Bed Nets Research Articles

Malaria parasite burden and heterogeneity of risk factors among Central African Republic refugees: a cross-sectional study in the Gado-Badzere refugee camp in Eastern Cameroon

BackgroundRefugees are vulnerable populations especially in malaria endemic areas where the disease claims many lives and constitutes an emerging challenge for humanitarian response. This study assessed how the influx and settlement of Central African Republic (CAR) refugees influences malaria burden in the Gado-Badzere refugee camp, Eastern Cameroon.MethodsA cross-sectional malariometric survey was conducted between November 2022 and October 2023 in 324 households comprising 1,304 individuals aged 1 month and above. Malaria parasite burden was determined using rapid diagnostic tests (RDTs) and Giemsa-stained microscopy. Demographic characteristics, malaria risk factors, treatment-seeking behaviors and costs to cure malaria were assessed using semi-structured questionnaires.ResultsOf the 1,304 participants, 525 (40.3%) were malaria parasite positive with moderate geometric mean parasite density (GMPD) of 1100 parasites/μl of blood. Plasmodium falciparum was the main species (99.8%), with mixed P. vivax infections (0.2%). Insecticide treated net (ITN) ownership was 53.7%, but its utilization was significantly low (22.4%) (P < 0.001). Reason for no ITN ownership was net damaged (74.7%). Net insufficiency (77.8%) accounted for non-frequent ITN use. Mean expenditure to treat malaria in the hospital was higher (USD 13.64 ± 8.67) than auto-medication (USD 1.13 ± 1.18). Significantly, malaria parasite prevalence and risk were higher for 0-5 years age (43.7%, OR = 1; P = 0.02), residents of sector 8 (49.2%, OR = 2.53; P < 0.001) of the camp, non-frequent ITN users (41.7%, OR = 2.08; P < 0.001), people living around stagnant water (44.4%, OR = 1.55; P < 0.001) and during the rainy season (43.5%, OR = 1.31; P = 0.02). The GMPD/µl was significantly higher in the 0-5 years age group (1456, P < 0.0001), inhabitants of sector 9 (1626, P = 0.04) and participants living around stagnant water (2097, P = 0.01).ConclusionThe malaria burden in CAR refugees may represent the reservoir for malaria transmission, especially with the circulation of P. vivax. The improper use of ITNs could be ameliorated through sensitization. Seasonal chemoprevention mainly during the rainy season and Indoor Residual Spraying (IRS) might be implemented for effective malaria control in refugee settings.

The epidemiological benefit of pyrethroid–pyrrole insecticide treated nets against malaria: an individual-based malaria transmission dynamics modelling study

Insecticide treated nets (ITNs) are the most important malaria prevention tool in Africa but the rise of pyrethroid resistance in mosquitoes is likely impeding control. WHO has recommended a novel pyrethroid-pyrrole ITN following evidence of epidemiological benefit in two cluster-randomised, controlled trials (CRTs). It remains unclear how effective more costly pyrethroid-pyrrole ITNs are compared with other tools, or whether they should be deployed when budgets are limited. We aimed to compare the epidemiological impact and cost-effectiveness of the mass distribution of pyrethroid-pyrrole ITNs relative to other ITNs over 3 years in different African settings. In this individual-based malaria transmission dynamics modelling study we characterise the entomological impact of ITNs using data from a systematic review of experimental hut trials from across Africa. This African entomological data was used to inform an individual-based malaria transmission dynamics model, which was validated against CRT results from Benin and Tanzania. The full impact of new ITNs was quantified for trial sites and simulation was used to project impact in different settings which were included within an accessible interface (the Malaria Intervention Tool) to support National Malaria Programmes to explore how vector control tools and budgets could be allocated across regions to avert the most cases. The model projects that distributing pyrethroid-pyrrole ITNs averted 65% (95% credible interval 48-74) of cases over 3 years in Tanzania, and 75% (28-93) in Benin. The model indicates that trials might have underestimated the benefits of switching ITNs by 12-16% over 3 years because participants stopped using trial-allocated nets. In moderate endemicity non-trial settings, pyrethroid-pyrrole ITNs are projected to reduce malaria prevalence by 25-60% and switching from pyrethroid-only ITNs is probably highly cost-effective in most locations given current prices, averting an additional 10-30% of cases. The benefit of pyrethroid-pyrrole ITNs varies by setting but is generally the most cost-effective indoor vector control intervention in Africa. National Malaria Programmes can strategise deployment to maximise impact. Entomological data could broadly predict epidemiological impact, although there are some inconsistencies, illustrating the challenge in capturing the dynamics across diverse settings. Unitaid, Bill & Melinda Gates Foundation, the UK Medical Research Council, Wellcome Trust, and the UK Foreign, Commonwealth & Development Office.

Efektifitas Kelambu Berinsektisida Long Lasting Insecticidal Nets (LLINS) terhadap Anopheles maculatus

Malaria is a vector-borne disease problem in several parts of Indonesia, including the Rejang Lebong Regency, Bengkulu Province. One way to break the chain of malaria transmission is by using insecticide-treated mosquito nets. The effectiveness of using insecticide-treated mosquito nets in the community needs to be studied. This study was conducted to evaluate the effectiveness of insecticide-treated mosquito nets against Anopheles maculatus based on the duration of use by the community. A fully randomized design study was used to compare the effectiveness of mosquito nets used for six months, six months to two years, and more than two years from 3 different sub-districts. The method used was the WHO bioassay cone test with an untreated polyester mosquito net as a control. Female Anopheles maculatus was tested in a cone bioassay and transferred to paper cups to observe for knockdown or death after 10, 30, and 60 minutes to 24 hours. The results showed that the mosquito nets used for <1 year resulted in 92% knockdown and 80% death. Meanwhile, the use of mosquito nets for 1-2 and >2 years resulted in 92.6% and 75.2% knockdown mosquitoes and 78% and 67.8% dead mosquitos. We concluded that insecticide-treated mosquito nets used for less than one year were still effective for use in controlling malaria.Routine monitoring and evaluation should be carried out to assess the effectiveness of the mosquito nets used.

Socio-demographic factors, housing characteristics, and clinical symptoms associated with falciparum malaria in two rapidly urbanizing areas in the Ashanti region of Ghana

BackgroundMalaria has been described as a disease of poverty, affecting the poorest populations typically living in rural areas. As hitherto rural areas transition into semi-urban environments, this study investigated the prevalence of falciparum malaria and associated risk factors in two rapidly urbanizing districts in the Ashanti Region of Ghana.MethodsA cross-sectional, hospital-based study was conducted at Agona and Mankranso Government Hospitals located within the Sekyere South and Ahafo Ano Southwest districts respectively, in the Ashanti Region of Ghana. Five µL of venous blood was obtained from suspected malaria patients and tested for malaria using rapid diagnostic test (RDT). Data on socio-demographic factors, clinical symptoms, and housing characteristics were collected using a structured questionnaire. Univariate and multivariate logistic regression analysis were performed to identify risk factors associated with malaria.ResultsA total of 1739 participants were enrolled in the study between January and June 2021 with median age of 22 years (IQR = 6–36). Overall malaria prevalence was 24.8%. Compared to > 30-year-olds, children between 0 and 5 years (aOR = 3.36) and those aged between 6 and 14 (aOR = 6.71) were three and six times more likely to test positive for malaria, respectively. Similarly, farming (aOR = 1.74), compared to other occupations, living close to stagnant water (aOR = 1.34), experiencing chills (aOR = 1.5), and vomiting (aOR = 1.93) were associated with increased odds of malaria infection. Having roofing ceiling (aOR = 0.66) and screened doors (aOR = 0.75) were associated with decreased risk of malaria. However, sleeping under insecticide-treated nets (ITNs), using mosquito coils/repellents, and indoor residual spraying (IRS) were not statistically significantly associated with infection.ConclusionChildren between 0 and 5 years and those aged between 6 and 14 years continue to shoulder the highest burden of malaria. Efforts to improve housing characteristics such as installation of roofing ceiling, screening doors, and clearing potential mosquito breeding sites should be encouraged in these rapidly urbanizing areas.

What happens to old insecticide-treated nets after households use in Burkina Faso?

BackgroundInsecticide-treated nets (ITNs) are the most commonly deployed tools for controlling malaria transmission in sub-Saharan Africa. However, some reports associate multiple alternative uses of nets with poor disposal practices, prompting this study to assess existing alternative uses and disposal practices of old ITNs in Burkina Faso after four universal distribution campaigns.MethodsA quantitative survey combined with qualitative data collection was used to describe existing alternative uses and disposal practices for old ITNs in households from selected study sites in the three climatic zones of Burkina Faso. A survey questionnaire was distributed to 3,780 participants, and 12 focus groups were held to elucidate responses regarding existing disposal practices and alternative uses of ITNs.ResultsOf the 3780 households surveyed, 87.4% (3,330) reported having disposed of their ITNs when they were no longer usable due to age or wear. The most commonly cited disposal methods included alternative uses (67.4%), disposal with other garbage (61.4%), and burying (9%). In addition, the most common alternative uses included fencing for crops and seedlings (51.8%); ropes for tying items (40.4%); animal protection fencing (17.8%); house fencing (16.8%); bed covers (13.3%) and curtains for doors or windows (12.6%). Furthermore, trends in ITNs disposal mechanisms and alternative uses differed between study sites in each climate zone. All these ITNs disposal mechanisms and the different types of alternative use of old ITNs were confirmed in the focus group discussions.ConclusionThe findings underscore the need for comprehensive strategies to manage the disposal and repurposing of old ITNs in Burkina Faso. Addressing gaps in disposal guidelines, promoting safe and beneficial reuse practices, and actively involving communities in the decision-making process can help mitigate health risks associated with the improper disposal and repurposing of old insecticide-treated nets and improve the overall effectiveness of malaria control programmes. Through these efforts, both public health and environmental concerns can be addressed in a sustainable and collaborative manner.

Community Knowledge, Attitudes and Practices About Malaria: Insights from a Northwestern Colombian Endemic Locality.

Malaria prevention and control programs are mainly oriented to vector control, timely diagnosis and adequate treatment. Malaria transmission is influenced by several factors, including biological and social aspects. Thus, it is relevant to consider community beliefs and practices to ensure sustainable prevention and control strategies. This study aimed to determine knowledge, attitudes and practices (KAP) towards malaria in an endemic locality in northwestern Colombia. Preliminary data were collected through a focus group discussion. Subsequently, a KAP survey was administered to the community. KAP scores were associated with both sociodemographic characteristics and with previous malaria infection. Focus group data revealed knowledge gaps and the absence of or having worn-out nets. Survey results showed that participants recognized a mosquito bite as the transmission mode (72.09%), followed by dirty water (44.19%), high fever (86.05%) and headache (79.07%) as the main symptoms. Regarding attitudes, 44.19% of the people would go to the hospital in the case of having symptoms. The most recognized practices for disease prevention were the use of mosquito nets (65.12%) and fans (23.26%). The results showed that some people had misconceptions about the disease transmission mode. The analysis showed significant associations of either female gender and homemaker occupation with a good knowledge [OR = 3.74, (p = 0.04), OR = 3.55, (p = 0.04), respectively] or female with a positive attitude towards malaria control and prevention [OR = 4.80, (p = 0.04)]. These results showed that the identified gaps in KAP require increasing education among the community in addition to applying public health prevention efforts. The data may be useful in designing malaria control strategies that involve community participation.

Field surveys in rural Tanzania reveal key opportunities for targeted larval source management and species sanitation to control malaria in areas dominated by Anopheles funestus

BackgroundLarval source management (LSM) is re-emerging as a critical malaria intervention to address challenges associated with core vector control tools, such as insecticide-treated nets (ITNs), and to accelerate progress towards elimination. Presently, LSM is not widely used in rural settings and is instead more commonly applied in urban and arid settings. A systematic entomological assessment was conducted in rural communities of southeastern Tanzania, where insecticide-treated nets (ITNs) are widely used, to explore opportunities for deploying LSM to improve malaria control.MethodsAquatic habitat surveys were conducted in 2022 and 2023 to understand habitat usage by different mosquito vectors, covering five villages during the rainy season and seven villages during the dry season. Additionally, samples of adult mosquitoes were collected to assess the role of various Anopheles species in malaria transmission in the area, and to explore opportunities for species sanitation using targeted LSM.ResultsAdult mosquito surveys showed that in this area, the total entomological inoculation rates (EIR) for indoor collections were 20.1 and 6.5 infectious bites per person per year for outdoors. Anopheles funestus and Anopheles arabiensis were the only Anopheles vectors identified. Anopheles funestus was responsible for over 97.6% of the malaria transmission indoors and 95.4% outdoors. The concurrent larval surveys found that habitats with late instar An. arabiensis and An. funestus comprised only a small subset of 11.2%–16.5% of all water bodies in the rainy season, and 9.7%–15.2% in the dry season. In terms of size, these habitats covered 66.4%–68.2% of the total habitat areas in the wet season, reducing to 33.9%–40.6% in the dry season. From the rainy season to the dry season, the surface area of habitats occupied by An. arabiensis and An. funestus decreased by 92.0% to 97.5%, while the number of habitats occupied by An. arabiensis and An. funestus decreased by 38.0% to 57.3%. Anopheles funestus preferred large, permanent habitats with clear water and vegetation year-round, while An. arabiensis showed contrasting seasonal preferences, favouring sunlit still waters in the rainy season and larger, opaque habitats in the dry season.ConclusionThese findings suggest that An. funestus, which is the dominant malaria vector in the area, mediating over 95% of malaria transmission, preferentially occupies only a small subset of uniquely identifiable aquatic habitats in both wet and dry seasons. This presents an opportunity to expand LSM in rural settings by carefully targeting An. funestus habitats, which might be effective and logistically feasible as a complementary approach alongside existing interventions. Further research should assess the impact of targeted LSM for species sanitation compared to blanket LSM.

Socioeconomic determinants of malaria and hepatitis infections: insights from the Federal Medical Center, Makurdi, North Central, Nigeria

BackgroundMalaria and hepatitis are prevalent public health issues in Nigeria, significantly impacting health outcomes. Given the importance of the Federal Medical Center, Makurdi, as a key healthcare provider in the region, it is crucial to understand the prevalence and factors associated with these diseases within this setting. This study is designed to address this need, aiming to evaluate the prevalence and risk factors of malaria and hepatitis B and C among patients at the Federal Medical Center, Makurdi.MethodologyA cross-sectional study design was employed, involving the meticulous analysis of patient records and diagnostic data from the Federal Medical Center, Makurdi. Data on malaria and hepatitis B and C prevalence were collected from laboratory reports and patient interviews. Socioeconomic information, including income, education level, and healthcare access, was also gathered. Statistical analyses were performed with utmost care to identify associations between disease prevalence and risk factors.ResultsThe study examined 248 patients at the Federal Medical Centre, Makurdi, assessing malaria, Hepatitis B surface antigen (HBsAg), and Hepatitis C virus (HCV). Malaria prevalence was 52.4%, with higher rates in males (57.7%) than females (47.2%). HBsAg prevalence was 6.9%, and HCV was 4.8%, with no significant differences by sex or marital status. Income level impacted HCV rates, with middle-income individuals showing higher prevalence (21.4%). Malaria was most common in the 26–40 age group (35.4%).DiscussionThe findings underscore the need for targeted public health interventions. Enhanced access to preventive measures, such as insecticide-treated nets and safer blood transfusion practices, and educational disease prevention programs, are essential. Addressing socioeconomic disparities is crucial for effective disease control.ConclusionTo mitigate the burden of malaria and hepatitis B and C at the Federal Medical Center, Makurdi, a multifaceted approach is required. Improving preventive measures, healthcare access, and addressing socioeconomic determinants will reduce disease prevalence and improve patient outcomes.

Efficacy of attractive targeted sugar bait stations against malaria in Western Province Zambia: epidemiological findings from a two-arm cluster randomized phase III trial

BackgroundAttractive targeted sugar bait (ATSB) stations containing bait (to attract) and ingestion toxicant (to kill) sugar-foraging mosquitoes are hypothesized to reduce malaria transmission by shortening the lifespan of Anopheles vectors.MethodsA two-arm cluster-randomized controlled trial (cRCT) was conducted in Western Province Zambia. Seventy clusters of 250–350 households were assigned (1:1) by restricted randomization to an intervention arm (ATSB) or control arm (no ATSB) in the context of standard of care vector control (insecticide-treated nets and/or indoor residual spraying). Two ATSB stations (Westham Sarabi, 0.11% dinotefuran w/w) were maintained on exterior walls of eligible household structures for a 7-month deployment period (December-June) during the high malaria transmission season. The primary outcome was clinical malaria incidence among two consecutive seasonal cohorts of children aged 1–14 years, followed-up monthly from January-June in 2022 and 2023. Secondary outcome was Plasmodium falciparum prevalence among individuals aged over six months. Analysis compared clinical malaria incidence and prevalence between arms among the intention-to-treat population.ResultsATSB coverage, assessed by cross-sectional survey, was 98.3% in March–April 2022 and 89.5% in March–April 2023. 4494 children contributed any follow-up time to the cohort, with 2313 incident malaria cases in the intervention arm (1.28 per child per six-month transmission season), and 2449 in the control arm (1.38 per child-season). The incidence rate ratio between the two arms was 0.91 (95% CI 0.72–1.15, p = 0.42). 2536 individuals participated in cross-sectional surveys, with prevalence of P. falciparum 50.7% in the intervention arm and 53.5% in the control arm. The odds ratio between the two arms was 0.89 (95% CI 0.66–1.18, p = 0.42). Secondary covariable-adjusted and subgroup analyses did not substantially alter the findings. No serious adverse events associated with the intervention were reported.ConclusionsTwo ATSB stations deployed per eligible structure for two consecutive transmission seasons did not result in a statistically significant reduction in clinical malaria incidence among children aged 1–14 years or in P. falciparum prevalence in rural western Zambia. Further studies are needed to assess the efficacy of ATSB stations in different settings and with different deployment strategies.Trial registrationThe trial is registered with Clinicaltrials.gov (NCT04800055).

Perception of caregivers on ITNs utilisation and its effectiveness among children under 5 years of age in Chikwawa district, Malawi

BackgroundIn 2020, Malawi had 6.9 million malaria cases and 2551 deaths, mainly in children under five years of age. The 2017–2022 Malawi malaria control strategic plan promoted the consistent use of insecticide-treated nets through free distribution and mass campaigns. Despite widespread availability of the control strategy plan, Chikwawa District continues to suffer from high malaria burden especially among under five children, due to inconsistent insecticide-treated (ITN) net usage. For this reason, this study aimed at exploring caregivers’ perceptions on insecticide-treated net utilisation and also find out about its effectiveness among those who consistently use them.MethodsThis study used a sequential exploratory mixed methods design. The data used for quantitative analysis was drawn from the population of under-five children’s caregivers within the catchment area of Chikwawa district hospital. The sample size was 96 participants, as determined by Cochran’s formula. The data collection lasted from December 2023 to April 2024 and included four in-depth interviews and three focus group discussions to address the objectives qualitatively.ResultsThe study revealed that 91.67% of households used ITNs, with 87.50% using them daily. The significant factors influencing ITN utilisation included the number of nets, user satisfaction, perceived impact, user habits, acquisition method, and usage frequency (all p values < 0.001). Under-five malaria cases were also significant (p = 0.025). The odds of the perceived net impact influencing utilisation were 4.956 times greater. Non-usage was due to heat, quality concerns, limited access, breathing difficulties, health conditions such as asthma, and misconceptions about net treatment.ConclusionThe study revealed a strong belief in insecticide-treated net efficacy. However, some challenges such as access, durability, and misinformation of insecticide-treated nets were discovered. These challenges affected utilisation of insecticide-treated nets in agreement with some literature reviewed. The insights found in this study will help policymakers in addressing health interventions for the reduction of malaria cases in Malawi.

Environmental Factors to Malaria Incidence : A Literature Review

Malaria remains a major public health concern in Indonesia, particularly due to its high mortality rate among children under five, accounting for approximately two-thirds of all cases. The disease is transmitted by female Anopheles mosquitoes, which carry the Plasmodium parasite. In 2019, malaria caused 409,000 deaths globally, with 229 million cases reported, particularly in remote areas with poor access to healthcare, commonly in low-income countries. This literature review highlighted the environmental risk factors contributing to malaria incidence, based on studies from 24 scientific journals using data from the Sinta and Scopus databases. The study identified key environmental factors, including physical, chemical, biological, and socio-cultural elements, with the most significant risk linked to vector breeding sites. Among the reviewed articles, 62.5% (15 out of 24) found a statistically significant association between the presence of mosquito breeding sites and malaria incidence. Additional risk factors included the use of mosquito nets, housing conditions (specifically wall density), and nighttime outdoor activities. Effective malaria control measures require addressing these environmental factors, as they play a crucial role in the disease’s transmission. Strategies to disrupt the transmission cycle include eliminating mosquito breeding sites, applying larvicides to stagnant water, cleaning vector resting areas, promoting the use of insecticide-treated nets, and implementing Indoor Residual Spraying (IRS). A community-based, integrated approach to environmental management is essential to reducing malaria transmission and controlling its spread in affected regions.

Jumantik Education: Strategy Toward Malaria Elimination in the Resettlement Area of Osi Island, West Seram Regency

The Covid-19 pandemic, which has been global for 3 years, tends to have a domino effect in various aspects, such as individuals, groups, and countries. One of the causes of decreased immune system in the host is due to comorbid diseases suffered by the host (patients). Those at risk of Covid-19 may also be at risk of infectious diseases caused by viruses, parasites, and bacteria. In a pandemic situation like Covid-19, health behavior change education with a risk communication approach needs to be implemented in preventing, treating, and rehabilitating environmental stages of worm infection risk in the community of Osi Island hamlet. This education aims to increase public knowledge of potential health risks and threats. Thus, they can determine appropriate steps and actions to protect themselves from these issues. The method used is education with the project-based learning model, which combines lecture, discussion, and field practice methods. The target group is high school students of PGRI Pelita Jaya Seram Western Part. The achieved results are that the JUMANTIK cadres know about malaria-free health (cognitive), can collect trash (containers) from yards (psychomotor), do not allow stagnant water (affective), can drain water storage containers inside and around the house (psychomotor), can make simple mosquito traps using recycled materials, can sleep under mosquito nets (psychomotor), can observe larvae and pupae (psychomotor). Kyewords: Jumantik education, malaria elimination, Osi Island

Societal uses of the main water bodies inhabited by malaria vectors and implications for larval source management

BackgroundLarval source management (LSM) effectively reduces mosquito populations at their breeding sites, addressing issues like insecticide resistance that limit the effectiveness of primary interventions such as insecticide-treated nets (ITNs). Although traditionally used in urban and dry areas, recent research suggests it might also be effective in rural settings in eastern and southern Africa, where Anopheles funestus thrives in permanent water bodies that sustain year-round transmission. Targeting these habitats could enhance LSM, but it requires understanding local community practices, as mosquito breeding sites often overlap with community water resources. This study examined how communities use aquatic habitats and how these practices may impact LSM strategies, with a focus on habitats used by An. funestus.MethodsThis study was conducted in three villages in the Ulanga and Malinyi districts of southeastern Tanzania using a mixed-methods approach. Quantitative data were collected through cross-sectional surveillance, and qualitative data through unstructured interviews, focus group discussions, and field observations. Data analysis integrated both quantitative and qualitative findings to develop a comprehensive understanding of community perspectives.ResultsA survey of 931 aquatic habitats found mosquito larvae in 73% of them, with late instar An. funestus present in 23%. River streams made up 41% of the habitats, while ground pools accounted for 4%. Most habitats (90%) were used by communities, including 95% of those with An. funestus larvae, for activities such as domestic chores, agriculture, livestock rearing, brickmaking, and fishing. Focus group discussions revealed a willingness to adopt LSM, with a preference for larviciding and habitat modification over habitat removal, as the water sources were vital for daily use. Community concerns centered on the safety of larvicides for humans and animals, the environmental impact, and the need for better awareness of how LSM affects health and livelihoods.ConclusionThis study highlights community perspectives on LSM, focusing on the dual function of aquatic habitats as mosquito breeding sites and essential community water sources. This dual role presents both challenges and opportunities, suggesting that LSM strategies must balance public health needs with socio-economic realities. There was a clear preference for larviciding and habitat modification over removal, with a strong emphasis on health and environmental safety. The study emphasizes the importance of educating communities on the safety and effectiveness of LSM, and tailoring LSM strategies to fit the needs and preferences of local communities.

Impact of Climate Variability and Interventions on Malaria Incidence and Forecasting in Burkina Faso.

Malaria remains a climate-driven public health issue in Burkina Faso, yet the interactions between climatic factors and malaria interventions across different zones are not well understood. This study estimates time delays in the effects of climatic factors on malaria incidence, develops forecasting models, and assesses their short-term forecasting performance across three distinct climatic zones: the Sahelian zone (hot/arid), the Sudano-Sahelian zone (moderate temperatures/rainfall); and the Sudanian zone (cooler/wet). Monthly confirmed malaria cases of children under five during the period 2015-2021 were analyzed using Bayesian generalized autoregressive moving average negative binomial models. The predictors included land surface temperature (LST), rainfall, the coverage of insecticide-treated net (ITN) use, and the coverage of artemisinin-based combination therapies (ACTs). Bayesian variable selection was used to identify the time delays between climatic suitability and malaria incidence. Wavelet analysis was conducted to understand better how fluctuations in climatic factors across different time scales and climatic zones affect malaria transmission dynamics. Malaria incidence averaged 9.92 cases per 1000 persons per month from 2015 to 2021, with peak incidences in July and October in the cooler/wet zone and October in the other zones. Periodicities at 6-month and 12-month intervals were identified in malaria incidence and LST and at 12 months for rainfall from 2015 to 2021 in all climatic zones. Varying lag times in the effects of climatic factors were identified across the zones. The highest predictive power was observed at lead times of 3 months in the cooler/wet zone, followed by 2 months in the hot/arid and moderate zones. Forecasting accuracy, measured by the mean absolute percentage error (MAPE), varied across the zones: 28% in the cooler/wet zone, 53% in the moderate zone, and 45% in the hot/arid zone. ITNs were not statistically important in the hot/arid zone, while ACTs were not in the cooler/wet and moderate zones. The interaction between climatic factors and interventions varied across zones, with the best forecasting performance in the cooler/wet zone. Zone-specific intervention planning and model development adjustments are essential for more efficient early-warning systems.

Socioeconomic disparities in Plasmodium falciparum infection risk in Southern Malawi: mediation analyses

This study investigated the mediators of the association between socioeconomic position (SEP) and Plasmodium falciparum (Pf) infection in Southern region of Malawi. We utilized data from the 2014 International Center of Excellence for Malaria Research (ICEMR) surveys from Malawi in which blood samples of all individuals from selected households in Blantyre, Thyolo and Chikhwawa were tested for Pf parasitemia. We assessed household SEP and potential mediators – housing quality, food security, education status of household heads, and use of long-lasting Insecticide-treated nets (LLINs) and nutritional status. We conducted causal mediation analyses to assess the proportion of SEP effect that is attributed to each mediator and combination of mediators. The mediation analysis shows that during the rainy season, improved housing and educational attainment explained 39.4% and 17.0% of the SEP effect on Pf infection, respectively, and collectively 66.4%. In the dry season, housing, educational attainment, and LLIN usage collectively mediated 33.4% of SEP’s effect with individual contributions of 15.6%, 11.2%, and 3.8%, respectively. Nutrition also played a role, particularly for children, mediating 9.2% of SEP’s effect in the rainy season and 3.7% in the dry season. The study concluded that multifaceted interventions targeting housing, education, LLIN usage, and nutrition are vital to reducing socioeconomic disparities in Pf infection risk in the Southern region of Malawi.

Assessing agricultural practices and insecticides resistance for effective malaria vector control in northwestern Iran

BackgroundAfter three years with no local transmission of malaria, an outbreak occurred in Iran in 2022. Key malaria control methods in Iran are including indoor residual spraying (IRS), long-lasting insecticide-treated nets (LLINs), and prompt diagnosis and treatment of malaria cases. Anopheles sacharovi is one of the main malaria vectors in Iran. This study aimed to determine the insecticides resistance status of An. sacharovi in northwestern Iran, to inform effective vector control programs in this region.MethodsLarval stages of An. sacharovi were collected from various larval habitats located in the villages along the Aras River. Adult susceptibility tests were performed on An. sacharovi using diagnostic doses of insecticides accordance to World Health Organization (WHO) guidelines. The study also evaluated agricultural insecticide and fertilizer usage alongside the presence of natural mosquito predators in breeding sites in the study area.ResultsAlongside various chemicals such as silica, humic acid, superphosphate, sulfur, urea, and solupotasse at different dose levels, organophosphorus and pyrethroid insecticides are commonly used in rice fields and orchards. Anopheles sacharovi displayed diverse reactions to insecticides, demonstrating resistance to DDT but sensitivity to malathion, and showing similar reactions to carbamate and pyrethroid insecticides.ConclusionsThese results provide significant insights into agricultural practices and the presence of mosquito larvae in the study area. The extensive use of a specific herbicide illustrates its popularity among farmers for weed control, while other agricultural products focus on enhancing soil fertility and productivity. The absence of mosquito larvae in habitats with predators indicates the usefulness of these predators in controlling the population of mosquitoes. The resistance of mosquitoes to certain insecticides highlights the need for careful selection and intermittent use of insecticides in vector control programs. These findings can inform the development of targeted strategies to reduce malaria transmission risks. Further research is essential for assessing the effectiveness of these interventions.

Mathematical Exploration of Malaria Transmission Dynamics: Insights from Fractional Models and Numerical Simulation

AbstractThis study presents an innovative mathematical model denoted as the fractional SIP(H)–SI(M) model, which aims to analyze and understand the dynamics of malaria transmission and spread. This model is distinguished by incorporating memory effects through fractional differential equations, allowing for a more accurate and realistic analysis of disease spread compared to traditional models. The proposed model is applied to Algeria by estimating its parameters using recent health data (from 2000). The results revealed that the disease‐free equilibrium is stable only when the basic reproduction number is less than one, indicating that controlling the spread of malaria and possibly eradicating it can be achieved by implementing appropriate preventive measures. Simulations also demonstrated a direct correlation between the rate of infection transmission and an increase in the number of infected individuals, highlighting the need for swift action when signs of an outbreak emerge. Based on these findings, a set of preventive measures is recommended, including insecticide spraying programs, widespread distribution of insecticide‐treated bed nets, and implementation of effective treatment protocols for infected individuals. This study also emphasizes the importance of continuous monitoring of health data and updating model parameters to ensure the effectiveness and sustainability of preventive measures.

Risk of transfusion-associated malaria in sub-Saharan Africa: The case of Mali.

Malaria is a health threat in sub-Saharan Africa, where Plasmodium is not tested in blood bags. Our objective was to determine the prevalence of plasmodial carriage in blood bags and the associated factors, and the involvement of these bags in the occurrence of malaria in recipients. From 1st April to 30th November, 2020, we conducted a prospective cross-sectional study of 348 blood bags stored at 4°C in Bamako. Using SPSS 21.0 software, statistical analyses were performed using a binary logistic regression model with a significance threshold of p < 0.05 and the odds ratio (OR) framed by its 95% confidence interval (CI). During this period, 348 blood bags were transfused into 108/152 hospitalised patients, generating a transfusion frequency of 71.1%, with a prevalence of plasmodial carriage of 22%. Among the 54 initially malaria-negative recipients, all 20 (37%) who received malaria-positive blood bags and slept under long-acting insecticide-treated nets (LLINs) developed malaria. We recorded 33.3% deaths. Donor age ≤ 34 years (p = 0.011; OR = 2.55[CI.95% = 1.25-5.23]), replacement donation (p = 0.000; OR = 0.04[CI.95% = 0.0-0.19]) and not regular use of LLINs by donors (p = 0.048; OR = 0.53[CI.95% = 0.29-1]) were factors associated with plasmodial carriage of blood bags. CD4 count<200 cells/mm3 (p = 0.002; OR = 0.2[CI.95% = 0.10-0.52]), severe anaemia (p = 0.034; OR = 0.26[CI.95% = 0.10-0.90]) and decompensated anaemia (p = 0.034; OR = 3.88[CI.95% = 1.11-13.56]) were factors independently associated with recipient death. The prevalence of plasmodial carriage among blood donors is increasing in Mali. Transfusion malaria is a reality to be feared, with the risk increasing with the level of malaria endemicity of the blood donor.

Prevalence of Malaria Infection among Pregnant Women Attending Antenatal Clinic in Nnamdi Azikiwe University Teaching Hospital, Nnewi

Malaria is a major health problem affecting people in the tropics and sub-tropical regions of the world. This cross-sectional hospital-based study was carried out to determine the prevalence of malaria infection among pregnant women attending a tertiary hospital in Nnewi, Anambra State, Nigeria. A total of 100 venous blood samples were collected from pregnant women into EDTA tubes and examined using field-stained thick and thin films for identification of malaria parasites. Demographic information such as age, trimester and insecticide-treated nets usage was obtained using a structured questionnaire. Data was analyzed using Statistical Package for the Social Sciences version 22. The chi-square test was used to determine the difference among the variables studied and P≤ 0.05 were considered significant. Out of the 100 blood samples examined, 27 were infected and had an overall prevalence of 27%. Women within the age bracket of 31-35 years had the highest prevalence rate 11(36.7%) while no infection was recorded in the 41-45 years age group 0(0.0%). Pregnant women in their first trimester had the highest infection prevalence of 13(35.1%) while those in their third trimester had the least prevalence of 5(17.9%). In relation to ITN’s usage, pregnant women who don’t normally sleep under ITNs had the highest infection prevalence 23(31.5%) while those who usually sleep under ITNS had the least prevalence rate 4(14.8%). It is pertinent to periodically check the malaria infection status of pregnant women attending antenatal services. Prophylactic treatment should be routinely administered to avoid pregnancy complications due to malaria infection.

Malaria risk factors amongst forest going populations in Mondulkiri Province and Kampong Speu Province, Cambodia: a large cross-sectional survey.

Cambodia strives to eliminate all species of human malaria by 2025, requiring that foci among forest-exposed populations in remote settings be addressed. This study explores malaria risk factors amongst forest-exposed groups in Mondulkiri and Kampong Speu Provinces, Cambodia as part of a multi-stage study on novel bite prevention tools (Project BITE). A serial cross-sectional survey explored the demographics, housing structure openness, mosquito bite prevention habits, and gaps in protection amongst three target groups: forest goers who work in the forest, forest dwellers who live in the forest, and forest rangers who patrol forested regions. Malaria prevalence data was collected at three time points using rapid diagnostic tests (RDTs) for febrile individuals and qPCR for all participants. Infection locations and travel patterns of P. falciparum-infected individuals were analyzed for clustering and the potential movement of infections. 2,935 participants were enrolled between October 2022 and February 2023, consisting of 1,093 (37%) forest goers and 1,787 (61%) forest dwellers across both provinces, and 55 (5%) forest rangers in Mondulkiri province. Most worked outdoors as farmers, day laborers, and forest collectors, and reported going to the forest five to seven days a week. For housing, 29% and 39% of participants reported living in partially open primary and secondary structures, respectively. The main methods of mosquito bite protection used were insecticide-treated nets, wearing long sleeves, and burning mosquito coils, with gaps in protection during the daytime and outside at night. All febrile individuals had negative RDT test results. For qPCR, 24 P. falciparum infections (<1%) were detected among forest goers and dwellers, clustered in Pu Trom and Pu Nhav villages in Mondulkiri Province, and Banteay Roka and Banteay Roka Kirisenchey (M) villages in Kampong Speu Province. P. vivax cases were detected (216 cases, 5%) across all enrolled villages. Only two infections were found in forest rangers. Malaria elimination strategies for forest-exposed populations in Cambodia should focus on vector intervention strategies that offer protection during the day and outside at night, and the use of drug-based strategies to clear subpatent infections, targeting forest goers and dwellers in villages where cases are detected.