Publications by authors named "Yukich J"

Background: Malaria incidence in the Greater Mekong Subregion has been on the decline, and most remaining malaria risk in the region is concentrated among hard-to-reach populations, especially those with exposure to forested areas. New vector control tools focused on outdoor protection in forest settings are needed for these populations.

Methods: The delivery of a 'forest pack' containing a volatile pyrethroid spatial repellent (VPSR), a topical repellent, and pyrethroid treatment of clothing was evaluated in an operational study in Cambodia.

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Background: Progress towards malaria elimination in the Greater Mekong Subregion has left much of the residual malaria transmission concentrated among forest-exposed populations for whom traditional domicile focused malaria vector control is unlikely to be effective. New tools to protect these populations from vector biting outdoors are needed.

Methods: Alongside implementation research on the deployment of a "forest pack" consisting of a volatile pyrethroid (transfluthrin)-based spatial repellent (VPSR), a picaridin-based topical repellent and etofenprox treatment of clothing, an assessment was made of participant willingness to pay for the forest packs and variants of the packs using a discrete choice experiment.

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Background: Attractive targeted sugar bait (ATSB) stations containing bait (to attract) and ingestion toxicant (to kill) sugar-foraging mosquitoes are hypothesized to reduce malaria transmission by shortening the lifespan of Anopheles vectors.

Methods: A two-arm cluster-randomized controlled trial (cRCT) was conducted in Western Province Zambia. Seventy clusters of 250-350 households were assigned (1:1) by restricted randomization to an intervention arm (ATSB) or control arm (no ATSB) in the context of standard of care vector control (insecticide-treated nets and/or indoor residual spraying).

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Background: Some settings continue to experience a high malaria burden despite scale-up of malaria vector control to high levels of coverage. Characterisation of persistent malaria transmission in the presence of standard control measures, also termed residual malaria transmission, to understand where and when individuals are exposed to vector biting is critical to inform refinement of prevention and control strategies.

Methods: Secondary analysis was performed using data collected during a phase III cluster randomized trial of attractive targeted sugar bait stations in Western Province, Zambia.

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Objective: We aimed to investigate sociodemographic factors associated with self-reported COVID-19 infection.

Methods: The study population was a prospective multicenter cohort of adult volunteers recruited from healthcare systems located in the mid-Atlantic and southern United States. Between April 2020 and October 2021, participants completed daily online questionnaires about symptoms, exposures, and risk behaviors related to COVID-19, including self-reports of positive SARS CoV-2 detection tests and COVID-19 vaccination.

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Background: Attractive Targeted Sugar Baits (ATSBs) are a proposed new vector control tool for malaria that contain sugar and an ingestion toxicant, and are designed to attract and kill sugar-feeding mosquitoes. During a two-arm cluster randomized Phase III trial conducted in Zambia to test the efficacy of ATSB stations on malaria incidence, ATSB stations deployed on eligible household structures within intervention clusters were routinely monitored to ensure their good physical condition and high coverage. This study investigates trends in prevalence and rate of damage to ATSB stations during year 2 of the two-year trial.

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Background: Community acceptance is an important criterion to assess in community trials, particularly for new tools that require high coverage and use by a target population. Installed on exterior walls of household structures, the attractive targeted sugar bait (ATSB) is a new vector control tool designed to attract and kill mosquitoes. ATSBs were evaluated in Western Zambia during a two-year cluster randomized controlled trial to assess the efficacy of ATSBs in reducing malaria transmission.

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Background: Attractive targeted sugar bait (ATSB) stations are a novel tool with potential to complement current approaches to malaria vector control. To assess the public health value of ATSB station deployment in areas of high coverage with standard vector control, a two-arm cluster-randomized controlled trial (cRCT) of Sarabi ATSB® stations (Westham Ltd., Hod-Hasharon, Israel) was conducted in Western Province, Zambia, a high-burden location were Anopheles funestus is the dominant vector.

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Background: Attractive Targeted Sugar Baits (ATSBs) offer a complementary vector control strategy to interventions targeting blood feeding or larval control by attacking the sugar feeding behaviour of adult mosquitoes using an attract-and-kill approach. Western Zambia was the first location to receive and deploy ATSB Sarabi version 1.2 stations in a Phase III cluster randomized controlled trial.

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Background: The primary vector control interventions in Zambia are long-lasting insecticidal nets and indoor residual spraying. Challenges with these interventions include insecticide resistance and the outdoor biting and resting behaviours of many Anopheles mosquitoes. Therefore, new vector control tools targeting additional mosquito behaviours are needed to interrupt transmission.

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Background: The attractive targeted sugar bait (ATSB) is a novel malaria vector control tool designed to attract and kill mosquitoes using a sugar-based bait, laced with oral toxicant. Western Province, Zambia, was one of three countries selected for a series of phase III cluster randomized controlled trials of the Westham ATSB Sarabi version 1.2.

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Quality improvement of malaria services aims to ensure that more patients receive accurate diagnosis, appropriate treatment, and referral. The Outreach Training and Supportive Supervision Plus (OTSS+) approach seeks to improve health facility readiness and provider competency through onsite supportive supervision, troubleshooting, and on-the-job training. As part of a multicomponent evaluation, qualitative research was conducted to understand the value of the OTSS+ approach for malaria quality improvement.

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Genomic epidemiology holds promise for malaria control and elimination efforts, for example by informing on Plasmodium falciparum genetic diversity and prevalence of mutations conferring anti-malarial drug resistance. Limited sequencing infrastructure in many malaria-endemic areas prevents the rapid generation of genomic data. To address these issues, we developed and validated assays for P.

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Article Synopsis
  • - The study investigates the effectiveness of two seasonal malaria chemoprevention (SMC) regimens, sulfadoxine-pyrimethamine (SP) plus amodiaquine (AQ) versus dihydroartemisinin-piperaquine (DHA-PQ), in preventing malaria in children aged 3 months to 9 years in Mali, where rising SP resistance is a concern.
  • - Conducted in the Koulikoro District of Mali, the research employs a 3-arm cluster-randomized design to compare the two regimens, focusing on malaria incidence rates and exploring the potential of DHA-PQ as a second-line treatment if SP-AQ proves ineffective.
  • - The primary goal is to determine if DHA-PQ
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Outreach Training and Supportive Supervision (OTSS) of malaria services at health facilities has been adopted by numerous malaria-endemic countries. The OTSS model is characterized by a hands-on method to enhance national guidelines and supervision tools, train supervisors, and perform supervision visits. An independent evaluation was conducted to evaluate the effectiveness of OTSS on health worker competence in the clinical management of malaria, parasitological diagnosis, and prevention of malaria in pregnancy.

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This manuscript is a master statistical analysis plan for each of three-cluster randomized controlled trials to evaluate the efficacy of attractive targeted sugar baits (ATSB) described in an already published protocol. The master SAP contains an overarching plan for all three trials, which can be adapted to trial-specific circumstances. The primary objective of the trials is to evaluate the efficacy of ATSB in the presence of universal vector control coverage with insecticide-treated nets (ITN) or indoor residual spraying (IRS) after two transmission seasons on clinical malaria incidence as compared with universal vector control coverage with ITN or IRS alone.

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Background: Malaria is endemic throughout Mozambique, contributing significantly to the country's burden of disease. Prompt and effective treatment for fevers in children can limit the mortality and morbidity impacts of the disease but many children in the country are not taken for formal care when ill. Using an ideational model of behaviour, this study assesses the magnitude of the relationships for potential drivers of care-seeking, including interpersonal communication, malaria messaging, and knowledge and attitudes about malaria, with actual care-seeking behaviours for under-five children with fever in Magoé district, Mozambique.

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Background: Zanzibar has made substantial progress in malaria control with vector control, improved diagnosis, and artemisinin-based combination therapy. Parasite prevalence in the population has remained around 1% but imported infections from mainland Tanzania contribute to sustained local transmission. Understanding travel patterns between mainland Tanzania and Zanzibar, and the risk of malaria infection, may help to control malaria importation to Zanzibar.

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Background: Insecticide-treated nets (ITNs) have served as the cornerstone of malaria vector control in sub-Saharan Africa for the past two decades. Over 2.5 billion ITNs have been delivered since 2004 primarily through periodic mass distribution campaigns scheduled at approximately three-year intervals, aligning with the expected lifespan of nets.

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Zanzibar has made significant progress toward malaria elimination, but recent stagnation requires novel approaches. We developed a highly multiplexed droplet digital PCR (ddPCR)-based amplicon sequencing method targeting 35 microhaplotypes and drug-resistance loci, and successfully sequenced 290 samples from five districts covering both main islands. Here, we elucidate fine-scale Plasmodium falciparum population structure and infer relatedness and connectivity of infections using an identity-by-descent (IBD) approach.

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Malaria cases can be classified as imported, introduced or indigenous cases. The World Health Organization's definition of malaria elimination requires an area to demonstrate that no new indigenous cases have occurred in the last three years. Here, we present a stochastic metapopulation model of malaria transmission that distinguishes between imported, introduced and indigenous cases, and can be used to test the impact of new interventions in a setting with low transmission and ongoing case importation.

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Background: The functional survival time of long-lasting insecticidal nets (LLINs), which varies across different field contexts, is critical for the successful prevention of malaria transmission. However, there is limited data on LLIN durability in field settings in Ethiopia.

Methods: A three-year longitudinal study was conducted to monitor attrition, physical integrity, and bio-efficacy and residual chemical concentration of LLINs in four regions in Ethiopia.

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Background: Attractive targeted sugar bait (ATSB) stations are a promising new approach to malaria vector control that could compliment current tools by exploiting the natural sugar feeding behaviors of mosquitoes. Recent proof of concept work with a prototype ATSB Sarabi Bait Station (Westham Co., Hod-Hasharon, Israel) has demonstrated high feeding rates and significant reductions in vector density, human biting rate, and overall entomological inoculation rate for Anopheles gambiae sensu lato (s.

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Article Synopsis
  • The study explores the relationship between human mobility, livelihood activities, and malaria risk in Jazan, Saudi Arabia, aiming to improve malaria elimination strategies in the region.
  • It involved a case-control design with 261 participants, including 81 confirmed malaria cases and 180 controls, who were interviewed about their travel history and livelihood activities.
  • Findings suggest that recent travel from home villages, along with certain agricultural activities, may increase the risk of malaria infection, indicating the need for targeted interventions in the area.
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