A Rapid Loa Antibody Test to Support High Resolution Onchocerciasis Elimination Mapping
Can a rapid diagnostic test (RDT) for Loa loa antibodies be used successfully by field teams, in conjunction with the LoaScope, to map loaiasis and determine where it is safe to offer treatment for onchocerciasis?
In principle, the Loa Antibody Rapid Test could be used to conduct rapid surveys to document that Loa prevalence in the surveyed community or district is below an agreed upon threshold, opening up areas to use the of MDA to eliminate onchocerciasis. This tool would complement the use of the Loascope to make treatment decisions. The antibody test would be used at the periphery of the Loa belt or in areas where Loa prevalence was thought to be low (based on previous RAPLOA or environmental factors) to carry out “confirmatory mapping.” The Loascope would be used to make treatment decisions at the community level using the Diggle model or to guide individual treatment decisions based on the TNT strategy. To design a confirmatory mapping survey for Loa based on antibody testing, a number of key scientific questions must be answered: 1) What is the relationship between community Loa prevalence as assessed by the Loascope and Loa rapid antibody test?
This study supported the field validation of a new Loa antibody rapid diagnostic test (described here: https://pubmed.ncbi.nlm.nih.gov/28749939/) and the production of 50,000 tests to support onchocerciasis elimination mapping in areas where loaiasis is co-endemic.