Distribution Of Insecticide-treated Nets Research Articles

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.

Under utilization of long-lasting insecticidal nets (LLINs) is challenging malaria elimination program in Ethiopia: a systematic review and meta-analysis

BackgroundMalaria is one of the most common causes of morbidity and mortality in developing countries including Ethiopia. Mass distribution of insecticide-treated nets and indoor residual spray for high malaria risk groups are the major prevention measures in different countries. Achievement of the malaria elimination plan is highly determined by the level of effective utilization of intervention measures. However, there is scarce information showing the national level of insecticide-treated nets utilization.ObjectiveTo estimate the pooled prevalence of insecticide-treated nets utilization in Ethiopia, 2023.MethodA Systematic Review and Meta-analysis employed to assess the utilization of long-lasting insecticidal nets in Ethiopia. Published articles were searched from Google Scholar, PubMed, Web Sciences, CINAHIL, EMBASE, and Scopus. The collected articles were screened for data extraction and further analysis using preferred reporting items for systematic review and meta-analysis (PRISMA) flow chart. The quality of each study was assessed using the Jonna Briggs Institute (JBI) checklist. The data were extracted using Microsoft Excel and exported to STATA version 17.0 for analysis. The overall pooled prevalence of long-lasting insecticidal nets utilization was determined using a random effects model.ResultOut of 1657 articles reviewed, only 21 of them were eligible for final analysis. All of the included studies were used to estimate the pooled prevalence of long-lasting insecticidal net utilization. The point prevalence of LLIN utilization ranged from 14.23 to 91.9%. The Meta-analysis estimated that the overall pooled prevalence of insecticidal nets utilization among all study participants in Ethiopia was 56.26% (95%CI: 44.04–68.48%). Subgroup analysis revealed that insecticidal nets utilization was relatively highest in the Amhara region [63.0, 95%CI (37.0–89.0%)] and during 2020–2023 [61, 95% CI (53.0–69.0%)].ConclusionLong-lasting insecticidal nets utilization in Ethiopia is lower than the national target plan. Hence, it needs extra follow-up and intervention to enhance its utilization.

Epidemiology and risk factors of malaria among pregnant women attending antenatal clinics in Osun State, Nigeria

Globally, malaria in pregnancy leads to severe complications such as abortion, stillbirth, premature delivery, low birth weight, and fetal underdevelopment. This study examined the prevalence and risk factors of malaria among pregnant women attending antenatal care in Osun State, Nigeria. Between July and December 2020, 555 pregnant women from ten primary health centres in Osogbo, Ejigbo and Ilobu Local Government Areas participated in the study. Employing pre-tested questionnaires, qualitative data on the demographic and risk behaviours of participants were obtained. Malaria prevalence, determined by rapid diagnostic tests and blood smear microscopy was 15% caused by Plasmodium falciparum. The highest malaria prevalence was found among women who didn't use insecticides (23.1%), followed by those who did not use insecticide-treated nets (16.5%). The lowest prevalence was among women in their second and third trimesters who had taken Intermittent Preventive Treatment (IPT) (6.3%). The highest prevalence occurred among women aged 17-24 years (17.4%), while the lowest was among women aged 25-34 years (12.9%). All participants were aware of malaria but their knowledge about transmission (67%), symptoms (64%) and prevention (44%) varied. The study highlights the vulnerability of pregnant women who do not use insecticide-treated nets and emphasizes the need for improved malaria preventive practices. Control efforts should focus on the distribution of insecticide-treated nets, health education during antenatal visits and increased usage of IPT as recommended by the World Health Organization.

Unveiling Malaria's Silent Threat: From Socioeconomic Divides to Religious Influences, A Path to Effective Prevention in India.

Malaria remains a formidable public health challenge in India, particularly in low-socioeconomic regions, where it exacts a heavy toll on lives every year. This pressing issue gains prominence in light of a recent study conducted by Ronald et al. in Uganda, which illuminates the factors contributing to the elevated prevalence of malaria in economically disadvantaged areas. The study underscores the efficacy of interventions such as insecticide-treated nets (ITNs) and indoor residual spraying (IRS) in curtailing malaria incidence. Additionally, the World Health Organization's endorsement of the RTS, S/AS01 (RTS, S) malaria vaccine presents a promising development in the battle against this devastating disease. This letter underscores the imperative nature of implementing comprehensive strategies in India, which encompass widespread ITN distribution, the expansion of IRS programs, and the integration of the RTS, S/AS01 vaccine into the national immunization regimen. These concerted efforts are pivotal in furnishing cost-effective preventive measures to counter the mounting wave of malaria cases in India. Confronting malaria through a multifaceted approach stands as an essential approach to mitigate the disease's burden and ultimately safeguard the lives of India's vulnerable populations.

Measuring quality of facility-based ITN distribution in Ghana

BackgroundContinuous distribution channels are effective methods to deliver malaria interventions such as insecticide treated nets (ITNs) to pregnant women attending antenatal care clinics and children under five attending immunization visits. Facility-based and provider-based checklists were used during supportive supervision visits to measure the quality of facility-based services and interventions. This study looks at ITN distributions at health facilities in Ghana, with the aim of providing insights on how quality can be measured and monitored.MethodsVarious quality improvement approaches for malaria services occur in Ghana. Selected indicators were analysed to highlight the similarities and differences of how the approaches measured how well the channel was doing. Generally, the approaches assessed (1) service data management, (2) logistics data management, and (3) observation of service provision (ITN issuance, malaria education, ITN use and care education). Two approaches used a binary (Yes/No) scale, and one used a Likert scale.ResultsResults showed that most data reported to the national HMIS is accurate. Logistics data management remained an issue at health facilities, as results showed scores below average across facility stores, antenatal care, and immunization. Though the supervision approaches differed, overall results indicated that almost all eligible clients received ITNs, data were recorded accurately and reported on-time, and logistics was the largest challenge to optimal distribution through health facilities.ConclusionThe supervision approaches provided valuable insights into the quality of facility-based ITN distribution. Ghana should continue to implement supportive supervision in their malaria agenda, with additional steps needed to improve reporting of collected data and increase the number of facilities visited for supportive supervision and the frequency. There were various supervision approaches used with no clear guidance on how to measure quality of facility-based ITN distribution, so there is also need for the global community to agree on standardized indicators and approaches to measuring quality of facility-based ITN distribution. Additionally, future studies can review the effect of multiple rounds of supervision visits on the quality of ITN distribution as well as understand the facilitators and barriers to scaling up supervision of facility-based ITN distribution.

Estimating population ITN access at council level in Tanzania

BackgroundSince 2013, the National Malaria Control Programme in mainland Tanzania and the Zanzibar Malaria Elimination Programme have implemented mass insecticide-treated net (ITN) distribution campaigns, routine ITN distribution to pregnant women and infants, and continuous distribution through primary schools (mainland) and community leaders (Zanzibar) to further malaria control efforts. Mass campaigns are triggered when ITN access falls below 40%. In this context, there is a need to monitor ITN access annually to assess whether it is below threshold and inform quantification of ITNs for the following year. Annual estimates of access are needed at the council level to inform programmatic decision-making.MethodsAn age-structured stock and flow model was used to predict annual net crops from council-level distribution data in Tanzania from 2012 to 2020 parameterized with a Tanzania-specific net median lifespan of 2.15 years. Annual nets-per-capita (NPC) was calculated by dividing each annual net crop by mid-year council projected population. A previously fit nonparametric conditional quantile function for the proportion of the population with access to an ITN (ITN access) as a function of NPC was used to predict ITN access at the council level based on the predicted NPC value. These estimates were compared to regional-level ITN access from large household surveys.ResultsFor regions with the same ITN strategy for all councils, predicted council-level ITN access was consistent with regional-level survey data for 79% of councils. Regions where ITN strategy varied by council had regional estimates of ITN access that diverged from the council-specific estimates. Predicted ITN access reached 60% only when “nets issued as a percentage of the council population” (NPP) exceeded 15%, and approached 80% ITN access when NPP was at or above 20%.ConclusionModelling ITN access with country-specific net decay rates, council-level population, and ITN distribution data is a promising approach to monitor ITN coverage sub-regionally and between household surveys in Tanzania and beyond.

Countrywide insecticide resistance monitoring and first report of the presence of the L1014S knock down resistance in Niger, West Africa

BackgroundMass distribution of insecticide-treated nets (ITNs) is the principal malaria vector control strategy adopted by Niger. To better inform on the most appropriate ITN to distribute, the National Malaria Control Programme (NMCP) of Niger and its partners, conducted insecticide resistance monitoring in selected sites across the country.MethodsThe susceptibility of Anopheles gambiae sensu lato (s.l.) to chlorfenapyr and pyrethroid insecticides was investigated in a total of sixteen sites in 2019 and 2020, using 2–5-day-old adults reared from wild collected larvae per site. The susceptibility status, pyrethroid resistance intensity at 5 and 10 times the diagnostic concentrations, and piperonyl butoxide (PBO) synergism with diagnostic concentrations of deltamethrin, permethrin and alpha-cypermethrin were assessed using WHO bioassays. Two doses (100 and 200 µg/bottle) of chlorfenapyr were tested using the CDC bottle assay method. Species composition and allele frequencies for knock-down resistance (kdr-L1014F and L1014S) and acetylcholinesterase (ace-1 G119S) mutations were further characterized using polymerase chain reaction (PCR).ResultsHigh resistance intensity to all pyrethroids tested was observed in all sites except for alpha-cypermethrin in Gaya and Tessaoua and permethrin in Gaya in 2019 recording moderate resistance intensity. Similarly, Balleyara, Keita and Tillabery yielded moderate resistance intensity for alpha-cypermethrin and deltamethrin, and Niamey V low resistance intensity against deltamethrin and permethrin in 2020. Pre-exposure to PBO substantially increased susceptibility with average increases in mortality between 0 and 70% for tested pyrethroids. Susceptibility to chlorfenapyr (100 µg/bottle) was recorded in all sites except in Tessaoua and Magaria where susceptibility was recorded at the dose of 200 µg/bottle. Anopheles coluzzii was the predominant malaria vector species in most of the sites followed by An. gambiae sensu stricto (s.s.) and Anopheles arabiensis. The kdr-L1014S allele, investigated for the first time, was detected in the country. Both kdr-L1014F (frequencies [0.46–0.81]) and L1014S (frequencies [0.41–0.87]) were present in all sites while the ace-1 G119S was between 0.08 and 0.20.ConclusionThe data collected will guide the NMCP in making evidence-based decisions to better adapt vector control strategies and insecticide resistance management in Niger, starting with mass distribution of new generation ITNs such as interceptor G2 and PBO ITNs.

Inequalities in the use of insecticide-treated nets by pregnant women in Ghana, 2011 and 2017

Pregnant women and children are the mostvulnerable group of people usually affected by malaria. The use of insecticide-treated nets is one of the proven interventions for mitigating malaria and itsassociated deaths in endemic regions,including Ghana. Meanwhile, there is limited evidence on the extent of inequality in insecticide-treated nets use by pregnant womenin Ghana. This study assessed the inequalities in insecticide-treated nets use by pregnant women in Ghana. Data from the 2011 and 2017 versions of the Ghana Multiple Indicator Cluster Surveys were used. The 2019 updated World Health Organization (WHO) HEAT software (version 3.1) was used for all analyses. Four equity stratifiers were employed to disaggregate insecticide-treated nets use by pregnant women in Ghana. These are economic status, level of education, place ofresidence, and sub-national region. Four measures were used to compute inequality namely Difference (D), Population Attributable risk (PAR), Population Attributable Fraction (PAF) and Ratio (R). The analyses indicated a rise in pregnant women's insecticide-treated nets use from 32.6% in 2011 to 49.7% in 2017. Except sub-nationalregion, all the factors showed mild inequality in insecticide-treated nets use. For instance, with respect to theeconomic status of pregnant women, only a slight inequality was exhibited by one of the simple measures in both 2011 (R = 0.3; 95% UI = 0.2-0.6) and 2017 (R = 0.5; 95% UI = 0.3-0.7). Marginal inequality in insecticide-treated nets use was noted in 2011 (R = 0.6; 95% UI = 0.5-0.9) and 2017 (R = 0.8; 95% UI = 0.6-0.9) for level of education. In the same vein, slight inequality was realized with respect to place of residence in 2011 (R = 0.4; 95% UI = 0.3-0.6) and 2017 (R = 0.6; 95% UI = 0.5-0.7). For sub-national region, both simple (D = 50.5; 95% UI = 30.7-70.4) and complex (PAF = 91.3; 95% UI = 72.3-110.3) measures demonstrated substantial inequality in 2011. In the case of 2017, considerable inequality in insecticide-treated netsuse occurred (D = 58; 95% UI = 42.2-73.8, PAF = 51.9; 95% UI = 36.2-67.6). In conclusion, insecticide-treated nets utilization by pregnant Ghanaianwomen increased between 2011 and 2017. The findings show that Ghana's Ministry of Health in collaboration with anti-malarial non-governmental organizations must review patterns of insecticide-treated nets distribution and intensify advocacy among educated pregnant women, those in urban settings and the rich, to assuage the magnitude of inequality.

Diversity and behavioral activity of Anopheles mosquitoes on the slopes of Mount Cameroon

BackgroundMalaria remains endemic in Cameroon, with heterogeneous transmission related to eco-climatic variations, vector diversity and spatial distribution. The intensification of malaria prevention and control through the free distribution of insecticide-treated nets in recent years may have altered the composition, geographic distribution and natural infection rate of Anopheles species, with implications for malaria transmission dynamics. The present study seeks to assess the vectorial diversity, dynamics and infectivity across different seasons and altitudes in relationship to parasite prevalence around the slopes of Mount Cameroon, southwestern region.MethodMosquitoes were sampled (indoors and outdoors) in 11 eco-epidemiological settings at low (18–197 m), intermediate (371–584 m) and high (740–1067 m) altitude by nightly human landing catches. The mosquitoes were identified morphologically and Anopheles gambiae sibling species identified by PCR. Parity status was ascertained by examining the ovaries and the entomological inoculation rates (EIR) determined by Plasmodium falciparum circumsporozoite antigen ELISA of the head-thorax. The prevalence of Plasmodium infection across target communities was assessed using rapid diagnostic tests.ResultsA total of 7327 (18.0 mosquitoes/trap/night) mosquitoes were trapped, mainly during the rainy season (5678, 77.5%) and at low altitude (3669, 50.1%). Anopheles spp. (5079, 69.3%) was the most abundant genera and An. gambiae complex (2691, 36.7%) the major vector, varying with altitude (χ2 = 183.87, df = 8, P < 0.001) and season (χ2 = 28.14, df = 4, P < 0.001). Only An. gambiae (s.s.) was identified following molecular analysis of An. gambiae complex siblings. The overall biting peak for An. gambiae complex was 2—3 a.m. Anopheles cinctus was the most abundant secondary vector in the area. The average EIR in the area was 2.08 infective bites per person per night (ib/p/n), higher at low (2.45 ib/p/n) than at intermediate altitude (1.39 ib/p/n) and during the rainy (1.76 ib/p/n) compared to the dry season (0.34 ib/p/n). Anopheles funestus was most infectious overall (28.1%, 16/57) while An. gambiae had the highest inoculation rates averaging 1.33 ib/p/n. Most Anopheles species across all altitudes and seasons were parous, highest in communities with the highest proportion of malaria parasite infections.ConclusionAnopheles gambiae (s.s.) remains the major malaria vector in the area and An. cinctus possibly a secondary vector of the disease in the slopes of Mt. Cameroon. The seasonal and altitudinal effects on the distribution of these mosquitoes may have implications for the transmission of malaria and its control strategies in the area. Regular monitoring of the bionomics of local Anopheles vector species and targeted control interventions in the ‘hotspots’ is necessary to curb the prevalence of the infection and incidence of disease.

Annual distributions of insecticide-treated nets to schoolchildren and other key populations to maintain higher ITN access than with mass campaigns: a modelling study for mainland Tanzania

BackgroundSince 2013, the National Malaria Control Programme in mainland Tanzania has deployed annual distributions of insecticide-treated nets (ITNs) through primary schools to maintain ITN access and use. This School Net Programme (SNP) is slated to be used throughout mainland Tanzania by 2023. This modelling study projects ITN access under different ITN distribution strategies and quantification approaches.MethodsA stock and flow model with a Tanzania-specific ITN decay rate was used to calculate annual net crops for four different ITN distribution strategies, varying quantification approaches within each strategy. Annual nets-per-capita (NPC) was derived from net crop and a standardized population projection. Nonparametric conditional quartile functions for the proportion of the population with access to an ITN (ITN access) as a function of NPC were used to predict ITN access and its variability. The number of ITNs required under the varying quantification approaches for the period 2022–2030 was calculated.ResultsAnnual SNP quantified using a “population times 15%” approach maintained ITN access between 80 and 90%, when combined with reproductive and child health (RCH) ITN distribution, requiring 133.2 million ITNs. The same strategy quantified with “population times 22%” maintained ITN access at or above 90%, requiring 175.5 million ITNs. Under 5-year mass campaigns with RCH distribution for pregnant women and infants, ITN access reached 90% post-campaign and fell to 27–35% in the 4th year post-campaign, requiring 120.5 million ITNs over 8 years. 3-yearly mass campaigns with RCH reached 100% ITN access post-campaign and fell to 70% in the 3rd year post-campaign, requiring 154.4 million ITNs.ConclusionGiven an ITN retention time in Tanzania of 2.15 years, the model predicts that mass campaigns conducted every 3 years in mainland Tanzania will not maintain ITN access at target levels of 80%, even with strong RCH channels. Mainland Tanzania can however expect to maintain ITN access at 80% or above by quantifying SNP using “population × 15%”, in addition to RCH ITN delivery. This strategy requires 14% fewer ITNs than a 3-year campaign strategy while providing more consistent ITN coverage. Meeting the targets of 80% ITN use would require maintaining 90% ITN access, achievable using a “population times 22%” quantification approach for SNP.

High parasitaemia correlates with malaria episodes and the socioeconomic impact of recurrent malaria infection in high-transmission zone of Nigeria

BackgroundRecurrent malaria infection is a major phenomenon in a hightransmission zone with deplorable health and socioeconomic consequences on individuals and the public. However, the association between parasitaemia, repeated episodes of the infection, and its socioeconomic impact is less studied. Therefore, this study aimed at bridging this research gap by conducting an epidemiological survey in selected malaria-endemic settings of Kwara state, Nigeria.ResultsHigh prevalence and intensity of infection were observed, 56.6% of 572 study participants were infected with average parasitaemia of 3022.25 ± 1001.51 per µl of blood and the majority of heavy infection was due to Plasmodium falciparum. The heavily asymptomatic infected participants were among the younger age group particularly ≤ 20 years, and infection decreases with increasing age. Parasitaemia and the number of episodes of malaria attacks were positively correlated (R2 = 0.2388, p < 0.0001). Highrecurrent malaria was associated with male (p = 0.001), younger age (p = 0.0012), low-income status (p = 0.0004), bush around habitation (0.0014), and unavoidability of preventive strategies and treatment (p < 0.0001) of malaria. Our study further revealed socioeconomic factors as cause and/or consequence of recurrent malaria infection. Low income individuals (aOR 1.948 95%CI 0.945–2.512) and illiterates (aOR 1.920 95%CI 1.470–2.149), those living close to bush (aOR 2.501 95%CI 2.033–3.714) and dumpsite (aOR 2.718 95%CI 1.661–3.118) are at least twice likely to have recurrent infection. The socioeconomic consequence of recurrent malaria episodes includes reduced economic activities, personal savings, and change of lifestyle in adults, while infected children suffered declined academic performance and sports activities.ConclusionsThis study underscores high malaria intensity as a prevalent health problem in our study location and demonstrates a positive correlation between malaria episodes and parasitaemia which can be explored in the clinic for the screening of suitable antimalarial drugs that cure beyond a single infection. Our finding also advocates for mass distribution of insecticide-treated nets, provision of socio-infrastructural amenities such as medical centers, good drainage system and highly subsidized malaria treatment in endemic endemic rural communities

Impact of mass distribution of insecticide-treated nets in Mozambique, 2012 to 2025: Estimates of child lives saved using the Lives Saved Tool.

Malaria was the leading cause of post-neonatal deaths in Mozambique in 2017. The use of insecticide treated nets (ITNs) is recognized as one of the most effective ways to reduce malaria mortality in children. No previous analyses have estimated changes in mortality attributable to the scale-up of ITNs, accounting for provincial differences in mortality rates and coverage of health interventions. Based upon annual provincial ownership coverage of ITNs, the Lives Saved Tool (LiST), a multi-cause mathematical model, estimated under-5 lives saved attributable to increased household ITN coverage in 10 provinces of Mozambique between 2012 and 2018, and projected lives saved from 2019 to 2025 if 2018 coverage levels are sustained. An estimated 14,040 under-5 child deaths were averted between 2012 and 2018. If 2018 coverage levels are maintained until 2025, an additional 33,277 child deaths could be avoided. If coverage reaches at least 85% in all ten provinces by 2022, then a projected 36,063 child lives can be saved. From 2012 to 2018, the estimated number of lives saved was highest in Zambezia and Tete provinces. Increases in ITN coverage can save a substantial number of child lives in Mozambique. Without continued investment, thousands of avoidable child deaths will occur.

A practical approach for geographic prioritization and targeting of insecticide-treated net distribution campaigns during public health emergencies and in resource-limited settings

BackgroundThe use of data in targeting malaria control efforts is essential for optimal use of resources. This work provides a practical mechanism for prioritizing geographic areas for insecticide-treated net (ITN) distribution campaigns in settings with limited resources.MethodsA GIS-based weighted approach was adopted to categorize and rank administrative units based on data that can be applied in various country contexts where Plasmodium falciparum transmission is reported. Malaria intervention and risk factors were used to rank local government areas (LGAs) in Nigeria for prioritization during mass ITN distribution campaigns. Each factor was assigned a unique weight that was obtained through application of the analytic hierarchy process (AHP). The weight was then multiplied by a value based on natural groupings inherent in the data, or the presence or absence of a given intervention. Risk scores for each factor were then summated to generate a composite unique risk score for each LGA. This risk score was translated into a prioritization map which ranks each LGA from low to high priority in terms of timing of ITN distributions.ResultsA case study using data from Nigeria showed that a major component that influenced the prioritization scheme was ITN access. Sensitivity analysis results indicate that changes to the methodology used to quantify ITN access did not modify outputs substantially. Some 120 LGAs were categorized as ‘extremely high’ or ‘high’ priority when a spatially interpolated ITN access layer was used. When prioritization scores were calculated using DHS-reported state level ITN access, 108 (90.0%) of the 120 LGAs were also categorized as being extremely high or high priority. The geospatial heterogeneity found among input risk factors suggests that a range of variables and covariates should be considered when using data to inform ITN distributions.ConclusionThe authors provide a tool for prioritizing regions in terms of timing of ITN distributions. It serves as a base upon which a wider range of vector control interventions could be targeted. Its value added can be found in its potential for application in multiple country contexts, expediated timeframe for producing outputs, and its use of systematically collected malaria indicators in informing prioritization.

Factors affecting usage of insecticide treated nets for malaria control by pregnant women in Enugu, South East Nigeria.

The National Malaria Strategic Plan (NMSP) was set up to ensure transition from malaria control to malaria elimination in Nigeria. One of the targets was to reduce malaria-related mortality by 50% by the year 2020, by ensuring that at least 80% of the targeted populations utilize appropriate preventive measures. This study was aimed at reviewing the success of insecticide treated net (ITN) malaria control efforts and understanding the failures and the need to boost up the intervention measures. The research design used for this study was the descriptive method. Structured questionnaires were used to collect data from 316 pregnant women receiving antenatal care at the Federal Teaching Hospital Abakaliki. Amongst the respondents, 180 (57.0%) owned an ITN while 136 (43.0%) did not. A greater percentage (72.9%) of those who used the ITNs purchased their nets, only 8.4% of mothers who received their ITNs free of charge used the net (P=0.159). Dislike by spouses (63.3%), hot weather discomfort (17.8%) and forgetfulness (17.2%) were some of the factors that contributed to failures of net usage by the pregnant women. Cost Free distribution of ITN did not necessarily improve usage. Rather, success of this strategy will require carrying out more awareness campaign.

The effect of a mass distribution of insecticide-treated nets on insecticide resistance and entomological inoculation rates of Anopheles gambiae s.l. in Bandundu City, Democratic Repub`lic of Congo.

Introductioninsecticide-treated nets (ITNs) remain the mainstay of malaria vector control in the Democratic Republic of Congo. However, insecticide resistance of malaria vectors threatens their effectiveness. Entomological inoculation rates and insecticide susceptibility in Anopheles gambiae s.l. were evaluated before and after mass distribution of ITNs in Bandundu City for possible occurrence of resistance.Methodsa cross-sectional study was conducted from 15th July 2015 to 15th June 2016. Adult mosquitoes were collected using pyrethrum spray catches and human landing catches and identified to species level and tested for the presence of sporozoites. Bioassays were carried out before and after distribution of ITNs to assess the susceptibility of adult mosquitoes to insecticides. Synergist bioassays were also conducted and target site mutations assessed using Polymerase chain reaction (PCR).Resultsa total of 1754 female An. gambiae s.l. were collected before and after deployment of ITNs. Fewer mosquitoes were collected after the distribution of ITNs. However, there was no significant difference in sporozoite rates or the overall entomological inoculation rate before and after the distribution of ITNs. Test-mosquitoes were resistant to deltamethrin, permethrin, and Dichlorodiphenyltrichloroethane but susceptible to bendiocarb. Pre-exposure of mosquitoes to Piperonyl butoxide increased their mortality after exposure to permethrin and deltamethrin. The frequency of the Kinase insert domain receptor (kdr)-West gene increased from 92 to 99% before and after the distribution of nets, respectively.Conclusionseasonal impacts could be a limiting factor in the analysis of these data; however, the lack of decrease in transmission after the distribution of new nets could be explained by the high-level of resistance to pyrethroid.

Time-Varying Effects of Meteorological Variables on Malaria Epidemiology in the Context of Interrupted Control Efforts in the Amazon Rainforest, 2000-2017.

Successful malaria control interventions, mostly based on the training of health workers, distribution of insecticide-treated nets, and spraying, decrease malaria incidence; however, when these interventions are interrupted, a resurgence may occur. In the Peruvian Amazon, after discontinuing the control activities implemented by the PAMAFRO project (2006–2010)-a Global Fund-sponsored project for the strengthening of malaria control and surveillance in multiple countries in Latin America– malaria cases re-emerged dramatically. In parallel, meteorological factors determine the conditions suitable for the development, reproduction, and survival of mosquito vectors and parasites. This study hypothesized that interruption of malaria interventions may have modified the meteorological-malaria relationships over time (i.e., temporal changes in the dose-response between meteorological variables and malaria incidence). In this panel data analysis, we assessed the extent that relationships between meteorological variables and malaria changed temporally using data of monthly malaria incidence due to Plasmodium vivax or P. falciparum in Loreto, Peru (2000–2017). Generalized additive models were used to explore how the effects of meteorological variables changed in magnitude before, during, and after the PAMAFRO intervention. We found that once the PAMAFRO intervention had been interrupted, the estimated effects (dose-response) of meteorological variables on incidence rates decreased for both malaria parasite species. However, these fitted effect estimates did not reach their baseline levels (before the PAMAFRO period); variations of time-varying slopes between 0.45 and 2.07 times were observed after the PAMAFRO intervention. We also reported significant heterogeneity in the geographical distributions of malaria, parasite species, and meteorological variables. High malaria transmission occurred consistently in the northwestern provinces of Loreto Department. Since the end of the PAMAFRO period, a higher effect of precipitation and actual evapotranspiration was described on P. falciparum compared to P. vivax. The effect of temperature on malaria was greater over a shorter time (1-month lag or less), compared with precipitation and actual evapotranspiration (12-month lag). These findings demonstrate the importance of sustained malaria control efforts since interruption may enhance the links between meteorological factors and malaria. Our results also emphasize the importance of considering the time-varying effect of meteorological factors on malaria incidence to tailor control interventions, especially to better manage the current and future climate change crisis.

Insecticide-treated net distribution in Western Kenya: impacts related to COVID-19 and health worker strikes.

We examined the impact of coronavirus disease (COVID) mitigation, supply and distribution interruptions on the delivery of long-lasting insecticide-treated nets (LLINs) in Western Kenya. The median monthly distribution of LLINs declined during COVID mitigation strategies (March–July 2020) and during the health worker strikes (December 2020–February 2021). Recovery periods followed initial declines, indicative of a ‘catching up’ on missed routine distribution. Mass community campaigns were delayed by 10 months. These observations offer encouragement for routine net distribution resilience, but complete interruptions of planned mass distributions require alternate strategies during pandemics.

Determination of the discriminating concentration of chlorfenapyr (pyrrole) and Anopheles gambiae sensu lato susceptibility testing in preparation for distribution of Interceptor\xae G2 insecticide-treated nets

BackgroundFollowing agricultural use and large-scale distribution of insecticide-treated nets (ITNs), malaria vector resistance to pyrethroids is widespread in sub-Saharan Africa. Interceptor® G2 is a new dual active ingredient (AI) ITN treated with alpha-cypermethrin and chlorfenapyr for the control of pyrethroid-resistant malaria vectors. In anticipation of these new nets being more widely distributed, testing was conducted to develop a chlorfenapyr susceptibility bioassay protocol and gather susceptibility information.MethodsBottle bioassay tests were conducted using five concentrations of chlorfenapyr at 12.5, 25, 50, 100, and 200 µg AI/bottle in 10 countries in sub-Saharan Africa using 13,639 wild-collected Anopheles gambiae sensu lato (s.l.) (56 vector populations per dose) and 4,494 pyrethroid-susceptible insectary mosquitoes from 8 colonized strains. In parallel, susceptibility tests were conducted using a provisional discriminating concentration of 100 µg AI/bottle in 16 countries using 23,422 wild-collected, pyrethroid-resistant An. gambiae s.l. (259 vector populations). Exposure time was 60 min, with mortality recorded at 24, 48 and 72 h after exposure.ResultsMedian mortality rates (up to 72 h after exposure) of insectary colony mosquitoes was 100% at all five concentrations tested, but the lowest dose to kill all mosquitoes tested was 50 µg AI/bottle. The median 72-h mortality of wild An. gambiae s.l. in 10 countries was 71.5, 90.5, 96.5, 100, and 100% at concentrations of 12.5, 25, 50, 100, and 200 µg AI/bottle, respectively. Log-probit analysis of the five concentrations tested determined that the LC95 of wild An. gambiae s.l. was 67.9 µg AI/bottle (95% CI: 48.8–119.5). The discriminating concentration of 203.8 µg AI/bottle (95% CI: 146–359) was calculated by multiplying the LC95 by three. However, the difference in mortality between 100 and 200 µg AI/bottle was minimal and large-scale testing using 100 µg AI/bottle with wild An. gambiae s.l. in 16 countries showed that this concentration was generally suitable, with a median mortality rate of 100% at 72 h.ConclusionsThis study determined that 100 or 200 µg AI/bottle chlorfenapyr in bottle bioassays are suitable discriminating concentrations for monitoring susceptibility of wild An. gambiae s.l., using mortality recorded up to 72 h. Testing in 16 countries in sub-Saharan Africa demonstrated vector susceptibility to chlorfenapyr, including mosquitoes with multiple resistance mechanisms to pyrethroids.

Malaria prevention knowledge, attitudes, and practices in Zambezia Province, Mozambique

BackgroundIn Mozambique, socio-economic and cultural factors influence the wide adoption of disease preventive measures that are relevant for malaria control strategies to promote early recognition of disease, prompt seeking of medical care, sleeping under insecticide-treated nets (ITNs), and taking intermittent preventive treatment for pregnant women. However, there is a critical information gap regarding previous and ongoing malaria social and behavioural change (SBC) interventions. The aim of this study is to assess the knowledge, attitudes, practices of beneficiaries of SBC interventions.MethodsA descriptive cross-sectional survey was undertaken in 2018 in two rural districts of Zambezia Province, Mozambique. A structured questionnaire was administered to 773 randomly selected households. Respondents were the adult heads of the households. Descriptive statistics were done.ResultsThe main results show that 96.4% of respondents recalled hearing about malaria in the previous 6 months, 90.0% had knowledge of malaria prevention, and 70.0% of preventive measures. Of the 97.7% respondents that had received ITNs through a mass ITN distribution campaign, 81.7% had slept under an ITN the night before the survey. In terms of source of health information, 70.5% mentioned the role of community volunteers in dissemination of malaria prevention messages, 76.1% of respondents considered worship places (churches and mosques) to be the main places where they heard key malaria prevention messages, and 79.1% asserted that community dialogue sessions helped them better understand how to prevent malaria.ConclusionsResults show that volunteers/activists/teachers played an important role in dissemination of key malaria prevention messages, which brought the following successes: community actors are recognized and people have knowledge of malaria transmission, signs and symptoms, preventive measures, and where to get treatment. There is, however, room for improvement on SBC messaging regarding some malaria symptoms (anaemia and convulsions) and operational research is needed to ascertain the drivers of malaria prevalence and inform the SBC approach.

Modeling the relationship between malaria prevalence and insecticide-treated bed net coverage in Nigeria using a Bayesian spatial generalized linear mixed model with a Leroux prior

OBJECTIVESTo evaluate malaria transmission in relation to insecticide-treated net (ITN) coverage in Nigeria.METHODSWe used an exploratory analysis approach to evaluate variation in malaria transmission in relation to ITN distribution in 1,325 Demographic and Health Survey clusters in Nigeria. A Bayesian spatial generalized linear mixed model with a Leroux conditional autoregressive prior for the random effects was used to model the spatial and contextual variation in malaria prevalence and ITN distribution after adjusting for environmental variables.RESULTSSpatial smoothed maps showed the nationwide distribution of malaria and ITN. The distribution of ITN varied significantly across the 6 geopolitical zones (p<0.05). The North-East had the least ITN distribution (0.196±0.071), while ITN distribution was highest in the South-South (0.309±0.075). ITN coverage was also higher in rural areas (0.281±0.074) than in urban areas (0.240±0.096, p<0.05). The Bayesian hierarchical regression results showed a non-significant negative relationship between malaria prevalence and ITN coverage, but a significant spatial structured random effect and unstructured random effect. The correlates of malaria transmission included rainfall, maximum temperature, and proximity to water.CONCLUSIONSReduction in malaria transmission was not significantly related to ITN coverage, although much could be achieved in attempts to curtail malaria transmission through enhanced ITN coverage. A multifaceted and integrated approach to malaria control is strongly advocated.