating the acceptability of the main trial, focus group discussions with field staff, observations of practice and authors’ experiences are used to: 1) highlight the challenges faced in obtaining assent/consent; and 2) strategies taken to try to both protect participant rights (including to refuse and to withdraw) and ensure the success of the trial.

Results

Early meetings with national, district and local level stakeholders were important in establishing their co-operation and support for the project. Despite this support, both practical and ethical challenges were encountered during consenting and assenting procedures. Our strategy for addressing these challenges focused on improving communication and understanding of the trial, and maintaining dialogue with all the relevant stakeholders throughout the study period.

Conclusions

A range of stakeholders within and beyond schools play a key role in school based health trials. Community entry and information dissemination strategies need careful planning from the outset, and with on-going consultation and feedback mechanisms established in order to identify and address concerns as they arise. We believe our experiences, and the ethical and practical issues and dilemmas encountered, will be of interest for others planning to conduct school-based research in Africa.

Trial registration

National Institute of Health NCT00878007

Plasmodium infection, anaemia and mosquito net use among school children across different settings in Kenya

OBJECTIVE

To investigate risk factors, including reported net use, for Plasmodium infection and anaemia among school children and to explore variations in effects across different malaria ecologies occurring in Kenya.

METHODS

This study analysed data for 49 975 school children in 480 schools surveyed during a national school malaria survey, 2008-2010. Mixed effects logistic regression was used to investigate factors associated with Plasmodium infection and anaemia within different malaria transmission zones.

RESULTS

Insecticide-treated net (ITN) use was associated with reduction in the odds of Plasmodium infection in coastal and western highlands epidemic zones and among boys in the lakeside high transmission zone. Other risk factors for Plasmodium infection and for anaemia also varied by zone. Plasmodium infection was negatively associated with increasing socio-economic status in all transmission settings, except in the semi-arid north-east zone. Plasmodium infection was a risk factor for anaemia in lakeside high transmission, western highlands epidemic and central low-risk zones, whereas ITN use was only associated with lower levels of anaemia in coastal and central zones and among boys in the lakeside high transmission zone.

CONCLUSIONS

The risk factors for Plasmodium infection and anaemia, including the protective associations with ITN use, vary according to malaria transmission settings in Kenya, and future efforts to control malaria and anaemia should take into account such heterogeneities among school children.

Local perceptions of intermittent screening and treatment for malaria in school children on the south coast of Kenya

Background

The intermittent screening and treatment (IST) of school children for malaria is one possible intervention strategy that could help reduce the burden of malaria among school children. Future implementation of IST will not only depend on its efficacy and cost-effectiveness but also on its acceptability to parents of the children who receive IST, as well as those responsible for its delivery. This study was conducted alongside a cluster-randomized trial to investigate local perceptions of school-based IST among parents and other stakeholders on the Kenyan south coast.

Methods

Six out of the 51 schools receiving the IST intervention were purposively sampled, based on the prevalence of Plasmodium infection, to participate in the qualitative study. Twenty-two focus group discussions and 17 in-depth interviews were conducted with parents and other key stakeholders involved in the implementation of school health programmes in the district. Data analysis was guided by the framework analysis method.

Results

High knowledge of the burden of clinical malaria on school children, the perceived benefits of preventing clinical disease through IST and previous positive experiences and interactions with other school health programmes facilitated the acceptability of IST. However, lack of understanding of the consequences of asymptomatic parasitaemia for apparently healthy school children could potentially contribute to non-adherence to treatment, and use of alternative anti-malarial drugs with simpler regimens was generally preferred. The general consensus of stakeholders was that health workers were best placed to undertake the screening and provide treatment, and although teachers’ involvement in the programme is critical, most participants were opposed to teachers taking finger-prick blood samples from children. There was also a strong demand for the distribution of mosquito nets to augment IST.

Conclusion

School-based malaria control through IST was acceptable to most parents and other stakeholders, but careful consideration of the various roles of teachers, community health workers, and health workers, and the use of anti-malarial drugs with simpler regimens are critical to its future implementation.