October 2024 Lassa virus introduced into Iowa, USA from Liberia

On October 28, 2024, Lassa virus (LASV) was identified in an individual residing in Iowa, USA with travel history from Liberia. Initial diagnostic testing was performed at the University of Nebraska Medical Center and the specimen was confirmed LASV positive by the Viral Special Pathogens Branch (VSPB) at the US Centers for Disease Control and Prevention (CDC). No secondary transmission cases were identified over the following 3-week time span. The virus was sequenced using unbiased next generation sequencing on a MiSeq in VSPB. The LASV genome is 100% complete and most closely related to specimens collected from Bong County, Liberia in February-April 2011, February 2016 and 2017 and January 2018.

The genomes can be accessed through github here: https://github.com/evk3/LASV_Iowa_introduction_2024

Figure 1: Inferred phylogenetic relatedness of Lassa virus large (L) segments, including the LASV sequence from Iowa, US collected on October 28, 2024. A) All available LASV L segments with clade containing imported LASV sequence highlighted red. B) Clade containing the Iowa sequence and viral isolate sequence generated from the original blood specimen (green).

Figure 2: Inferred phylogenetic relatedness of Lassa virus small (S) segments, including the LASV sequence from Iowa, US collected on October 28, 2024. A) All available LASV S segments with clade containing imported LASV sequence highlighted red. B) Clade containing the Iowa sequence and viral isolate sequence generated from the original blood specimen (green).

DISCLAIMER

The unpublished sequences are shared via the website virological.org under the following conditions: The Lassa virus sequences by VSPB support the public health response as well as the development and evaluation of Lassa virus disease diagnostics and therapeutics. The data may be used and analyzed for these purposes. In the meantime, this post may be cited. If you intend to use the sequences for publication prior to our own publication, please contact us directly.

Shannon Whitmer, Ph.D.

(Microbiologist (CDC/VSPB), [email protected])