Malaria amongst children under five in sub-Saharan Africa: a scoping review of prevalence, risk factors and preventive interventions

GIS-based spatiotemporal mapping of malaria prevalence and exploration of environmental inequalities

Malaria poses a significant threat to global health, with particular severity in Nigeria. Understanding key factors influencing health outcomes is crucial for addressing health disparities. Disease mapping plays a vital role in assessing the geographical distribution of diseases and has been instrumental in epidemiological research. By delving into the spatiotemporal dynamics of malaria trends, valuable insights can be gained into population dynamics, leading to more informed spatial management decisions. This study focused on examining the evolution of malaria in Nigeria over twenty years (2000-2020) and exploring the impact of environmental factors on this variation. A 5-year-period raster map was developed using malaria indicator survey data for Nigeria's six geopolitical zones. Various spatial analysis techniques, such as point density, spatial autocorrelation, and hotspot analysis, were employed to analyze spatial patterns. Additionally, statistical methods, including Principal Component Analysis, Spearman correlation, and Ordinary Least Squares (OLS) regression, were used to investigate relationships between indicators and develop a predictive model. The study revealed regional variations in malaria prevalence over time, with the highest number of cases concentrated in northern Nigeria. The raster map illustrated a shift in the distribution of malaria cases over the five years. Environmental factors such as the Enhanced Vegetation Index, annual land surface temperature, and precipitation exhibited a strong positive association with malaria cases in the OLS model. Conversely, insecticide-treated bed net coverage and mean temperature negatively correlated with malaria cases in the same model. The findings from this research provide valuable insights into the spatiotemporal patterns of malaria in Nigeria and highlight the significant role of environmental drivers in influencing disease transmission. This scientific knowledge can inform policymakers and aid in developing targeted interventions to combat malaria effectively.

Malaria in under-five children: prevalence and multi-factor analysis of high-risk African countries

BACKGROUND

Malaria remains a significant public health challenge in Sub-Saharan Africa (SSA), particularly affecting under-five (UN5) children. Despite global efforts to control the disease, its prevalence in high-risk African countries continues to be alarming, with records of substantial morbidity and mortality rates. Understanding the association of multiple childhood, maternal, and household factors with malaria prevalence, especially among vulnerable young populations, is crucial for effective intervention strategies.

OBJECTIVE

This study examines the prevalence of malaria among UN5 children in selected high-risk SSA countries and analyzes its association with various childhood, maternal, and household factors.

METHODS

Data from the Malaria Indicator Surveys (MIS) spanning from 2010 to 2023 were analyzed. A weighted sample of 35,624 UN5 children from seven countries in sub-Saharan Africa (SSA) known for high malaria prevalence was considered in the analyses. Descriptive statistics and modified Poisson regression analysis were used to assess the association of multiple factors with malaria prevalence. Stata version 15 software was used in analyzing the data and statistical significance was set at a 5% significance level.

RESULTS

The overall pooled prevalence of malaria among the studied population was 26.2%, with substantial country-specific variations observed. In terms of child factors, a child's age was significantly associated with malaria prevalence (APR = 1.010, 95% CI: 1.007-1.012). Children of mothers with higher education levels (APR for higher education = 0.586, 95% CI: 0.425-0.806) and Fansidar uptake during pregnancy (APR = 0.731, 95% CI: 0.666-0.802) were associated with lower malaria risk. Children from middle-wealth (APR = 0.783, 95% CI: 0.706-0.869) and rich (APR = 0.499, 95% CI: 0.426-0.584) households had considerably lower malaria prevalence compared to those from poor households. Additionally, rural residency was associated with a higher risk of malaria compared to urban residency (APR = 1.545, 95% CI: 1.255-1.903).

CONCLUSION

The study highlights a notable malaria prevalence among under-five (UN5) children in high-risk SSA countries, influenced significantly by factors such as maternal education, Fansidar uptake during pregnancy, socioeconomic status, and residency. These findings underscore the importance of targeted malaria prevention strategies that address these key determinants to effectively reduce the malaria burden in this vulnerable population.

Community readiness and acceptance for the implementation of a novel malaria vaccine among at-risk children in sub-saharan Africa: a systematic review protocol

BACKGROUND

The World Health Organization novel malaria vaccine for at-risk children has the potential to greatly reduce the current malaria burden in sub-Saharan Africa. However, most studies have reported contradictory findings regarding community willingness for the vaccine, which could easily undermine the expected benefits of the vaccine. This study aims to ascertain the current state of community readiness and acceptance for the implementation of a novel malaria vaccine (RTS,S/ASO1) among at-risk children in sub-Saharan Africa, based on available evidence.

METHODS

This study will follow the Preferred Reporting Items for Systematic Reviews and Meta-analyses protocol (PRISMA-P) guidelines. Relevant studies will be comprehensively searched from PubMed, ScienceDirect, Web of Science, Google Scholar, and African journals online, in accordance with the Cochrane search guidelines. Two independent reviewers will screen titles, abstracts and full texts of eligible studies based on some specified eligibility criteria. When it is feasible to conduct a meta-analysis, a random effects model will be employed to estimate the common effect due to anticipated high heterogeneity of the data. The effect measure for readiness or acceptance will be reported as a pooled proportion with corresponding 95% confidence interval. Additionally, odds ratios with 95% confidence interval will be estimated to assess factors associated with readiness. These will be presented on a forest plot.

DISSEMINATION PLANS

The findings of the study will be peer-reviewed and published in a scientific journal. Conference presentations will also be made to the different stakeholders in the malaria vaccination campaigns.

SYSTEMATIC REVIEW REGISTRATION

The protocol has been registered with PROSPERO Registration Number: CRD42023480528.

Prevalence of Malaria and Associated Factors during the Minor Malaria Season among Febrile Under-Five Children Attending Mohammed Akile Memorial General Hospital

Malaria is one of the major public health problems in sub-Saharan Africa, including Ethiopia. Children under the age of five are immunologically naive to plasmodium parasites, making them the most vulnerable group to clinical manifestations of malaria infection. Despite the severity of the disease in children under five years of age, most studies on malaria focus on the adult population. In the present study, a cross-sectional study design based on health facilities was used during the minor malaria season from February 18 to May 28, 2023, at Mohammed Akile Memorial General Hospital, in Afar Regional State, district of Amibara located in the town of Berta. The finding revealed that 19.8% prevalence among symptomatic children with 61.04% and 38.96% of P. falciparum and P. vivax, respectively. In the present study area, malaria infection in children under five years of age is significantly associated with the presence of stagnant water in the residential area, inappropriate or no use of insecticide-treated net, and indoor residual spraying (IRS). The prevalence of malaria among symptomatic children under five years of age is higher compared to the national prevalence of malaria among the general population. Therefore, community mobilization through health promotion, aiming to interrupt the transmission of malaria at the community level, is paramount.

Factors associated with the risk of malaria among children: analysis of 2021 Nigeria Malaria Indicator Survey

BACKGROUND

Malaria remains a burden globally, with the African region accounting for 94% of the overall disease burden and deaths in 2019. It is the major cause of morbidity and mortality among children in Nigeria. Though different environmental factors have been assessed to influence the distribution and transmission of malaria vectors, there is a shortage of information on how they may influence malaria transmission among under-fives in Nigeria.

METHODS

This study was based on the secondary data analysis of the Nigeria Malaria Indicator Survey 2021. The study sample comprised 10,645 women (aged 15-49) who delivered a child in the 2 years preceding the survey. The study was restricted to under-fives. Logistic regression was used to identify factors associated with the risk of malaria.

RESULTS

There was a positive association between the risk of malaria and heard/seen malaria messages in the last 6 months (AOR 1.39, 95% CI 1.19-1.62), houses with walls built using rudimentary materials (AOR = 1.38, 95% CI 1.04-1.83), at least 6 children living in the house (AOR 1.22, 95% CI 1.00-1.49), children being 1 or 2 years old was associated with increased odds (AOR 1.89, 95% CI 1.50-2.34 and AOR 1.89, 95% CI 1.52-2.36), children from households with only treated nets (AOR 1.23, 95% CI 1.04-1.46) and those from the North West or South East regions (AOR 1.50, 95% CI 1.10-2.05 and AOR 1.48, 95% CI 1.01-2.16), respectively. All other predictors were not associated with the risk of malaria.

CONCLUSION

The factors associated with the risk of malaria in this study included sleeping under treated mosquito nets, the age of the children, residing in the northwest and southeast regions, wall construction material, 6 children and above in the household and hearing/seen malaria messages in the last 6 months. Continuous health education and public health interventions, such as the provision of LLITNs, will reduce the risk of malaria and improve the health and well-being of children under 5 years of age.

The Malaria Burden: A South African Perspective

Malaria is a deadly disease caused by protozoan pathogens of the Plasmodium parasite. Transmission to humans occurs through the bite of an infected female Anopheles mosquito. According to the World Health Organization (WHO), an estimated 247 million cases of malaria were recorded worldwide in 2021, with approximately 619 000 malaria deaths. The initial signs of malaria can be mild and challenging to diagnose due to the signs and symptoms being similar to those of other illnesses. The malaria burden remains largely concentrated in the WHO sub-Saharan African region and has been recognised as a significant contributor to morbidity and mortality. This review aims to contribute to the existing knowledge on malaria in South Africa, a region within sub-Saharan Africa, focusing on the epidemiology and life cycle of the malaria parasite as well as diagnostic approaches for detecting malaria. In addition, nonpharmacological and pharmacological interventions for treating and preventing malaria infections will also be discussed herein. While there has been a significant reduction in the global burden of this disease, malaria remains a public health issue in South Africa. As such, the implementation of effective preventative measures and strategies, early diagnosis, and appropriate treatment regimens are crucial to reducing the malaria burden in South Africa.

Methemoglobin levels in malaria: a systematic review and meta-analysis of its association with Plasmodium falciparum and Plasmodium vivax infections and disease severity

Reports indicate that Plasmodium infections influence methemoglobin levels. However, findings have been inconclusive or have varied across different geographic and demographic contexts. This systematic review and meta-analysis aimed to consolidate existing data regarding the association between Plasmodium infections and alterations in methemoglobin levels related to the severity of the infection. A comprehensive literature search of several databases, including Ovid, ProQuest, Embase, Scopus, MEDLINE, and PubMed, was conducted to identify relevant studies that examined methemoglobin levels in patients with malaria. Qualitative synthesis and meta-analysis of the pooled standardized mean difference were conducted to synthesize the differences in methemoglobin levels between: (1) patients with malaria and those without malaria and (2) patients with severe malaria and those with uncomplicated malaria based on various themes including publication year, study design, study area, Plasmodium species, age group, symptomatic status, severity status, and method of malaria detection. Of the 1846 studies that were initially identified from the main databases and additional searches on Google Scholar, 10 studies met the eligibility criteria and were selected for this review. The systematic review distinctly highlighted an association between malaria and elevated methemoglobin levels, an observation consistent across diverse geographical regions and various Plasmodium species. Furthermore, the meta-analysis confirmed this by demonstrating increased methemoglobin levels in patients with malaria compared to those without malaria (P < 0.001, Hedges' g 2.32, 95% CI 1.36-3.29, I2 97.27, 8 studies). Moreover, the meta-analysis found elevated methemoglobin levels in patients with severe malaria compared to those with uncomplicated malaria (P < 0.001, Hedges' g 2.20, 95% CI 0.82-3.58, I2 96.20, 5 studies). This systematic review and meta-analysis revealed increased methemoglobin levels in patients with P. falciparum and P. vivax infections, with a notable association between elevated methemoglobin levels and severe malaria. Future research should focus on elucidating the specific mechanisms by which changes in methemoglobin levels are related to infections by P. falciparum and P. vivax, particularly in terms of severity, and how these alterations could potentially impact patient management and treatment outcomes.

Understanding the mechanisms underlying the disruption of the blood-brain barrier in parasitic infections

Parasites have a significant impact on the neurological, cognitive, and mental well-being of humans, with a global population of over 1 billion individuals affected. The pathogenesis of central nervous system (CNS) injury in parasitic diseases remains limited, and prevention and control of parasitic CNS infections remain significant areas of research. Parasites, encompassing both unicellular and multicellular organisms, have intricate life cycles and possess the ability to infect a diverse range of hosts, including the human population. Parasitic illnesses that impact the central and peripheral nervous systems are a significant contributor to morbidity and mortality in low- to middle-income nations. The precise pathways through which neurotropic parasites infiltrate the CNS by crossing the blood-brain barrier (BBB) and cause neurological harm remain incompletely understood. Investigating brain infections caused by parasites is closely linked to studying neuroinflammation and cerebral impairment. The exact molecular and cellular mechanisms involved in this process remain incomplete, but understanding the exact mechanisms could provide insight into their pathogenesis and potentially reveal novel therapeutic targets. This review paper explores the underlying mechanisms involved in the development of neurological disorders caused by parasites, including parasite-derived elements, host immune responses, and modifications in tight junctions (TJs) proteins.

Trends and determinants of anemia in children 6-59 months and women of reproductive age in Chad from 2016 to 2021

BACKGROUND

Hemoglobin assessments in children and women have been conducted annually in Chad since 2016 through the Standardized Monitoring and Assessment of Relief and Transitions (SMART) cross-sectional surveys. This analysis aims to characterize national and sub-national trends in anemia among children under five and women of reproductive age from 2016 to 2021 and to compare risk factors for anemia before and during the COVID-19 pandemic.

METHODS

Hemoglobin concentrations were measured in approximately half of the 12,000 to 15,000 included households each year, except for 2020 when hemoglobin tests were omitted. For children 6 to 59 months of age, anemia was defined as hemoglobin less than 11.0 g/dL. Anemia was defined as hemoglobin less than 11.0 g/dL and 12.0 g/dL for pregnant women and non-pregnant women, respectively. Trends were stratified by agroecological zone, and tests of proportions were used to assess statistical significance. Simple and multivariate logistic regression models were conducted for 2019 and 2021 to identify risk factors for anemia.

RESULTS

Reductions in anemia over the 6-year period were significant among women (47.6-30.8%, p = 0.000) and children (68.6-59.6%, p = 0.000). The Sudanian zone had consistently higher rates, particularly in children, compared to the Sahelian and Saharan zones. Significant declines in women's anemia were observed in all zones from 2019 to 2021, but this global decline was not observed among children, where rates in the Saharan zone significantly increased. In 2019, only minimum dietary diversity significantly reduced the odds of anemia in children (AOR: 0.65, 95%CI: 0.46-0.92), whereas in 2021, improvements in all diet indicators were associated with lower odds of anemia. Improved household socio-economic factors, including head of household literacy, were associated with lower odds of anemia in children (2019 AOR: 0.76, 95%CI: 0.67, 0.88) and women (2019 AOR: 0.75, 95%CI: 0.65, 0.87; 2021 AOR: 0.81, 95%CI: 0.70, 0.93).

CONCLUSIONS

Anemia declined significantly in Chad among women of reproductive age and children from 2016 to 2021, but the national prevalence of 60% among children remains unacceptably high. Sub-national differences in anemia rates underline the need to identify and address regional causes of anemia while strengthening national level programs.

Bayesian belief network modelling approach for predicting and ranking risk factors for malaria infections among children under 5 years in refugee settlements in Uganda

BACKGROUND

Malaria risk factors at household level are known to be complex, uncertain, stochastic, nonlinear, and multidimensional. The interplay among these factors, makes targeted interventions, and resource allocation for malaria control challenging. However, few studies have demonstrated malaria's transmission complexity, control, and integrated modelling, with no available evidence on Uganda's refugee settlements. Using the 2018-2019 Uganda's Malaria Indicator Survey (UMIS) data, an alternative Bayesian belief network (BBN) modelling approach was used to analyse, predict, rank and illustrate the conceptual reasoning, and complex causal relationships among the risk factors for malaria infections among children under-five in refugee settlements of Uganda.

METHODS

In the UMIS, household level information was obtained using standardized questionnaires, and a total of 675 children under 5 years were tested for malaria. From the dataset, a casefile containing malaria test results, demographic, social-economic and environmental information was created. The casefile was divided into a training (80%, n = 540) and testing (20%, n = 135) datasets. The training dataset was used to develop the BBN model following well established guidelines. The testing dataset was used to evaluate model performance.

RESULTS

Model accuracy was 91.11% with an area under the receiver-operating characteristic curve of 0.95. The model's spherical payoff was 0.91, with the logarithmic, and quadratic losses of 0.36, and 0.16 respectively, indicating a strong predictive, and classification ability of the model. The probability of refugee children testing positive, and negative for malaria was 48.1% and 51.9% respectively. The top ranked malaria risk factors based on the sensitivity analysis included: (1) age of child; (2) roof materials (i.e., thatch roofs); (3) wall materials (i.e., poles with mud and thatch walls); (4) whether children sleep under insecticide-treated nets; 5) type of toilet facility used (i.e., no toilet facility, and pit latrines with slabs); (6) walk time distance to water sources (between 0 and 10 min); (7) drinking water sources (i.e., open water sources, and piped water on premises).

CONCLUSION

Ranking, rather than the statistical significance of the malaria risk factors, is crucial as an approach to applied research, as it helps stakeholders determine how to allocate resources for targeted malaria interventions within the constraints of limited funding in the refugee settlements.

Differences in catalase levels between malaria-infected individuals and uninfected controls: a systematic review and meta-analysis

Inconsistent catalase (CAT) research necessitates a comprehensive review of CAT levels among patients with malaria to achieve better therapeutic strategies. This study aimed to systematically review and meta-analyze available literature on CAT levels in nonpregnant and pregnant individuals with malaria compared with those in uninfected controls, with the goal of providing a robust evidence base for future research and potential interventions. Following PRISMA guidelines, a systematic literature search across six databases was conducted to examine CAT levels in patients with malaria. Data was extracted independently by two reviewers, and study quality was assessed using the Joanna Briggs Institute (JBI) critical appraisal checklist. The standardized mean difference of CAT levels was calculated with heterogeneity assessment. Subgroup and sensitivity analyses were conducted to explore heterogeneity and assess the robustness of the findings. Publication bias was visually and statistically assessed and corrected, if necessary. Statistical analyses were performed using Stata software, with a significance level set at P < 0.05. Nineteen studies were included in the review. These studies, published from before 2000 to 2023, primarily from Africa and Asia, focused on different Plasmodium species and age groups. Results of qualitative synthesis among nonpregnant individuals consistently showed lower CAT levels in malaria-infected individuals, although some studies reported higher levels. No significant differences in CAT levels were found between malaria-infected and uninfected individuals, as demonstrated by a meta-analysis overall (P = 0.05, Hedges' g: - 0.78, 95% confidence interval (CI): (- 1.56)-0.01, I2: 98.47, 15 studies), but subgroup analyses showed significant differences in CAT levels in studies conducted in Africa (P = 0.02, Hedges' g: - 0.57, 95% CI: - 1.02-(0.11), I2: 91.81, 7 studies), and in studies that specifically focused on children (P = 0.03, Hedges' g: - 0.57, 95% CI: - 1.07-(- 0.07), I2: 87.52, 4 studies). Pregnant women showed variations in CAT levels across trimesters. This study provides valuable insights into the association between malaria infection and CAT enzyme levels, particularly in nonpregnant individuals. Furthermore, well-designed studies are essential to decoding the intricacies of this relationship, which could have significant implications for understanding disease processes and improving patient care.

Evaluation of CRP as a marker for bacterial infection and malaria in febrile children at the Douala Gyneco-Obstetric and Pediatric Hospital

BACKGROUND

C reactive protein (CRP), a marker for the presence of inflammation, has been extensively studied for distinguishing bacterial from non-bacterial infection in febrile patients, but its role in excluding malaria in the febrile child has not been thoroughly evaluated.

METHOD

This was a cross-sectional study at the Douala Gyneco-Obstetric and Pediatric Hospital which included all patients between the ages of one month and 16 years presenting with fever. Consenting patients received complete clinical examinations, then venous blood samples were collected and tested for CRP values, bacterial infection and malaria.

RESULTS

Samples of 220 children were analyzed. 142/220 had viral infections, 50/220 had malaria and 49/220 had bacterial infections. 7/220 had both malaria and bacterial infection. There was no significant difference between mean CRP values in malaria and bacterial infection (p = 1), but CRP means were significantly higher in malaria/bacterial infection than in viral infection (p<0.0001). Area Under the Receiver Operating Characteristics Curve (AUROC) values were 0.94 for malaria and 0.86 for bacterial infection, with a calculated cut-off of 23.6mg/L for malaria and 36.2mg/L for bacterial infection. At these cut-offs, CRP had a Positive Predictive Value (PPV) of 68.75% and 85.00% for malaria and bacterial infection respectively, with a Negative Predictive Value (NPV) of 94.74% and 89.05% respectively.

CONCLUSION

CRP can effectively exclude malaria and bacterial infection in febrile children in low-resource settings without the need for additional tests.