Conference Abstract | Volume 8, Abstract ELIC2025230 (Poster 035) | Published:  30 Jul 2025

Lassa virus strains sequenced during the January 2009 – December 2012 Lassa fever epidemics setbacks and prospects of disease burden: An epoch

Donatus Itsoghiaonode Adomeh1,2,3,&, Emmanuel Oyakhilome Omomoh1,2, Jennifer Oyakhilome1,2, Meike Pahlmann2, Stephan Guenther2, Frederick Ikechukwu Esumeh3

1Institute of Viral and Emergent Pathogens Control and Research (IVEPCR), Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria, 2Virology Department, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany, 3Faculty of Natural Sciences, Department of Microbiology, Ambrose Alli University, Ekpoma, Edo State, Nigeria.

&Corresponding author: Donatus Itsoghiaonode Adomeh, Diagnostics and Research Laboratory, Institute of Viral and Emergent Pathogens Control and Research (IVEPCR), Irrua Specialist Teaching Hospital, Edo State, Nigeria, Email: dadomeh2015@gmail.com

Received: 13 Apr 2025, Accepted: 09 Jul 2025, Published: 30 Jul 2025

Domain: Infectious Disease Epidemiology

This is part of the Proceedings of the ECOWAS 2nd Lassa fever International Conference in Abidjan, September 8 – 11, 2025

Keywords: Lassa virus, Lassa fever, Outbreaks, Epidemics, Diagnostics and Sequencing

©Donatus Itsoghiaonode Adomeh et al Journal of Interventional Epidemiology and Public Health (ISSN: 2664-2824). This is an Open Access article distributed under the terms of the Creative Commons Attribution International 4.0 License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Cite this article: Donatus Itsoghiaonode Adomeh et al Lassa virus strains sequenced during the January 2009 – December 2012 Lassa fever epidemics setbacks and prospects of disease burden: An epoch. Journal of Interventional Epidemiology and Public Health. 2025;8(ConfProc5):00179. https://doi.org/jieph-confpro5-00179

Introduction

Study aimed at determining epidemiology and strains distribution of Lassa Virus (LV) in patients attending Irrua Specialist Teaching Hospital (ISTH) and perform molecular characterization of LV in Nigeria.

Methods

Between 2009 – 2012, 4727 suspected cases of LV samples were processed using standard methods.  Molecular detection was in Nigeria and Germany, while molecular species and strains identification was done in a company in Germany (LCGgenomics, Ostendstrasse, Berlin, Germany. Sequences analyzed with SeqMan software (DNASTAR), Virus evolution reconstructed using BEAST software.                                                                                                                                                          

Results

Sequence lies within lineage II- a separate clade further subdivided into three clusters. Phylogenetic analyses revealed the relatedness of the new strains Nig 12-451 and 553 to strains from Owerri. Strains from Jalingo were closely related to strains from Onitsha. New strains Nig 11-725 and 870 were closely related to other strains from Edo-State. Order of the branches in lineage II indicated that the virus spread from the South of the country (Port Harcourt, Aba, Owerri, Onitsha, Irrua, Ekpoma, Oheluse) to North Eastern part (Jalingo) of the country.  
Viral lineages in Nigeria are different from other West African countries – Sierra Leone, Guinea and Liberia. Pathological findings also differ. The genomic sequences of eight recent Nigerian strains, representing lineage II. These novel sequences will aid in the design of molecular detection assays for LV. Phylogenetic analysis sequences implies the presence of an additional sub-lineage of LV in Nigeria, a directional and transverse-directional evolutionary spread within the country.

                                                                                                                             

Conclusion

Phylogenetic tree shows strains from the same geographic area were closely related. In the DNA alignment, nucleic acids positions were conserved in all nucleoproteins in LV. 1st and 2nd positions of the codons for the amino acids were usually conserved. Mutation takes place in the 3rd position
 
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Keywords

  • Lassa virus
  • Lassa fever
  • Outbreaks
  • Epidemics
  • Diagnostics and Sequencing
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