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Background: Indoor residual spraying has been a key national malaria prevention and control strategy in Ethiopia. However, there is a gap in monitoring and evaluation of house-wall modification after indoor residual spraying before the end of residual lifespan. This study has determined the prevalence of house-wall modification after indoor residual spraying and identified the associated factors in Shashogo district, southern Ethiopia., Methods: A community-based cross-sectional study was conducted from April to May 2022. Data were collected from 640 randomly selected households using a pre-tested questionnaire and an observational checklist. The binary logistic regression models were used to identify factors associated with house-wall modification after indoor residual spraying before the end of the potency period., Results: The prevalence of house-wall modification after indoor residual spraying was found to be 30.4% (95% CI 27.4-34.2%). Educational status of could not read and write [AOR = 1.76, 95% CI (1.16, 2.68)], monthly income of more than birr 3000 [AOR = 3.27, 95% CI (1.78, 6.01)], low level of knowledge about indoor residual spraying [AOR = 3.81, 95% CI (2.39, 6.06)], lack of information within two weeks before spraying [AOR = 2.23, 95% CI (1.44, 3.46)], absence of supervision after spraying [AOR = 1.79, 95% CI (1.14, 2.81)], absence of stagnant water near house [AOR = 3.36, 95% CI (2.13, 5.39)], and thatched roof [AOR = 1.82, 95% CI (1.04, 3.16)] were factors significantly associated with house-wall modification after indoor residual spraying., Conclusion: This study has revealed that the prevalence of house-wall modification after indoor residual spraying before the end of the residual lifespan in the study area was higher compared to other studies in developing countries. Therefore, special emphasis should be given to providing community education about indoor residual spraying, conducting regular supervision before and after residual spraying, enforcing some legislative strategies for modifying the house-wall before six months after spraying, and improving environmental and housing conditions., (© 2023. The Author(s).)

Background: Malaria continues to be one of the leading causes of mortality and morbidity, especially among children and pregnant women. The use of Long-Lasting Insecticide Nets (LLINs) has been recognized and prioritized as a major intervention for malaria prevention in Ghana. This study aims to establish the factors influencing the universal coverage and utilization of LLINs in Ghana., Methods: The data used for this study was from a cross-sectional survey carried out to assess LLINs ownership and use in 9 out of the 10 old regions of Ghana from October 2018 to February 2019 where free LLIN distribution interventions were implemented. The EPI "30 × 7" cluster sampling method (three-stage sampling design) was modified to "15 × 14" and used for the study. A total of 9,977 households were interviewed from 42 districts. Descriptive statistics using percentages as well as tests of associations such as Pearson Chi-square and the magnitude of the associations using simple and multivariable logistic regression were implemented., Results: Of the 9,977 households in the study, 88.0% of them owned at least one LLIN, universal coverage was 75.6%, while utilization was 65.6% among households with at least one LLIN. In the rural and urban areas, 90.8% and 83.2% of households, respectively, owned at least one LLIN. The was a 44% increase in universal coverage of LLINs in rural areas compared to urban areas (AOR: 1.44, 95% CI: 1.02-2.02). There were 29 higher odds of households being universally covered if they received LLIN from the PMD (AOR: 29.43, 95% CI: 24.21-35.79). Households with under-five children were 40% more likely to utilize LLIN (AOR: 1.40, 95% CI: 1.26-1.56). Respondents with universal coverage of LLIN had 25% increased odds of using nets (AOR: 1.25 95% CI: 1.06-1.48). Rural dwelling influences LLIN utilization, thus there was about 4-fold increase in household utilization of LLINs in rural areas compared to urban areas (AOR: 3.78, 95% CI: 2.73-5.24). Household size of more than 2 has high odds of LLINs utilization and awareness of the benefit of LLINs (AOR: 1.42, 95% CI: 1.18-1.71)., Conclusion: About nine in 10 households in Ghana have access at least to one LLIN, three-quarters had universal coverage, and over two-thirds of households with access used LLIN. The predictors of universal coverage included region of residence, rural dwellers, and PMD campaign, while households with child under-five, in rural areas, and with universal coverage were positively associated with utilization., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Afagbedzi, Alhassan, Kenu, Malm, Bandoh, Peprah, Ansah and Guure.)

Background: As many countries aim to eliminate malaria, use of comprehensive approaches targeting the mosquito vector and environment are needed. Integrated malaria prevention advocates the use of several malaria prevention measures holistically at households and in the community. The aim of this systematic review was to collate and summarize the impact of integrated malaria prevention in low- and middle-income countries on malaria burden., Methods: Literature on integrated malaria prevention, defined as the use of two or more malaria prevention methods holistically, was searched from 1st January 2001 to 31st July 2021. The primary outcome variables were malaria incidence and prevalence, while the secondary outcome measures were human biting and entomological inoculation rates, and mosquito mortality., Results: A total of 10,931 studies were identified by the search strategy. After screening, 57 articles were included in the review. Studies included cluster randomized controlled trials, longitudinal studies, programme evaluations, experimental hut/houses, and field trials. Various interventions were used, mainly combinations of two or three malaria prevention methods including insecticide-treated nets (ITNs), indoor residual spraying (IRS), topical repellents, insecticide sprays, microbial larvicides, and house improvements including screening, insecticide-treated wall hangings, and screening of eaves. The most common methods used in integrated malaria prevention were ITNs and IRS, followed by ITNs and topical repellents. There was reduced incidence and prevalence of malaria when multiple malaria prevention methods were used compared to single methods. Mosquito human biting and entomological inoculation rates were significantly reduced, and mosquito mortality increased in use of multiple methods compared to single interventions. However, a few studies showed mixed results or no benefits of using multiple methods to prevent malaria., Conclusion: Use of multiple malaria prevention methods was effective in reducing malaria infection and mosquito density in comparison with single methods. Results from this systematic review can be used to inform future research, practice, policy and programming for malaria control in endemic countries., (© 2023. The Author(s).)

Background: India has made considerable progress in malaria reduction over the past two decades, with government-sponsored indoor residual spraying (IRS) and insecticide-treated bed net (ITN) or long-lasting insecticidal nets (LLIN) distribution being the main vector-related prevention efforts. Few investigations have used non-participant observational methods to assess malaria control measures while they were being implemented, nor documented people's perceptions and acceptance of IRS or LLINs in India, and none have done so in the northeast region. This study evaluated household (HH)-level operation of IRS and distribution of LLINs by India's National Vector Borne Disease Control Programme (NVBDCP) in 50 villages of Meghalaya state, and documented their acceptance and use., Methods: Study field teams accompanied the government health system teams during August-October, 2019 and 2020 to observe deployment of LLINs, and record HH-level data on LLIN numbers and use. In addition, NVBDCP spray teams were followed during 2019-2021 to observe IRS preparation and administration. HH members were interviewed to better understand reasons for acceptance or refusal of spraying., Results: A total of 8386 LLINs were distributed to 2727 HHs in 24 villages from five Primary Health Centres, representing 99.5% of planned coverage. Interviews with 80 HH residents indicated that they appreciated the LLIN dissemination programme, and generally made regular and appropriate use of LLINs, except during overnight travel or when working in agricultural fields. However, HH-level IRS application, which was observed at 632 HHs, did not always follow standard insecticide preparation and safety protocols. Of 1,079 occupied HHs visited by the spray team, 632 (58.6%) refused to allow any spraying. Only 198 (18.4%) HHs agreed to be sprayed, comprising 152 (14.1%) that were only partly sprayed, and 46 (4.3%) that were fully sprayed. Reasons for refusal included: inadequate time to rearrange HH items, young children were present, annoying smell, staining of walls, and threat to bee-keeping or Eri silk moth cultivation., Conclusions: These findings are among the first in India that independently evaluate people's perceptions and acceptance of ongoing government-sponsored IRS and LLIN programmes for malaria prevention. They represent important insights for achieving India's goal of malaria elimination by 2030., (© 2022. The Author(s).)

Background: Despite widespread use of long-lasting insecticidal nets (LLINs) and other tools, malaria caused 409,000 deaths worldwide in 2019. While indoor residual spraying (IRS) is an effective supplement, IRS is moderately expensive and logistically challenging. In endemic areas, IRS requires yearly application just before the main rainy season and potential interim reapplications. A new technology, insecticide-treated wall liner (ITWL), might overcome these challenges., Methods: We conducted a 44-cluster two-arm randomized controlled trial in Muheza, Tanzania from 2015 to 2016 to evaluate the cost and efficacy of a non-pyrethroid ITWL to supplement LLINs, analyzing operational changes over three installation phases. The estimated efficacy (with 95% confidence intervals) of IRS as a supplement to LLINs came mainly from a published randomized trial in Muleba, Tanzania. We obtained financial costs of IRS from published reports and conducted a household survey of a similar IRS program near Muleba to determine household costs. The costs of ITWL were amortized over its 4-year expected lifetime and converted to 2019 US dollars using Tanzania's GDP deflator and market exchange rates., Results: Operational improvements from phases 1 to 3 raised ITWL coverage from 35.1 to 67.1% of initially targeted households while reducing economic cost from $34.18 to $30.56 per person covered. However, 90 days after installing ITWL in 5666 households, the randomized trial was terminated prematurely because cone bioassay tests showed that ITWL no longer killed mosquitoes and therefore could not prevent malaria. The ITWL cost $10.11 per person per year compared to $5.69 for IRS. With an efficacy of 57% (3-81%), IRS averted 1162 (61-1651) disability-adjusted life years (DALYs) per 100,000 population yearly. Its incremental cost-effectiveness ratio (ICER) per DALY averted was $490 (45% of Tanzania's per capita gross national income)., Conclusions: These findings provide design specifications for future ITWL development and implementation. It would need to be efficacious and more effective and/or less costly than IRS, so more persons could be protected with a given budget. The durability of a previous ITWL, progress in non-pyrethroid tools, economies of scale and competition (as occurred with LLINs), strengthened community engagement, and more efficient installation and management procedures all offer promise of achieving these goals. Therefore, ITWLs merit ongoing study., First Posted: 2015 ( NCT02533336 )., (© 2021. The Author(s).)

Background: Malaria is a huge global health burden due to its mortality, morbidity and cost to economies. It is necessary to eliminate the disease in all countries where possible to achieve the World Health Organization target of > 90% reduction by 2030. Successful previous campaigns suggest elimination is feasible in Peru. However, the incidence has recently been rising, focalized to the region of Loreto. Currently, the distribution of long-lasting insecticide-treated nets (LLINs) is a major part of Peru's malaria control strategy, however these may be having a limited effect in Loreto, because of the recent behavioural adaption of the mosquito vector, Anopheles darlingi, to earlier biting times, as well as local perceptions and practices towards LLINs. It was, therefore, necessary to investigate how perceptions, practices and lifestyle factors affect the efficacy of LLINs in Loreto., Methods: Qualitative research was carried out in 5 rural communities along the Iquitos-Nauta Road in Loreto, which have increased exposure and have received nets in a distribution scheme prior to the study. Twenty semi-structured interviews as well as observations of the bed nets were conducted in participants' homes, using a topic guide. Thematic content analysis was used to produce the findings., Results: All participants viewed malaria prevention as a high priority, and the use of bed nets was deeply embedded in the culture. They expressed preference for LLINs over traditional-type nets. However there were too few LLINs distributed, participants did not maintain the nets correctly, washed them too frequently and did not repair holes. The earlier mosquito biting times were also problematic. Additionally, poor housing construction and proximity to mosquito breeding sites further increased transmission., Conclusion: The positive findings in attitudes of the respondents can be used to improve malaria control in these communities. Interventions providing education on effective LLIN use should be implemented. A change in strategy away from vector control methods is also necessary, as these do not provide long-term protection due to the adaptability of An. darlingi. Interventions focusing on parasite control are recommended, and socio-economic factors which increase malaria risk should be addressed.

Background: Indoor residual spraying (IRS), the coating of interior walls of houses with insecticides, is common in malaria-endemic areas. While important in malaria control, IRS potentially exposes residents to harmful insecticides. The World Health Organization recommends steps to minimize exposure; however, no programme has focused on educating populations., Methods: A dramatic presentation and song were developed by study personnel and performed by lay performers in order to spread awareness of the importance of IRS and to minimize insecticide exposure. Performances were staged at 16 sprayed villages in the Vhembe District of Limpopo, South Africa, at which 592 attendees completed short questionnaires before and after the performance about behaviors that might limit insecticide exposure. Overall indices of the attendees' change in knowledge of precautions to take prior to and after spraying to prevent insecticide exposure were analyzed using hierarchical mixed models to assess the effect of the performance on change in participants' knowledge., Results: Approximately half of attendees lived in homes that had been sprayed for malaria and 62% were female. Over 90% thought it better to allow IRS prior to the presentation, but knowledge of proper precautions to prevent exposure was low. The proportion answering correctly about proper distance from home during spraying increased from 49.4% pre-performance to 62.0% post-performance (RR = 1.26, 95% CI = 1.13, 1.41), and the proportion reporting correctly about home re-entry interval after spraying increased from 58.5 to 91.1% (RR = 1.54, 95% CI 1.35, 1.77). Attendees improved in their knowledge about precautions to take prior to and after spraying from mean of 57.9% correct to a mean of 69.7% (β = 12.1%, 95% CI 10.9, 13.4). Specifically, increased knowledge in closing cupboards, removing food and bedding from the home, covering immoveable items with plastic, and leading animals away from the home prior to spraying were observed, as was increased knowledge in sweeping the floors, proper disposal of dead insects, and discarding dirty washrags after spraying., Conclusions: A dramatic presentation and song were able to increase the attendees' knowledge of precautions to take prior to and after spraying in order to limit their insecticide exposure resulting from IRS. This approach to community education is promising and deserves additional study.

Personal protective measures against hematophagous vectors constitute the first line of defense against arthropod-borne diseases. However, guidelines for the standardized testing and licensing of insecticide-treated clothing are still lacking. The aim of this study was to analyze the preventive effect of long-lasting polymer-coated permethrin-impregnated clothing (PTBDU) against malaria after exposure to high-level disease transmission sites as well as the corresponding loss of permethrin and bioactivity during worst-case field use. Between August 2011 and June 2012, 25 personnel wearing PTBDUs and exposed for 9.5 person-months in hyperendemic malaria foci in the rain forest of French Guiana contracted no cases of malaria, whereas 125 persons wearing untreated uniforms only, exposed for 30.5 person-months, contracted 11 cases of malaria, indicating that PTBDU use significantly (p = 0.0139) protected against malaria infection. In the field, PTBDUs were laundered between 1 and 218 times (mean 25.2 ± 44.8). After field use, the mean remaining permethrin concentration in PTBDU fabric was 732.1 ± 321.1 min varying between 130 and 1270 mg/m 2 (mean 743.9 ± 304.2 mg/m 2 ) in blouses, and between 95 and 1290 mg/m 2 (mean 720.2 ± 336.9 mg/m 2 ) in trousers. Corresponding bioactivity, measured according to internal licensing conditions as KD 99 times against Aedes aegypti mosquitoes, varied between 27.5 and 142.5 min (mean 47.7 ± 22.1 min) for blouses, and between 25.0 and 360 min (mean 60.2 ± 66.1 min) for trousers. We strongly recommend the use of long-lasting permethrin-impregnated clothing for the prevention of mosquito-borne diseases, including chikungunya, dengue, and zika fevers, which are currently resurging globally.

Background: Optimal use of long-lasting insecticidal (LLINs) for malaria prevention depends on mass distribution, the users' perception and behaviour of local malaria vectors. This study was aimed at assessing knowledge, attitude and practice (KAP) of communities about LLINs and fabric integrities and insecticidal activities of nets under use in Wolaita zone, Sothern Ethiopia., Methods: Semi-structured interview questionnaires were used to collect data on KAP variables and WHO cone bioassay was used to test the insecticidal activity of sampled nets against an insectary colony of Anopheles arabiensis. Holes and repairs on surfaces of sample nets were counted and categorized following WHO guidelines to assess their fabric integrities. Chi-square (χ(2)) tests were used to verify associations between the demographic profiles of the respondents and their responses to KAP questionnaires., Results: Out of a total of 770 household heads interviewed, 323 (42%) and 447 (58%) were males and females, respectively. The average family size in the surveyed households was 5.25 (±0.70 SE, range 1-12). The majority (81.1%) of the households owned at least one LLIN. The average numbers of LLINs being used and sleeping places in the households were 1.61 (0.04 SE, range 0-4) and 2.27(0.03 SE, range 1-6), respectively. Most of the respondents (n = 687; 89.2%) believed LLINs prevent malaria by killing or acting as physical barriers against mosquitoes. About 21 and 14% of the respondents considered children under five years and pregnant women as priority groups for sleeping under LLINs. Households use LLINs consistently throughout the year (86.4%) and tuck nets into bedding materials while sleeping (90.1%). Physical inspection of fabric integrity of sampled LLINs revealed holes ranging from size 1 (0.5-2 cm) to size 4 (> 25 cm) mostly on lower ("right/left") surfaces. Moreover, most surfaces of sampled LLINs caused 100% knockdown and mortality on insectary colonies of Anopheles arabiensis., Conclusions: The overall knowledge, attitude and practice about LLINs were satisfactory in the study areas. However, the family size net ratio must be narrowed and attention needs to be given to malaria vulnerable groups (children < 5 years of age and pregnant women). Continuous monitoring and evaluation of use and durability (fabric integrity and insecticidal activity) of LLINs should be conducted to avoid misuse and associated attrition of nets before the intended period.

Malaria still presents a grave threat to the health of pregnancies worldwide with prevention currently stalling as traditional control and prevention strategies are limited by both insecticide and drug resistance. Furthermore, climate change is bringing malaria to locations where it was once eradicated and intensifying malaria in other areas. Even where malaria is not currently common, obstetricians will need to understand the pathogenesis of the disease, how it is transmitted, methods for prevention and treatment in pregnancy, and promising emerging strategies such as vaccines. A renewed global response is needed for this age-old disease in which pregnancy poses specific susceptibility. [ABSTRACT FROM AUTHOR]

Background: Proper utilization of Insecticide Treated Nets (ITNs) has been shown to be very effective in preventing malaria and in reducing the incidence of the disease. Getting people to buy and utilize ITNs has proven very difficult especially in low-income settings of sub-Saharan Africa where the disease is endemic. This research work, therefore assesses the effectiveness of the application of social marketing strategies in encouraging the acquisition and utilization of ITNs. Focus of the Article: The marketing mix concept which is usually referred to as the 4Ps of social marketing-price, place, product and promotion-were put to test to identify how the respondents will respond to variation in any of them. The research aims to assess the people's response to a favorable change in the price of ITNs, product quality, product location and target advertisement. Research Question: The research questions that this study aimed to answer is; will the introduction of the traditional marketing mix of social marketing help drive the acquisition and utilization of ITNs by the people in rural communities of Imo State, Nigeria? Program Design/Approach: The research report contained in this manuscript is targeted at health products (tangible and intangible) marketing researchers in resource-limited settings. These researchers who may not be able to afford the acquisition of large quantity health products like the ITNs to conduct their study can adopt the method employed in this study. Here the "prospect" of using social marketing strategies like the traditional marketing mix, to determine a possible increase in the acquisition and utilization of ITNs by the people. Importance to the Social Marketing Field: This study describes how researchers in low-and-middle income countries could conduct a social marketing research on tangible products such as the ITN without really selling ITNs. The people's intent to buy and use ITNs were assessed. More than 10 previous studies from as far back as 1999 were assessed, none of them employed the current methodology. Methodology: This study was a descriptive cross-sectional study where a multi-stage sampling technique was employed to recruit the study participants. Results: It was found that 55.1% had ITNs, good utilization rate of 80.6% was recorded among those who possessed ITNs. Using the social marketing principle to assess respondents' intent to own and use ITNs, an increase of 27.2%, 38.1%, 31.3%, and 35.9% will be achieved if the cost of acquiring ITNs becomes affordable, when ITNs become accessible, when practical guidance on use was provided, and when quality was improved. The study also revealed that, the vigorous pursue of social marketing techniques can enhance the sales of ITNs and its usage among the people. Recommendation for Research or Practice: This study has justified the usefulness of social marketing in engendering positive behavioural change where people can be motivated to adopt a health innovation. It is therefore recommended that health innovations and products must be sold to the people using social marketing strategies as this has been proven not only to encourage adoption/acquisition, but also utilization. [ABSTRACT FROM AUTHOR]

This work discusses the challenge posed by the simultaneous occurrence of malaria and COVID-19 coinfection on global health systems. We propose a novel fractional order mathematical model malaria and COVID-19 coinfection. To assess the impact of control strategies on both diseases, we consider two control strategies which are, personal protection against mosquito bites ( u 1 (t) ) and preventive measures for COVID-19 ( u 2 (t) ). Numerical simulations demonstrate that consistent application of these measures leads to significant reductions in disease transmission. Using insecticide-treated nets and repellents during day and night effectively reduces malaria transmission, while implementing facial masks and hand hygiene controls COVID-19 spread. The most substantial impact is observed when both sets of protection measures are simultaneously adopted, highlighting the importance of integrated strategies. The study provides valuable insights into malaria and COVID-19 coinfection dynamics and emphasizes the impact of the control measures. of individual behavior and consistent adoption of personal protection measures to control both diseases. It underscores the need for integrated public health interventions to combat the dual burden of malaria and COVID-19, contributing to the development of targeted and efficient control measures. [ABSTRACT FROM AUTHOR]

Background: The decreasing residual efficacy of insecticides is an important factor when making decisions on insecticide choice for national malaria control programmes. The major challenge to using chemicals for vector control is the selection for the development of insecticide resistance. Since insecticide resistance has been recorded for most of the existing insecticides used for indoor residual spraying, namely, DDT, pyrethroids, organophosphates and carbamates, and new chemicals are necessary for the continued success of indoor residual spraying. The aim of this study was to assess the residual efficacy of Actellic 300CS, SumiShield™ 50WG and Fludora®Fusion by spraying on different wall surfaces. Methods: One hundred and sixty-eight houses with different wall surface types (mud, cement, painted cement, and tin) which represented the rural house wall surface types in KwaZulu-Natal, South Africa were used to evaluate the residual efficacy of Actellic 300CS, SumiShield 50WG and Fludora®Fusion with DDT as the positive control. All houses were sprayed by experienced spray operators from the Malaria Control Programme. Efficacy of these insecticides were evaluated by contact bioassays against Anopheles arabiensis, a vector species. The residual efficacy of the insecticide formulations was evaluated against a susceptible insectary-reared population of An. arabiensis using WHO cone bioassays. Results: Effectiveness of the three insecticides was observed up to 12 months post-spray. When assessing the achievement of 100% mortality over time, SumiShield performed significantly better than DDT on mud (OR 2.28, 95% CI 1.72–3.04) and painted cement wall types (OR 3.52, 95% CI 2.36–5.26). On cement wall types, Actellic was found to be less effective than DDT (OR 0.55, 95% CI 0.37–0.82) while Fludora®Fusion was less effective on tin wall types (OR 0.67, 95% CI 0.47–0.95). When compared to the combined efficacy of DDT on mud surfaces, SumiShield applied to each of the mud, cement and painted cement wall types and DDT applied to the cement wall types was found to be significantly more effective. These insecticides usually resulted in 100% mortality for up to 12 months with a delayed mortality period of 96–144 h, depending on the insecticide evaluated and the surface type sprayed. Conclusion: Field evaluation of these insecticides have shown that Actellic, SumiShield and Fludora®Fusion are suitable replacements for DDT. Each of these insecticides can be used for malaria vector control, requiring just one spray round. These insecticides can be used in rotation or as mosaic spraying. [ABSTRACT FROM AUTHOR]

Vector control is a vital tool utilised by malaria control and elimination programmes worldwide, and as such it is important that we can accurately quantify the expected public health impact of these methods. There are very few previous models that consider vector-control-induced changes in the age-structure of the vector population and the resulting impact on transmission. We analytically derive the steady-state solution of a novel age-structured deterministic compartmental model describing the mosquito feeding cycle, with mosquito age represented discretely by parity—the number of cycles (or successful bloodmeals) completed. Our key model output comprises an explicit, analytically tractable solution that can be used to directly quantify key transmission statistics, such as the effective reproductive ratio under control, Rc, and investigate the age-structured impact of vector control. Application of this model reinforces current knowledge that adult-acting interventions, such as indoor residual spraying of insecticides (IRS) or long-lasting insecticidal nets (LLINs), can be highly effective at reducing transmission, due to the dual effects of repelling and killing mosquitoes. We also demonstrate how larval measures can be implemented in addition to adult-acting measures to reduce Rc and mitigate the impact of waning insecticidal efficacy, as well as how mid-ranges of LLIN coverage are likely to experience the largest effect of reduced net integrity on transmission. We conclude that whilst well-maintained adult-acting vector control measures are substantially more effective than larval-based interventions, incorporating larval control in existing LLIN or IRS programmes could substantially reduce transmission and help mitigate any waning effects of adult-acting measures. Author summary: Parity is a term used to describe the number of feeding and egg-laying cycles (or gonotrophic cycles) a mosquito has completed. The parity of a mosquito is an important factor when considering vector-borne infectious diseases, since it takes at least two bloodmeals for transmission to occur—one for the mosquito to pick up infection, and one to pass on infection to a new host. In practice, the more bloodmeals a mosquito has taken, or the higher its parity, the more likely it is to contribute to transmission. Therefore, a population consisting of older mosquitoes will represent a higher risk of transmission. Vector control methods act to reduce the mosquito population and include adult-acting measures (such as long-lasting insecticide-treated nets and indoor residual spraying) and larval-acting measures (such as insecticidal treatment of larval sites). Although these measures all act to reduce population size, they also have different impacts on the age-structure of the population. Here we develop an analytically tractable, parity-structured model of mosquito infection dynamics to consider the comparative effects of different vector control methods. Our results reinforce the important of adult-acting interventions, as well as providing an analytical model framework for quantifying key transmission statistics for vector-borne diseases. [ABSTRACT FROM AUTHOR]

Background: The massive scale-up of long-lasting insecticidal nets (LLIN) has led to a major reduction in malaria burden in many sub-Saharan African (SSA) countries. The World Health Organization (WHO) has recently issued a strong recommendation for the use of chlorfenapyr-pyrethroid LLINs compared to standard pyrethroid-only LLINs in areas of high insecticide resistance intensity. However, there is still a lack of conclusive evidence on the efficacy of piperonyl butoxide-pyrethroid (PBO-py) LLINs, especially in West Africa, where vector composition and resistance mechanisms may be different from vectors in East Africa. Methods: This is a three-arm, superiority, triple-blinded, cluster randomised trial, with village as the unit of randomisation. This study conducted in Côte d'Ivoire will evaluate the efficacy on epidemiological and entomological outcomes of (1) the control arm: MAGNet® LN, which contains the pyrethroid, alpha-cypermethrin, (2) VEERALIN® LN, a net combining the synergist PBO and alpha-cypermethrin, and (3) Interceptor® G2 LN, which incorporates chlorfenapyr and alpha-cypermethrin, two adulticides with different mechanisms of action. A total of 33 villages with an average of 200 households per village will be identified, mapped, and randomised in a ratio of 1:1:1. Nets will be distributed at a central point following national guidelines with 1 net for every 2 people. The primary outcome of the trial will be incidence of malaria cases (confirmed by rapid diagnostic test (RDT)) in a cohort of 50 children aged 6 months to 10 years in each cluster, followed for 12 months (active case detection). Secondary outcomes are cross-sectional community prevalence of malaria infection (confirmed by RDT) in the study population at 6 and 12 months post-intervention (50 randomly selected persons per cluster), vector density, entomological inoculation rate (EIR), and phenotypic and genotypic insecticide resistance at baseline and 12 months post-intervention in 3 sentinel villages in each treatment arm. Discussion: In addition to generating further evidence for next-generation LLINs, this study will also provide the first evidence for pyrethroid-PBO nets in a West African setting. This could further inform WHO recommendations on the pragmatic use of pyrethroid-PBO nets. Trial registration: ClinicalTrials.gov NCT05796193. Registered on April 3, 2023. [ABSTRACT FROM AUTHOR]

Malaria is a significant public health concern, especially in tropical regions. It remains endemic in many areas where malaria mosquitoes are prevalent. This study investigates the viability of insecticide zooprophylaxis (IZ) in conjunction with Long Lasting Insecticidal Nets (LLINs) as a strategic approach to combat malaria transmission, particularly in regions dominated by zoophagic vectors. Through the presentation and analysis of a mathematical model that integrates IZ and LLINs for the control of Anopheles arabiensis (An. arabiensis), the research underscores IZ's role in reducing zoophagic vector populations and enhancing malaria control efforts. Notably, the study reveals that achieving comprehensive coverage of LLINs and IZ distribution systems can reduce the basic reproduction number (R0) below 1. Furthermore, the research highlights the potential for substantial reductions in human biting rates, vectorial capacity and Entomological Inoculation Rate (EIR) when high intervention coverage encompasses all zoophagy blood sources for malaria vectors. [ABSTRACT FROM AUTHOR]

This paper presents an age-structured mathematical model for malaria transmission dynamics with asymptomatic carrier and temperature variability. The temperature variability function is fitted to the temperature data, and the malaria model is then fitted to the malaria cases and validated to check its suitability. Time-dependent controls were considered, including Long Lasting Insecticide Nets, treatment of symptomatic, screening and treatment of asymptomatic carriers and spray of insecticides. Pontryagin's Maximum Principle is used to derive the necessary conditions for optimal control of the disease. The numerical simulations of the optimal control problem reveal that the strategy involving the combination of all four controls is the most effective in reducing the number of infected individuals. Furthermore, the cost-effectiveness analysis shows that treatment of symptomatic, screening and treatment of asymptomatic carriers and insecticide spraying is the most cost-effective strategy to implement to control malaria transmission when available resources are limited. [ABSTRACT FROM AUTHOR]

VECTRON™ T500 is a wettable powder IRS formulation of broflanilide, a newly discovered insecticide. We performed a two-arm non-inferiority community randomised evaluation of VECTRON™ T500, compared to Fludora® Fusion against pyrethroid-resistant Anopheles gambiae s.l. in an area of high coverage with pyrethroid-only nets in the Za-Kpota District of central Benin. One round of IRS was applied in all consenting households in the study area. Sixteen clusters were randomised (1:1) to receive VECTRON™ T500 (100 mg/m2 for broflanilide) or Fludora® Fusion (200 mg/m2 for clothianidin and 25 mg/m2 for deltamethrin). Surveys were performed to assess adverse events and the operational feasibility and acceptability of VECTRON™ T500 among spray operators and household inhabitants. Human landing catches were conducted in 6 households every 1–2 months for up to 18 months post-intervention to assess the impact on vector densities, sporozoite rates and entomological inoculation rates. Bottle bioassays were performed to monitor vector susceptibility to pyrethroids, broflanilide and clothianidin. Monthly wall cone bioassays were conducted for 24 months to assess the residual efficacy of the IRS formulations using susceptible and pyrethroid-resistant An. gambiae s.l. A total of 26,562 female mosquitoes were collected during the study, of which 40% were An. gambiae s.l., the main malaria vector in the study area. The vector population showed high intensity pyrethroid resistance but was susceptible to broflanilide (6 µg/bottle) and clothianidin (90 µg/bottle). Using a non-inferiority margin of 50%, vector density indicated by the human biting rate (bites/person/night) was non-inferior in the VECTRON™ T500 arm compared to the Fludora® Fusion arm both indoors (0.846 bites/p/n in Fludora® Fusion arm vs. 0.741 bites/p/n in VECTRON™ T500 arm, IRR 0.54, 95% CI 0.22–1.35, p = 0.150) and outdoors (0.691 bites/p/n in Fludora® Fusion arm vs. 0.590 bites/p/n in VECTRON™ T500 clusters, IRR 0.75, 95% CI 0.41–1.38, p = 0.297). Sporozoite rates and entomological inoculation rates did not differ significantly between study arms (sporozoite rate: 0.9% vs 1.1%, p = 0. 0.746, EIR: 0.008 vs 0.006 infective bites per person per night, p = 0.589). Cone bioassay mortality with both VECTRON™ T500 and Fludora® Fusion was 100% for 24 months post-IRS application on both cement and mud treated house walls with both susceptible and pyrethroid-resistant strains of An. gambiae s.l. Perceived adverse events reported by spray operators and householders were generally very low (< 6%) in both study arms. VECTRON™ T500 was non-inferior to Fludora® Fusion in reducing the risk of malaria transmission by pyrethroid resistant vectors when applied for IRS in communities in central Benin. The insecticide showed prolonged residual efficacy on house walls, lasting over 24 months and had a high acceptability with homeowners. Community application of VECTRON™ T500 for IRS provides improved and prolonged control of pyrethroid resistant malaria vectors and enhances our capacity to manage insecticide resistance. [ABSTRACT FROM AUTHOR]

Malaria is a severe, life-threatening infectious disease transmitted through the bite of infected female Anopheles mosquitoes. In Asahan Regency, four areas are endemic for malaria, with Silau Laut District having an API rate of 4.8‰ (Annual Parasite Incidence per 1000 at-risk individuals annually). Indoor residual spraying (IRS) with Lambda Cyhalothrin (Icon 100 CS) is used to eradicate mosquito vectors by applying insecticide to walls and ceilings, interrupting transmission. Research aimed to assess IRS effectiveness in reducing malaria incidence in Silau Laut District found a strong positive correlation (0.826 and 0.912) between RDT and microscopic examination results before and after IRS. However, correlations between education and malaria control using IRS and changes in knowledge and attitudes were weak (0.490 and 0.438). Paired Ttests revealed differences in RDT examination results (p = 0.044) and knowledge and attitude levels (p = 0.000) before and after IRS education. No significant difference was observed in microscopic examination results (p = 0.159). Recommendations include intensified efforts in malaria prevention and control, including active case finding, mosquito nest elimination, continued IRS, mesh installation, insecticide-treated bed net use, health education, and regular bioassay testing every 1-2 months for 3-6 months in Silau Laut District. [ABSTRACT FROM AUTHOR]

Malaria is the main public health issue in Ethiopia since it infects more than 75% of the country. This study's goal was to evaluate the risk factors for malaria in Dansha town and the area around it as well as the prevalence of the disease. Structured questionnaires and a Health facility-based study of confirmed malaria cases were conducted to determine the five-year (2012-2016) trend of malaria prevalence. In order to evaluate the data, SPSS version 20 was used. There were 28.4% more people who had malaria overall. The major plasmodium species identified was Plasmodium falciparum, followed by Plasmodium vivax. The prevalence of malaria parasite infections was significantly associated with age, while it was nonsignificantly associated with sex. Although the prevalence of Plasmodium falciparum was 3.413 times more likely to be higher than the prevalence of Plasmodium vivax among the age group under five years, the prevalence of Plasmodium falciparum was 0.793 times less likely to be higher than the prevalence of Plasmodium vivax among the age group from five to nine years. About 95% of the respondents had adequate knowledge about malaria. At the time of this study, 82.7% of the respondents had: a practice of using impregnated mosquito nets, 92.4% had risk factors for mosquito breeding sites near their homes, and 20.9% had headache symptoms. Health workers and responsible administrators should focus on giving health education about the prevention and control activities of malaria and how individual households use insecticide-treated nets correctly. [ABSTRACT FROM AUTHOR]

Background: Insecticide Treated Nets are one of the backbones of malaria prevention in Africa where the vector mosquitos bite at night and prefer humans for feeding. Children who sleep under Insecticide Treated Nets though protected still get malaria infections. This study aimed to assess the risk factors of malaria infection among under-five children who sleep under insecticide-treated Treated Nets. Methodology: This was a secondary analysis of a cross-sectional survey the Malaria Indicator survey of 2021 in Zambia. Data was extracted from the database at the Ministry of Health and analysed in STATA version 14. Data was analysed in counts and frequencies, cross-tabulations and associations assessed using logistic regressing using complex data analysis. Results: A total of 1695 children aged below five years who had slept under an Insecticide Treated Net the night before the survey were included in the study, 50.9% were female while 49.1 were male. Over a third of them (23.9%) had a fever in the previous two weeks, over half 51.9% of them had anaemia and 28.8% of them had malaria infection tested using Rapid Diagnostic tests. There was a 3.46 (95%CI 2.67 - 4.49) increase in the odds of having malaria if the under-five child was anaemic (haemoglobin less than 11mg/dl). Other factors that are usually associated with malaria infection such as younger age group, low socio-economic status, residing in rural areas and having had a fever in the previous two weeks. Conclusion: In Zambia, about a third of under-five children who slept under insecticide-treated nets still had evidence of malaria infection. A significant risk factor for malaria infection among the under-five children who slept under ITNs was anaemia. Other known risk factors for malaria among under-five children such as age, rural residence, wealth status, province of residence and education of guardians were not statistically significant. [ABSTRACT FROM AUTHOR]

Vector control remains the preferred method for effective malaria control. The impressive results of vector control are however, threatened by emerging resistance to insecticides among Anopheles gambiae s.l. mosquitoes. This study aimed at determining the pattern of resistance to selected insecticides in each class of carbamates, organochlorines, organophosphates, and pyrethriods using World Health Organisation tubes and Centre for Disease prevention and Control standard bottle assay protocols. Larvae and pupae of Anopheles mosquitoes were collected in villages of Buruku and Katsina-Ala Local Government Areas of Benue State between April and May 2019 and reared at 27oC and 80% relative humidity to adults at the Nasarawa state University Insectary. Susceptibility tests were carried out on 2-3 days old non-blood fed female adults. With WHO test method, Anopheles mosquitoes were completely susceptible (100% mortality) to Primiphos-methyl (organophosphate), Lambdacyhalothrin (pyrethroids) in Buruku and Katsina Ala but were resistant (54% mortality) to DDT (Organochlorine) in both sites. Mosquitoes were resistant (88% mortality) to Bendiocarb (Carbamates) in Katsina Ala but susceptible in Buruku with 99% mortality. However, the results for CDC bottle bioassays showed that Anopheles mosquitoes were susceptible to Primiphos methyl, Lambdacyhalothrin and Bendiocarb (>98% mortality) except for DDT which was resistant (<85% mortality) in both LGAs. Overall, this study shows that Anopheles gambiae s.l are resistant to DDT. The resistance may have arisen from indiscriminate use of the pesticide in households and for agricultural purposes. This study provides baseline and useful information on the susceptibility status of Anopheles mosquito populations to four classes of insecticides approved for public health use. Proper regulation should therefore be put in place on the procurement and use of this insecticide. [ABSTRACT FROM AUTHOR]

Background: Malaria prevention is important among HIV patients to mitigate its associated complications. This study explored the predictors of insecticide-treated net (ITN) usage among HIV patients attending an antiretroviral therapy (ART) clinic in Ebonyi state, Nigeria. Methodology: It was a cross-sectional study that involved 297 patients who attended an ART clinic in Ebonyi State. An interviewer-administered questionnaire was used to collect relevant data which included perception of malaria prevention, ownership of ITN, condition of ITN, duration of use and ITN usage. The relationship between ITN usage and other variables was assessed using bivariate analysis and the predictors were determined using multivariate logistic regression. Results: There were 64 (21.5%) males and 233(78.5%) females. Knowledge of the use of ITN (mean= 4.24 ±0.93) was rated better than knowledge of the use of mosquito repellent (mean = 3.79 ± 1.21) and knowledge of the use of protective clothes (mean= 3.86 ±1.26). 246 (83%) of the study population owned ITN. Only 48% (118) of those who had ITNs reported having optimal nets (nets without holes). 135 (45.5%) of the participants reported sleeping under the net every day in the past week. There was a significant relationship between ITN usage and knowledge of the use of ITN, ownership of ITN, duration of use and condition of nets. Predictors of usage of ITN were duration of use (AOR=0.386, 95%C.I for AOR=0.224-0.665) and condition of the nets (AOR=0.399, 95%C.I for AOR=0.226-0.706). Conclusion: Perception of malaria prevention was high among the study group. Ownership of ITN was high although many of the ITNs were not in good condition. Usage of ITN was largely determined by duration of use and good condition of nets. Yearly assessment of the condition of ITNs and replacement exercise of ITNs (2-3 years) at ART clinics to replace old and worn-out nets among HIV patients are recommended. [ABSTRACT FROM AUTHOR]

Malaria vectors have demonstrated resistance to pyrethroid-based insecticides used in insecticide-treated nets, diminishing their effectiveness. This systematic review and meta-analysis investigated two forms of dual active-ingredient (DAI) insecticide-treated nets (ITN(s)) for malaria prevention. A comprehensive search was conducted on July 6th 2022. The databases searched included PubMed, Embase, CINAHL, amongst others. Trials were eligible if they were conducted in a region with ongoing malaria transmission. The first DAI ITN investigated were those that combined a pyrethroid with a non-pyrethroid insecticides. The second DAI ITN investigated were that combined a pyrethroid with an insect growth regulator. These interventions were compared against either a pyrethroid-only ITN, or ITNs treated with pyrethroid and piperonyl-butoxide. Assessment of risk of bias was conducted in duplicate using the Cochrane risk of bias 2 tool for cluster-randomised trials. Summary data was extracted using a custom data-extraction instrument. This was conducted by authors THB, JCS and SH. Malaria case incidence was the primary outcome and has been meta-analysed, adverse events were narratively synthesised. The review protocol is registered on PROSPERO (CRD42022333044). From 9494 records, 48 reports were screened and 13 reports for three studies were included. These studies contained data from 186 clusters and all reported a low risk of bias. Compared to pyrethroid-only ITNs, clusters that received pyrethroid-non-pyrethroid DAI ITNs were associated with 305 fewer cases per 1000-person years (from 380 fewer cases to 216 fewer cases) (IRR = 0.55, 95%CI: 0.44–0.68). However, this trend was not observed in clusters that received pyrethroid-insect growth regulator ITNs compared to pyrethroid-only ITNs (from 280 fewer cases to 135 more) (IRR = 0.90, 95%CI: 0.73–1.13). Pyrethroid-non-pyrethroid DAI ITNs demonstrated consistent reductions in malaria case incidence and other outcomes across multiple comparisons. Pyrethroid-non-pyrethroid DAI ITNs may present a novel intervention for the control of malaria. [ABSTRACT FROM AUTHOR]

Background: Malaria, transmitted by the bite of infective female Anopheles mosquitoes, remains a global public health problem. The presence of invasive Anopheles stephensi, capable of transmitting Plasmodium vivax and Plasmodium falciparum, was first reported in Ethiopia in 2016. The ecology of this mosquito species differs from that of Anopheles arabiensis, the primary malaria vector in Ethiopia. This study aimed to evaluate the efficacy of selected insecticides, which are used in indoor residual spraying (IRS) and selected long-lasting insecticidal nets (LLINs) for malaria vector control against adult An. stephensi. Methods: Anopheles stephensi mosquitoes were collected as larvae and pupae from Awash Subah Kilo Town and Haro Adi village, Ethiopia. Adult female An. stephensi, reared from larvae and pupae collected from the field, aged 3–5 days were exposed to impregnated papers of IRS insecticides (propoxur 0.1%, bendiocarb 0.1%, pirimiphos-methyl 0.25%), and insecticides used in LLINs (alpha-cypermethrin 0.05%, deltamethrin 0.05% and permethrin 0.75%), using diagnostic doses and WHO test tubes in a bio-secure insectary at Aklilu Lemma Institute of Pathobiology, Addis Ababa University. For each test and control tube, batches of 25 female An. stephensi were used to test each insecticide used in IRS. Additionally, cone bioassay tests were conducted to expose An. stephensi from the reared population to four brands of LLINs, MAGNet™ (alpha-cypermethrin), PermaNet® 2.0 (deltamethrin), DuraNet© (alpha-cypermethrin) and SafeNet® (alpha-cypermethrin). A batch of ten sugar-fed female mosquitoes aged 2–5 days was exposed to samples taken from five positions/sides of a net. The data from all replicates were pooled and descriptive statistics were used to describe features of the data. Results: All An. stephensi collected from Awash Subah Kilo Town and Haro Adi village (around Metehara) were resistant to all tested insecticides used in both IRS and LLINs. Of the tested LLINs, only MAGNet™ (alpha-cypermethrin active ingredient) caused 100% knockdown and mortality to An. stephensi at 60 min and 24 h post exposure, while all other net brands caused mortality below the WHO cut-off points (< 90%). All these nets, except SafeNet®, were collected during LLIN distribution for community members through the National Malaria Programme, in December 2020. Conclusions: Anopheles stephensi is resistant to all tested insecticides used in IRS and in the tested LLIN brands did not cause mosquito mortality as expected, except MAGNet. This suggests that control of this invasive vector using existing adult malaria vector control methods will likely be inadequate and that alternative strategies may be necessary. [ABSTRACT FROM AUTHOR]

This article details the study protocol for a double-blind, randomized placebo-controlled trial to determine the effectiveness of permethrin-treated baby wraps to prevent Plasmodium falciparum malaria infection in children 6–24 months of age. Participating mother-infant dyads will be randomized to receive either a permethrin-treated or a sham-treated wrap, known locally as a "lesu." After a baseline home visit, during which time all participants will receive new long-lasting insecticidal nets, participants will attend scheduled clinic visits every two weeks for a period of 24 weeks. In the event of an acute febrile illness or other symptoms that may be consistent with malaria (e.g., poor feeding, headache, malaise), participants will be instructed to present to their respective study clinic for evaluation. The primary outcome of interest is the incidence of laboratory-confirmed, symptomatic malaria in participating children. Secondary outcomes of interest include: (1) change in children's hemoglobin levels; (2) change in children's growth parameters; (3) prevalence of asymptomatic parasitemia in children; (4) hospitalization for malaria in children; (5) change in the mother's hemoglobin level; and (6) clinical malaria in the mother. Analyses will be conducted using a modified intent-to-treat approach, with woman-infant dyads who attend one or more clinic visits analyzed according to the arm to which they were randomly assigned. This is the first use of an insecticide-treated baby wrap for prevention of malaria in children. The study began recruitment in June 2022 and is ongoing. ClinicalTrials.gov Identifier: NCT05391230, Registered 25 May 2022. [ABSTRACT FROM AUTHOR]

Malaria control uses insecticides to kill Anopheles mosquitoes. Recent successes in malaria control are threatened by increasing levels of insecticide resistance (IR), requiring insecticide resistance management (IRM) strategies to mitigate this problem. Field trials of IRM strategies are usually prohibitively expensive with long timeframes, and mathematical modeling is often used to evaluate alternative options. Previous IRM models in the context of malaria control assumed IR to have a simple (monogenic) basis, whereas in natural populations, IR will often be a complex polygenic trait determined by multiple genetic variants. A quantitative genetics model was developed to model IR as a polygenic trait. The model allows insecticides to be deployed as sequences (continuous deployment until a defined withdrawal threshold, termed "insecticide lifespan", as indicated by resistance diagnosis in bioassays), rotations (periodic switching of insecticides), or full‐dose mixtures (two insecticides in one formulation). These IRM strategies were compared based on their "strategy lifespan" (capped at 500 generations). Partial rank correlation and generalized linear modeling was used to identify and quantify parameters driving the evolution of resistance. Random forest models were used to identify parameters offering predictive value for decision‐making. Deploying single insecticides as sequences or rotations usually made little overall difference to their "strategy lifespan", though rotations displayed lower mean and peak resistances. Deploying two insecticides in a full‐dose mixture formulation was found to extend the "strategy lifespan" when compared to deploying each in sequence or rotation. This pattern was observed regardless of the level of cross resistance between the insecticides or the starting level of resistance. Statistical analysis highlighted the importance of insecticide coverage, cross resistance, heritability, and fitness costs for selecting an appropriate IRM strategy. Full‐dose mixtures appear the most promising of the strategies evaluated, with the longest "strategy lifespans". These conclusions broadly corroborate previous results from monogenic models. [ABSTRACT FROM AUTHOR]

Background: Vector control is the most effective malaria control and prevention measure. Among these, IRS and LLINs are the most important chemical insecticide interventions used in malaria prevention and control strategies in Ethiopia. However, the long-term effectiveness of these strategies is under threat due to the emergency and spread of insecticide resistance in the principal malaria vector. Therefore, this study was carried out, under standardized laboratory conditions to assess the killing effect of some insecticides against An. gambiae s.l. Methods: Mosquitoes in late instar larvae and pupae stages were collected from different breeding habitats of the study sites using a soup ladle (350 ml capacity). The immature was reared to adults at optimum temperature and humidity in a field insectary using the WHO protocol. Four insecticides representing three chemical classes were used against adult mosquitoes. These were permethrin, deltamethrin, pirimiphos-methyl and bendiocarb. Susceptibility tests were carried out from September to December 2021 using the WHO standard procedures. Mortality rate, variation, interaction effect and knockdown times (KDT50 and KDT95%) were computed using descriptive statistics, multivariate analysis of variance and log-probit regression model using SPSS version 20 software. Results: Totally, 1300 Anopheles gambiae s.l. were tested to determine the susceptibility status to the four insecticides. Among these, 90.7% of them were susceptible to insecticides, whereas the remaining 9.3% of specimens were resistant to the insecticides. The results of the analysis of variance showed that mortality significantly varied between insecticides (F = 26.06, DF = 3, P <.0001), but not between study locations (F = 1.56, DF = 3, P = 0.212). On the other hand, the mean comparison of dead mosquitoes showed some signs of interaction between bendiocarb and locations, but not other insecticides and locations. Conclusions: This study revealed that the knockdown times and effectiveness of different insecticides varied in different study sites. Therefore, insecticide resistance information is very essential for concerned bodies to make informed and evidence-based decisions on vector control. [ABSTRACT FROM AUTHOR]

Background: Insecticide treated bed nets (ITN) are considered a core malaria vector control tool by the WHO and are the main contributor to the large decline in malaria burden in sub-Saharan Africa over the past 20 years, but they are less effective if they are not broadly and regularly used. ITN use may depend on factors including temperature, relative humidity, mosquito density, seasonality, as well as ideational or psychosocial factors including perceptions of nets and perceptions of net use behaviours. Methods: A cross–sectional household survey was conducted as part of a planned randomized controlled trial in Magoe District, Mozambique. Interviewers captured data on general malaria and ITN perceptions including ideational factors related to perceived ITN response efficacy, self-efficacy to use an ITN, and community norms around ITN using a standardized questionnaire. Only households with sufficient ITNs present for all children to sleep under (at least one ITN for every two children under the age of five years) were eligible for inclusion in the study. Additional questions were added about seasonality and frequency of ITN use. Results: One-thousand six hundred sixteen mother–child dyads were interviewed. Responses indicated gaps in use of existing nets and net use was largely independent of ideational factors related to ITNs. Self-reported ITN use varied little by season nor meaningfully when different methods were used to solicit responses on net use behaviour. Mothers' perceived response efficacy of ITNS was negatively associated with net use (high perceived response efficacy reduced the log-odds of net use by 0.27 (95% CI − 0.04 to − 0.51), implying that stronger beliefs in the effectiveness of ITNs might result in reduced net use among their children. Conclusions: In this context, ITN use among children was not clearly related to mothers' ideational factors measured in the study. Scales used in solicitation of ideation around ITN use and beliefs need careful design and testing across a broader range of populations in order to identify ideational factors related to ITN use among those with access. [ABSTRACT FROM AUTHOR]

Proof-of-concept studies demonstrate that antimalarial drugs designed for human treatment can also be applied to mosquitoes to interrupt malaria transmission. Deploying a new control tool is ideally undertaken within a stewardship programme that maximises a drug's lifespan by minimising the risk of resistance evolution and slowing its spread once emerged. We ask: what are the epidemiological and evolutionary consequences of targeting parasites within mosquitoes? Our synthesis argues that targeting parasites inside mosquitoes (i) can be modelled by readily expanding existing epidemiological frameworks; (ii) provides a functionally novel control method that has potential to be more robust to resistance evolution than targeting parasites in humans; and (iii) could extend the lifespan and clinical benefit of antimalarials used exclusively to treat humans. Counter-evolution of the targeted organisms (i.e., mosquitoes resist insecticides, and parasites resist antimalarial drugs) threatens the future of malaria control. The discovery of new compounds for either insecticides or antimalarials is being outpaced by evolution, and so novel interventions to augment the current arsenal are urgently needed. A promising new approach is to target malaria parasites inside mosquitoes (i.e., sporogony) which is considered one of the most vulnerable stages of the parasite's entire malaria life cycle. Many chemical compounds have been shown to be effective against Plasmodium parasites during sporogony. Deploying a new control tool is ideally undertaken within a stewardship programme that minimises the risk of resistance evolution and slowing its spread. Yet, evolutionary consequences of targeting malaria parasites in mosquitoes remain unexplored. [ABSTRACT FROM AUTHOR]

Background: Broflanilide is a newly discovered insecticide with a novel mode of action targeting insect γ-aminobutyric acid receptors. The efficacy of VECTRON™ T500, a wettable powder formulation of broflanilide, was assessed for IRS against wild pyrethroid-resistant malaria vectors in experimental huts in Benin. Methods: VECTRON™ T500 was evaluated at 100 mg/m2 in mud and cement-walled experimental huts against wild pyrethroid-resistant Anopheles gambiae sensu lato (s.l.) in Covè, southern Benin, over 18 months. A direct comparison was made with Actellic® 300CS, a WHO-recommended micro-encapsulated formulation of pirimiphos-methyl, applied at 1000 mg/m2. The vector population at Covè was investigated for susceptibility to broflanilide and other classes of insecticides used for vector control. Monthly wall cone bioassays were performed to assess the residual efficacy of VECTRON™ T500 using insecticide susceptible An. gambiae Kisumu and pyrethroid-resistant An. gambiae s.l. Covè strains. The study complied with OECD principles of good laboratory practice. Results: The vector population at Covè was resistant to pyrethroids and organochlorines but susceptible to broflanilide and pirimiphos-methyl. A total of 23,171 free-flying wild pyrethroid-resistant female An. gambiae s.l. were collected in the experimental huts over 12 months. VECTRON™ T500 induced 56%-60% mortality in wild vector mosquitoes in both cement and mud-walled huts. Mortality with VECTRON™ T500 was 62%-73% in the first three months and remained > 50% for 9 months on both substrate-types. By comparison, mortality with Actellic® 300CS was very high in the first three months (72%-95%) but declined sharply to < 40% after 4 months. Using a non-inferiority margin defined by the World Health Organization, overall mortality achieved with VECTRON™ T500 was non-inferior to that observed in huts treated with Actellic® 300CS with both cement and mud wall substrates. Monthly in situ wall cone bioassay mortality with VECTRON™ T500 also remained over 80% for 18 months but dropped below 80% with Actellic® 300CS at 6–7 months post spraying. Conclusion: VECTRON™ T500 shows potential to provide substantial and prolonged control of malaria transmitted by pyrethroid-resistant mosquito vectors when applied for IRS. Its addition to the current list of WHO-approved IRS insecticides will provide a suitable option to facilitate rotation of IRS products with different modes of action. [ABSTRACT FROM AUTHOR]

Background: Malaria continues to be a leading cause of morbidity and mortality in Africa and conventional malaria control strategies, such as indoor residual spraying and insecticide-treated bed nets, have limited effectiveness for some malarial vectors. Consequently, the development of alternative or supplementary strategies is required. One potential strategy is the use of livestock-administered endectocides to control vector mosquitoes that feed outdoors on livestock. However, since this strategy requires support from local communities and livestock owners consenting for their animals to be treated, it can only be implemented if agreed to by affected communities. The aim of this study was to assess the social acceptance of the use of livestock-administered endectocides in the malaria endemic villages of Vhembe District, Limpopo Province, South Africa, where malaria incidence is high. Methods: Questionnaires were administered to 103 livestock-owning households from four villages, namely, Gumbu, Malale, Manenzhe and Bale. The assessment included questions on the acceptability of the strategy, the type and number of livestock owned, distances between houses and kraals (overnight pens) as well as previous use and awareness of endectocides. The results were analysed using descriptive statistics and multinomial logistic regression. Results: The types of livestock owned by the participants comprised, cattle, goats, sheep and donkeys, with the most dominant being goats (n = 1040) and cattle (n = 964). The majority of kraals were less than 10 m from homesteads. Most participants (72.5%) were already using chemicals to treat their livestock for parasites. All participants were amenable to the implementation of the strategy, and would give consent for their animals to be treated by endectocides. Conclusions: The use of livestock-administered endectocides appears to be a feasible and acceptable approach for control of animal-feeding malaria vector species in the malaria endemic villages of Vhembe District. This is based on a high percentage of rural residents keeping suitable livestock close to their homes and expressing willingness to use endectocides for mosquito control. [ABSTRACT FROM AUTHOR]

Background: Malaria is among the leading causes of mortality and morbidity among under five children in developing countries. Ethiopia has set targets for controlling and eliminating malaria through at-risk group interventions. However, the disease remains a serious public health concern in endemic areas like in Wollo, Northeast Ethiopia. Therefore, this study aimed to determine malaria prevalence, risk factors and parasite density among under five children in Ziquala district. Method: A facility—based cross-sectional study was conducted in Ziquala hospital, and Tsitsika, Mishra and Hamusit health centers in Ziquala district, Northeast Ethiopia, from January 2022 to April 2022. The study enrolled a total of 633 under five children using a systematic sampling technique. A capillary blood sample was collected from each child to prepared thin and thick blood smears. Smears were then stained with 10% Giemsa and examined under light microscope. A pretested structured questionnaire was used to collect on socio-demographic data, parental/caregiver knowledge, and malaria determining factors. Bivariable and multivariable logistic regression analysis was done to identify factors associated with malaria. Result: The overall prevalence of malaria among children visiting Ziquala district health institutions was 24.6% (156/633). Plasmodium falciparum, P. vivax, and mixed infection (both species) accounted for 57.1%, 38.5%, and 4.5% of the cases, respectively. Regarding to parasite load, moderate parasitemia was the most common, followed by low and high parasitemia with the proportion of 53.8%, 31.4% and 14.7% parasite density, respectively. Malaria infection was linked to irregular utilization of insecticide-treated bed nets (AOR = 5.042; 95% CI: 2.321–10.949), staying outside at night (AOR = 2.109; 95% CI: 1.066–4.173), and parents not receiving malaria health education in the past six months (AOR = 4.858; 95% CI: 2.371–9.956). Conclusion: Malaria was prevalent among children under the age of five enrolled in the study. The local government should focus on regular insecticide treated net utilization, reducing the risk of mosquito bites while sleeping outdoors at night and increasing public understanding of malaria prevention and control through health education would also help to minimize the burden of malaria. [ABSTRACT FROM AUTHOR]

Background: Malaria is a risk factor for adverse pregnancy outcomes. Indoor residual spraying with insecticide (IRS) reduces malaria infections, yet the effects of IRS on pregnancy outcomes are not well established. We evaluated the impact of a large-scale IRS campaign on pregnancy outcomes in Eastern Uganda.Methods: Birth records (n = 59 992) were obtained from routine surveillance data at 25 health facilities from five districts that were part of the IRS campaign and six neighbouring control districts ∼27 months before and ∼24 months after the start of the campaign (January 2013-May 2017). Campaign effects on low birthweight (LBW) and stillbirth incidence were estimated using the matrix completion method (MC-NNM), a machine-learning approach to estimating potential outcomes, and compared with the difference-in-differences (DiD) estimator. Subgroup analyses were conducted by HIV and gravidity.Results: MC-NNM estimates indicated that the campaign was associated with a 33% reduction in LBW incidence: incidence rate ratio (IRR) = 0.67 [95% confidence interval (CI): 0.49-0.93)]. DiD estimates were similar to MC-NNM [IRR = 0.69 (0.47-1.01)], despite a parallel trends violation during the pre-IRS period. The campaign was not associated with substantial reductions in stillbirth incidence [IRRMC-NNM = 0.94 (0.50-1.77)]. HIV status modified the effects of the IRS campaign on LBW [βIRSxHIV = 0.42 (0.05-0.78)], whereby HIV-negative women appeared to benefit from the campaign [IRR = 0.70 (0.61-0.81)], but not HIV-positive women [IRR = 1.12 (0.59-2.12)].Conclusions: Our results support the effectiveness of the campaign in Eastern Uganda based on its benefit to LBW prevention, though HIV-positive women may require additional interventions. The IRS campaign was not associated with a substantively lower stillbirth incidence, warranting further research. [ABSTRACT FROM AUTHOR]

Background. Malaria remains a disease of great public health importance in 85 countries globally. Developing countries face resource constraints in implementing public health interventions aiming at controlling malaria. Promoting community participation may contribute to rational and effective use of resources and therefore facilitating achievement of intervention goals in a cost-effective manner while fostering sustainability. However, this can be possible if the community is engaged at all stages of the intervention, from designing, implementation, monitoring, and evaluation of results. This study aimed at understanding community participation in the implementation of a biolarviciding intervention for malaria vectors control in Southern Tanzania. Methods. The current study adopted explanatory mixed method study design in collecting data. Quantitative data were collected from 400 community members and 12 vector control coordinators using structured questionnaire while qualitative data was collected through key informant interviews to 32 participants and in-depth interviews to 5 vector control coordinators who were purposively selected from the 12 councils. Quantitative data analysis involved descriptive and inferential statistics. Thematic analysis was used to analyse qualitative data. Results. Of 400 community members, only 90 (22.5%) participated in biolarviciding implementation. Predictors of community participation were willingness to participate (AOR = 3.15 , 95 % CI = 1.14 − 8.71 , P value = 0.027) and community involvement (AOR = 6.07 , 95 % CI = 2.69 − 13.71 , P value < 0.001). The study revealed that the main barriers to community participation were lack of effective involvement and lack of incentive to community volunteers while high willingness to participate was a facilitating factor for community participation. Conclusion. The study revealed low community participation in biolarviciding implementation in Southern Tanzania with willingness to participate and community involvement being the main predictors for community participation while lack of incentive to community volunteers was one major barrier to community participation. This explains the persistence of an unresolved challenge of community participation in malaria interventions. Therefore, more efforts are needed to improve the participation of community members in Malaria interventions through advocacy, awareness creation of respective roles, and responsibilities of the community members and fostering community ownership. Additionally, councils need to design customized motivation package for the community members. [ABSTRACT FROM AUTHOR]

Long-lasting insecticidal nets (LLINs) are being promoted by World Health Organization (WHO) as key vector control tool for the prevention and control of malaria and other vector-borne diseases. A laboratory study was conducted to evaluate the bio-efficacy of a new alphacypermethrin LN (HILNET®) against insecticide-susceptible Anopheles culicifacies s.l.. This study presents the observations on (a) regeneration time, the period required to regenerate insecticide in the LLIN after three consecutive WHO standard washes in a single day to deplete the insecticide on the net surface, and (b) wash resistance of the LLIN to retain bio-efficacy up to 20 repeated washes at intervals corresponding to the regeneration time in days. In the present evaluation, the regeneration time of HILNet® was determined as 2 days. Wash resistance studies of HILNet® showed a knockdown rate of 100% up to 15 washes and 97% at the 20th wash and complied with the criteria of WHO knockdown rate of ≥ 95%. The mean active ingredient content from 0 to 20 washes was in the range of 5.8 to 6.04 g/kg and met the WHO criteria of the product claim (± 25% g/kg). The insecticide un-impregnated control net has shown no detectable levels of alphacypermethrin. In this evaluation, HILNet® fulfilled the WHO laboratory (phase I) efficacy criteria based on the rates of knockdown up to 20 standard WHO washes. [ABSTRACT FROM AUTHOR]

Number of children under-five at risk of malaria in Nigeria is overwhelming and despite several reported effectiveness of Insecticide Treated Nets (ITNs) in malaria prevention, many factors deterring utilization have been reported. To examine spatial variation in South-West region of Nigeria, this study examines level of utilization among under-five children in the region. Data from the 2018 Nigeria Demographic Health Survey is used to examine relationships between different covariates and spatial variation using a semi-parametric model. Gaussian, Poisson and Zero Inflated Poisson distributions were assumed for the response variable and comparisons were made. The Deviance Information Criteria (DIC) is used as selection criteria. With lowest DIC among the competing distributions, Gaussian has the best fit for the model. Spatial variation is observed in the utilization across states. Ondo state has highest net usage among children follow by Ogun state. Both Lagos and Ekiti states have the least. Higher utilizations are observed among rural residents and households without some basic amenities and mass media. Utilization is found to be higher among respondents in the poor category of wealth index. Educational status of mothers is found to affect ITNs utilization. Non-linear effect of age of the children on the number of children sleeping under net has a bathtub shape, indicating decrease in number of children sleeping under net as age increases till around two years and then starts increasing. For effective utilization of ITNs, more efforts are to be put into campaigns on the importance of utilization rather than only ownership. [ABSTRACT FROM AUTHOR]

Background: Pregnant women who are infected with malaria usually have more severe symptoms and negative health outcomes than women who are not pregnant, with higher rates of miscarriage, intrauterine demise, premature delivery, low-birth-weight neonates, and neonatal death. Based on evidence from the 2016 Ethiopia Demographic and Health Survey, this study assessed the variation in insecticide-treated nets (ITNs) usage and its associated factors among pregnant women in Ethiopia. Methods: Data from a total of 1122 women who were pregnant at the time of the survey were included in the final analysis. Bivariate and multilevel analyses were conducted. Multilevel modeling with fixed and random coefficients was used to estimate the variation in pregnant women's ITNs usage across communities (residence areas) and regions of Ethiopia. Results: Out of the total 1122 pregnant women, 58.37% slept under a net and 41.63% did not sleep under nets. Significant variations were observed in pregnant women's ITNs usage across communities (residence areas) and regions of Ethiopia, with between variations in pregnant women's ITNs usage across communities (residence areas) and regions. In addition, the region, place of residence, wealth index, educational level, and age of the women as well as whether they believed that mosquito bites cause malaria were significant factors in pregnant women's usage of ITNs. Pregnant women in Ethiopia had moderate usage of ITNs with varied risk factors at the individual, community, and regional levels. Conclusion: Based on the factors identified, there is a need to implement and/or strengthen programs (e.g., regular sensitization) that intensify high coverage of ITNs for effective malaria prevention in Ethiopia, especially among pregnant women who do not use ITNs. [ABSTRACT FROM AUTHOR]

Widespread insecticide resistance in African malaria vectors raises concerns over the potential to compromise malaria vector control interventions. Understanding the evolution of resistance mechanisms, and whether the selective disadvantages are large enough to be useful in resistance management or designing suitable control strategies is crucial. This study assessed whether insecticide resistance to pyrethroids has an effect on the gonotrophic cycle and reproductive potential of malaria vector Anopheles gambiae. Comparative tests were performed with pyrethroid-resistant and susceptible colonies of Anopheles gambiae colonized from the same geographical area, and the reference Kisumu strain was used as a control. Adult females aged 3 days old were given a blood meal and kept separately for individual egg-laying. The number of days taken to lay eggs post-blood-feeding was recorded to determine the length of the gonotrophic cycle. To measure adult longevity and reproduction potential, newly emerged males and females of equal numbers were aspirated into a cage and females allowed to blood feed daily. The number of eggs laid and the surviving mosquitoes were recorded daily to determine fecundity, net reproduction rate, intrinsic growth rate and adult longevity. Overall, the resistant females had a significantly longer (1.8 days) gonotrophic cycle than susceptible females (F2, 13 = 9. 836, P < 0.01). The proportion of resistant females that laid eggs was lower 31.30% (94/300) compared to 54% (162/300) in the susceptible colony and 65.7% (197/300) in the Kisumu strain. The mean number of eggs laid per female was significantly lower in the resistant colony (88.02 ± 20) compared to the susceptible colony (104.9 ±.28.8) and the Kisumu strain (97.6 ± 34.8). The adult longevity was significantly higher for resistant (39.7 ± 1.6 days) compared to susceptible (29.9 ± 1.7 days) and the Kisumu strain was (29.6 ± 1.1 days) (F2,8 = 45.05, P < 0.0001). Resistant colony exhibited a lower fecundity (4.3 eggs/females/day) and net reproductive rate (2.6 offsprings/female/generation) compared to the susceptible colony (8.6 eggs/female/day; 4.7 offsprings/female/generation respectively) and Kisumu strain (9.7 eggs/female/day; 4.1 offsprings/female/generation respectively). The study suggests high fitness cost on reproductive parameters of pyrethroid-resistant mosquitoes particularly on the duration of gonotrophic cycle, fecundity and net reproductive rate. These fitness costs are likely associated with maintaining both target site and metabolic mechanisms of resistance to pyrethroids. Despite these costs, resistant mosquitoes had longer longevity. These results give insights to understanding the fitness cost of insecticide resistance and thus are critical when predicting the epidemiological impact of insecticide resistance. [ABSTRACT FROM AUTHOR]

Background: Mosquito-borne diseases such as malaria and encephalitis are still the cause of several hundred thousand deaths annually. The excessive use of chemical insecticides for transmission control has led to environmental pollution and widespread resistance in mosquitoes. Botanical insecticides' efficacies improvement has thus received considerable attention recently. Methods: The larvicidal effects of three essential oils from the Citrus family and limonene (their major ingredient) were first investigated against malaria and filariasis mosquito vectors. An attempt was then made to improve their efficacies by preparing nanoliposomes containing each of them. Results: The larvicidal effect of nanoformulated forms was more effective than non-formulated states. Nanoliposomes containing Citrus aurantium essential oil with a particle size of 52 ± 4 nm showed the best larvicidal activity (LC50 and LC90 values) against Anopheles stephensi (6.63 and 12.29 µg/mL) and Culex quinquefasciatus (4.9 and 16.4 µg/mL). Conclusion: Due to the green constituents and high efficacy of nanoliposomes containing C. aurantium essential oil, it could be considered for further investigation against other mosquitoes' populations and field trials. [ABSTRACT FROM AUTHOR]

Background: Insecticide-treated net (ITN) is a cost-effective means to control malaria and morbidity in under-five children. This study synthesizes the factors associated with using the ITN as a malaria prevention tool in sub-Saharan Africa.Methods: There was an advanced search of four electronic databases, including PubMed Central, CINAHL, EMBASE, and Google Scholar, and identified articles between 2016 to April 2021. Following the title, abstract and full-text reading, 13 articles were deemed appropriate for this review. All the researchers developed, discussed, and accepted a matrix to extract relevant information from the studies. A convergent synthesis was adopted and allowed for integrating qualitative, quantitative, and mixed-method studies and transforming them into qualitative findings.Results: Household and caregiver related factors that influenced utilization of the ITN were, Household heads having two or more sleeping places, a knowledge that ITN prevents malaria, the presence of hanging ITNs, high literacy, living female-headed households, birth spacing, unmarried mothers, and antenatal clinic attendance promoted utilization. Perceived malaria risk was a critical determinant of ITN ownership and utilization. Some factors that hindered the use of the ITN included hotness of the weather, absence of visible mosquitoes, cost, inadequate number, rooms designs, unaffordability, insufficient knowledge on causes of malaria, and poor attitude to use. Specific ITN factors that hindered use were color, chemicals use, odor, and shape.Conclusion: It is important to use integrated multi-sectoral and culturally appropriate interventions to encourage households to prioritize and utilize the ITN in under-5 children. [ABSTRACT FROM AUTHOR]

Simple Summary: New types of bed nets are being developed which contain a pyrethroid plus a second chemical because of the development and increased frequency of mosquito mechanisms to avoid being killed by pyrethroids. When insecticide-treated bed nets are being trialed for efficacy or released onto the market it is essential to measure how effective the net is in killing mosquitoes, which includes testing how quickly insecticide is lost or degraded due to routine wear and tear. Pyrethroid-resistant mosquitoes are needed to test the effectiveness and insecticidal persistence of the second chemical, because they are not all killed by the pyrethroid, allowing the killing effect of the two chemicals to be evaluated independently. However, because resistance status varies between populations of mosquitoes that possess different resistance mechanisms, and because resistance intensity in a population can change over time, a method is needed to characterise the resistant mosquitoes. A focus group of experts discussed how this should best be done, considering pros and cons of different approaches, and co-wrote a protocol, which will be valuable for malaria control programmes and stakeholders wanting to test the effective lifespan of a new bed net in terms of the active ingredient bioefficacy. Durability monitoring of insecticide-treated nets (ITNs) containing a pyrethroid in combination with a second active ingredient (AI) must be adapted so that the insecticidal bioefficacy of each AI can be monitored independently. An effective way to do this is to measure rapid knock down of a pyrethroid-susceptible strain of mosquitoes to assess the bioefficacy of the pyrethroid component and to use a pyrethroid-resistant strain to measure the bioefficacy of the second ingredient. To allow robust comparison of results across tests within and between test facilities, and over time, protocols for bioefficacy testing must include either characterisation of the resistant strain, standardisation of the mosquitoes used for bioassays, or a combination of the two. Through a series of virtual meetings, key stakeholders and practitioners explored different approaches to achieving these goals. Via an iterative process we decided on the preferred approach and produced a protocol consisting of characterising mosquitoes used for bioefficacy testing before and after a round of bioassays, for example at each time point in a durability monitoring study. We present the final protocol and justify our approach to establishing a standard methodology for durability monitoring of ITNs containing pyrethroid and a second AI. [ABSTRACT FROM AUTHOR]

Introduction: malaria in children with Sickle Cell Anaemia (SCA) results in severe morbidity and mortality, thus like in pregnant women and young children, malaria prevention in them should involve a multipronged approach. In addition to the use of chemoprophylaxis, sleeping under Insecticide-Treated Net/Long-Lasting Insecticide-Treated Net (ITN/LLIN) has been found to be efficacious and effective in reducing malaria by vector control and preventing bites by mosquitoes. The aim of this study is to determine the ownership and utilization of ITN/LLIN and socioeconomic factors influencing the ownership/utilisation of ITN/LLIN in children with SCA. Methods: this was a cross-sectional study involving children with SCA aged 6 months to 17 years; conducted using semistructured interviewer-administered questionnaire. Results: a total of 806 questionnaires on the ownership and utilization of ITN/LLIN were filled and retrieved from children with SCA and their caregivers. The mean age of study population was 80.1±48.5 months. A total of 421 (52.2%) respondents owned at least one ITN/LLIN in their homes, while 291 (36.1%) slept under an ITN the previous night. The use of malaria chemoprophylaxis was a significant predictor of both ownership and utilisation of ITN/LLIN (p=0.000; OR: Odds ratio = 2.3 and p=0.001; OR=2.0). Clinic attendance at University of Benin Teaching Hospital (UBTH) was the only significant predictor of ownership of ITN/LLIN (p=0.002, OR =2.1). Conclusion: the ownership and utilization of ITN/LLIN amongst respondents was low. Chemoprophylaxis use and attending clinic at the UBTH were significant predictors for the ownership of ITN/LLIN. [ABSTRACT FROM AUTHOR]

Background: Haiti is planning targeted interventions to accelerate progress toward malaria elimination. In the most affected department (Grande-Anse), a combined mass drug administration (MDA) and indoor residual spraying (IRS) campaign was launched in October 2018. This study assessed the intervention's effectiveness in reducing Plasmodium falciparum prevalence.Methods: An ecological quasi-experimental study was designed, using a pretest and posttest with a nonrandomized control group. Surveys were conducted in November 2017 in a panel of easy access groups (25 schools and 16 clinics) and were repeated 2-6 weeks after the campaign, in November 2018. Single-dose sulfadoxine-pyrimethamine and primaquine was used for MDA, and pirimiphos-methyl as insecticide for IRS.Results: A total of 10 006 participants were recruited. Fifty-two percent of the population in the intervention area reported having received MDA. Prevalence diminished between 2017 and 2018 in both areas, but the reduction was significantly larger in the intervention area (ratio of adjusted risk ratios, 0.32 [95% confidence interval, .104-.998]).Conclusions: Despite a moderate coverage, the campaign was effective in reducing P. falciparum prevalence immediately after 1 round. Targeted MDA plus IRS is useful in preelimination settings to rapidly decrease the parasite reservoir, an encouraging step to accelerate progress toward malaria elimination. [ABSTRACT FROM AUTHOR]

Background: Indoor residual spraying (IRS) using a capsule suspension formulation of the organophosphate insecticide, pirimiphos-methyl, has provided substantial malaria control in many communities in Africa. However, only one brand of this product has been recommended by the World Health Organisation for IRS. To help increase the diversity of the portfolio of IRS insecticides and offer suitable options to procurers and malaria vector control programmes, additional product brands of this highly effective and long-lasting insecticide formulation for IRS will be needed. Methods: We evaluated the efficacy of Pirikool® 300CS, a new capsule suspension formulation of pirimiphos-methyl developed by Tianjin Yorkool, International Trading, Co., Ltd in standard WHO laboratory bioassays and experimental hut studies. The efficacy of the insecticide applied at 1000mg/m2 was assessed in laboratory bioassays for 6 months on cement, plywood and mud block substrates and for 12 months in cement and mud-walled experimental huts against wild free-flying pyrethroid-resistant Anopheles gambiae sensu lato in Covè, Benin. Actellic® 300CS, a WHO-recommended capsule suspension formulation of pirimiphos-methyl was also tested. WHO cylinder tests were performed to determine the frequency of insecticide resistance in the wild vector population during the hut trial. Results: The vector population at the hut station was resistant to pyrethroids but susceptible to pirimiphos-methyl. Overall mortality rates of wild free-flying pyrethroid-resistant An. gambiae (s.l.) entering Pirikool®300CS treated experimental huts during the 12-month trial were 86.7% in cement-walled huts and 88% in mud-walled huts. Mortality of susceptible An. gambiae (Kisumu) and pyrethroid-resistant An. gambiae s.l. (Covè) mosquitoes in monthly wall cone bioassays on Pirikool® 300CS treated hut walls remained over 80% for 10–12 months. The laboratory bioassays corroborated the hut findings with Pirikool® 300CS on mud and wood block substrates but not on cement block substrates. Conclusion: Indoor residual spraying with Pirikool® 300CS induced high and prolonged mortality of wild pyrethroid-resistant malaria vectors for 10–12 months. Addition of Pirikool®300CS to the current portfolio of IRS insecticides will provide an extra choice of microencapsulated pirimiphos-methyl for IRS. [ABSTRACT FROM AUTHOR]

Background: Resistance to major public health insecticides in Côte d'Ivoire has intensified and now threatens the long-term effectiveness of malaria vector control interventions.Methods: This study evaluated the bioefficacy of conventional and next-generation long-lasting insecticidal nets (LLINs), determined resistance profiles, and characterized molecular and metabolic mechanisms in wild Anopheles coluzzii from Southeast Côte d'Ivoire in 2019.Results: Phenotypic resistance was intense: >25% of mosquitoes survived exposure to 10 times the doses of pyrethroids required to kill susceptible populations. Similarly, the 24-hour mortality rate with deltamethrin-only LLINs was very low and not significantly different from that with an untreated net. Sublethal pyrethroid exposure did not induce significant delayed vector mortality effects 72 hours later. In contrast, LLINs containing the synergist piperonyl butoxide, or new insecticides clothianidin and chlorfenapyr, were highly toxic to A. coluzzii. Pyrethroid-susceptible A. coluzzii were significantly more likely to be infected with malaria, compared with those that survived insecticidal exposure. Pyrethroid resistance was associated with significant overexpression of CYP6P4, CYP6P3, and CYP6Z1.Conclusions: Study findings raise concerns regarding the operational failure of standard LLINs and support the urgent deployment of vector control interventions incorporating piperonyl butoxide, chlorfenapyr, or clothianidin in areas of high resistance intensity in Côte d'Ivoire. [ABSTRACT FROM AUTHOR]

Background: The program to eradicate malaria is at a critical juncture as a new wave of insecticides for mosquito control enter their final stages of development. Previous insecticides have been deployed one-at-a-time until their utility was compromised, without the strategic management of resistance. Recent investment has led to the near-synchronous development of new insecticides, and with it the current opportunity to build resistance management into mosquito-control methods to maximize the chance of eradicating malaria. Methods: Here, building on the parameter framework of an existing mathematical model, resistance-management strategies using multiple insecticides are compared to suggest how to deploy combinations of available and new insecticides on bed nets to achieve maximum impact. Results: Although results support the use of different strategies in different settings, deploying new insecticides ideally together in (or at least as a part of) a mixture is shown to be a robust strategy across most settings. Conclusions: Substantially building on previous works, alternative solutions for the resistance management of new insecticides to be used in bed nets for malaria vector control are found. The results support a mixture product concept as the most robust way to deploy new insecticides, even if they are mixed with a pyrethroid that has lower effectiveness due to pre-existing resistance. This can help deciding on deployment strategies and policies around the sustainable use of these new anti-malaria tools. [ABSTRACT FROM AUTHOR]