An alarming rise in reported Lassa fever cases continues in West Africa. Liberia has the largest reported per capita incidence of Lassa fever cases in the region, but genomic information on the circulating strains is scarce. Dr. Michael Wiley from the University of Nebraska Medical Center (UNMC) College of Public Health – led a study to increase the available pool of data to help foster the generation of targeted diagnostics and therapeutics.
Dr. Wiley’s team collected clinical serum samples from 17 positive Lassa fever cases originating from Liberia (16 cases) and Guinea (one case) within the past decade and processed them at the Liberian Institute for Biomedical Research using a targeted-enrichment sequencing approach, producing 17 near-complete genomes. An additional 17 Lassa virus sequences (two from Guinea, seven from Liberia, four from Nigeria, and four from Sierra Leone) were generated from viral stocks at the U.S. Centers for Disease Control and Prevention (Atlanta, GA) from samples originating from the Mano River Union (Guinea, Liberia, and Sierra Leone) region and Nigeria.
The study found that the 23 new Liberian Lassa virus genomes grouped within two clades (IV.A and IV.B) and were genetically divergent from those circulating elsewhere in west Africa. The commonly used Lassa Josiah-MGB assay was up to 25 percent divergent across the target sites when aligned to the Liberian Lassa virus genomes. The authors conclude, “the large amount of novel genomic diversity of Lassa virus observed in the Liberian cases emphasizes the need to match deployed diagnostic capabilities with locally circulating strains and underscores the importance of evaluating cross-lineage protection in the development of vaccines and therapeutics.”Tags: Friday Letter Submission, Publish on December 06