As we move from malaria control to elimination, fewer individuals are infected and typically harbour low-density parasitaemia. These individuals contribute significantly to malaria transmission but are not identified by current malaria infection diagnostic tests. A shift in operational approach is needed to detect these remaining hot-spots/hot-pops of transmission. By identifying malaria-exposed individuals based on the presence of antimalarial antibodies in their blood, serosurveillance could serve an integral role in malaria elimination. It can facilitate identifying remaining hot-spots/hot-pops of transmission, monitor Plasmodium transmission levels to prevent reintroduction of malaria and assess vaccine response/coverage. A point-of-contact serosurveillance test allows serosurveillance of remote regions where lab-resources may not be available and where hot-spots/hot-pops of transmission likely persist.
We developed a highly specific and sensitive lateral flow point-of-care serosurveillance tool for exposure to Plasmodium falciparum malaria. When compared against a lab-based reference test for antimalarial antibody detection (ELISA), our point-of-care test was able to detect recent malaria infection with 94.3% sensitivity and 100% specificity (n=95). Samples from individuals with naturally-acquired antibodies from an endemic setting were used to establish the test capacity to identify recently-exposed individuals as well as to highlight the prospect of large-scale sero-epidemiological studies to monitor temporal and spatial changes in transmission levels and enhance the planning process of control and treatment activities. Malaria-exposed travellers were tested to ascertain the capacity of the test to carry out serosurveillance of mobile communities (e.g. migrant workers) to prevent reintroduction of malaria. A vaccine trial population was tested to establish the potential use of the test for monitoring of vaccine response/coverage.
This test is currently being expanded to other malaria parasite species, especially Plasmodium vivax. Future studies will move onto field validation, as this test holds great promises to be a powerful and useful weapon in the fight against malaria.