Impact and Cost-Effectiveness of Long-Lasting Microbial Larvicides in Reducing Malaria Transmission and Clinical Malaria Incidence: a Cluster-Randomized Controlled Trial in Western Kenya
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Enrollment
- 240,000
- Locations
- 1
- Primary Endpoint
- Changes in clinical malaria incidence rate
Study Overview
Brief Summary
In the past decade, massive scale-up of insecticide-treated nets (ITN) and indoor residual spraying (IRS), together with the introduction of artemisinin-combination treatments, have led to substantial reductions in malaria prevalence and incidence in African highlands. However, rising insecticide resistance and increased outdoor transmission have greatly hampered the effectiveness of ITN and IRS because the current indoor-based interventions do not target the outdoor-biting mosquitoes. Therefore, new supplemental interventions that can tackle outdoor transmission and pyrethroid insecticide resistance are urgently needed. The central objective of this study is to determine the efficacy and cost-effectiveness of EPA-approved long-lasting microbial larvicides in reducing malaria transmission and clinical malaria incidence in western Kenya highlands.
Detailed Description
In the past decade, massive scale-up of insecticide-treated nets (ITNs) and indoor residual spraying (IRS), together with the use of artemisinin combination treatments, have led to major changes in malaria epidemiology and vector biology. Along with the significant reduction in overall malaria prevalence and incidence, extensive use of insecticides has created large selection pressures for resistance in the malaria vector populations and for potential outdoor transmission, which appears to be limiting the success of ITNs and IRS. Because IRS and ITN have little impact on outdoor resting and early biting vectors, outdoor transmission represents one of the most important challenges in malaria control. Therefore, new interventions that can augment the current public health measures to reduce outdoor transmission are urgently needed. Larval control has historically been very successful and is widely used for mosquito control in many parts of the world, except in Africa. Factors limiting the use of larvicides include high costs associated with frequent habitat re-treatment. Now a new US EPA-approved long-lasting formulation, potentially effective for 6 months is available. The central objective of this study is to determine the effect of long-lasting microbial larviciding on the incidence of clinical malaria and reduction of transmission intensity. Our hypothesis is that addition of long-lasting microbial larviciding to ongoing ITN and IRS programs will lead to significant reductions in both indoor and outdoor malaria transmission and malaria incidence.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Other
- Masking
- Single (Participant)
Eligibility Criteria
- Ages
- 7 Months to — (Child, Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •All clinical malaria cases from participated local hospitals and clinics.
Exclusion Criteria
- •Infants younger than 6 months.
Arms & Interventions
Intervention arm
Fourstar® granule formulation, 90day and 180 day briquettes Bti/Bs in larval habitats of malaria vectors.
Intervention: Fourstar® granule, 90 day and 180 day briquettes Bti/Bs (Biological)
Control arm
No larvicide application.
Outcomes
Primary Outcomes
Changes in clinical malaria incidence rate
Time Frame: baseline and 4 months following the interventions
Human population for each site stratified into three age groups, under 5 years, 6-15 years and \>15 years, will be ascertained from our existing demographic database. Age group level aggregate morbidity data with number of clinical malaria cases without any identifiers will be obtained from local hospitals and clinics where the study residents seek treatment. This data is reported to the Ministry of Health of Kenya and hence, is publicly available.
Secondary Outcomes
- Changes in vector abundance(baseline and 4 months following the interventions)
- EIR(baseline and 4 months following the interventions)