Utilising community malaria volunteers to expand molecular and serological surveillance of malaria in pre-elimination settings

Clinical malaria incidence is decreasing in the GMS including Myanmar, and the region aims to achieve malaria elimination by 2030. Reductions in malaria morbidity and mortality and progression towards malaria elimination have been largely attributed to high coverage of insecticide-treated mosquito nets and the increased availability and accessibility of testing and treatment typically distributed through community malaria volunteers in the GMS. 

Molecular and serological assays can determine residual malaria transmission not detected by routine diagnostics in the field such as RDT and microscopy. However, the application of sensitive molecular methods such as PCR to detect malaria is mostly utilised as a research tool and is yet to be approved and incorporated into routine surveillance in the GMS. Similarly, measuring antibodies specific for malarial antigens is not routinely performed for surveillance but may be a useful tool for monitoring ongoing malaria transmission in the GMS as it approaches malaria elimination as it has the potential to measure both current and historical malaria exposure. In the GMS, community malaria volunteers are the cornerstone of malaria control and elimination programs, they provide RDTs and treatment as well as reporting malaria cases in their villages to fulfil national surveillance. Because of the high coverage of volunteers, particularly in hard-to-reach and remote locations, community malaria volunteers could perform an important sample collection role to expand the use of more sensitive molecular and serological surveillance in pre-elimination regions.

In a previous study, we trained volunteers in hard-to-reach areas to integrate collection of samples (RDTs and dried blood spots [DBS]s) for molecular and serological surveillance into their routine provision of malaria services in their communities. Although the volunteer experienced extra burden of work for DBS collection, this study demonstrated that molecular and serological surveillance performed with samples collected at the level of the community malaria volunteer is capable of detecting a significant burden of subclinical infections missed by routine RDT. Archival RDTs have been utilised to perform surveillance of emerging drug resistance genotypes at sentinel sites, and serological surveillance performed using serum proteins derived from RDTs is comparable to matched dried blood spots. However, these latter proof-of-concept laboratory studies were undertaken using samples from health centers in high transmission areas. Whether RDTs can serve as a good source of molecular and serological material in low transmission areas where parasite densities are lower are yet to be determined.

Recently in Myanmar, Burnet Institute has implemented a stepped-wedge cluster randomised controlled trial lasting six months across 74 villages in Yangon Region, that primarily evaluated the effectiveness of a Community Delivered Malaria Elimination Model. Volunteers collected ~2,000 RDTs which will be shipped to Burnet Institute labs in Melbourne.

RDT processing: RDT cassettes will be disassembled, and the sample pad will be processed for DNA extraction and antibody elution according to previously defined methods. Detection of Plasmodium spp. infection: Infection with Plasmodium spp. (P. falciparum and P. vivax) will be determined by quantitative PCR (qPCR) according to previously defined methods. Immunoassays: We will determine levels and seroprevalence of IgG in response to validated markers of recent transmission events and ongoing malaria exposure (Pf/PvCSP, Pf/PvAMA1, Anopheles spp. SG6-P1) using an established ELISA protocol optimised for a high-throughput liquid-handling robotic platform (JANUS, Perkin-Elmer).

Surveillance

Jun 2022 — Oct 2023

$15,000

Australia
Myanmar

Australian Centre for Research Excellence in Malaria Elimination (ACREME)