Evolutionary dynamics of Usutu virus: Worldwide dispersal patterns and transmission dynamics in Europe

Marina Siljic; Rastko Sehovic; Marko Jankovic; Gorana Stamenkovic; Ana Loncar; Marija Todorovic; Maja Stanojevic; Valentina Cirkovic

doi:10.3389/fmicb.2023.1145981

Evolutionary dynamics of Usutu virus: Worldwide dispersal patterns and transmission dynamics in Europe

Front Microbiol. 2023 Mar 23:14:1145981. doi: 10.3389/fmicb.2023.1145981. eCollection 2023.

Authors

Marina Siljic¹, Rastko Sehovic¹, Marko Jankovic¹, Gorana Stamenkovic², Ana Loncar³, Marija Todorovic¹, Maja Stanojevic¹, Valentina Cirkovic⁴

Affiliations

¹ Faculty of Medicine, Institute of Microbiology and Immunology, University of Belgrade, Belgrade, Serbia.
² Department for Genetic Research, Institute for Biological Research "Sinisa Stankovic", National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia.
³ Institute for Biocides and Medical Ecology, Belgrade, Serbia.
⁴ Group for Medical Entomology, Centre of Excellence for Food- and Vector-Borne Zoonoses, National Institute of Republic of Serbia, Institute for Medical Research, University of Belgrade, Belgrade, Serbia.

Abstract

Background: Usutu virus (USUV) is an emerging mosquito-borne Flavivirus, with birds as the main zoonotic reservoir. Humans are accidental hosts and mostly develop mild or even asymptomatic infections, although severe complications such as encephalitis can also arise. Detailed characterization of the pathogen's phylogenetics may offer valuable insights into the prediction and prevention of potential epidemics; however, lack of uniformity and the number of available USUV sequences worldwide hamper comprehensive investigation.

Aim: The study aimed to investigate USUV spatio-temporal dispersal inter- and intracontinentally and to estimate the dynamics of viral spread within Europe.

Methods: Phylogeographic and phylodynamic analyses were done using advanced phylogenetic methods implemented in Beast 1.10.4 and Beast 2.6.4 software packages.

Results: Herein, we report on a new USUV isolate from Culex pipiens collected in 2019 from Serbia. The results of this research revealed two newly described intercontinental migration events of USUV from Africa to Germany in the 1970s and from Africa to the Middle East (Israel) in the late 90s. Finally, phylodynamic analysis substantiated the ongoing active expansion of USUV in Europe.

Conclusion: The data would imply a high potential for further USUV expansion in Europe. Detailed phylogenetic characterization of the pathogen may offer valuable insights into prediction and prevention of potential epidemics; however, lack of uniformity and number of available USUV sequences worldwide hampers comprehensive investigation. This study draws attention to the need for upscaling USUV surveillance.

Keywords: Usutu virus; emerging disease; evolutionary dynamic; mosquito vectors; phylodynamics; phylogeography.

Grants and funding

This research was supported by the Science Fund of the Republic of Serbia (SFRS), the Program for Excellent Projects of Young Researchers (PROMIS) project grant, grant no. 6059147, IN-DEPTH, and the Ministry of Education, Science and Technological Development of the Republic of Serbia, grant no. 200110. The SFRS as the funding source had no role in study design, data collection, interpretation, or the decision to submit the study for publication.