Use Of Insecticide-treated Nets Research Articles

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.

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

In 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. This 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. The 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. The 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.

Relationship between malaria vector survival, infectivity, and insecticide-treated net use in western Kenya.

Significant effort and resources have been invested to control malaria transmission in sub-Saharan Africa, but it remains a major public health problem. For the parasite to be transmitted, the female Anopheles vector must survive 10-14days following an infective bite to allow Plasmodium gametocytes to develop into infectious sporozoites. The goal of this study was to assess factors associated with wild-caught Anopheles survival and infection following host-seeking and indoor resting. The study was conducted between January 2020 to March 2022 in a longitudinal cohort of 75 households in 5 villages including a total of 755 household members in Bungoma County, Kenya. Monthly adult mosquito collection was conducted by attenuated aspiration in all enrolled households, and mosquitoes were reared for 7days. The daily mortality rate was determined through day 7. All mosquitoes were morphologically identified. Female Anopheles were dissected, and species-level members of the Anopheles gambiae complex were resolved by molecular methods. The abdomens of all samples were processed for Plasmodium falciparum oocyst detection by PCR. Within a 25-month period, the total numbers of non-Anopheles and Anopheles mosquitoes collected indoors were 12,843 and 712, respectively. Anopheles gambiae and An. funestus were the major vectors, though their distributions varied between different villages; 61.2% (n = 436/712) of the Anopheles mosquitoes survived up to day 7, with the lowest mortality rate recorded on day 5 of captivity. The survival rate also varied between the different Anopheles species. Six hundred eighty-three of 712 mosquito abdomens were tested for P. falciparum; 7.8% (53/683) tested positive for P. falciparum, with An. funestus having a higher (10%) prevalence than An. gambiae s.s. (6.0%, p = 0.095, Pearson Chi-square test). The proportion of household members sleeping under a bednet the night before mosquito collection varied across time and village. Anopheles funestus survival times were refractory to household ITN usage, and An. gambaie s.s. survival was reduced only under very high (100%) ITN usage. Despite ITN usage, mosquitoes still acquired blood meals and P. falciparum infections. Survival differed across species and was inversely correlated with high ITN usage in the household but not oocyst development.

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.

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

Background: 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). Methods: 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. Results: 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. Conclusions: 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.

Analysis of the 24-h biting patterns and human exposures to malaria vectors in south-eastern Tanzania

BackgroundAfrotropical malaria vectors are generally believed to bite nocturnally, leading to the predominant use of insecticide-treated nets (ITNs), which target indoor, nighttime-biting mosquitoes. This focus is reinforced by biases in entomological surveys, which largely overlook daytime mosquito activity. However, recent evidence challenges this paradigm, showing that Anopheles biting can extend way into the daytime, coinciding with human activities at dawn, daytime and evenings, suggesting a broader risk spectrum and potential protection gaps. We have therefore investigated the diurnal and nocturnal biting patterns of the malaria vectors Anopheles arabiensis and Anopheles funestus in south-eastern Tanzania, to better understand the scope of residual transmission and inform strategies for improved control.MethodsHost-seeking mosquitoes were collected hourly using miniaturized double net traps, both indoors and outdoors over 24-h periods between June 2023 and February 2024. Concurrently, human activities indoors and outdoors were monitored half-hourly to correlate with mosquito collections. A structured questionnaire was used to assess household members’ knowledge, perceptions and experiences regarding exposure to mosquito bites during both nighttime and daytime.ResultsNocturnal biting by An. arabiensis peaked between 7 p.m. and 11 p.m. while that of An. funestus peaked later, between 1 a.m. and 3 a.m. Daytime biting accounted for 15.03% of An. arabiensis catches, with peaks around 7–11 a.m. and after 4 p.m., and for 14.15% of An. funestus catches, peaking around mid-mornings, from 10 a.m. to 12 p.m. Nighttime exposure to An. arabiensis was greater outdoors (54.5%), while daytime exposure was greater indoors (80.4%). For An. funestus, higher exposure was observed indoors, both at nighttime (57.1%) and daytime (69%). Plasmodium falciparum sporozoites were detected in both day-biting and night-biting An. arabiensis. Common daytime activities potentially exposing residents during peak biting hours included household chores, eating, sleeping (including due to sickness), resting in the shade or under verandas and playing (children). From evenings onwards, exposures coincided with resting, socializing before bedtime and playtime (children). Nearly all survey respondents (95.6%) reported experiencing daytime mosquito bites, but only 28% believed malaria was transmissible diurnally.ConclusionsThis study updates our understanding of malaria vector biting patterns in south-eastern Tanzania, revealing considerable additional risk in the mornings, daytime and evenings. Consequently, there may be more gaps in the protection provided by ITNs, which primarily target nocturnal mosquitoes, than previously thought. Complementary strategies are needed to holistically suppress vectors regardless of biting patterns (e.g. using larval source management) and to extend personal protection limits (e.g. using repellents). Additionally, community engagement and education on mosquito activity and protective measures could significantly reduce malaria transmission risk.Graphical

Delivering insecticide-treated nets (ITNs) through a digitized single-phase door-to-door strategy: lessons from Ondo state, Nigeria

BackgroundThe use of insecticide-treated nets (ITNs) is a strategy recommended by the World Health Organization (WHO) for malaria prevention. In Nigeria, ITNs have been periodically distributed since 2007 through campaigns. Campaign activities and assets are typically tracked using either a paper-based or digital system. In 2017, a digital approach was introduced in Ondo state for tracking attendance at training sessions as part of the ITN campaign. Following the success of the 2017 introduction, subsequent campaigns planned to digitise other aspects of the campaign to improve accountability and efficiency of the ITN distribution. The COVID-19 pandemic posed additional challenges for the ITN distribution planned for 2021 and adaptations were made to the programme strategy to ensure the campaign could go ahead safely. This article presents lessons and experiences from the 2021 ITN distribution campaign in Ondo state, Nigeria.MethodsThe campaign used RedRose, a customised mobile application, to monitor the planning and delivery of the campaign, collect household information including training personnel and tracking the transfer of ITNs between distribution hubs and households. ITNs were delivered through a single-phase door-to-door distribution strategy.ResultsThe campaign distributed 2,965,125 ITNs covering 1,057,577 households across Ondo state. The digital application was beneficial for monitoring the quality of implementation and tracking assets and staff to ensure safety.. The single-phase door-to-door approach was more convenient for households compared to fixed-point distribution but increased the workload for mobilization and distribution teams.ConclusionsSingle phase door-to-door strategy using digital tools was an effective method to increase coverage of ITNs while closely tracking the progress of distribution campaigns. High-quality population data are needed to further improve the planning and implementation of ITN campaigns and other health interventions.

The influence of malaria control interventions and climate variability on changes in the geographical distribution of parasite prevalence in Kenya between 2015 and 2020

BackgroundThe burden of malaria in Kenya was showing a declining trend, but appears to have reached a plateau in recent years. This study estimated changes in the geographical distribution of malaria parasite risk in the country between the years 2015 and 2020, and quantified the contribution of malaria control interventions and climatic/ environmental factors to these changes.MethodsBayesian geostatistical models were used to analyse the Kenyan 2015 and 2020 Malaria Indicator Survey (MIS) data. Bivariate models were fitted to identify the most important control intervention indicators and climatic/environmental predictors of parasitaemia risk by age groups (6–59 months and 5–14 years). Parasitaemia risk and the number of infected children were predicted over a 1 × 1 km2 grid. The probability of the decline in parasitaemia risk in 2020 compared to 2015 was also evaluated over the gridded surface and factors associated with changes in parasitaemia risk between the two surveys were evaluated.ResultsThere was a significant decline in the coverage of most malaria indicators related to Insecticide Treated Nets (ITN) and Artemisinin Combination Therapies (ACT) interventions. Overall, there was a 31% and 26% reduction in malaria prevalence among children aged < 5 and 5–14 years, respectively. Among younger children, the highest reduction (50%) and increase (41%) were in the low-risk and semi-arid epi zones, respectively; while among older children there was increased risk in both the low-risk (83%) and semi-arid (100%) epi zones. Increase in nightlights and the proportion of individuals using ITNs in 2020 were associated with reduced parasitaemia risk.ConclusionIncreased nightlights and ITN use could have led to the reduction in parasitaemia risk. However, the reduction is heterogeneous and there was increased risk in northern Kenya. Taken together, these results suggest that constant surveillance and re-evaluation of parasite and vector control measures in areas with increased transmission is necessary. The methods used in this analysis can be employed in other settings.

Evaluating a phone-based Interactive Voice Response system for reducing misinformation and improving malaria literacy

ABSTRACT In Burkina Faso, malaria remains a major issue despite the use of insecticide-treated nets (ITNs), especially in underserved communities. A study assessed a mobile phone-based Interactive Voice Response (IVR) service in local languages to improve malaria health literacy. A randomized trial compared users of the local language version with those using a French version. The results showed a 30.33% increase in knowledge, 21.77% in attitude, and 35.38% in practice among the local language group, while the French group had lower improvements. Key factors for adoption included usability, privacy, trust, and compatibility. Participants preferred local language and voice interfaces, with younger users favoring games and older ones preferring text-based interfaces. This study highlights the potential of local language IVR to effectively boost malaria health literacy and combat misinformation in underserved areas.

Activity-based contracting for optimization of the mass distribution of insecticide-treated nets in the Democratic Republic of Congo: pilot implementation in Kwilu province

BackgroundPromoting the use of insecticide-treated mosquito nets (ITNs) is one of the main strategies for reducing malaria-related morbidity. An innovative activity-based contracting (ABC) approach has been implemented in Kwilu Province, Democratic Republic of Congo to optimize ITN mass distribution campaigns, with payments based on contractually defined programmatic outcomes for key campaign activities following independent verification of results.MethodsThis internal evaluation was carried out using a mixed methods approach combining qualitative and quantitative document and content analysis from a series of three workshops: validation workshops for campaign results at provincial level for the 2021 and 2022 campaigns; internal evaluation workshop for the Kwilu campaign as part of the ABC approach organized by “Santé pour tous en milieu rural” (SANRU) with its sub-contractors; and national campaign evaluation workshop organized by the National Malaria Control Program.ResultsThe pilot campaign with the ABC approach in Kwilu has demonstrated better results than campaigns conducted using the standard, non-ABC, approach: better household coverage (99.9% vs. 97.3%) and improved compliance with ITN allocation to households based on the household size (98. 9% vs. 84.7%); lower loss of ITNs (0.3% vs. 0.5%) with immediate penalties for lost ITNs in the province under the ABC approach; shorter campaign lead times (14 vs. 28 weeks from the start of training to the launch of distribution). This last point is crucial, as it is likely to generate efficiencies and contribute to ensuring timely ITN replacement campaigns.ConclusionThe challenges encountered and the lessons learned in the implementation of the pilot ABC approach in Kwilu could guide future distribution campaigns in the DRC and other African countries that would like to engage in distribution campaigns based on performance-based incentive contracts.

Mosquito Species Composition in Nasarawa Local Government Area, Nasarawa State, Nigeria

Study’s Excerpt The resting densities, biting rates, and indoor mosquito populations in Nasarawa LGA were assessed. Prokopack aspirator is applied for morning mosquito collection and the dissecting microscope for identification of species-specific attributes. The results highlight critical areas for targeted vector control to mitigate malaria transmission in the region. Full Abstract Numerous mosquito species are capable of carrying various tropical diseases. This study ascertained the composition of mosquitoes in Nasarawa Local Government Area, Nasarawa State, Central Nigeria. Adult mosquitoes were collected between 0600 and 0900 hours in the morning using a battery-operated Prokopack aspirator. The mosquitoes were then placed in a petri dish with proper labelling and taken to a laboratory for identification and dissection. Using a dissecting microscope and identification key, mosquitoes were sorted and morphologically classified according to their morphological features. The mosquito midgut was dissected to check for sporozoites infectivity. The man-biting rate (MBR) and indoor resting density (IRD) were computed. A total of 314 adult mosquitoes, spanning four species and belonging to the Anopheline and Culicine mosquito groups, were found to be resting indoors with An. gambiae representing 39.2% of the total composition. A significant difference in mosquito abundance (χ2= 58.866, df = 3, P=0.001) was observed between the four species that were reported. There is no discernible variation in the mosquito composition in the research region (χ2= 4.861, df = 2, P = 0.088). A statistically significant variance in sex was noted (χ2=285.235, df = 2, P = 0.000). The biting rate was recorded at 2.6 bites per person per night, and an indoor resting density of 5.23 mosquitoes per room per night was recorded. There was a noteworthy distinction in the abdomen condition of the mosquitoes (χ2 = 45.564, df = 3, p &lt; 0.001). Mosquito species abundance in October was 200 (63.7%), compared to 114 (36.3) in September. Nonetheless, a noteworthy distinction was observed in the abundance of mosquito species throughout the research months (χ2= 7.5076, df = 1, P-value = 0.006). Based on the study's findings that provided insight into the species composition of the mosquito population in the study area, it is recommended to remove possible breeding grounds, promote the use of insecticide-treated nets, and prioritize interrupting vector-human contact as a means of halting the spread of malaria parasites.

Malaria Prevention and Control in Nigeria: Evaluating the Effectiveness of Current Strategies

Malaria has been a significant public health challenge in Nigeria, contributing to high morbidity and mortality rates, particularly among children under five and pregnant women. Despite all efforts made to control and prevent malaria, Nigeria continued to bear a disproportionate share of the global malaria burden. This review critically evaluated the effectiveness of current malaria prevention and control strategies in Nigeria, including the use of insecticide-treated nets (ITNs), indoor residual spraying (IRS), chemoprevention, and public health education campaigns. The methodology involved a comprehensive analysis of peer-reviewed studies, government reports, and data from international health organizations to assess these strategies. The review identified gaps in the implementation of these strategies and explored innovative approaches that could enhance their impact. It also discussed the role of environmental management, community engagement, and the integration of technology in malaria control efforts. The findings suggested that while existing strategies have made significant progress in reducing malaria transmission, challenges such as resistance to insecticides, inconsistent use of preventive measures, and limited healthcare infrastructure hindered their overall effectiveness. The review concluded by proposing recommendations for strengthening malaria prevention and control efforts in Nigeria, with a focus on sustainability, scalability, and community involvement. Keywords: Malaria Control, Insecticide-Treated Nets (ITNs), Indoor Residual Spraying (IRS), Chemoprevention, Environmental Management.

Assessment of knowledge, attitude, and practices toward malaria in the Lunglei district, Mizoram, North-East India

BackgroundThe western districts of Mizoram (Lunglei, Mamit, and Lawngtlai) are malaria hotspots. Understanding the knowledge, attitude, and practices of the tribal communities in Mizoram’s western districts will aid the development of specific interventions.MethodsAn explanatory sequential mixed-method study was conducted from April to November 2023 in the Lunglei district. In a community-based cross-sectional survey of 353 participants, the knowledge, attitude, practices, and care-seeking behaviour toward malaria were assessed using a semi-structured questionnaire. Data was analysed using SPSS version 29 software; univariate variables were presented in percentage, and bivariate and multivariate variables were analysed using the chi-square test and logistic regression, respectively. This was followed by in-depth telephonic interviews of twelve participants, and the data was analysed using NVivo.ResultsOut of the 353 respondents, 77.9%, 82.7%, 55.5%, and 63.2% of the participants had good knowledge, attitude, practices, and care-seeking behaviour, respectively. The in-depth qualitative interviews highlighted the villagers’ good knowledge of the various aspects of malaria transmission, treatment, and prevention practices (indoor residual spraying and use of insecticide-treated nets).ConclusionHigh disease endemicity, awareness programmes and vector control interventions might be contributing to the overall good knowledge, attitude, and practices toward malaria among the villagers. In addition to vector control measures, active parasite surveillance is key to malaria control in this region.

Home-based care practices on prevention of malaria in children under 5 years: A narrative review.

Malaria is a major threat to lives in developing countries, especially in Africa. A lot of measures have been tried to curb the increased mortality and morbidity associated with malaria. A lot of resources have been channeled to control the devastating effects of malaria in these parts of the world. The aim of this paper is to discuss home-based care practices on prevention of malaria in children under 5 years. By cutting back on bushes and upholding good hygiene and sanitation, malaria in young children can be prevented in homes. This lessens disease and transmission while also assisting in death prevention and disease reduction. In Africa, Uganda is the third most affected country by malaria, which is a major cause of high morbidity and mortality in young children and pregnant women. This has forced the Government of Uganda and implementing partners, including the Global Fund and the Roll Back Malaria initiative, to redouble efforts to increase the use of insecticide-treated mosquito nets. Effective use of insecticide-treated bed nets is necessary to eliminate the above serious sequelae in children under 5 years old. Households and especially caregivers apply the use of impregnated mosquito nets and cleaning of surrounding bushes. According to research results, the use of indoor residual spray nets and insecticide-impregnated nets has significantly contributed to the prevention of malaria in children.

Malaria prevalence and transmission in the Zakpota sub-district of central Benin: baseline characteristics for a community randomised trial of a new insecticide for indoor residual spraying

BackgroundMalaria transmission is known to be perennial and heterogeneous in Benin. Studies assessing local malaria prevalence, transmission levels and vector characteristics are critical for designing, monitoring and evaluating new vector control interventions in community trials. We conducted a study in the Zakpota sub-district of central Benin to collect baseline data on household characteristics, malaria prevalence, vector characteristics and transmission dynamics in preparation for a randomised controlled trial to evaluate the community impact of VECTRON™ T500, a new broflanilide indoor residual spraying (IRS) product.MethodsA total of 480 children under 5 years of age from the 15 villages of the sub-district were tested for malaria by rapid diagnostic tests (RDTs). Mosquitoes were collected by human landing catches (HLCs), pyrethrum spray catches (PSCs) and Centers for Disease Control and Prevention miniature light traps (CDC-LTs) in selected houses in each village to assess vector density, composition, vector infectivity and prevalence of insecticide resistance markers. Bioassays were performed to detect vector susceptibility to pyrethroids, broflanilide (6 µg/bottle) and clothianidin (90 µg/bottle).ResultsA total of 9080 households were enumerated in the 15 study villages. Insecticide-treated net (ITN) usage was > 90%, with 1–2 ITNs owned per household. Houses were constructed mainly with cement (44%) and mud (38%) substrates or a mixture of cement and mud (18%), and 60% of them had open eaves. The overall prevalence of P. falciparum infection was 19% among surveyed children: 20% among females and 18% among males. The haemoglobin rate showed an anaemia (< 11 g/dl) prevalence of 66%. Anopheles coluzzii and An. gambiae sensu stricto (s.s.) were the two vector species present at an overall proportion of 46% versus 54%, respectively. The human biting rate was 2.3 bites per person per night (b/p/n) and biting occurred mostly indoors compared with outdoors (IRR = 0.776; P = 0.001). The overall proportion of outdoor biting was 44% and exceeded indoor biting in three villages. The sporozoite rate was 2% with a combined yearly entomological inoculation rate (EIR) of 16.1 infected bites per person per year (ib/p/y). There was great variability in malaria transmission risk across the villages, with EIR ranging from 0 to 29.3 ib/p/y. The vector population showed a high intensity of resistance to pyrethroids across the study villages but was largely susceptible to broflanilide and clothianidin.ConclusionsThis study found high levels of malaria prevalence, vector density and transmission in the Zakpota sub-district despite the wide use of insecticide-treated nets. The vector population was mostly indoor resting and showed a high intensity of pyrethroid resistance but was generally fully susceptible to broflanilide. These findings demonstrated the suitability of the study area for the assessment of VECTRON™ T500 in a community randomised trial.Graphical

Efficacy of Interceptor G2, Royal Guard and PermaNet 3.0 against pyrethroid-resistant Anopheles gambiae s.l. from Za-Kpota, southern Benin: an experimental hut trial

BackgroundThe widespread use of insecticide-treated nets (ITNs) has significantly contributed to the reduction in malaria cases and deaths observed across Africa. Unfortunately, this control strategy is threatened by the rapid spread of pyrethroid resistance in malaria vectors. Dual-active-ingredient insecticidal nets are now available to mitigate the impact of pyrethroid resistance. To facilitate evidence-based decisions regarding product selection in specific use settings, data are needed on the efficacy of these different nets against local mosquito populations.MethodsTwo experimental hut trials were performed in Za-Kpota, southern Benin in 2021 to evaluate the performance of Interceptor G2 (BASF), Royal Guard (Disease Control Technologies) and PermaNet 3.0 (Vestergaard Frandsen), all dual-active-ingredient bednets, in comparison to untreated or standard pyrethroid-treated bednets, against free-flying wild Anopheles gambiae mosquitoes. The performance of some of these next-generation nets was compared to the same type of nets that have been in use for up to 2 years. Mosquitoes collected in the huts were followed up after exposure to assess the sublethal effects of treatments on certain life-history traits.ResultsThe predominant species in the study site was Anopheles gambiae sensu stricto (An. gambiae s.s.). Both Anopheles coluzzii and An. gambiae s.s. were resistant to pyrethroids (deltamethrin susceptibility was restored by piperonyl butoxide pre-exposure). In the experimental hut trials, the highest blood-feeding inhibition (5.56%) was recorded for the Royal Guard net, relative to the standard PermaNet 2.0 net (44.44% inhibition). The highest 72-h mortality rate (90.11%) was recorded for the Interceptor G2 net compared to the PermaNet 2.0 net (56.04%). After exposure, the risk of death of An. gambiae sensu lato (An. gambiae s.l.) was 6.5-fold higher with the Interceptor G2 net and 4.4-fold higher with the PermaNet 3.0 net compared to the respective untreated net. Lower mosquito mortality was recorded with an aged Interceptor G2 net compared to a new Interceptor G2 net. Oviposition rates were lower in mosquitoes collected from huts containing ITNs compared to those of untreated controls. None of the mosquitoes collected from huts equipped with Royal Guard nets laid any eggs.ConclusionsThe Royal Guard and Interceptor G2 nets showed a potential to significantly improve the control of malaria-transmitting vectors. However, the PermaNet 3.0 net remains effective in pyrethroid-resistant areas.Graphical

Investigation on Malaria Parasitaemia, Knowledge and Attitudes towards Mosquito Control among Residents of Wukari Metropolis

This study was conducted to investigate malaria parasitaemia, knowledge and attitudes towards mosquito control. 162 subjects were selected at random from different locations in Wukari Metropolis and were examined for malaria parasitaemia. Blood samples from each of the subjects were collected by finger pricking for the determination of malaria parasite using the Rapid Diagnostic Test method. Out of 162 samples examined, the prevalence of malaria parasitaemia was 91(56.17%). Female subjects had the highest prevalence of malaria parasitaemia of (72.0%), while the male had (35.0%) and the difference was statistically significant (p&lt;0.05) between the rate of infection and gender. Age group ≥20 years recorded the highest infection rate of (62.12%), age group 14-16 years had the lowest infection rate of (48.94%), and there was no significant difference p&gt;0.05 between malaria prevalence and age groups. The hospital location had the highest prevalence of malaria parasitaemia at (64.44%) and (31.89%) within malaria, while the Fuwukari location had the least prevalence of malaria parasitaemia of (47.22%) and (18.68%) within malaria. The test on knowledge and awareness of malaria indicates that (31.48%) of the subjects have erroneous perception about the cause and means through which malaria is transmitted. It can be concluded that despite the high infectivity rate of malaria in the study area there is much knowledge and awareness of malaria in the study. There is a need for a comprehensive strategy for preventing malaria transmission such as effective use of insecticide-treated nets, public awareness campaigns, proper environmental sanitation and use of drugs.

Comparison of the Trapping Efficacy of Locally Modified Gravid Aedes Trap and Autocidal Gravid Ovitrap for the Monitoring and Surveillance of Aedes aegypti Mosquitoes in Tanzania.

The study assessed the trapping efficacy of locally modified (1) Gravid Aedes Trap (GAT) lined with insecticide-treated net (ITN) as a killing agent and (2) Autocidal Gravid Ovitrap (AGO) with sticky board in the semi-field system (SFS) and field setting. Fully balanced Latin square experiments were conducted to compare GAT lined with ITN vs. AGO, both with either yeast or grass infusion. Biogent-Sentinel (BGS) with BG-Lure and no CO2 was used as a standard trap for Aedes mosquitoes. In the SFS, GAT outperformed AGO in collecting both nulliparous (65% vs. 49%, OR = 2.22, [95% CI: 1.89-2.60], p < 0.001) and gravid mosquitoes (73% vs. 64%, OR = 1.67, [95% CI: 1.41-1.97], p < 0.001). Similar differences were observed in the field. Yeast and grass infusion did not significantly differ in trapping gravid mosquitoes (OR = 0.91, [95% CI: 0.77-1.07], p = 0.250). The use of ITN improved mosquito recapture from 11% to 70% in the SFS. The same trend was observed in the field. Yeast was chosen for further evaluation in the optimized GAT due to its convenience and bifenthrin net for its resistance management properties. Mosquito density was collected when using 4× GATs relative to BGS-captured gravid mosquitoes 64 vs. 58 (IRR = 0.82, [95% CI: 0.35-1.95], p = 0.658) and showed no density dependence. Deployment of multiple yeast-baited GAT lined with bifenthrin net is cost-effective (single GAT < $8) compared to other traps such as BGS ($160).

Prevalence of and factors associated with placental malaria in the White Nile State: a cross-sectional study.

Malaria during pregnancy can lead to maternal and perinatal adverse effects. Despite the preventive measures, recent research has shown that malaria during pregnancy is still a threatening health problem, especially in Sub-Saharan African countries. The current study was conducted to determine the prevalence of and factors associated with placental malaria in Rabak Hospital in central Sudan. A cross-sectional study was conducted from September to October 2021. Pregnant women who delivered at the Rabak Maternity Hospital in Central Sudan were included. A questionnaire was used to gather both obstetric and socio-demographic information. Blood films for malaria were prepared using the maternal, placental, and cord blood, and a placental histology was performed. A logistic regression analysis was performed. For the 208 women, the medians (interquartile range) of their age and parity were 25 (21.0 ‒30.0) years and 2 (1‒4), respectively. Twenty-five (12.0%) of the women had used insecticide-treated nets. Active infection, active-chronic infection, and past-chronic infection were detected in four (1.9%), five (2.4%), and 35 (16.8%) placentas, respectively. One hundred and sixty-four (78.8%) placentas showed no signs of infection. Logistic regression analysis showed that none of the examined factors (age, parity, education, antenatal care level, use of insecticide-treated nets, and blood group) was associated with placental malaria. Malaria affects 20% of pregnant women, regardless of their age and parity. Preventative measures should therefore be encouraged in this area.

Ownership and use of insecticide-treated nets in Myanmar: insights from a nationally representative demographic and health survey

BackgroundMalaria poses a substantial public health threat in Myanmar, indicating the need for rigorous efforts to achieve elimination of the disease nationwide by 2030. The use of insecticide-treated nets (ITNs) forms part of a pivotal strategy for preventing transmission. This study explored the ownership and use of ITNs in Myanmar and identified factors associated with non-use of ITNs.MethodsHousehold datasets from the 2015–2016 Myanmar Demographic and Health Survey were utilised, which encompassed all household members except children under the age of five. Descriptive statistics and inferential tests, including simple and multiple logistics regression models and Pearson correlations, were employed for analysis. All analyses, taking the two-stage stratified cluster sampling design into account, used weighting factors and the “svyset” command in STATA. The ownership and use of bed nets were also visualised in QGIS maps.ResultsAmong the 46,507 participants, 22.3% (95% CI 20.0%, 24.5%) had access to ITNs, with only 15.3% (95% CI 13.7, 17.1%) sleeping under an ITN the night before the survey. Factors associated with the non-use of ITNs included age category (15–34 years—aOR: 1.17, 95% CI 1.01, 1.30; 50+ years—aOR: 1.19, 95% CI 1.06, 1.33), location (delta or lowland—aOR: 5.39, 95% CI 3.94, 7.38; hills—aOR: 1.80, 95% CI 1.20, 2.71; plains—aOR: 3.89, 95% CI 2.51, 6.03), urban residency (aOR: 1.63, 95% CI 1.22, 2.17), and wealth quintile (third—aOR: 1.38, 95% CI 1.08, 1.75; fourth—aOR: 1.65, 95% CI 1.23, 2.23; fifth—aOR: 1.47, 95% CI 1.02, 2.13). A coherent distribution of the ownership and use of ITNs was seen across all states/regions, and a strong correlation existed between the ownership and use of ITNs (r: 0.9795, 95% CI 0.9377, 0.9933, alpha < 0.001).ConclusionsThis study identified relatively low percentages of ITN ownership and use, indicating the need to increase the distribution of ITNs to achieve the target of at least one ITN per every two people. Strengthening the use of ITNs requires targeted health promotion interventions, especially among relatively affluent individuals residing in delta or lowland areas, hills, and plains.