Reducing the Burden of Malaria by Targeting Hotspots of Malaria Transmission

Not Applicable

Completed

• Conditions: Malaria
• Interventions: Drug: Artemether-lumefantrine combination; Biological: Bacillus thuringiensis; Biological: Long lasting insecticide treated net (LLINs); Biological: Indoor Residual Spraying (IRS)

• Registration Number: NCT01575613
• Lead Sponsor: Radboud University Medical Center

Brief Summary

In this study, the investigators propose to determine the value of rolling out four targeted malaria control efforts in reducing overall malaria transmission. These targeted control efforts include local upscaling of IRS and ITNs in hotspots of malaria transmission. In addition, larviciding will be employed to target malaria vectors, also those that are less susceptible to IRS and ITNs as a consequence of outdoor feeding and resting. Lastly, the human infectious reservoir will be reduced in hotspots of malaria transmission by treating parasite carriers and their household members with the current first-line antimalarial drug. The impact of these targeted interventions on overall transmission intensity will be assessed in the context of currently ongoing malaria control activities in a plausibility study. Hotspots of malaria transmission are defined in an area of 100km2 and randomized to receive hotspot targeted interventions and compared with their baseline and with control clusters where the routine (untargeted) malaria control activities continue. The interventions will be evaluated based on changes in parasite prevalence measured in community surveys inside and outside hotspots of malaria transmission. Parasite prevalence will be compared before and after the intervention in intervention clusters and between intervention and control clusters.

In addition to malaria surveys in the human population, an entomological evaluation will take place where the densities of mosquito larvae and adult mosquitoes are monitored longitudinally.

Detailed Description

DEFINITIONS This study uses a plausibility design to determine the plausible impact of hotspot-targeted interventions on overall malaria transmission. Hotspots will be detected in the 100km2 study area. Hotspots are defined as areas with a level of transmission intensity that exceeds that in the surrounding area; indicated by a higher sero-conversion rate and/or age-adjusted density of malaria-specific antibodies.

Clusters for the intervention are defined as a hotspot and the area surrounding this hotspot in each direction up to 500 meters.

INTERVENTION Half of the clusters will be randomized to hotspot-targeted interventions, while the other half will serve as control. The plausible impact of hotspot targeted interventions will be evaluated by comparing malaria indices in intervention clusters with their baseline and with control clusters.

In each phase four hotspot-targeted interventions will be superimposed on ongoing control measures: hotspots will be targeted with a combination IRS, long-lasting insecticide treated nets (LLINs), larviciding and a focal screening and treatment (FSAT).

EVALUATION The primary outcome will be parasite prevalence in evaluation zones (i.e. the area surrounding malaria hotspots) of targeted and untargeted clusters. In addition, parasite prevalence will be determined inside hotspots of malaria transmission and in evaluation zones in relation to distance to the hotspot boundary. For this, community surveys are planned prior to the intervention and at two time-points after the intervention.

An entomological evaluation will take place concurrently in which mosquito breeding sites are monitored for productivity and mosquitoes will be sampled indoors and outdoors.

Malaria morbidity is assessed by passive case detection.

Study Timeline

• Study First Submitted: 2012-03-19
• Study Start: 2012-04
• Study First Submitted QC: 2012-04-10
• Study First Posted: 2012-04-11
• Status Verified: 2012-11
• Primary Completion: 2012-11
• Study Completion: 2012-11
• Last Update Submitted: 2012-11-26
• Last Update Posted: 2012-11-27

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 17506

Inclusion Criteria

Not provided

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Exclusion Criteria

• For LLINs, IRS and larviciding there are no exclusion criteria
• Pregnant women and children < 6 months of age are excluded from FSAT

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Hotspot Targeting	Indoor Residual Spraying (IRS)	Four hotspot-targeted interventions will be superimposed on ongoing control measures: hotspots will be targeted with a combination of IRS, long-lasting insecticide treated nets (LLINs), larviciding and a focal screening and treatment (FSAT)campaign.
Hotspot Targeting	Artemether-lumefantrine combination	Four hotspot-targeted interventions will be superimposed on ongoing control measures: hotspots will be targeted with a combination of IRS, long-lasting insecticide treated nets (LLINs), larviciding and a focal screening and treatment (FSAT)campaign.
Hotspot Targeting	Bacillus thuringiensis	Four hotspot-targeted interventions will be superimposed on ongoing control measures: hotspots will be targeted with a combination of IRS, long-lasting insecticide treated nets (LLINs), larviciding and a focal screening and treatment (FSAT)campaign.
Hotspot Targeting	Long lasting insecticide treated net (LLINs)	Four hotspot-targeted interventions will be superimposed on ongoing control measures: hotspots will be targeted with a combination of IRS, long-lasting insecticide treated nets (LLINs), larviciding and a focal screening and treatment (FSAT)campaign.

Primary Outcome Measures

Name	Time	Method
Parasite prevalence in the evaluation zone surrounding malaria hotspots	3 cross-sectional surveys in up to 210 days, the timing being: at enrolment; 45-75 days post enrolment (coinciding with the peak malaria transmission season) and 150-210 days post enrolment (coinciding with the end of the malaria transmission season)	Parasite prevalence, determined by PCR, in the evaluation zone surrounding hotspots in intervention and control clusters

Secondary Outcome Measures

Name	Time	Method
Parasite prevalence inside malaria hotspots	3 cross-sectional surveys in up to 210 days, the timing being: at enrolment; 45-75 days post enrolment (coinciding with the peak malaria transmission season) and 150-210 days post enrolment (coinciding with the end of the malaria transmission season)	Parasite prevalence, determined by PCR, inside hotspot of malaria transmission in intervention and control clusters
Parasite prevalence in the evaluation zone as function of distance to the hotspot boundary	3 cross-sectional surveys in up to 210 days, the timing being: at enrolment; 45-75 days post enrolment (coinciding with the peak malaria transmission season) and 150-210 days post enrolment (coinciding with the end of the malaria transmission season)	Parasite prevalence, determined by PCR, in relation to distance to the boundary of malaria hotspots in intervention and control clusters
Anopheles mosquito density	determined during fortnightly trapping, starting at enrolment and continuing until up to 210 days after enrolment	Indoor and outdoor anopheles mosquito density inside and outside hotspots of malaria transmission in intervention and control clusters
Passive case detection	determined continuously for a period of up to 210 days after enrolment	Number of malaria cases reporting at health facilities, coming from intervention and control clusters
Safety and acceptability of interventions	at a single cross-sectional survey 15-45 days after enrolment	Side effects of FSAT, LLINs and IRS in targeted households
Mosquito breeding site productivity	determined on a weekly basis for a period of up to 210 days after enrolment	The presence and density of anopheles larvae in mosquito breeding sites in malaria hotspots in intervention and control clusters