Evaluation of Long-Lasting Microbial Larvicides in Reducing Malaria Transmission and Clinical Malaria Incidence

NCT ID: NCT02392832

Last Updated: 2021-03-29

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 240000 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2015-04-30
• Study Completion Date: 2019-09-30

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.

Conditions

Malaria

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: OTHER
• Blinding Strategy: SINGLE

Study Groups

Intervention arm

Fourstar® granule formulation, 90day and 180 day briquettes Bti/Bs in larval habitats of malaria vectors.

Group Type: EXPERIMENTAL

Fourstar® granule, 90 day and 180 day briquettes Bti/Bs

Intervention Type: BIOLOGICAL

In 2015: Two sites each in Kakamega and Vihiga counties in western Kenya will be randomly selected and treated with larvicides (intervention) and the other two sites will serve as control (no-intervention). Temporary habitats will be treated with FourStar® controlled release granule formulation, semi-permanent habitats will be treated with 90 day briquettes, and permanent habitats with 180 day briquettes. No retreatment.

Starts from 2016, a total of 34 clusters in the two study sites will be assigned to treatment or control by a block randomization method. The Bti treatment will be the same as in 2015. The retreatment interval will be 4-5 months. After the third treatment, no treatment will be performed for the next 8 months. After this, a cross over will be performed. Previous control sites will receive 3 rounds of the same LLML treatment at appropriate time intervals and previous treatment sites will not receive any LLMLs.

Control arm

No larvicide application.

Group Type: NO_INTERVENTION

No interventions assigned to this group

Interventions

Fourstar® granule, 90 day and 180 day briquettes Bti/Bs

In 2015: Two sites each in Kakamega and Vihiga counties in western Kenya will be randomly selected and treated with larvicides (intervention) and the other two sites will serve as control (no-intervention). Temporary habitats will be treated with FourStar® controlled release granule formulation, semi-permanent habitats will be treated with 90 day briquettes, and permanent habitats with 180 day briquettes. No retreatment.

Starts from 2016, a total of 34 clusters in the two study sites will be assigned to treatment or control by a block randomization method. The Bti treatment will be the same as in 2015. The retreatment interval will be 4-5 months. After the third treatment, no treatment will be performed for the next 8 months. After this, a cross over will be performed. Previous control sites will receive 3 rounds of the same LLML treatment at appropriate time intervals and previous treatment sites will not receive any LLMLs.

Intervention Type: BIOLOGICAL

Eligibility Criteria

Inclusion Criteria

• All clinical malaria cases from participated local hospitals and clinics.

Exclusion Criteria

• Infants younger than 6 months.

• Minimum Eligible Age: 7 Months
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Kenya Medical Research Institute

OTHER

Sponsor Role: collaborator

University of California, Irvine

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Guiyun Yan, Ph.D.

Role: PRINCIPAL_INVESTIGATOR

University of California at Irvine

Locations

Kenya Medical Research Institute

Kisumu, , Kenya

Countries

Kenya

References

Zhou G, Wiseman V, Atieli HE, Lee MC, Githeko AK, Yan G. The impact of long-lasting microbial larvicides in reducing malaria transmission and clinical malaria incidence: study protocol for a cluster randomized controlled trial. Trials. 2016 Aug 25;17(1):423. doi: 10.1186/s13063-016-1545-4.

Reference Type: DERIVED

PMID: 27558161 (View on PubMed)

Other Identifiers

R01A1050243 [HS# 2008-6148]

Identifier Type: -

Identifier Source: org_study_id