Malaria Transmission Research Articles

Intermittent preventive treatment for malaria in pregnancy and infant growth: a mediation analysis of a randomised trial

Intermittent preventive treatment for malaria in pregnancy (IPTp) can improve birth outcomes, but whether it confers benefits to postnatal growth is unclear. We investigated the effect of IPTp on infant growth in Uganda and its pathways of effects using causal mediation analyses. We analysed data from 633 infants born to mothers enrolled in a randomised trial of monthly IPTp with dihydroartemisinin-piperaquine (DP) vs. sulfadoxine-pyrimethamine (SP) (NCT02793622). Weight and length were measured from 0 to 12 months of age. Using generalised linear models, we estimated effects of DP vs. SP on gravidity-stratified mean length-for-age (LAZ) and weight-for-length Z-scores (WLZ). We investigated mediation by placental malaria, gestational weight change, maternal anaemia, maternal inflammation-related proteins, preterm birth, birth length, and birth weight. Mediation models adjusted for infant sex, gravidity, gestational age at enrolment, maternal age, maternal parasitaemia at enrolment, education, and wealth. SP increased mean LAZ by 0.18-0.28 Z from birth through age 4 months compared to DP, while DP increased mean WLZ by 0.11-0.28 Z from 2 to 8 months compared to SP among infants of multigravidae; at these ages, confidence intervals for mean differences excluded 0. We did not observe differences among primigravida. Mediators of SP included birth weight, birth length, maternal stem cell factor, and DNER. Mediators of DP included placental malaria and birth length, maternal IL-18, CDCP1, and CD6 at delivery. In high malaria transmission settings, this exploratory study suggests different IPTp regimens may influence infant growth among multigravidae, potentially through distinct pathways, in the exclusive breastfeeding period, when few other interventions are available. Stanford Center for Innovation in Global Health, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bill & Melinda Gates Foundation.

Climate change and epidemiological trends of malaria and Lassa fever transmission in Nigeria (2015-2022): A systematic review and meta-analysis

Background: Climate change exacerbates infectious disease transmission in Nigeria, a country with a high burden of infectious diseases. Objective: To conduct a systematic review and meta-analysis examining the relationship between climate variability and infectious disease transmission in Nigeria. Methods: We systematically searched major databases, identifying 25 studies, with 11 studies meeting the inclusion criteria for meta-analysis using R version 4.4.1. Results: The meta-analysis revealed significant associations between temperature increases and malaria (pooled effect estimate = 1.034, 95% CI: 1.016-1.052) and Lassa fever (pooled effect estimate = 1.029, 95% CI: 1.015-1.043) transmission. Egger's funnel plot showed no significant publication bias, and sensitivity analysis confirmed the robustness of the findings. Conclusion: This study provides evidence for the association between climate variability and infectious disease transmission in Nigeria. This underscores the urgent need for targeted interventions to protect vulnerable populations, including children under 5, pregnant women, the elderly, people with comorbidity, and low-income communities.

Assessing contextual factors influencing scale-up: a interactive approach involving stakeholders

Abstract Issue Pilot interventions are not always put into practice at scale. When they are, effectiveness is often highly reduced in the field due to contextual factors. To effectively implement a scale-up, stakeholders’ involvement is crucial. Curema is an international research evaluating an intervention aiming to reduce malaria transmission by distributing RDTs and treatments in mobile hard-to-reach populations. This intervention might be scaled-up in Brazil, Suriname, and French Guiana as a tool of national malaria programs for specific areas and populations. Description of the problem An interactive pre-planning assessment was conducted involving key stakeholders -implementers, decision-makers, and researchers - in working sessions, semi-structured interviews, and formal meetings. Mendelow’s Power/Interest Matrix was used to map stakeholders and a SWOT analysis was conducted using ExpandNet/WHO Framework to evaluate contextual factors and identify levers and obstacles influencing the scale-up. Results A total of 23 participants were involved. Health authorities had high power and generally high interest, while implementers and recipients had lower power and different interest levels. National engagement for WHO E2025 or E2030 enhanced scalability and represented a main opportunity in the three countries. Nevertheless, several regulatory and administrative aspects were identified as potential obstacles to be addressed to make scale-up realistic. Funding was also a major concern for sustainability. The need for regional cooperation was emphasized to achieve malaria elimination. Lessons Despite financial and regulatory challenges, a window of opportunity is open to scale-up Curema. Identifying and involving stakeholders in a pre-planning assessment and advocating for foster regional cooperation are crucial steps to support the scale-up. Stakeholder analysis should be refined during the scaling-up to capture further changes in factors that might influence the process. Key messages • Engagements with WHO represent windows of opportunity to enhance Curema scale-up. • Stakeholder involvement and regional cooperation are crucial for scaling up Curema in Brazil, French Guiana and Suriname.

Locally Acquired (Autochthonous) Mosquito-Transmitted Plasmodium vivax Malaria - Saline County, Arkansas, September 2023.

A case of locally acquired (autochthonous) mosquito-transmitted Plasmodium vivax malaria was diagnosed in Arkansas in September 2023. This represents the 10th autochthonous case identified nationally in 2023, after 20 years without recorded local mosquitoborne malaria transmission in the United States. The public health response included case investigation, active case surveillance, mosquito surveillance and control, assessment of medical countermeasures, and clinical and public outreach. Prompt diagnosis and appropriate treatment of malaria can improve clinical outcomes and, in addition to vector control, minimize risk for local transmission. Clinicians should consider malaria among patients who have traveled to countries where malaria is endemic, or with unexplained fever regardless of travel history. Although the risk for autochthonous malaria in the United States remains very low, its reemergence highlights the importance of vectorborne disease preparedness and response. Examples of such efforts include improving awareness among clinicians, access to diagnostics and antimalarial medications, and capacity for mosquito surveillance and control. Collaboration and communication among CDC, health departments, local jurisdictions, clinicians, hospitals, laboratories, and the public can support rapid malaria diagnosis, prevention, and control. Before traveling internationally to areas where malaria is endemic, travelers should consult with their health care provider regarding recommended malaria prevention measures, including chemoprophylaxis and precautions to avoid mosquito bites, to reduce both personal and community risk.

Ecological change increases malaria risk in the Brazilian Amazon

Ecological change in the Brazilian Amazon is closely linked to human mobility and health. Mining, agriculture, logging, and other activities alter highly diverse ecological and demographic contexts and subsequent exposure to diseases such as malaria. Studies that have attempted to quantify the impact of deforestation on malaria in the Brazilian Amazon have produced conflicting results. However, they varied in methodology and data sources. Most importantly, all studies used annual data, neglecting the subannual seasonal dynamics of malaria. Here, we fill the knowledge gap on the subannual relationship between ecological change in the Brazilian Amazon and malaria transmission. Using the highest spatiotemporal resolution available, we estimated the effect of deforestation on malaria cases between 2003 and 2022 using a stratified Bayesian spatiotemporal hierarchical zero-inflated Poisson model fitted with the Integrated Nested Laplace Approximation. The model was also stratified by state. We found that a 1% increase in 1-mo lagged deforestation increased malaria cases in a given month and municipality by 6.3% [95% credible interval (Crl): 6.2, 6.5%]. Based on an interaction term included in the model, the effect of deforestation on malaria was even larger in areas with higher forest cover. We found that the coefficients for deforestation and mobility were highly variable when stratified by state. Our results provide detailed evidence that, on average, deforestation increases malaria transmission, but that the relationship is not spatiotemporally uniform. These results have implications for stratifying malaria control interventions based on ecological dynamics to help Brazil achieve its goal of malaria elimination by 2035.

Host Preferences and Impact of Climate on Blood Feeding in Anopheles funestus Group from South Africa.

Anopheles vaneedeni and Anopheles parensis (members of the An. funestus group) are generally not considered malaria vectors. However, both species were recently identified as potential vectors in South Africa. A critical factor needed to determine their role in malaria transmission is their preference for human blood. The human blood index of An. vaneedeni and An. parensis and their potential role in the ongoing residual malaria transmission in South Africa is unknown. This study aimed to identify host blood meals from the wild-caught An. funestus group in a longitudinal study, and to establish the relationship between temperature, relative humidity, and precipitation on host feeding preferences. Anopheles leesoni, An. parensis, An. vaneedeni, and Anopheles rivulorum were collected, and females mainly fed on cattle. Climatic parameters did not influence the host feeding preferences of these four members of the An. funestus group, but impacted the proportion of females that took a blood meal. Significant changes in feeding proportions were driven by relative humidity, temperature, and precipitation. The role of these species in the ongoing residual malaria transmission in South Africa needs further investigation, as no human blood meals were identified. It is recommended that vector surveillance teams incorporate climatic monitoring and host blood meal identification into their routine activities. This information could provide the malaria vector control programmes with scientific evidence to evaluate the importance of the An. funestus group in residual malaria transmission.

Assessing the burden of submicroscopic Plasmodium infections in a pre-elimination malaria setting in sub-Saharan Africa, Guinea-Bissau.

Submicroscopic Plasmodium infections can be a source of persistent malaria transmission. The aim of this study was to assess their frequency, distribution, morbidity and associated factors in a pre-elimination malaria setting in sub-Saharan Africa, Guinea-Bissau, where the Plasmodium falciparum is the predominant Plasmodium species. Dried fingerprick whole blood samples from 601 participants in the 2017 national, household-based, cross-sectional survey to estimate malaria prevalence were subjected to DNA extraction. The DNA was used in nested end-point PCR assays targeting genus- and species-specific regions of the Plasmodium 18S rRNA genes. Statistical analysis of socio-demographic, clinical and molecular data was carried out using the Statistical Package for the Social Sciences, version 29. Factors associated with submicroscopic P. falciparum infections and their magnitude were sought using Chi-square test and multiple logistic regression models, respectively. Statistically significant level was considered at P-value < 0.05. Nested PCR assays detected submicroscopic P. falciparum infections in 20.3% (95% CI = 16.8-23.8) of individuals microscopically negative for Plasmodium species in the general population and in 21.4% (95% CI = 9.9-36.5) of microscopically negative pregnant women. Submicroscopic Plasmodium malariae infections were also detected as co-infections in 3.0% individuals who were microscopically positive only for P. falciparum. Infections with other Plasmodium species were not detected. Submicroscopic P. falciparum infections were not associated with age, sex, or the presence of fever. A logistic regression model adjusted for ethnicity and health region showed that individuals from the Balanta and Bijagos ethnic groups, most of whom live in the low malaria-transmission areas of Quinara and Bissau, and the Bijagos archipelago, respectively, were less likely to have submicroscopic P. falciparum infections than individuals from the large Fula ethnic group, most of whom live in the high malaria-transmission area of Gabu. Submicroscopic P. falciparum infections were not associated with anaemia in children under 5years of age. The results obtained highlight the contribution of asymptomatic and submicroscopic P. falciparum infections to malaria transmission in high malaria-transmission areas and the need for molecular-based tools to detect submicroscopic Plasmodium species.

Knowledge, attitudes, and practices regarding malaria transmission and prevention in an indigenous Maijuna community: a qualitative study in the Peruvian Amazon

BackgroundPeru is a low-endemic transmission area for malaria, where the majority (84%) of incident malaria cases are localized to the department of Loreto, which is composed of several geographically isolated rural communities. Recent intervention efforts targeting at-risk Indigenous populations that live in riverine communities in Loreto place emphasis on preventive behaviours to decrease transmission. However, malaria related behaviour change is often dependent upon local knowledge, beliefs, and practices, especially in areas where malaria is viewed an embedded and unavoidable aspect of life.MethodsThis exploratory case study used semi-structured interviews conducted in Spanish between February and March of 2019 to examine the knowledge, attitudes, and practices related to malaria prevention among the Indigenous Maijuna people of Sucusari, Loreto, Peru. Participants who consented were also administered a rapid diagnostic test (RDT) upon the time of interview.ResultsA total of 33 community members were interviewed, and 31 were tested via malaria rapid diagnostic tests, with RDT filter paper subsequently tested using PCR. All test results were negative for malaria. Themes that emerged included: varying knowledge of methods to prevent malaria, reports of observed changes in malaria incidence over time, confusion surrounding malaria transmission, treatment-seeking as a common behaviour, the belief that medications are effective, and the acceptance of bed nets which were viewed as a lifestyle norm.ConclusionThese shared narratives should be used as a foundation for further studies and health interventions among communities in the Peruvian Amazon with limited access to health services where culturally resonant, community-based health programming is essential to improving health. Takeaways regarding confusion surrounding malaria transmission should also be considered.

Simulated Malaria Online Tool: an instrument for evaluating healthcare providers' practices and contributing to the evidence base for certifying malaria elimination and preventing its re-establishment

BackgroundHealthcare providers (HCPs) practice and correct management of suspected malaria (CMSM) are central components of malaria elimination and prevention of re-establishment (POR) in countries in the elimination phase. However, knowledge of malaria surveillance systems and HCPs practices often wanes in countries aiming to eliminate malaria due to the low numbers of cases. The study aimed to implement a valid Simulated Malaria Online Tool (SMOT) for assessment HCP performance in CMSM and POR in a malaria-free area.MethodsHCPs were evaluated using SMOT tool based on four criteria including presenting a suspected malaria case for detection of HCPs’ failures in recognition (a), diagnosis (b), appropriate treatment (c), and urgent reporting (d); and compared with simulated patients (SP). Multiple logistic regression analysis was carried out to estimate adjusted odds ratios (ORs) for the risk of HCPs failures.ResultsThe overall failure proportion was 237 (83%), and the majority of failures were in recognition (a). There was no significant difference between the SMOT and SP based on all failure criteria (P > 0.05). The private clinic (93%) and the public specialized clinic (70%) had the highest and lowest failure proportions. After passing the recognition stage (a), the overall failure proportions decreased to 47.8% and 25.0% for total HCPs and infectious disease specialists, respectively. In the final analysis, private sector (AOR = 4.36: 1.25–15.2), not-specialist providers (AOR = 2.84: 1.29–6.25) and HCPs with ≥ 5 years’ experience (AOR = 2.03: 1.01–6.25) increased the risk of failure.ConclusionFindings confirmed the implementation of SMOT tool in settings where malaria transmission is low or interrupted. The tool is able to identify sub-groups of providers needing strengthening, and contributes to the prevention of malaria re-establishment.

Long lasting insecticidal nets (LLINs) intervention impact on use, misuse and challenges in malaria and lymphatic filariasis transmission

To assess the effectiveness and misuse status of Long Lasting Insecticidal Nets (LLINs), intervention, a study was conducted in areas of malaria and lymphatic filariasis endemicity from November 2021 to August 2022. A preliminary survey preceded a cross-sectional survey of the misuse of LLINs. Considering the outcome of the former, 57 households misusing LLINs were reported. Thirty (30) cohorts each from LLIN misusing and LLIN non misusing households served as permanent cohorts for mosquito collections (60 rooms in 60 households in 3 sentinel villages). The study also investigated the status of LLIN usage and non usage. Mosquitoes caught with Aspirators and Pyrethrum Knockdown (PKD) techniques were identified using standard morphological keys. Among those who used LLIN, 68.42% used it for other purposes than vector control while 31.58% didn’t utilize it for mosquito control. About 59.65% didn’t know the effect of using it for purposes other than malaria/LF control while 40.35% were familiar. Of 8,180 endophilic mosquitoes caught and assessed for parity, infection/infectivity status, 60.07% (4,914/8,180) and 39.93% (3,266/8,180) represented LLIN misusing and LLIN non-misusing catches respectively. Overall, insignificantly higher catches were made in LLIN misusing cohorts than LLIN non misusing cohorts (63.54% versus 36.45%, 58.89% versus 41.11%, 58.86% versus 41.18%) for 2015, 2016 and 2017 respectively. Specifically, malaria/LF vector densities showed that Anopheles gambiae s.l. (82.53% versus 74.04%) was the highest followed by An. funestus s.l. (10.15% versus 12.19%) and Culex quinquefasciatus (6.82% versus 3.83%) while other species were rarely present. The physiological, infection (0.28% versus 0.49%) and infectivity (0.00% versus 0.00%) statuses with Wuchereria bancrofti were insignificant between the cohorts (p&gt;0.05). None of the Anopheles assessed for Plasmodium sporozoite were positive for both cohorts. The percentage level of LLIN household use was 43.33% while 41.03% slept under LLIN daily, 58.97% slept sometimes. Obstacles to LLIN use included hot/heat (56.86%), dislike (21.57%), lack of protection (11.86%) and ineffectiveness (9.80%). The role of significant misuse of LLIN was highlighted by the study. The results indicated the intensity of filariasis transmission by transmitting vectors was higher than that of malaria and re-emphasis the need to promote positive attitude towards the use of LLIN for control of the two diseases.

Why does malaria transmission continue at high levels despite universal vector control? Quantifying persistent malaria transmission by Anopheles funestus in Western Province, Zambia

BackgroundSome settings continue to experience a high malaria burden despite scale-up of malaria vector control to high levels of coverage. Characterisation of persistent malaria transmission in the presence of standard control measures, also termed residual malaria transmission, to understand where and when individuals are exposed to vector biting is critical to inform refinement of prevention and control strategies.MethodsSecondary analysis was performed using data collected during a phase III cluster randomized trial of attractive targeted sugar bait stations in Western Province, Zambia. Two seasonal cohorts of children aged 1–14 years were recruited and monitored monthly during the malaria transmission season, concurrent with entomological surveillance using a combination of human landing catch (HLC) and Centres for Disease Control (CDC) light traps at randomly selected households in study clusters. Behavioural data from cohort participants were combined with measured Anopheles funestus landing rates and sporozoite positivity to estimate the human behaviour-adjusted entomological inoculation rate (EIR).ResultsBehavioural data from 1237 children over 5456 child-visits in 20 entomology surveillance clusters were linked with hourly landing rates from 8131 female An. funestus trapped by HLC. Among all An. funestus tested by enzyme-linked immunosorbent assay (ELISA), 3.3% were sporozoite-positive. Mean EIR directly measured from HLC was 0.07 infectious bites per person per night (ib/p/n). When accounting for child locations over the evening and night, the mean behaviour-adjusted EIR was 0.02 ib/p/n. Children not sleeping under insecticide-treated nets (ITNs) experienced 13.6 infectious bites per person per 6 month season, 8% of which occurred outdoors, while ITN users received 1.3 infectious bites per person per 6 month season, 86% of which were received outdoors. Sleeping under an ITN can prevent approximately 90% of potential An. funestus bites among children.ConclusionsIn this setting ITNs have a high personal protective efficacy owing to peak An. funestus biting occurring indoors while most individuals are asleep. However, despite high household possession of ITNs (>90%) and high individual use (>70%), children in this setting experience more than one infectious bite per person per 6 month transmission season, sufficient to maintain high malaria transmission and burden. New tools and strategies are required to reduce the malaria burden in such settings.Graphical

Geospatial analysis of malaria burden in Kagera region, northwestern Tanzania using health facility and community survey data

Abstract Background Malaria transmission in Tanzania has declined significantly over the last two decades due to scaled-up control interventions. However, recent confirmation of artemisinin partial resistance (ART-R) in Kagera region in northwest Tanzania threatens the ongoing efforts to eliminate malaria in the country. This study was conducted according to the World Health Organization recommendation to generate evidence of malaria burden in areas with confirmed ART-R as the first step before developing a response strategy to the resistance. Methods We assessed the local burden of malaria in Kagera region by geospatial analysis, using data collected retrospectively from health facilities (HFs) and community surveys from 2015 to 2023 to identify malaria hotspots. Results From 2017 to 2023, a total of 8,124,363 suspected malaria cases were reported by HFs, and 2,983,717 (36.7%, 95% range across wards: 22.7 - 50.7%) tested positive by rapid diagnostic tests. Test positivity rates were similar among under-fives (33.1%, 95% range: 19.7–46.5%) and patients aged ≥5 years (33.7%, 95% range: 21.0–46.5%). Malaria prevalence was 10.0% (95% range across wards: 5.1–14.9%%, n=84,999/853,761) in pregnant women and 26.1% (95% range across wards: 11.7–40.6%, n=3,409/13,065) in school children. Despite high temporal variations, we identified hotspots and coldspots, including persistently high burden in 69/192 (35.9%) wards. Conclusion Malaria burden in Kagera exhibited high temporal and spatial heterogeneity, with school children showing the highest prevalence. This demographic pattern underlines the need for targeted interventions and provides evidence for developing an ART-R response for the region.

A global mathematical model of climatic suitability for Plasmodium falciparum malaria

Climatic conditions are a key determinant of malaria transmission intensity, through their impacts on both the parasite and its mosquito vectors. Mathematical models relating climatic conditions to malaria transmission can be used to develop spatial maps of climatic suitability for malaria. These maps underpin efforts to quantify the distribution and burden of malaria in humans, enabling improved monitoring and control. Previous work has developed mathematical models and global maps for the suitability of temperature for malaria transmission. In this paper, existing temperature-based models are extended to include two other important bioclimatic factors: humidity and rainfall. This model is combined with fine spatial resolution climatic data to produce a more biologically-realistic global map of climatic suitability for Plasmodium falciparum malaria. The climatic suitability index developed corresponds more closely than previous temperature suitability indices with the global distribution of P. falciparum malaria. There is weak agreement between the Malaria Atlas Project estimates of P. falciparum prevalence in Africa and the estimates of suitability solely based on temperature (Spearman Correlation coefficient of ρ=0.24\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\rho = 0.24$$\\end{document}). The addition of humidity and then rainfall improves the comparison (ρ=0.62\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\rho = 0.62$$\\end{document} when humidity added; ρ=0.70\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\rho =0.70$$\\end{document} when both humidity and rainfall added). By incorporating the impacts of humidity and rainfall, this model identifies arid regions that are not climatically suitable for transmission of P. falciparum malaria. Incorporation of this improved index of climatic suitability into geospatial models can improve global estimates of malaria prevalence and transmission intensity.

Force of Infection (FOI) and Multiplicity of Infection (MOI) in Plasmodium falciparum Infected Children Aged 1.5-12 Years Living in the Malaria Endemic Area of Banfora, Burkina Faso.

The aim of this study was to explore molecular measures of P. falciparum malaria burden (FOI and MOI) in the context of seasonal malaria chemoprevention. We analyzed malaria cases collected as part of a longitudinal cohort study. The cohort included P. falciparum-negative children aged 1.5 to 12, as confirmed by PCR 21 days after a radical cure using DHA-PQ or AS. Children were followed up for six months using active and passive case detection methods. At each visit, dried blood spots and blood smears were collected by finger prick, along with clinical data. Parasite DNA was extracted and analyzed by nested PCR for detection and genotyping of P. falciparum parasites. A total of 458 P. falciparum isolates collected during follow-up from October 2020 to March 2021 were genotyped. During the follow-up, children contracted 1.05 (95% IC [0.81-1.30]) new P. falciparum infections/child/time of exposure, and the MOI value was 3.00 (SD 1.60). Age is a protective factor (IRR: 0.74; 95% CI: 0.61, 0.90) against the occurrence of an episode of malaria, unlike an increase in MOI (IRR: 1.63; 95% CI: 1.04, 1.99), which is a favorable factor (p < 0.05). This study confirms the reduction in malaria transmission in our study area, probably due to the massive deployment of control tools.

Influence of future climate scenarios using CMIP 5 data on malaria transmission in India

BackgroundVector-borne diseases, such as malaria, pose a significant global threat, and climatological factors greatly influence their intensity. Tropical countries, like India, are particularly vulnerable to such diseases, making accurate estimation of malaria risk crucial.MethodsThis study utilized the well-known Vector-borne Disease Community Model, VECTRI, developed by the International Centre for Theoretical Physics in Trieste. The model was implemented to estimate malaria’s Entomological Inoculation Rate (EIR). Future climatic prediction datasets, including CMIP 5 and population data sets, were used as inputs for the analysis. Three RCP scenarios are considered (Representative Concentration Pathways are climate change scenarios that project radiative forcing to 2100 due to future greenhouse gas concentrations). The projections covered the period from 1 Jan, 2020, to 31 Dec, 2029.ResultsThe estimated mean EIR for the years 2020–2029 ranged, and a significant decline in malaria risk was observed with all RCP 2.6, 4.5, and 8.5 scenarios. Each year 0.3 to 2.6 [min–max] EIR/person/day decline is observed with a strong decline in man rainfall ranging from 5 to 17 [min–max] mm/year and associated high temperatures ranging from 0.03 to 0.06 [min–max] °C/year. During the post-monsoon period, August to November were identified as highly prone to malaria transmission. Spatial analysis revealed that the east coast of India faced a higher vulnerability to malaria risk, which kept increasing through RCP scenarios. Thus, it is essential to exercise caution, especially in areas with heavy rainfall.ConclusionThis research provides valuable insights for policy-makers, highlighting the need to implement future strategies to mitigate malaria risk effectively. By utilizing these findings, appropriate measures can be taken to combat the threat posed by malaria and protect public health.

Fractional-order analysis of temperature- and rainfall-dependent mathematical model for malaria transmission dynamics

Malaria remains a substantial public health challenge and economic burden globally. Currently, malaria has been declared as endemic in 85 countries. In this study, we developed and analyzed a fractional-order mathematical model for malaria transmission dynamics that incorporates variability of temperature and rainfall using Caputo-type AB operators. The existence and uniqueness of the model's solutions were established using the Banach fixed-point theorem. The model system's equilibria (both disease-free and endemic) were identified, and lemmas and theorems were developed to prove their stability. Furthermore, we used different temperature ranges and rainfall data, validating them against existing literature. Numerical simulations using the Toufik-Atangana schemes with various fractional-order alpha values revealed that as the value of alpha approaches 1, the behavior of the fractional-order model converges to that of the classical model. The numerical results are promising and are expected to be valuable for future research related to fractional-order models.

Variability Effects of Meteorological Factors on Reported Malaria Cases in Kano and Lagos States of Nigeria

Abstract: Malaria is one of life’s threatening disease that contributed significantly to morbidity and mortality in Nigeria. The variability effects of meteorological factors between the Northern and Southern region of Nigeria on malaria transmission remain unclear and not well researched. This research was aimed at comparing the non-linear effects of seasonal, trend and meteorological variables on monthly malaria cases in Kano and Lagos State of Nigeria. The monthly malaria cases for age group above 5-year for Kano and Lagos State were obtained from DHIS for the period of January, 2016 to December, 2022. Also, the predictors/meteorological variables (Rainfall, Relative Humidity, Minimum Temperature and Maximum Temperature) were obtained from Nigeria Meteorological Agent. Generalized Additive Model was fitted using Negative Binomial to apply smooth function to estimate and compare the effects of the selected predictors on the malaria transmission in Kano and Lagos States. Rainfall and Maximum temperature were found not significant in explaining the effect of malaria transmission. Malaria transmission was found to be seasonal and varying in Kano State with highest transmission between September and October while the seasonal effect was reduced to linear in Lagos State. The long term trend had a significant increasing effect on malaria transmission in Kano Sate compared to non-significant effect in Lagos State. The effect of Relative Humidity was reduced to linear and increasing in the both State. Paying attention to the variability in the influence of season, trend and meteorological variables on malaria transmission will enhance respective State Government to develop an early warning and awareness that will help in controlling the malaria outbreak in their State.

Bridging the gaps: prioritizing research strategies for enhanced malaria control and elimination.

Malaria continues to be a significant global health challenge, with millions of cases and hundreds of thousands of deaths reported annually. To combat this disease effectively, it is imperative to identify and address significant research gaps in malaria control and elimination efforts. This review synthesizes current knowledge and highlights critical gaps in several crucial areas of malaria research. Firstly, we discuss the complexities of vector biology and control, emphasizing the need for a deeper understanding of vector behavior, particularly in urban settings. Secondly, the study examines the challenges posed by drug resistance and the urgent need for alternative treatment strategies and novel drug targets. Thirdly, the review explores the ongoing quest for an effective malaria vaccine, underscoring the importance of understanding immunological correlates of protection. The study also explores medication resistance genes and genomic epidemiology, highlighting the need for more investigation into potential targets for drugs and vaccine candidates. Furthermore, it addresses the socioeconomic and environmental determinants of malaria transmission, highlighting the importance of integrating multidisciplinary approaches to address transmission dynamics. The study concludes with a discussion of how malaria transmission is impacted by climate change and the necessity of research to guide adaptation measures.

High-resolution spatio-temporal risk mapping for malaria in Namibia: a comprehensive analysis

BackgroundNamibia, a low malaria transmission country targeting elimination, has made substantial progress in reducing malaria burden through improved case management, widespread indoor residual spraying and distribution of insecticidal nets. The country's diverse landscape includes regions with varying population densities and geographical niches, with the north of the country prone to periodic outbreaks. As Namibia approaches elimination, malaria transmission has clustered into distinct foci, the identification of which is essential for deployment of targeted interventions to attain the southern Africa Elimination Eight Initiative targets by 2030. Geospatial modelling provides an effective mechanism to identify these foci, synthesizing aggregate routinely collected case counts with gridded environmental covariates to downscale case data into high-resolution risk maps.MethodsThis study introduces innovative infectious disease mapping techniques to generate high-resolution spatio-temporal risk maps for malaria in Namibia. A two-stage approach is employed to create maps using statistical Bayesian modelling to combine environmental covariates, population data, and clinical malaria case counts gathered from the routine surveillance system between 2018 and 2021.ResultsA fine-scale spatial endemicity surface was produced for annual average incidence, followed by a spatio-temporal modelling of seasonal fluctuations in weekly incidence and aggregated further to district level. A seasonal profile was inferred across most districts of the country, where cases rose from late December/early January to a peak around early April and then declined rapidly to a low level from July to December. There was a high degree of spatial heterogeneity in incidence, with much higher rates observed in the northern part and some local epidemic occurrence in specific districts sporadically.ConclusionsWhile the study acknowledges certain limitations, such as population mobility and incomplete clinical case reporting, it underscores the importance of continuously refining geostatistical techniques to provide timely and accurate support for malaria elimination efforts. The high-resolution spatial risk maps presented in this study have been instrumental in guiding the Namibian Ministry of Health and Social Services in prioritizing and targeting malaria prevention efforts. This two-stage spatio-temporal approach offers a valuable tool for identifying hotspots and monitoring malaria risk patterns, ultimately contributing to the achievement of national and sub-national elimination goals.

From eradication to reemergence: the growing threat of malaria in Turkey.

According to WHO, between 2000 and 2021, there were approximately 247 million malaria cases and 627,000 deaths globally, with the majority of cases occurring in sub-Saharan Africa. In Turkey, indigenous P. vivax malaria was a major public health problem until its eradication was achieved in 2010. Although indigenous malaria transmission has been significantly reduced since 2010, the country is challenged with imported malaria due to increasing global travel and migration from endemic regions. In this study, all imported malaria cases admitted to Dr. Sadi Konuk Research and Training Hospital, Istanbul, between 2018 and 2023 were included. DNA extraction was performed using archived slides and EDTA blood samples. Real-time PCR was performed to identify samples at the species level using previously reported primers and probes. In addition, all available patient demographics are presented. During the six years between 2018 and 2023, 157 patients were diagnosed with imported malaria. According to the real-time PCR results, 149 cases were P. falciparum (94.9%), five cases were P. vivax (3.2%), two cases were P. ovale (1.3%), and one case was P. malariae (0.6%). The male/female ratio among diagnosed patients was 2.34 (110♂/47♀) among diagnosed patients. Plasmodium falciparum was detected in patients from all African regions, whereas P. vivax was detected only in patients from Liberia and Djibouti. Although malaria cases in Turkey have significantly decreased due to elimination efforts and effective public health interventions, the recent increase in both imported and indigenous cases, as well as the presence of suitable vector species in the country, indicates that malaria still remains a serious public health problem for Turkey.