Clinical trial NCT01575613: Reducing the Burden of Malaria by Targeting Hotspots of Malaria Transmission
Official title: Reducing the Burden of Malaria by Targeting Hotspots of Transmission and Improving Malaria Control Measures in the Highlands of Western Kenya: Simultaneous Rollout of Four Malaria Control Interventions and Evaluation by Cross-sectional Surveys
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Malaria
Keywords: malaria
heterogeneity
transmission
elimination
Lead sponsor: Radboud University Medical Center
Sponsor class: OTHER
Collaborators: name: London School of Hygiene and Tropical Medicine
name: Kenya Medical Research Institute
name: Centers for Disease Control and Prevention
name: International Centre of Insect Physiology and Ecology (ICIPE)
name: Division of Malaria Control, Ministry of Health, Nairobi, Kenya
First posted: 2012-04-11
Enrollment: 17506
Sex: ALL
Minimum age (years): 6
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

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.

Eligibility criteria: Exclusion Criteria:

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

Primary outcomes:
measure: Parasite prevalence in the evaluation zone surrounding malaria hotspots
timeFrame: 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)
Secondary outcomes:
measure: Parasite prevalence inside malaria hotspots
timeFrame: 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)
measure: Parasite prevalence in the evaluation zone as function of distance to the hotspot boundary
timeFrame: 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)
measure: Anopheles mosquito density
timeFrame: determined during fortnightly trapping, starting at enrolment and continuing until up to 210 days after enrolment
measure: Passive case detection
timeFrame: determined continuously for a period of up to 210 days after enrolment
measure: Safety and acceptability of interventions
timeFrame: at a single cross-sectional survey 15-45 days after enrolment
measure: Mosquito breeding site productivity
timeFrame: determined on a weekly basis for a period of up to 210 days after enrolment
Other outcomes:
Locations:
city: Rachuonyo District
country: Kenya
Study officials:
affiliation: Radboud University Medical Center
name: Teun Bousema, PhD
role: PRINCIPAL_INVESTIGATOR
affiliation: London School of Hygiene and Tropical Medicine
name: Jon Cox, PhD
role: PRINCIPAL_INVESTIGATOR
affiliation: London School of Hygiene and Tropical Medicine
name: Jennifer Stevenson, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Bousema T, Griffin JT, Sauerwein RW, Smith DL, Churcher TS, Takken W, Ghani A, Drakeley C, Gosling R. Hitting hotspots: spatial targeting of malaria for control and elimination. PLoS Med. 2012 Jan;9(1):e1001165. doi: 10.1371/journal.pmed.1001165. Epub 2012 Jan 31.
citation: Bousema T, Stresman G, Baidjoe AY, Bradley J, Knight P, Stone W, Osoti V, Makori E, Owaga C, Odongo W, China P, Shagari S, Doumbo OK, Sauerwein RW, Kariuki S, Drakeley C, Stevenson J, Cox J. The Impact of Hotspot-Targeted Interventions on Malaria Transmission in Rachuonyo South District in the Western Kenyan Highlands: A Cluster-Randomized Controlled Trial. PLoS Med. 2016 Apr 12;13(4):e1001993. doi: 10.1371/journal.pmed.1001993. eCollection 2016 Apr.
citation: Bousema T, Stevenson J, Baidjoe A, Stresman G, Griffin JT, Kleinschmidt I, Remarque EJ, Vulule J, Bayoh N, Laserson K, Desai M, Sauerwein R, Drakeley C, Cox J. The impact of hotspot-targeted interventions on malaria transmission: study protocol for a cluster-randomized controlled trial. Trials. 2013 Feb 2;14:36. doi: 10.1186/1745-6215-14-36.