Enhanced responses with various approaches to Active Case Detection: Re-Active case detection and investigation of Unofficial Border Crossings

Background:

The movement of populations between malaria-endemic areas is believed to be a major contributor to the spread of artemisinin resistance along the Vietnam-Cambodia border. Cross-border transmission also represents a challenge for malaria elimination as reintroduction of the disease into ‘malaria-free’ areas undermines these efforts. Populations crossing the border tend to be poorly connected to health systems, and their high mobility makes them difficult to track. They are also at higher risk of harbouring parasites due to the type of activities that they normally perform (e.g. forest and plantation work).

Interventions at borders have typically targeted formal border crossings. Economic migrants and high-risk communities living in border regions typically use unofficial border crossings however due to easier access when looking for work opportunities in forests, plantations and farms.

Current screening at official borders is based on eliciting a history of fever and followed by RDT or microscopy confirmation. The yield from such screening approaches has been low. This partly indicates that symptomatic individuals are less likely to be travelling, but also highlights that there needs to be greater focus on screening asymptomatic individuals crossing borders. The need for diagnostics with sufficient sensitivity to detect the low parasite densities typically seen in asymptomatic individuals has already been highlighted and is also addressed in the context of this grant. There is also a need for these diagnostic tests to have a rapid turn around time so that results and treatment can be administered in a timely manner, and to determine the volume of drug-resistant parasites transiting these border regions.

Overall goal:

This activity aims to implement high sensitivity and rapid screening at unofficial borders between Vietnam and Cambodia to reduce the cross border transit of malaria. It will link border-screening activities to the in-country surveillance systems and establish monitoring of drug resistant malaria parasites for these groups.

Project methodology:

Mobile Outreach Teams (MOTs) will commence screening to determine the extent of transmission, identify hotspots, and provide treatment to positive cases. MOTs will deploy for 1-2 days to passively monitor the number of persons crossing through the border crossing or transit point. Should it be established that the crossing/transit point is active, the location will be geo-tagged and the MOTs will begin a 1-2 day voluntary active case screening of border crossers/transiting persons at the location. Up to 5500 individuals will be invited to participate by having a brief clinical history, temperature recorded and finger prick samples taken for thick/ thin smear, filter paper collection and microtainer lithium heparin blood sample collected (up to 300ul). Any symptomatic individual will still be eligible to be enrolled, but will also receive routine care for malaria according to National treatment guidelines, including diagnosis with RDT (and/or microscopy) and to receive appropriate antimalarial treatment. Any study participant identified by LAMP will be followed up by the local MOT team and offered treatment according to the National treatment guidelines.

Measurement of Transmission
Surveillance
Vulnerable Populations

Oct 2015 — Dec 2016

Cambodia
Vietnam

Malaria Control and Outreach for Mobile and Migrant Populations along the Vietnam-Cambodia Border

Targeted Test and Treat (TTaT) strategies
Malaria Molecular Surveillance (MMS)