Cambodia has made huge progress towards eliminating Plasmodium falciparum (P. falciparum) malaria in recent years and is well on track to achieve its goal of eliminating P. falciparum malaria by the end of 2023 (1, 2). This can be attributed to intensified efforts to accelerate the elimination of P. falciparum malaria in the Greater Mekong Subregion (GMS) under the two consecutive Regional Artemisinin-resistance Initiative (RAI) programs since 2016.
In Cambodia, the RAI program focuses on international borders and forest areas where remaining malaria parasite reservoirs are clustered (3-5). In these areas, the population at highest risk of malaria infection are mobile and migrant populations and forest workers (6-9) who often spend several nights in the forest at a time or even stay there permanently (5, 10). These populations are hard to reach via the common community-based passive case detection system. This system requires people to actively seek care with village malaria workers (VMWs) while mobile and migrant populations might not know about the local health system or not be knowledgeable about malaria symptoms and appropriate health seeking behaviour if they migrated from other regions or non-malaria endemic areas (6, 11, 12). Expanding access to early diagnosis and effective treatment (EDAT) is a key element of the Cambodia National Strategic Plan For Elimination of Malaria (13). In 2009, the National Center for Parasitology, Entomology and Malaria Control (CNM) therefore introduced the community health worker role of mobile malaria workers (MMWs) to target these remote populations with active case detection approaches (11). In border areas, this is challenging due to highly heterogeneous micro-geographical epidemiology, unexplored forest areas, difficult to access terrain and changing movement and behavioural patterns of populations.
One component under the under the second RAI program (RAI2E) 2018-2020 was a project delivering a tailored package of active case detection approaches through MMWs in selected hard-to-reach border areas in north-eastern Cambodia. The approach was developed in alignment with the Cambodia National Strategic Plan for Elimination of Malaria{Kingdom of Cambodia, 2011 #683}, in close collaboration with the CNM. The RAI2E grant concluded by the end of 2020 and was followed by RAI3, the third 3-year-grant-cycle in the GMS. The conclusion of the second grant cycle is an appropriate occasion to look back on the achievements during the RAI2E implementation period, to investigate challenges faced along the way, and to discuss priorities for the final phase of malaria elimination.
Objectives
This case study aims 1) to outline the approach to deliver a tailored package of active case detection approaches with the aim of providing EDAT services to remote populations in border areas of three provinces in north-eastern Cambodia under the RAI2E program, and 2) to describe results achieved and discuss remaining challenges for the last malaria elimination phase.
Approach
Project setting
The project started in 2018 and ended in December 2020. It was implemented in border areas of the three Cambodian provinces Preah Vihear, Stung Treng and Ratanakiri along the Laos, Thailand and Vietnam borders. Border areas in these provinces are forested and difficult to access, especially during the rainy season between May and October. The existing network of eight to ten MMWs working in the area prior to 2018 was scaled up to 50 MMWs as part of the project. MMWs work under the CNM and are assigned to specific health facilities that oversee the activities of their assigned community health workers (MMWs and VMWs) and provide them with treatment supplies. The target population was everyone living and working within the catchment area of the project sites with a focus on reaching the high risk population of adult males over the age of 15 as defined by the Malaria Elimination Action Framework 2016-2020 (9).
Project design
The goal of this project was to contribute to the RAI2E objective of accelerating P. falciparum malaria elimination and the national objective of eliminating malaria by 2025 (13). The overall approach was to implement a tailored package of active case detection approaches through a network of MMWs in order to reach remote populations and deliver EDAT services in line with national treatment guidelines (14). The logic model of the project assumes that the efficient delivery of the package of tailored active case detection approaches in combination with quality case management would lead to effective detection and treatment of P. falciparum cases among target populations, contributing to the accelerated elimination of P. falciparum malaria in project areas.
The technical design of the project built on learnings from a project implemented under the first RAI program 2016-2017. Said project had initially started positioning MMWs at screening points at official and unofficial border crossings (15). Based on insights on population movements and refusal rates, this approach shifted towards positioning MMWs at mobile malaria posts and conducting outreach activities to reach mobile and migrant populations and forest workers. The lessons from this operational experience and other research projects in the same region can be summarized into five guiding principles that informed the design of the RAI2E project: The need to tailor case detection approaches to the local target population and context, using responsive monitoring systems, maintaining operational flexibility, building strong community relationships, and closely supervising the MMW network.
1. Tailoring service delivery to the local target population and context: Efficient active case detection approaches have to consider the whole spectrum of the target population. Remote populations consist of various subpopulations, including local and mobile forest-workers, construction workers, security personnel and border-crossers, who are each involved in different forest-related activities (12). Active case detection approaches targeting these populations have to be tailored to each subpopulation individually leveraging local knowledge on population behaviour, movements and work sites. Reactive approaches have to target individuals sharing the same exposure time and location as the index case, i.e. co-travellers rather than household members (15-17).
2. Using responsive monitoring systems: Responsive monitoring systems are a key component to efficiently target interventions. Hotspots and population movements change constantly (18, 19) which requires routinely adjusting and optimizing operational timing and locations of testing. This can only be achieved by systematic monitoring practices facilitating collaborative decisions between all relevant stakeholders based on quantitative evidence, operational experience and local insights.
3. Maintaining operational flexibility: In order to respond to the findings from the responsive monitoring system in a timely manner, the operational set-up must allow the flexible adaptation of project activities.
4. Building strong community relationships: Any approach to reach remote populations must involve strong and sustained relationships with these communities. A key factor in achieving this is the recruitment of MMWs directly from the target communities of forest-goers and mobile and migrant populations which is essential to establish them as trusted service providers based on existing relationships and expert knowledge about the local environment (13).
5. Facilitating close supervision systems: Closely supervising the MMW network is needed to ensure quality of service delivery and to sustain motivation among health workers. This includes routine supervision practices by national and project staff, as well as regular meetings for MMWs to share their experiences and knowledge. Operationally, this means it is necessary to factor extensive travel by project staff in difficult road conditions and proper deployment of staff to guarantee effective operations, particularly during the rainy season.
Translation into practice
All project activities were aligned with the National Strategic Plan for Elimination of Malaria 2011-2025 and the Malaria Elimination Action Framework 2016-2020 and were developed and delivered in close collaboration with the CNM (9, 13).
As per CNM guidelines, MMWs were directly recruited from local target communities (i.e. forest-goers or mobile and migrant populations) in high risk (i.e. annual parasite index greater than 5 per 1,000 population based on data from the national malaria information system (MIS)) and remote areas (i.e. more than 5 kilometres or more than one hour walk from the nearest health centre) where no other VMWs or MMWs worked. MMWs were trained on service delivery and case management in collaboration with the CNM which also conducted regular supervision visits. They were paid USD 20 per month by the CNM according to national guidelines, and an additional USD 5 per day for each workday through the RAI2E project.
The package of active case detection approaches consisted of proactive case detection delivered through mobile malaria posts and outreach activities, and occasional reactive case detection among co-travellers of index cases. MMWs were assigned to work either at a mobile malaria post or an outreach site from where to conduct outreach activities to different locations. Where needed, two MMWs were assigned to work at the same service delivery site with alternating shifts. Mobile malaria posts were placed at border crossings, at forest entry points or market places close to locations where the national MIS had reported high caseloads of P. falciparum or mixed (P. falciparum + second species) cases and where target populations frequently passed by on their way to and from the forest. MMWs positioned at mobile malaria posts approached everyone that passed their post for testing. Locations for outreach activities were selected by MMWs based on local knowledge about the area and usually targeted areas close to or within the forest not covered by mobile malaria posts or where communities could not easily access health services (such as remote forests and workplaces). During an outreach activity, MMWs would travel to the selected destination from their outreach site, and offer testing to everyone present at the location. Additionally, where feasible, MMWs were asked to conduct reactive case detection if a confirmed malaria case had spent time in the forest in the previous two weeks. This consisted of identifying and testing co-travellers of the confirmed index case for malaria. Active door-to-door screening was conducted in Preah Vihear in 2020 to confirm no new P. falciparum cases.
Operational targets for mobile malaria posts were to test 20 people per week and for outreach sites to conduct two outreach activities per week. Targets were set based on experiences from the first RAI program and feasibility considerations based on the available budget. In general, mobile malaria posts operated seven days per week with standard operating hours between 7 am and 7 pm with operational flexibility to adjust to local population movement patterns. These EDAT services were complemented by distributing long lasting insecticide-treated nets and hammock nets (LLINs/LLIHNs) as well as conducting health education among target communities as prescribed by the CNM.
Tests and treatment supplies were provided by associated health centres through the CNM. Malaria tests were conducted with P. falciparum/ Plasmodium vivax (P.vivax) rapid diagnostic tests (RDTs) (SD BIOLINE Malaria Ag P.f/P.v, Standard Diagnostics) applied as per product guidelines (20) without prior screening for fever. Uncomplicated P. falciparum, mixed and P. vivax cases were treated with artemisinin-based combination therapy (ACT) where feasible and referred to associated health centres in case of treatment stock-outs, severe cases or contraindications in line with national guidelines (14). First-line ACT therapy was artesunate-mefloquine with pyronaridine-artesunate used during prolonged stock-out of first line treatment. Single low-dose primaquine was given to P. falciparum and mixed cases.
The project further employed nine community mobilization officers placed at field sites to directly support MMWs, a field implementation manager placed at a coordination office and a technical specialist. The team was responsible for ensuring the quality and efficiency of project delivery through monthly assessments and supervision of service delivery by MMWs with standardized checklist, and responsive monitoring. The aim of responsive monitoring was to sustain and improve service delivery efficiency and effectiveness in terms of achieving high testing rates and detecting P. falciparum cases, and ensuring constant availability of test and treatment supplies. To achieve this, 1) quantitative evidence including testing rates, case clusterings, and stock information, 2) operational experience about the feasibility of operating service delivery sites in specific areas, and 3) local knowledge about frequented forest areas and population movements were regularly reviewed by the project team to recognize emerging needs early on. These insights were used to continuously adapt the positioning of mobile malaria posts, target locations of outreach activities and other operational aspects in collaboration with the CNM, local authorities and other implementing partners.