Eliminating Plasmodium Falciparum Malaria: Results From Tailoring Active Case Detection Approaches to Remote Populations in Forested Border Areas in North-eastern Cambodia

Abstract

Background: Remaining Plasmodium falciparum cases in Cambodia are concentrated in forested border areas and in remote populations who are hard to reach through passive case detection. A key approach to reach these populations is active case detection by mobile malaria workers (MMWs). However, this is operationally challenging because of changing movement patterns of the target population moving into less accessible areas. From 2018 to 2020, a tailored package of active case detection approaches was implemented in forested border areas of three provinces in north-eastern Cambodia to reach remote populations and support the elimination of P. falciparum malaria.Approach: Key elements of this project were to tailor approaches to local populations, use responsive monitoring systems, maintain operational flexibility, build strong relationships with local communities, and implement close supervision practices. MMWs were recruited from local communities. Proactive case detection approaches included mobile malaria posts positioned at frequented locations around and within forests, and locally informed outreach activities targeting more remote locations. Reactive case detection was conducted among co-travellers of confirmed cases. Tests were conducted independent of fever symptoms. Routine monitoring informed tactical adaptations, while supervision exercises ensured service quality. Results: Despite operational challenges, between January 2018 and June 2020, service delivery sites were able to maintain consistently high testing rates, with each site testing a monthly average of > 60 people in 2020. Over the project period, the P. falciparum/ P. vivax ratio has steadily inversed. In 2020, MMWs detected only 22 P. falciparum cases with constant testing rates. Including data from neighbouring health facilities and village malaria workers, 52% of all people tested and 40% of P. falciparum cases detected in the area can be attributed to MMWs.Remaining challenges: Maintaining intensified elimination efforts, addressing the issue of detecting low parasitemia cases and shifting focus to P. vivax malaria challenge the last phase of malaria elimination.Conclusions: Reaching remote populations through active case detection should remain a key strategy to eliminate P. falciparum malaria. We have presented a successful approach combining tailored proactive and reactive strategies that could be transferred to similar settings in other areas of the Greater Mekong Subregion.

The Role of Adaptive Surveillance as a Core Intervention to Achieve Malaria Elimination

“…The national programme has introduced the role of mobile malaria workers who go on outreach activities and actively approach forest workers including mobile and migrant populations, the population group most at risk of malaria infection. This approach has proven to be successful, with Cambodia aiming for P. falciparum malaria elimination by 2023 [18][19][20].…”