Uganda Housing Modification Study (UHMS)

Impact of Housing Modifications Combined With Piperonyl Butoxide (PBO) Long-lasting Insecticidal Nets (LLINs) on the Malaria Burden in Uganda: a Cluster-randomised Trial

Centers for Disease Control and Prevention, United States Agency for International Development (USAID), London School of Hygiene and Tropical Medicine, University of California, San Francisco

To explore housing modification as a malaria control intervention, and to assess the degree to which it may offer protection in moderate to high malaria endemicity settings, we propose a two-phase study evaluating epidemiological and entomological effectiveness, cost-effectiveness, feasibility, and acceptability of housing modification in Uganda. The first phase will be a pilot implementation assessing the feasibility of candidate housing modification interventions, followed by a cluster randomised control trial of the most effective, scalable, and cost-effective interventions.

The study will be conducted in two phases, beginning with a pilot (Phase I). The aim of the pilot will be to develop and test four types of housing modifications in both modern houses (those with brick or stone walls) and traditionally constructed houses (those with mud walls). The housing modifications will include: (1) full house screening (eaves and windows), (2) partial house screening (eaves or ceiling), (3) eave tubes, and (4) eave ribbons. Community input will be sought during the development of the housing prototypes. In the pilot, all 4 interventions will be implemented in both modern and traditional houses, plus a control arm in each group. All households will have access to PBO LLINs. Community input will be sought during the development of the housing prototypes. The pilot will include 10 arms in total, each consisting of 20 households, equal to 200 households (160 in the intervention and 40 in the control arm) in total. The feasibility and effectiveness of the interventions will be assessed through a qualitative study (FGDs and interviews), evaluation of the costs and implementation of the interventions, and entomology surveys (using CDC light traps). One to two housing interventions will be selected for Phase II following the review and discussion of the pilot results with the trial steering committee. Phase II will include a cluster-randomised trial. A cluster will be defined as a village (or segment of a village consisting of ~100 households). In the cluster-randomised trial, up to 2 interventions vs 1 control arm will be assessed in 20 clusters per arm (60 clusters total). The clusters will be non-contiguous, with a buffer zone of 300-500m. All households in the selected clusters will have PBO LLINs; households in intervention clusters will also receive the specified housing modifications. The impact of the interventions will be assessed through a cohort study, cross-sectional community surveys, entomology surveillance, a qualitative study, and an economic evaluation. The primary outcome of the trial will be clinical malaria incidence in children aged < 60 months as measured in the cohort study.

Phase II will be carried out as a cluster-randomized trial with 3 arms (2 interventions selected from the pilot study, and 1 control). There will be 20 clusters per arm (60 clusters total) and a cluster will be defined as an enumeration area within a village. All participating households in the selected clusters will have PBO LLINs, and households in intervention clusters will also receive the specified housing modifications. The impact of the interventions on malaria burden will be assessed through a cohort study, cross-sectional community surveys, entomology surveillance, a qualitative study, and an economic evaluation. The primary outcome of the trial will be clinical malaria incidence in children aged < 60 months.

Installation of partial screening, includee either screening of the eaves or installing a screened ceiling, in traditional homes.

Installation of partial screening, includee either screening of the eaves or installing a screened ceiling, in modern homes.

The eave tubes are PVC tubes with a diameter of 15 cm installed in the outer wall of occupied rooms (e.g. bedrooms and living rooms but not storage rooms) at 1.5-2 m intervals, fitted with electrostatic mesh inserts coated with insecticides. No additional screening will be done. All households will be provided with piperonyl butoxide (PBO) long-lasting insecticidal nets (LLINs) - one for every two residents.

Eave ribbons are 15 cm-wide triple-layered hessian fabrics (burlap-line fabric woven from sisal fibres, procured locally), in lengths starting 1 m that can be attached to houses using nails, adhesives or Velcro, without completely closing eave-spaces. The eave ribbons will be treated by study staff with a commonly used spatial repellent, transfluthrin. Eave ribbons will be retreated by study staff after 6 months (only in Phase II, if selected for inclusion in the cluster-randomised trial). All households will be provided with piperonyl butoxide (PBO) long-lasting insecticidal nets (LLINs) - one for every two residents.

Full house screening includes screening eaves/ceilings, ventilation openings, and windows. Eaves/ceiling, air vents, and windows of eligible houses will be screened with wire mesh or other locally available screening materials. or ceilings, if eaves are closed" and ventilation openings. We are also filling in any gaps in the walls. All households will be provided with piperonyl butoxide (PBO) long-lasting insecticidal nets (LLINs) - one for every two residents.

Partial screening will include either screening of the eaves or installing a screened ceiling, where no ceiling is present. In traditional houses, a netting (either insecticide-impregnated or untreated) may be either fixed in multiple places in the rafters or by hanging from a single central point and attached to the walls. No other screening or filling of the gaps will be done in partially screened houses.All households will be provided with piperonyl butoxide (PBO) long-lasting insecticidal nets (LLINs) - one for every two residents.

Number of incident episodes of clinical malaria per time of observation. Incident episodes of malaria defined as any treatment for malaria > 14 days after any prior treatment for malaria

Proportion of study participants with a thick blood smear positive for asexual parasites as measured by microscopy

Proportion of mosquitoes with phenotypic expression of insecticide resistance or containing genetic polymorphisms associated with resistance to insecticides of interest as identified by PCR

Proportion of households that require minimal maintenance of the implemented intervention over the period of the study, by study intervention

Longer term cost of the maintenance and upkeep of the implemented intervention, by study intervention

Phase I Inclusion criteria At least one adult aged 18 years or older present Agreement of the adult resident to provide informed consent for the pilot study Phase II Cohort Study Inclusion Criteria: Household considered their primary residence Child aged less than 59 months Agreement to come to the study clinic for any febrile illness Agreement to avoid antimalarial medications outside the study Provision of written informed consent (for parent or guardian in case of children) Cross-sectional Community Survey - Household Survey Inclusion Criteria: At least one household resident between 6 months and 14 years of age present (with an adult caregiver willing to provide informed consent for the clinical survey) At least one adult aged 18 years or older present Adult is a usual resident who slept in the sampled household on the night before the survey Agreement of the adult resident to provide informed consent for the household survey Exclusion Criteria: Dwelling destroyed or not found Household vacant No adult resident home on more than 3 occasions Cross-sectional Community Survey - Clinical Survey Inclusion Criteria: Child aged 6 months to 14 years Usual resident who was present in the sampled household on the night before the survey Agreement of parent/guardian to provide informed consent Agreement of child aged 8 years or older to provide assent Exclusion Criterion: Child not home on day of survey Recruitment of Field Workers for entomology activities (human landing catches). Inclusion Criteria: Willingness to take chemoprophylaxis for malaria Willingness to abstain from alcohol during working hours No significant past medical history.