MDA and Targeted Control Against Plasmodium Carriage in the Sahel

Summary

Strategies implemented since 2010 by the Senegalese National Malaria Control Program (NMCP) enabled a reduction of malaria transmission. However, malaria incidence increased again in recent years, especially in the "red zone" of Kedougou, Kolda and Tambacounda regions. Neighbouring Sahelian countries also documented an increase in malaria incidence in the same period. Current interventions include : long-lasting insecticidal nets, free diagnostic and treatment of clinical malaria, home-based case management (PECADOM), intermittent preventive treatment of pregnant women and seasonal malaria chemoprevention for children up to 10 years. These strategies, while efficient to reduce the burden of clinical malaria, do not account for individuals chronically infected with Plasmodium parasites. These carriers often remain asymptomatic and act as a reservoir for persistence during the dry season, and onwards transmission during the wet season. An observational study conducted in Kedougou in 2021 and 2022 by IRD Dakar shed light on the most affected age groups and on risk-factors associated with asymptomatic carriage.

Interventions against asymptomatic carriage could complement existing strategies and contribute to reducing malaria transmission. Mass drug administration (MDA) involves proposing a curative treatment of each member of the community, regardless of age, during a coordinated campaign. To this day, it is the only intervention available to deplete the reservoir of Plasmodium carriers, since a large proportion of asymptomatic infections remain undetectable with available field tests. A study conducted by NMCP and Iba Der Thiam University in Thiès (UIDT) in 2021 in Tambacounda showed that regular MDA campaigns during the high transmission season had a significant impact on clinical malaria incidence and on prevalence of carriage.

AMARETi project aims to evaluate an intervention to complete current control strategies. The design of this intervention combines the recent results from Kedougou and Tambacounda studies. The intervention consists of an MDA campaign at the start and at the end of the high transmission season, aiming at maximal depletion of the asymptomatic reservoir, and of age-group targeted interventions aiming to reduce chronic reinfection in individuals at highest risk of asymptomatic carriage.

The design and implementation of the intervention stem from a co-construction process with members of communities participating in the research, to maximize inclusiveness and adhesion. It aims to ensure the design of interventions that are adapted to age, gender and other factors deemed relevant by researchers and communities.

The project will evaluate if this intervention improves significantly the situation compared to current strategy in a stepped-wedge cluster-randomized controlled trial over 2 malaria high transmission seasons. If the results are conclusive, recommendations for scale-up can be made. The primary outcome will be Plasmodium falciparum infection prevalence at the end of the high transmission season. Secondary outcomes include clinical malaria incidence and malaria incidence dynamics, as well as participation, safety and acceptability.

Implementation outcomes (not detailed here) will include the assessment of implementation (CFIR's indicators), sustainability (Schell's indicators) and scalability (Coroa's indicators). These indicators use multiple dimensions stemming from qualitative and quantitative data and flexible design to understand each specific outcome (Proctor E, et al, Mental Health and Mental Health Services Research 2011).

In addition, a nested study in 10 villages will provide insights on transmission and reservoir restoration mechanisms through follow-up of a cohort and in-depth investigations.

AMARETi project will take place from 2024 to 2027 in 7 health posts and 50 villages of Kedougou department, under the leadership of the Kedougou Health District and Region authorities. The local health, administrative and community-based authorities at local and regional level are also key partners in the project, as well as local development committees and health community-based organisations. Healthpost staff and community health workers and volunteers will be essential for the operational field implementation.

Conditions

• Malaria, Falciparum
• Malaria, Asymptomatic Parasitaemia

Interventions

DRUG

MDA with DHAp and SLD Primaquine

MDA: 2 rounds of MDA with dihydroartemisinine-piperaquine + single low dose primaquine (PQ) administered instead of SMC round 1 and 5.

BEHAVIORAL

Targeted control (10-24 years) during the malaria high tranmission season: behaviour

Communication and community engagement activities by age-groups: * children aged 10-14 and their parents : promote early health seeking behaviour in case of symptoms * young adults (15-24) : promote early health seeking behaviour in case of symptoms, emphasing the importance of mild symptoms.

DIAGNOSTIC_TEST

Targeted control (15-24 years) during the malaria high tranmission season: test and treat

Voluntary testing for malaria in young adults (15-24 years) using rapid diagnostic tests performed by community health workers during home visits or group testing events organized by the village youth association.

Sponsors & Collaborators

• Programme National de Lutte contre le Paludisme (PNLP), Senegal

  collaborator UNKNOWN

• L'université de Thiès

  collaborator OTHER

• Cheikh Anta Diop University, Senegal

  collaborator OTHER

• Institut de Recherche pour le Developpement

  lead OTHER_GOV

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

NONE

Model

SEQUENTIAL

Eligibility

Min Age

3 Months

Max Age

100 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2024-09-23

Primary Completion

2026-12-31

Completion

2027-12-31

Countries

• Senegal

Study Locations