Tools to accelerate falciparum malaria elimination in Cambodia: a meeting report

Abstract

Cambodia targets malaria elimination by 2025. Rapid elimination will depend on successfully identifying and clearing malaria foci linked to forests. Expanding and maintaining universal access to early diagnosis and effective treatment remains the key to malaria control and ultimately malaria elimination in the Greater Mekong Subregion (GMS) in the foreseeable future. Mass Drug Administration (MDA) holds some promise in the rapid reduction of Plasmodium falciparum infections, but requires considerable investment of resources and time to mobilize the target communities. Furthermore, the most practical drug regimen for MDA in the GMS-three rounds of DHA/piperaquine-has lost some of its efficacy. Mass screening and treatment benefits asymptomatic P. falciparum carriers by clearing chronic infections, but in its current form holds little promise for malaria elimination. Hopes that "highly sensitive" diagnostic tests would provide substantial advances in screen and treat programmes have been shown to be misplaced. To reduce the burden on P. falciparum and Plasmodium vivax infections in people working in forested areas novel approaches to the use of malaria prophylaxis in forest workers should be explored. During an October 2019 workshop in Phnom Penh researchers and policymakers reviewed evidence of acceptability, feasibility and effectiveness of interventions to target malaria foci and interrupt P. falciparum transmission and discussed operational requirements and conditions for programmatic implementation.

Forest malaria in Cambodia: the occupational and spatial clustering of Plasmodium vivax and Plasmodium falciparum infection risk in a cross-sectional survey in Mondulkiri province, Cambodia

“…This study suggests that such a stratification of interventions could happen along a gradient of villages inside or outside the forest. Population-oriented interventions such as targeted mass drug administration or test and treat programmes with sensitive molecular or serological diagnostics [46,54] (together with their costs and risk of overtreatment) could be justified in forest villages. By contrast, approaches targeted at risk groups only may be effective at lower costs for the NMCP and the local population in residential settings outside of the forest.…”

Eliminating Plasmodium falciparum malaria: Results from tailoring active case detection approaches to remote populations in forested border areas in north-eastern Cambodia

“…At the end of 2020, the CNM started to implement case investigations for every P. falciparum case within 3 days of noti cation to determine if the infection was acquired locally. If it was, a focus investigation was conducted within 14 days of detection to determine the set of interventions to be undertaken (24). These intensi ed active case detection and surveillance activities will need to be maintained until malaria is eliminated.…”

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

“…Hence, many P. falciparum carriers, symptomatic and asymptomatic, are missed by eld diagnostics while they might still constitute an ongoing reservoir of further transmission. Diagnostic tools with higher sensitivity than conventional RDTs have been trialled, but either were not adopted as in the case mobile PCR laboratories that could have been used in eld settings (29) or were shown not to su ciently increase sensitivity as in the case of highsensitivity RDTs (25). Recently, researchers and policymakers in Cambodia discussed novel tools to further accelerate P. falciparum malaria elimination and considered approaches not depending on testing.…”

“…Recently, researchers and policymakers in Cambodia discussed novel tools to further accelerate P. falciparum malaria elimination and considered approaches not depending on testing. While mass drug administration and mass screening and treatment approaches were ruled out for various reasons, trialling malaria prophylaxis in forest workers was deemed a promising idea to be explored in the short term (25).…”