Reconstruction of the molecular evolution of Usutu virus in Germany: Insights into virus emersion and circulation

PLoS Negl Trop Dis. 2023 Oct 2;17(10):e0011203. doi: 10.1371/journal.pntd.0011203. eCollection 2023 Oct.

Abstract

Usutu virus (USUV) is a mosquito-borne flavivirus that is widely distributed in southern and central Europe. The zoonotic virus circulates primarily between birds and mosquitoes, can, however, in rare cases infect other mammals including humans. In the past, USUV has been repeatedly associated with mass mortalities in birds, primarily blackbirds and owls. Birds commonly succumb either due to the peracute nature of the infection or due to severe encephalitis. In Germany, USUV has spread rapidly since its first detection in 2010 in mosquitoes under the presence of susceptible host and vector species. Nonetheless, there is to date limited access to whole genome sequences resulting in the absence of in-depth phylogenetic and phylodynamic analyses. In this study, 118 wild and captive birds were sequenced using a nanopore sequencing platform with prior target enrichment via amplicons. Due to the high abundancy of Europe 3 and Africa 3 in Germany an ample quantity of associated whole genome sequences was generated and the most recent common ancestor could be determined for each lineage. The corresponding clock phylogeny revealed an introduction of USUV Europe 3 and Africa 3 into Germany three years prior to their first isolation in the avifauna in 2011 and 2014, respectively. Based on the clustering and temporal history of the lineages, evidence exists for the genetic evolution of USUV within Germany as well as new introductions thereof into the country.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Birds
  • Culicidae*
  • Evolution, Molecular
  • Flavivirus Infections* / epidemiology
  • Flavivirus Infections* / veterinary
  • Flavivirus*
  • Germany
  • Humans
  • Mammals
  • Mosquito Vectors
  • Phylogeny

Supplementary concepts

  • Usutu virus

Grants and funding

This research was funded by the German Federal Ministry of Food and Agriculture (BMEL) through the Federal Office for Agriculture and Food (BLE), grant number 2819113919 (MHG, UZ), by the German Ministry of Education and Research (BMBF) grant number 01KI2026D (MHG, UZ) and by the German Center for Infection Research (DZIF); Project Number TTU 01.804 (MHG, UZ) and 01.808 (UZ). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.