Malaria elimination challenges in countries approaching the last mile: a discussion among regional stakeholders.

The national malaria control programmes in Cambodia, Nepal, and Bhutan aim to achieve malaria elimination by 2025-2030. While the vivax malaria burden remains challenging, the consistent decline in falciparum malaria in these countries over the last five years suggests that the goal is achievable. However, unexpected cases in previously falciparum malaria-free districts continue to occur. A virtual meeting was convened in May 2024, followed by smaller meetings, to discuss and share experiences among regional partners, focusing on falciparum malaria elimination. The discussion among regional partners from these three countries was prompted by an isolated outbreak of falciparum malaria in April 2022 in a previously malaria-free district in Pursat province, Cambodia. The National Center for Parasitology, Entomology and Malaria Control (CNM) worked with stakeholders to contain the outbreak, which was likely to have originated in forest goers. Community-based village malaria workers (VMWs) were augmented with the additional resources required to test and treat malaria among forest goers under the supervision of health centres and district hospitals. This response rapidly reduced malaria cases in the subsequent months. Regional partners from Nepal and Bhutan, who are also engaged in the final phase of malaria elimination, reported that isolated malaria outbreaks in their countries were not unusual and were mostly imported from a neighbouring country, India. Importation of cases was facilitated by unsupervised transborder travel including the movement of migrant workers. The imported cases were only established during the case investigation such as when responding to the isolated outbreaks. In contrast, in Cambodia, spread of malaria was known to be facilitated by mobile and migrant workers, and forest goers within the country. The specific differences between Nepal and Bhutan (South Asia), and Cambodia (Greater Mekong Subregion) offered insights into strategies for malaria elimination. A relevant component for countries embarking on malaria elimination included strengthening of local malaria surveillance and response in collaboration with the community health workers, and community members targeting the 'at risk' population. In countries approaching malaria elimination, resourcing community-based health workers could play a critical role in enhancing malaria surveillance, early case detection and treatment, including interventions targeting migrant populations such as forest goers and seasonal migrant workers.