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Background: Significant effort and resources have been invested to control malaria transmission in sub-Saharan Africa, but it remains a major public health problem. For the parasite to be transmitted, the female Anopheles vector must survive 10-14 days following an infective bite to allow Plasmodium gametocytes to develop into infectious sporozoites. The goal of this study was to assess factors associated with wild-caught Anopheles survival and infection following host-seeking and indoor resting., Methods: The study was conducted between January 2020 to March 2022 in a longitudinal cohort of 75 households in 5 villages including a total of 755 household members in Bungoma County, Kenya. Monthly adult mosquito collection was conducted by attenuated aspiration in all enrolled households, and mosquitoes were reared for 7 days. The daily mortality rate was determined through day 7. All mosquitoes were morphologically identified. Female Anopheles were dissected, and species-level members of the Anopheles gambiae complex were resolved by molecular methods. The abdomens of all samples were processed for Plasmodium falciparum oocyst detection by PCR., Results: Within a 25-month period, the total numbers of non-Anopheles and Anopheles mosquitoes collected indoors were 12,843 and 712, respectively. Anopheles gambiae and An. funestus were the major vectors, though their distributions varied between different villages; 61.2% (n = 436/712) of the Anopheles mosquitoes survived up to day 7, with the lowest mortality rate recorded on day 5 of captivity. The survival rate also varied between the different Anopheles species. Six hundred eighty-three of 712 mosquito abdomens were tested for P. falciparum; 7.8% (53/683) tested positive for P. falciparum, with An. funestus having a higher (10%) prevalence than An. gambiae s.s. (6.0%, p = 0.095, Pearson Chi-square test). The proportion of household members sleeping under a bednet the night before mosquito collection varied across time and village. Anopheles funestus survival times were refractory to household ITN usage, and An. gambaie s.s. survival was reduced only under very high (100%) ITN usage., Conclusions: Despite ITN usage, mosquitoes still acquired blood meals and P. falciparum infections. Survival differed across species and was inversely correlated with high ITN usage in the household but not oocyst development., Competing Interests: Declarations Ethics approval and consent to participate Ethical approval was granted by Moi University Institutional Research and Ethics Committee (Formal Approval No. 0001863) and Duke University Institutional Review Board (Pro00082000). Written informed consent was obtained the household heads and participants prior to data and mosquito collection. All study methods were carried out in accordance with ethical guidelines and regulations set out by both Moi University and Duke Ethical Review Boards. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

In malaria-endemic countries, private retail outlets are a major source of antimalarials for individuals experiencing an acute febrile illness. However, there remains a challenge in how the decision to dispense the drugs is made. The lack of malaria diagnostic tools in the retail sector leads to a presumptive approach to diagnosis and overuse of ACTs. The TESTsmART study trained retail outlet attendants to perform malaria rapid diagnostic tests (mRDTs) in conjunction with a mobile application to capture testing and drug dispensing data. Concurrently, febrile clients were randomly selected for exit interviews outside the outlet, and analogous information about testing and drug purchasing was recorded based on self-report. A small subset of clients enrolled in exit interviews were also asked to participate in exit Plasmodium falciparum mRDT testing to confirm the accuracy of mRDTs in the outlet and to estimate malaria positivity amongst untested clients. In this sub-study, comparison of these two concurrent data sources showed the testing rate for eligible participants was slightly lower in the exit interview (42.8%, 2436/5695) than in the app (51.1%, 24,446/49,804). We noted important differences in the experiences of testing and adherence reported by outlets compared to clients; 11.0% of clients had positive mRDT reported in the app (and validated by photo review) compared to 35.3% from exit interviews. Outlets reported that 97% of test-positive clients received a first-line Artemether Combination Therapy (ACT), but only 77% of clients who reported a positive test also reported receiving the first-line ACT in the exit interview. For test-negative clients, 35% received an ACT based on outlet reports compared to 25% by exit interviews. Among 109 clients randomly selected for re-test at exit interview, nearly two-thirds of those who reported a positive test from the outlet had a negative mRDT (64.3%, 9/14) when retested. Contrasting outcomes reported by the provider and the client highlight barriers to improving testing and adherence for malaria as well as challenges for monitoring case management in the retail sector. These include accurate communication of results to the client, poor confidence in a negative result, and reluctance to withhold antimalarials from test-negative clients., Competing Interests: Competing interests: The authors declare that they have no competing interests

Malaria remains a major health priority in Nigeria. Among children with fever who seek care, less than a quarter gets tested for malaria, leading to inappropriate use of the recommended treatment for malaria; Artemisinin-based Combination Therapy (ACT). Here we test an innovative strategy to target ACT subsidies to clients seeking care in Nigeria's private retail health sector who have a confirmed malaria diagnosis. We supported point-of-care malaria testing (mRDTs) in 48 Private Medicine Retailers (PMRs) in the city of Lagos, Nigeria and randomized them to two study arms; a control arm offering subsidized mRDT testing for USD $0.66, and an intervention arm where, in addition to access to subsidized testing as in the control arm, clients who received a positive mRDT at the PMR were eligible for a free (fully subsidized) first-line ACT and PMRs received USD $0.2 for every mRDT performed. Our primary outcome was the proportion of ACTs dispensed to individuals with a positive diagnostic test. Secondary outcomes included proportion of clients who were tested at the PMR and adherence to diagnostic test results. Overall, 23% of clients chose to test at the PMR. Test results seemed to inform treatment decisions and resulted in enhanced targeting of ACTs to confirmed malaria cases with only 26% of test-negative clients purchasing an ACT compared to 58% of untested clients. However, the intervention did not offer further improvements, compared to the control arm, in testing rates or dispensing of ACTs to test-positive clients. We found that ACT subsidies were not passed on to clients testing positive in the intervention arm. We conclude that mRDTs could reduce ACT overconsumption in Nigeria's private retail health sector, but PMR-oriented incentive structures are difficult to implement and may need to be complemented with interventions targeting clients of PMRs to increase test uptake and adherence. Trials registration: Clinical Trials Registration Number: NCT04428307. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7816435/ Correction: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9476591/., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Visser et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The human infectious reservoir of Plasmodium falciparum is governed by transmission efficiency during vector-human contact and mosquito biting preferences. Understanding biting bias in a natural setting can help target interventions to interrupt transmission. In a 15-month cohort in western Kenya, we detected P. falciparum in indoor-resting Anopheles and human blood samples by qPCR and matched mosquito bloodmeals to cohort participants using short-tandem repeat genotyping. Using risk factor analyses and discrete choice models, we assessed mosquito biting behavior with respect to parasite transmission. Biting was highly unequal; 20% of people received 86% of bites. Biting rates were higher on males (biting rate ratio (BRR): 1.68; CI: 1.28-2.19), children 5-15 years (BRR: 1.49; CI: 1.13-1.98), and P. falciparum-infected individuals (BRR: 1.25; CI: 1.01-1.55). In aggregate, P. falciparum-infected school-age (5-15 years) boys accounted for 50% of bites potentially leading to onward transmission and had an entomological inoculation rate 6.4x higher than any other group. Additionally, infectious mosquitoes were nearly 3x more likely than non-infectious mosquitoes to bite P. falciparum-infected individuals (relative risk ratio 2.76, 95% CI 1.65-4.61). Thus, persistent P. falciparum transmission was characterized by disproportionate onward transmission from school-age boys and by the preference of infected mosquitoes to feed upon infected people., (© 2024. The Author(s).)

ACTs are responsible for a substantial proportion of the global reduction in malaria mortality over the last ten years, made possible by publicly-funded subsidies making these drugs accessible and affordable in the private sector. However, inexpensive ACTs available in retail outlets have contributed substantially to overconsumption. We test an innovative, scalable strategy to target ACT-subsidies to clients with a confirmatory diagnosis. We supported malaria testing(mRDTs) in 39 medicine outlets in western Kenya, randomized to three study arms; control arm offering subsidized mRDT testing (0.4USD), client-directed intervention where all clients who received a positive RDT at the outlet were eligible for a free (fully-subsidized) ACT, and a combined client and provider directed intervention where clients with a positive RDT were eligible for free ACT and outlets received 0.1USD for every RDT performed. Our primary outcome was the proportion of ACT dispensed to individuals with a positive diagnostic test. Secondary outcomes included proportion of clients tested at the outlet and adherence to diagnostic test results. 43% of clients chose to test at the outlet. Test results informed treatment decisions, resulting in targeting of ACTs to confirmed malaria cases- 25.3% of test-negative clients purchased an ACT compared to 75% of untested clients. Client-directed and client+provider-directed interventions did not offer further improvements, compared to the control arm, in testing rates(RD = 0.09, 95%CI:-0.08,0.26) or dispensing of ACTs to test-positive clients(RD = 0.01,95% CI:-0.14, 0.16). Clients were often unaware of the price they paid for the ACT leading to uncertainty in whether the ACT subsidy was passed on to the client. This uncertainty undermines our ability to definitively conclude that client-directed subsidies are not effective for improving testing and appropriate treatment. We conclude that mRDTs could reduce ACT overconsumption in the private retail sector, but incentive structures are difficult to scale and their value to private providers is uncertain. Trial registration: ClinicalTrials.gov NCT04428307., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Laktabai et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

ACTs are responsible for a substantial proportion of the global reduction in malaria mortality over the last ten years. These reductions would not have been possible without publicly-funded subsidies making these drugs accessible and affordable in the private sector. However, inexpensive ACTs available in retail outlets have contributed substantially to their overconsumption. We test an innovative, scalable, and sustainable strategy to target ACT subsidies to clients with a confirmatory diagnosis. We supported point-of-care malaria testing (mRDTs) in 39 retail medicine outlets in western Kenya and randomized them to three study arms; control arm offering subsidized RDT testing for 0.4USD, client-directed intervention where all clients who received a positive RDT at the outlet were eligible for a free (fully subsidized) first-line ACT, and a combined client and provider directed intervention where clients with a positive RDT were eligible for free ACT and outlets received 0.1USD for every RDT performed. Our primary outcome was the proportion of ACT dispensed to individuals with a positive diagnostic test. Secondary outcomes included proportion of clients tested at the outlet and adherence to diagnostic test results. 43% of clients chose to test at the outlet. Test results informed treatment decisions and resulted in targeting of ACTs to confirmed malaria cases - 25.3% of test-negative clients purchased an ACT compared to 75% of untested clients. Client-directed and client+provider-directed interventions did not offer further improvements, compared to the control arm, in testing rates (RD=0.09, 95%CI:-0.08,0.26) or dispensing of ACTs to test-positive clients (RD=0.01,95% CI: -0.14, 0.16). Clients were often unaware of the price they paid for the ACT leading to uncertainty in whether the ACT subsidy was passed on to the client. We conclude that mRDTs could reduce ACT overconsumption in the private retail sector, but incentive structures are difficult to scale and their value to private providers is uncertain.

Background: A large proportion of artemisinin-combination therapy (ACT) anti-malarial medicines is consumed by individuals that do not have malaria. The over-consumption of ACTs is largely driven by retail sales in high malaria-endemic countries to clients who have not received a confirmatory diagnosis. This study aims to target ACT sales to clients receiving a confirmatory diagnosis using malaria rapid diagnostic tests (mRDTs) at retail outlets in Kenya and Nigeria., Methods: This study comprises two linked four-arm 2 × 2 factorial cluster randomized controlled trials focused on malaria diagnostic testing and conditional ACT subsidies with the goal to evaluate provider-directed and client-directed interventions. The linked trials will be conducted at two contrasting study sites: a rural region around Webuye in western Kenya and the urban center of Lagos, Nigeria. Clusters are 41 and 48 participating retail outlets in Kenya and Nigeria, respectively. Clients seeking care at participating outlets across all arms will be given the option of paying for a mRDT-at a study-recommended price-to be conducted at the outlet. In the provider-directed intervention arm, the outlet owner receives a small monetary incentive to perform the mRDT. In the client-directed intervention arm, the client receives a free ACT if they purchase an mRDT and receive a positive test result. Finally, the fourth study arm combines both the provider- and client-directed interventions. The diagnosis and treatment choices made during each transaction will be captured using a mobile phone app. Study outcomes will be collected through exit interviews with clients, who sought care for febrile illness, at each of the enrolled retail outlets., Results: The primary outcome measure is the proportion of all ACTs that are sold to malaria test-positive clients in each study arm. For all secondary outcomes, we will evaluate the degree to which the interventions affect purchasing behavior among people seeking care for a febrile illness at the retail outlet., Conclusions: If our study demonstrates that malaria case management can be improved in the retail sector, it could reduce overconsumption of ACTs and enhance targeting of publicly funded treatment reimbursements, lowering the economic barrier to appropriate diagnosis and treatment for patients with malaria., Trial Registration: ClinicalTrials.gov NCT04428307 , registered June 9, 2020, and NCT04428385 , registered June 9, 2020.