Long-lasting Insecticidal Nets Usage Research Articles

Barriers of persistent long-lasting insecticidal nets utilization in Northwest Ethiopia: a qualitative study

BackgroundMalaria continues a significant public health challenge in Ethiopia, with Long-Lasting Insecticidal Nets (LLINs) proving effective in reducing transmission. Despite their effectiveness, consistent LLIN utilization is influenced by various factors. While previous research has quantitatively analyzed LLIN ownership and usage, there is a lack of in-depth examination of the behavioral, sociocultural, socioeconomic, and distribution-related factors affecting their sustained use. This study aimed to explore barriers to persistent LLIN use among communities in northwest Ethiopia.MethodsThe study area found in Northwest Ethiopia, specifically in East Belessa District, is located at 12° 14’ 60.00” N latitude and 37° 44’ 59.99” E longitude, with an altitude between 1,200 and 1,800 m above sea level. Thirty-nine community members from five focus group discussions, along with five key informants, were interviewed between February 1st and 30th, 2020, about their use of Long-Lasting Insecticidal Nets (LLINs). An interpretive description approach was employed to explore local contexts and factors affecting LLIN utilization. Focus group participants were selected based on residency status, pregnancy, caretaking of under-five children, and experience with LLINs. Key informants included health extension workers and the woreda malaria officer. Data were organized and analyzed using Open Code Version 4.03 software, with coding and theme identification conducted accordingly.ResultsAll 44 community members from the five focus group discussions and the five key informants participated fully in the study. The study categorized its findings into three main themes: knowledge of malaria and Long-Lasting Insecticidal Nets (LLIN) use, perception of malaria threat, and barriers to sustained LLIN utilization. It identified factors spanning individual, socio-cultural, institutional, and socio-economic realms that impede consistent LLIN usage. Key hindrances include cultural misinterpretations, discomfort from heat and bed bugs, diverse net shapes, insufficient sleeping spaces, lack of awareness, inadequate distribution, neglect of vulnerable groups, misuse of non-sleeping purposes, hesitancy to hang nets, and restricted accessibility.ConclusionsThis study reveals that practical concerns, including inadequate access to LLINs, distribution issues, discomfort from net shape and warmth, and unintended uses for non-malaria purposes, impact LLIN utilization. Socio-cultural norms, housing conditions, and varied understanding of malaria also contribute to inconsistent LLIN use. Strategies like providing compatible nets and comprehensive education could improve the Long-Lasting Insecticidal Nets program’s effectiveness in the area.

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

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

Healthcare innovation adoption in Africa: the case of long-lasting insecticide nets in Ghana using protection motivation theory

Objective Studies have shown that healthcare innovation adoption is complex. Using Long-lasting insecticidal nets (LLINs), an innovation for malaria prevention, the study aimed to understand factors considered in the adoption of healthcare innovations in Africa. Methods and Measures Using qualitative methods, we interviewed 10 household heads in Ghana who had freely received LLINs during a malaria campaign. We analyzed our data using a deductive thematic analysis approach utilizing the protection motivation theory (PMT) as our framework. Results We found that the constructs of PMT: perceived severity, perceived vulnerability, perceived response efficacy, and perceived self-efficacy influenced the adoption of healthcare innovation (i.e. LLINs). We also found that misconceptions about malaria infection and prevention influenced the perceived response efficacy of LLINs which could undermine LLINs usage. Conclusion The constructs of PMT are important in the decision to use LLINs. Misconceptions about malaria infection and prevention could undermine the decision to use LLINs. Future studies should investigate ways to address these misconceptions.

Long-Lasting Insecticidal Net Coverage and Utilization in Burla Town of Sambalpur District: A Cross-Sectional Study.

Background Vector-borne diseases continue to significantly contribute to mortality and morbidity, especially in developing nations. Vector management is a key pillar in combating these diseases, and long-lasting insecticidal nets (LLINs) are cost-effective tools. The Government of India, under the National Vector Borne Disease Control Programme (NVBDCP), has distributed LLINs for free to increase coverage and utilization. This study aims to estimate the coverage and utilization of LLINs in Burla town. Method This cross-sectional study was conducted from October to December 2022 in Burla town of Sambalpur in Odisha, India. The estimated sample size was 510 households, assuming 50% coverage. Multi-stage cluster sampling was adopted to select the Anganwadi centers and households. A pretested questionnaire was utilized for data collection by trained personnel through Epicollect5 (Centre for Genomic Pathogen Surveillance, Oxford, UK). Logistic regression was used to identify predictors for LLIN usage. Results The survey covered 516 households with 2,541 individuals and 1,165 nets. Household-level coverage was 94.2%, and regular utilization was 45.74%. Skin reactions (35.7%) were the most common reason for non-usage, followed by low mosquito density (12%). Logistic regression showed that the number of rooms (adjusted odds ratio (AOR) = 0.663, p = 0.012), number of bed nets (AOR = 2.757, p < 0.001), knowledge of malaria (AOR = 2.92, p = 0.04), adopting other measures for mosquito control (AOR = 0.295, p < 0.001), and washing the net (AOR =1.92, p = 0.028) significantly predicted sleeping under mosquito net. Conclusion Our study has depicted high coverage of LLINs in Burla town, but utilization needs further improvement. Counseling regarding proper use can decrease the skin reactions responsible for non-usage. Regular health education programs are required to emphasize the benefits of LLIN use, along with regular monitoring and supervision.

Predictors of Daily Utilization of Long-Lasting Insecticidal Nets for Malaria Prevention in Pregnancy among Antenatal Care Recipients in Southern Nigeria

Malaria remains a significant public health concern, particularly among pregnant women in sub-Saharan Africa. Long Lasting Insecticidal Nets (LLINs) have been recognized as an effective preventive measure against malaria transmission. However, the utilization of LLINs among pregnant women remains suboptimal. This study aimed to assess the level of daily LLIN utilization and identify its predictors among pregnant women receiving antenatal care in a tertiary healthcare centre in Southern Nigeria. A cross-sectional study was conducted among antenatal recipients at the University of Uyo Teaching Hospital in Uyo, AkwaIbom State. A total of 323 respondents were recruited for the study. Data were collected using a pre-tested semi-structured questionnaire. Multivariable logistic regression analyses were performed to identify predictors of daily LLIN usage. One hundred and twenty seven (39.3%) of the respondents had ever slept inside a LLIN during the index pregnancy, while 22.6% reported daily usage. LLIN ownership was reported by 47.7% of the respondents, highlighting a discrepancy between ownership and consistent use. Predictors of daily LLIN usage included LLIN ownership (aOR 3.83, 95% CI 1.95-7.48), absence of discomfort during LLIN use (aOR 9.33,95%CI 4.32-20.17), non-use of other malaria preventive measures (aOR 3.7,95% CI 11.51-8.93) and presence of mosquitoes in home dwelling (aOR 3.56 95%CI 1.35-9.37). Health education campaigns should emphasize the benefits of daily LLIN usage during pregnancy. Policy interventions are warranted to increase LLIN distribution and availability to pregnant women through antenatal care clinics.

Community-level impacts of the coronavirus pandemic on malaria prevention and health-seeking behaviours in rural Benin: A mixed methods study.

Globally, negative impacts of the COVID-19 pandemic on malaria prevention and control efforts have been caused by delayed distributions of long-lasting insecticidal nets (LLIN), decreased outpatient attendance, and disruptions to malaria testing and treatment. Using a mixed methods approach, we aimed to evaluate the impact of COVID-19 on community-level malaria prevention and health-seeking practices in Benin more than one year after the start of the COVID-19 pandemic. We collected data through community-based cross-sectional surveys with 4200 households and ten focus group discussions (FGDs). Mixed effect logistic regression models accounting for a clustered sampling design were used to identify variables associated with main outcomes (good COVID-19 knowledge, LLIN usage and access, and avoidance of health centres). Consistent with the experiences of FGD participants, receiving information from radios or televisions was significantly associated with good COVID-19 knowledge and avoiding health centres because of the pandemic (p<0.001 for both). Qualitative findings also revealed varying and polarizing changes in health-seeking behaviours with participants noting that they either did not change their health-seeking behaviours or went to health centres less or more often because of the pandemic. LLIN usage and access did not decrease in the study area because of the pandemic (LLIN usage: 88% in 2019 to 99.9% in 2021; LLIN access: 62% in 2019 to 73% in 2021). An unexpected change and unintended challenge for sustained malaria prevention included families socially distancing in their homes, resulting in a shortage of LLINs. Our findings showed that there were minimal community-level impacts of the coronavirus pandemic on malaria prevention and health seeking behaviours in rural Benin, which highlights the importance of efforts to sustain malaria prevention and control interventions in the context of the COVID-19 pandemic.

Asymptomatic Plasmodium Infection and Associated Factors in Selected Districts of the Kaffa Zone, Southwest Ethiopia: A Cross-Sectional Study.

Malaria remains a serious public health problem, particularly in resource scarce areas of the world. The number of malaria cases has dropped remarkably in Ethiopia over the last decade, and efforts to eliminate the disease are underway. Asymptomatic infections may pose significant challenges to the elimination program. The essence of this study was to assess the prevalence of asymptomatic Plasmodium infection and the associated factors among communities of the selected districts in the Kaffa zone. April to May and September to October 2021, were the two seasons in which the community-based cross-sectional survey was conducted. Capillary blood from a finger prick was examined by light microscopy (LM) and screened using rapid diagnostic tests (RDTs). The participants' sociodemographic characteristics and malaria prevention measures were collected using a pretested semistructured questionnaire. Data entry and analyses were carried out using EpiData and SPSS version 25.0. Logistic regression (bivariate and multivariable) analyses were carried out to assess the possible associations between the dependent variable and the associated factors. 566 study participants were involved in the two cross-sectional surveys, including 234 male and 332 female subjects with a mean age of 18.486 (SD ± 15.167). Thirty-eight blood samples (6.7%) were found to be positive for Plasmodium species tested by both LM and RDT. Last night's use of long-lasting insecticidal net (LLIN) (AOR = 2.448, 95% CI: 1.009 5.938, p=0.048), presence of eave (AOR = 4.144, 95% CI: 1.049-16.363, p=0.043), and house sprayed in the last year (AOR = 5.206, 95% CI: 2.176-12.455, p < 0.001) were among factors that showed significant association with asymptomatic Plasmodium infection. The asymptomatic Plasmodium infection prevalence recorded in the study area was low. Last night's LLIN usage, the presence of an eave, a house sprayed in the last year, and the presence of stagnant water near the home of the study participants were among the factors associated with an increased risk of catching the disease.

Quantifying the direct and indirect protection provided by insecticide treated bed nets against malaria

Long lasting insecticidal nets (LLINs) provide both direct and indirect protection against malaria. As pyrethroid resistance evolves in mosquito vectors, it will be useful to understand how the specific benefits LLINs afford individuals and communities may be affected. Here we use modelling to show that there is no minimum LLIN usage needed for users and non-users to benefit from community protection. Modelling results also indicate that pyrethroid resistance in local mosquitoes will likely diminish the direct and indirect benefits from insecticides, leaving the barrier effects intact, but LLINs are still expected to provide enhanced benefit over untreated nets even at high levels of pyrethroid resistance.

Efficacy of pyriproxyfen-pyrethroid long-lasting insecticidal nets (LLINs) and chlorfenapyr-pyrethroid LLINs compared with pyrethroid-only LLINs for malaria control in Benin: a cluster-randomised, superiority trial

New classes of long-lasting insecticidal nets (LLINs) combining mixtures of insecticides with different modes of action could put malaria control back on track after rebounds in transmission across sub-Saharan Africa. We evaluated the relative efficacy of pyriproxyfen-pyrethroid LLINs and chlorfenapyr-pyrethroid LLINs compared with standard LLINs against malaria transmission in an area of high pyrethroid resistance in Benin. We conducted a cluster-randomised, superiority trial in Zou Department, Benin. Clusters were villages or groups of villages with a minimum of 100 houses. We used restricted randomisation to randomly assign 60 clusters to one of three LLIN groups (1:1:1): to receive nets containing either pyriproxyfen and alpha-cypermethrin (pyrethroid), chlorfenapyr and alpha-cypermethrin, or alpha-cypermethrin only (reference). Households received one LLIN for every two people. The field team, laboratory staff, analyses team, and community members were masked to the group allocation. The primary outcome was malaria case incidence measured over 2 years after net distribution in a cohort of children aged 6 months-10 years, in the intention-to-treat population. This study is ongoing and is registered with ClinicalTrials.gov, NCT03931473. Between May 23 and June 24, 2019, 53 854 households and 216 289 inhabitants were accounted for in the initial census and included in the study. Between March 19 and 22, 2020, 115 323 LLINs were distributed to 54 030 households in an updated census. A cross-sectional survey showed that study LLIN usage was highest at 9 months after distribution (5532 [76·8%] of 7206 participants), but decreased by 24 months (4032 [60·6%] of 6654). Mean malaria incidence over 2 years after LLIN distribution was 1·03 cases per child-year (95% CI 0·96-1·09) in the pyrethroid-only LLIN reference group, 0·84 cases per child-year (0·78-0·90) in the pyriproxyfen-pyrethroid LLIN group (hazard ratio [HR] 0·86, 95% CI 0·65-1·14; p=0·28), and 0·56 cases per child-year (0·51-0·61) in the chlorfenapyr-pyrethroid LLIN group (HR 0·54, 95% CI 0·42-0·70; p<0·0001). Over 2 years, chlorfenapyr-pyrethroid LLINs provided greater protection from malaria than pyrethroid-only LLINs in an area with pyrethroid-resistant mosquitoes. Pyriproxyfen-pyrethroid LLINs conferred protection similar to pyrethroid-only LLINs. These findings provide crucial second-trial evidence to enable WHO to make policy recommendations on these new LLIN classes. This study confirms the importance of chlorfenapyr as an LLIN treatment to control malaria in areas with pyrethroid-resistant vectors. However, an arsenal of new active ingredients is required for successful long-term resistance management, and additional innovations, including pyriproxyfen, need to be further investigated for effective vector control strategies. UNITAID, The Global Fund.

Durable wall lining for malaria control in Liberia: results of a cluster randomized trial

BackgroundMalaria control in Liberia depends upon universal coverage with pyrethroid-impregnated long-lasting insecticidal nets (LLINs). Despite regular mass distribution, LLIN coverage and usage is patchy. Pyrethroid resistance in malaria vectors may further reduce LLIN efficacy. Durable Wall Lining (DWL), a novel material treated with two non-pyrethroid class insecticides, was designed to be installed onto the surface of inner walls, and cover openings and ceiling surfaces of rural houses.ObjectivesAimTo determine the malaria control efficacy of DWL.Primary objectiveTo determine if DWL has an additional protective effect in an area of pyrethroid resistance.Secondary objectivesTo compare surface bio-availability of insecticides and entomological effectiveness over the study duration.DesignA cluster randomized trial.ParticipantsChildren aged 2–59 months.Control arm50 houses per 20 clusters, all of which received LLIN within the previous 12 months.Active arm50 houses per 20 experimental clusters, all of which received LLINs with the previous 12 months, and had internal walls and ceilings lined with DWL.RandomisationCluster villages were randomly allocated to control or active arms, and paired on 4 covariates.Main outcome measuresPrimary measurePrevalence of infection with P. falciparum in children aged 2 to 59 months.Secondary measureSurface bioavailability and entomological effectiveness of DWL active ingredients.ResultsPlasmodium falciparum prevalence in active clusters after 12 months was 34.6% compared to 40.1% in control clusters (p = 0.052). The effect varied with elevation and was significant (RR = 1.3, p = 0.022) in 14 pairs of upland villages. It was not significant (RR = 1.3, p = 0.344) in 6 pairs of coastal villages. Pooled risk ratio (RR) was calculated in SAS (Cary, NC, USA) using the Cochran–Mantel–Haenszel (CMH) test for upland and coastal cluster pairs. DWL efficacy was sustained at almost 100% for 12 months.ConclusionsFindings indicate that DWL is a scalable and effective malaria control intervention in stable transmission areas with pyrethroid-resistant vectors, where LLIN usage is difficult to achieve, and where local housing designs include large gable and eve openings.Trial registration ClinicalTrials.gov identifier: NCT02448745 (19 May 2015): https://clinicaltrials.gov/ct2/show/NCT02448745

Coverage and usage of insecticidal treated bed-nets for preventing malaria in four peri-urban communities of Ijebu-North, Southwest Nigeria

Sleeping under insecticidal treated bed-nets has been proven as an effective tool towards preventing mosquito bites and malaria but the burden of malaria cases seems to be on the increase. This study therefore assessed the limiting factors associated with ownership and usage of Long-Lasting Insecticidal Nets (LLINs) in four periurban communities in Ogun State, Nigeria. A total of 499 residents above age 15, were recruited and interviewed at the healthcare facilities in the selected communities using a well-structured questionnaire. Data obtained were analyzed using SPSS 25.0 version for descriptive and chisquare statistics, with significance set at 95%. Of the 499 residents, 72.1% (360/499) owned at least one LLIN, while only 56.7% (204/360) affirmed to sleeping under the bed net. Heat was a major reason for non-usage, 70/135 (51.9%) followed by harboring dust 40/135 (29.6%), skin irritation 16/135 (11.9%) and problem of hanging nets 2/135 (1.5%). There were significance differences between the challenges in the use of LLIN by the respondents and the peri-urban communities (p= 0.000). Majority of the respondents also reported LLIN abuse; 59/93 (63.4%) used them as window or door nets, 13/93 (13.9%) and 13/93 (13.9%) used them as fishing nets and as sieves and sponges respectively. Other uses included using it as a means of protection against rodents on the farm and as football goal nets. There was no significance difference between the abuse of LLINs by the respondents and the peri-urban communities (p= 0.209). The non-usage and abuse of LLIN will dampen the efforts targeted at controlling malaria in the southwestern region of Nigeria. It is therefore important that malaria control programmes incorporate health awareness campaigns targeted at promoting usage and disapproving the abuse of LLINs

Blood-feeding patterns of Anopheles vectors of human malaria in Malawi: implications for malaria transmission and effectiveness of LLIN interventions

BackgroundAccess to human hosts by Anopheles mosquitoes is a key determinant of vectorial capacity for malaria, but it can be limited by use of long-lasting insecticidal nets (LLINs). In Malawi, pyrethroid-treated LLINs with and without the synergist piperonyl butoxide (PBO) were distributed to control malaria. This study investigated the blood-feeding patterns of malaria vectors and whether LLINs containing pyrethroid and PBO led to a reduction of human blood feeding than those containing only pyrethroids.MethodsMosquitoes were sampled inside houses from May 2019 through April 2020 by aspiration, pyrethrum spray catch, and light trap methods in two sites. One site (Namanolo, Balaka district) had LLINs containing only pyrethroids whereas the other (Ntaja, Machinga district) had LLINs with both pyrethroids and PBO. Anopheles species, their blood-meal host, and infection with Plasmodium falciparum were determined using PCR methods.ResultsA total of 6585 female Anopheles were sampled in 203 houses. Of these, 633 (9.6%) were blood-fed mosquitoes comprising of 279 (44.1%) Anopheles arabiensis, 103 (16.3%) Anopheles gambiae 212 (33.5), Anopheles funestus, 2 (0.3%), Anopheles parensis and 37 (5.8%) were unidentified Anopheles spp. Blood meal hosts were successfully identified for 85.5% (n = 541) of the blood-fed mosquitoes, of which 436 (81.0%) were human blood meals, 28 (5.2%) were goats, 11 (2.0%) were dogs, 60 (11.1%) were mixed goat-human blood meals, 5 (0.9%) were dog–human, and 1 was a mixed dog-goat. Human blood index (fraction of blood meals that were humans) was significantly higher in Namanolo (0.96) than Ntaja (0.89). Even though human blood index was high, goats were over-selected than humans after accounting for relative abundance of both hosts. The number of infectious Anopheles bites per person-year was 44 in Namanolo and 22 in Ntaja.ConclusionAlthough LLINs with PBO PBO may have reduced human blood feeding, access to humans was extremely high despite high LLIN ownership and usage rates in both sites. This finding could explain persistently high rates of malaria infections in Malawi. However, this study had one village for each net type, thus the observed differences may have been a result of other factors present in each village.

Predictors of knowledge and use of long-lasting insecticidal nets for the prevention of malaria among the pregnant women in Pakistan

BackgroundMalaria is endemic to Pakistan with high prevalence among pregnant women and linked with maternal anaemia, intrauterine growth retardation, preterm birth, and low birth weight. The use of long-lasting insecticidal nets (LLINs) is a proven and cost-effective intervention preventing malaria among pregnant women. The present study aimed to explore predictors of knowledge and use of LLINs among pregnant women in Pakistan.MethodsThis was part of a quasi-experimental study of 200 pregnant women conducted in a rural district of Sindh province in Pakistan. Data were collected using Malaria Indicator Survey questionnaires developed by Roll Back Malaria Partnership to end Malaria Monitoring and Evaluation Reference Group. Pregnant women and mothers with newborns of six months of age were interviewed in their homes.ResultsThe age of the women was from 18 to 45, two thirds of the respondents (72.5%) were uneducated and married (77%). Majority (92%) of the women had received antenatal care during pregnancy, and 29.5% women had received counseling on malaria during their antenatal care visits. Multiple linear regression showed that the type of latrine was the most significant (β = 0.285, p < 0.001) determinant of knowledge about malaria among pregnant women followed by the death of a newborn (β = 0.271, p < 0.001). The use of mobile phone was the most significant (β = 0.247, p < 0.001) predictor of usage of LLINs among pregnant women followed by the death of a newborn (β = 0.232, p < 0.05).ConclusionsMaternal education, type of latrine, use of mobile phone, malaria during previous pregnancy and newborn death were strong predictors of knowledge and use of LLINs in pregnant women in Pakistan. There is a need to scale-up programmes that aim to create awareness regarding malaria among pregnant women. Mobile phone technology can be used to implement awareness programmes focusing on malaria prevention among women.

Pre-intervention characteristics of the mosquito species in Benin in preparation for a randomized controlled trial assessing the efficacy of dual active-ingredient long-lasting insecticidal nets for controlling insecticide-resistant malaria vectors.

This study provides detailed characteristics of vector populations in preparation for a three-arm cluster randomized controlled trial (RCT) aiming to compare the community impact of dual active-ingredient (AI) long-lasting insecticidal nets (LLINs) that combine two novel insecticide classes-chlorfenapyr or pyriproxifen-with alpha-cypermethrin to improve the prevention of malaria transmitted by insecticide-resistant vectors compared to standard pyrethroid LLINs. The study was carried out in 60 villages across Cove, Zangnanando and Ouinhi districts, southern Benin. Mosquito collections were performed using human landing catches (HLCs). After morphological identification, a sub-sample of Anopheles gambiae s.l. were dissected for parity, analyzed by PCR for species and presence of L1014F kdr mutation and by ELISA-CSP to identify Plasmodium falciparum sporozoite infection. WHO susceptibility tube tests were performed by exposing adult An. gambiae s.l., collected as larvae from each district, to 0.05% alphacypermethrin, 0.75% permethrin, 0.1% bendiocarb and 0.25% pirimiphos-methyl. Synergist assays were also conducted with exposure first to 4% PBO followed by alpha-cypermethrin. An. gambiae s.l. (n = 10807) was the main malaria vector complex found followed by Anopheles funestus s.l. (n = 397) and Anopheles nili (n = 82). An. gambiae s.l. was comprised of An. coluzzii (53.9%) and An. gambiae s.s. (46.1%), both displaying a frequency of the L1014F kdr mutation >80%. Although more than 80% of people slept under standard LLIN, human biting rate (HBR) in An. gambiae s.l. was higher indoors [26.5 bite/person/night (95% CI: 25.2-27.9)] than outdoors [18.5 b/p/n (95% CI: 17.4-19.6)], as were the trends for sporozoite rate (SR) [2.9% (95% CI: 1.7-4.8) vs 1.8% (95% CI: 0.6-3.8)] and entomological inoculation rate (EIR) [21.6 infected bites/person/month (95% CI: 20.4-22.8) vs 5.4 (95% CI: 4.8-6.0)]. Parous rate was 81.6% (95%CI: 75.4-88.4). An. gambiae s.l. was resistant to alpha-cypermethrin and permethrin but, fully susceptible to bendiocarb and pirimiphos-methyl. PBO pre-exposure followed by alpha-cypermethrin treatment induced a higher 24 hours mortality compared to alphacypermethrin alone but not exceeding 40%. Despite a high usage of standard pyrethroid LLINs, the study area is characterized by intense malaria transmission. The main vectors An. coluzzii and An. gambiae s.s. were both highly resistant to pyrethroids and displayed multiple resistance mechanisms, L1014F kdr mutation and mixed function oxidases. These conditions of the study area make it an appropriate site to conduct the trial that aims to assess the effect of novel dual-AI LLINs on malaria transmitted by insecticide-resistant vectors.

Improvement of Indoor Residual Spraying and Long\u2010Lasting Insecticidal Net services through structured monitoring and supervision as part of the Malaria Elimination Demonstration Project in Mandla, Madhya Pradesh

BackgroundThe Government of Madhya Pradesh employed Indoor Residual Spraying (IRS) with alpha-cypermethrin synthetic pyrethroids in sub-centres with Annual Parasite Incidence (API) from 2 to 4.99. In sub-centres with API more than 5, Long-Lasting Insecticidal Nets (LLINs) were distributed. At the request of the State Government, the Malaria Elimination Demonstration Project (MEDP) staff observed and provided support to both IRS and LLINs campaigns. In the year 2017, the study team monitored only the IRS campaigns, however, in the year 2018, the supportive supervision was provided to the IRS campaign teams along with post-distribution monitoring of the LLINs.MethodsThe study was carried out during IRS spraying using a pre-tested, closed-ended monitoring checklist which consisted of two parts- observations of spraying team and observation of sprayed houses. For LLINs, a sample of the households that received the bed nets was taken for the study. For IRS, the spraying teams were monitored for quality and technique for a total of 159 times in 2017 and 183 times in the year 2018, respectively. For post spraying observations, a total of 1261 and 1791 households were observed in the years 2017 and 2018, respectively. The use of LLINs was observed in 5 % of the households in 2018 and 2020, which is about 2,000 houses in each survey where each house received about 2.5 LLINs per household. The results of surveys were compared to assess impact of supportive supervision and monitoring.ResultsSignificant improvement was noted after supportive supervision in year 2018 in various aspects of spraying. Preparedness of spraying, such as advance information to villagers, presence of equipment and records improved by up to 70 %. The methodology of spraying preparation improved from 50 to 90 %, spraying technique improved from 54 to 80 %, and proper use equipment during spraying improved from 51 to 92 %. After eight months post distribution of the LLINs in 2019, improvement was seen in regular usage of LLINs by 28 %. It was found that on-spot demonstrations during distribution and carrying of LLINs when sleeping outside homes increased by 56 %. Results of IEC campaigns revealed the reduction in adverse effects by 64 % and increase in awareness by 97 %.ConclusionsEffective supervision improved the quality of IRS and usage of LLINs in the study area. Based on these results, continued training and monitoring of staff that is deployed to spraying houses and distribute bed nets was suggested. The study also revealed that proper IEC/BCC drives help increase community acceptance of vector control measures and their rational usage.

Study of Epidemiological Behaviour of Malaria and Its Control in the Purulia District of West Bengal, India (2016-2020)

Background: Purulia is a malaria-prone district in West Bengal, India, with approximately half of the jurisdictional blocks defined as malaria endemic. Methods: We examined the malaria incidence in each block of the district of Purulia for the period between January 1, 2016 and December 31, 2020. Per the Annual Parasite Incidence (API), 20 blocks of Purulia district were assigned to four different categories (0-3) and mapped using ArcGIS software version 10.8. An exponential decay model was fitted to forecast the trend of malaria cases for each block of the district for the 2021-2025 timeline. Findings: There was a sharp decrease in total malaria cases and API from 2016 to 2020. Plasmodium vivax (Pv) cases were decreased by 96.43%, Plasmodium falciparum (Pf) by 90.34%, and mixed infection cases by 92.78%. The majority of cases (72.63%) were found in the 15 year and older age group. Males were more prone to malaria (60.09%) than females. Malaria was highly prevalent among Scheduled Tribes (ST) (48.44%). Six blocks were reported in Category 3 (high risk) and none in Category 0 (no risk) in 2016 while no blocks were determined to be in Category 3 and three blocks were in Category 0 in 2020. The exponential decay model prediction is oriented towards gaining malaria-free status in thirteen blocks of the Purulia district by 2025. Interpretation: By efficiently diagnosing malaria, implementing a GIS system to track malaria incidences, fair usage of Long-lasting insecticidal nets (LLINs), and conducting effective awareness campaigns, malaria control could be possible. Nevertheless, consistent funding is needed to avoid reappearance and sustain eradication goals. Funding Information: None. Declaration of Interests: We declare no competing interests. Ethics Approval Statement: This study was permitted by Zilla Swasthya Bhawan, Purulia, Govt. of West Bengal (Memo No. 2041; Dated: 03.11.2020).

Varying levels of protection against Plasmodium falciparium infection were conferred on non-users of long lasting insecticidal nets (LLINS) sleeping in rooms where different number of LLINS were hung in hyper endemic state of West Africa.

The use of Long Lasting Insecticidal Nets (LLINs) has greatly reduced the health and economic impact posed by malaria. This study evaluated the residual effect of LLINs on malaria parasite infections among non-LLIN users sleeping in rooms where nets were hung. This study was carried out at Federal University of Agriculture Abeokuta, Ogun State, Nigeria. A total of 259 students were systematically recruited into this study and were classified into two groups of LLINs users and non-users. The LLIN users were further classified according to the proportion of net usage and this includes; < 50%, exactly 50% and > 50% respectively. Finger prick blood samples were collected from the participants and microscopically analysed for the presence of parasites. Demographic characteristics were also recorded. A general prevalence of 40.5% positivity for malaria was recorded among the study population. A significantly high prevalence (p < 0.05) of malaria was recorded among non-users of LLINs compared to users (AOR 4.66, 95%CI 1.27-17.06). A significantly low prevalence of malaria parasite infection was recorded among non-users of LLINs occupying rooms where LLINs was hung compared with non-users from rooms where LLIN were not used. Furthermore, a reduction in prevalence of malaria and parasite densities was observed among non-users of LLINs (occupying rooms where LLINs was hung) as the proportion of LLIN usage increased in such rooms (p < 0.05). This study showed that some level of protection may be conferred on non-users of LLINs staying in rooms where LLINs are hung.

Evidence of high bed net usage from a list randomization experiment in rural Gambia

BackgroundRecording behaviours that have the potential to impact health can be doubly challenging if the behaviour takes place in private spaces that cannot be observed directly, and where respondents answer what they think the recorder may want to hear. Sleeping under a long-lasting insecticidal net (LLIN) is an important intervention for malaria prevention, yet it is difficult to gauge the extent to which coverage (how many nets are in the community) differs from usage (how many people actually sleep under a net). List randomization, a novel method which partially obscures respondents’ answers to sensitive questions, was employed to estimate LLIN usage in The Gambia.Methods802 heads-of-household from 15 villages were recruited into a randomized controlled trial assessing the effect of a housing intervention on malaria. These houses were randomly assigned to a housing intervention versus control, with stratification by village so as to ensure balance between arms. From these, 125 households (63 intervention, 52 control) were randomly selected for participation in the list randomization experiment, along with 68 households from the same villages but which were not part of the housing improvement study, resulting in a total of 196 households for the list randomization experiment. Approximately half (n = 97) of the 196 study participants were randomly assigned to the control group and received a four-question list about non-sensitive behaviours; the intervention group (n = 99) received the same list, with the addition of one question on a sensitive behaviour: whether or not they had used a bed net the previous night. Participants were read the list of questions and then said how many of the statements were true. Bed net usage was estimated by calculating the difference in means between the number of affirmative responses between the two groups.ResultsThe mean number of affirmative responses in the control group was 2.60 of four statements (95% confidence interval, 95% CI 2.50–2.70), compared with 3.68 (95% CI 3.59–3.78) in the intervention group. Such difference (1.08; 95% CI 94.9–100%) suggests near universal bed net usage.ConclusionsBed net usage by household heads in these rural villages was found to be high. Though not entirely unexpected given other studies’ estimates of high bed net usage in the area, the list randomization method should be further validated in an area with lower coverage.

Recent Travel History and Plasmodium falciparum Malaria Infection in a Region of Heterogenous Transmission in Southern Province, Zambia.

.As Zambia continues to reduce its malaria incidence and target elimination in Southern Province, there is a need to identify factors that can reintroduce parasites and sustain malaria transmission. To examine the relative contributions of types of human mobility on malaria prevalence, this analysis quantifies the proportion of the population having recently traveled during both peak and nonpeak transmission seasons over the course of 2 years and assesses the relationship between short-term travel and malaria infection status. Among all residents targeted by mass drug administration in the Lake Kariba region of Southern Province, 602,620 rapid diagnostic tests and recent travel histories were collected during four campaign rounds occurring between December 2014 and February 2016. Rates of short-term travel in the previous 2 weeks fluctuated seasonally from 0.3% to 1.2%. Travel was significantly associated with prevalent malaria infection both seasonally and overall (adjusted odds ratio [AOR]: 2.55; 95% CI: 2.28–2.85). The strength of association between travel and malaria infection varied by travelers’ origin and destination, with those recently traveling to high-prevalence areas from low-prevalence areas experiencing the highest odds of malaria infection (AOR: 7.38). Long-lasting insecticidal net usage while traveling was associated with a relative reduction in infections (AOR: 0.74) compared with travelers not using a net. Although travel was directly associated with only a small fraction of infections, importation of malaria via human movement may play an increasingly important role in this elimination setting as transmission rates continue to decline.

Sleeping space matters: LLINs usage in Ghana

ABSTRACT Long Lasting Insecticidal Net (LLIN) is an effective malaria prevention mechanism. However, ownership of LLIN does not imply its use among households. The availability of enough sleeping space is a natural prerequisite to install and use LLINs. The objective of this study was to explore the effect of sleeping space and other socio-demographic factors of households’ heads on LLINs usage among households. A cross-sectional household-based study was conducted using a quantitative approach. Data was collected exclusively from households that received LLINs at no direct financial cost to them in a mass malaria campaign conducted in the study area using a structured questionnaire. A total of 383 households sampled for the study received 1,181 LLINs with a range of 1 to 15 LLINs per household. Less than 16% of households that received more than 2 LLINs installed all the LLINs they received during the distribution. Among households that received LLINs, 45% of them did not use them at all and 36% of them used them every night including the night before data collection. The number of bedrooms, children and members per household, and the number of occupants per bedroom were also found statistically associated with the use of LLINs among households. The study used a quantitative approach to investigate sleeping space in relation to LLINs usage and malaria control, an area and topic that has not been adequately covered in the literature.