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Review
. 2024 Apr 12;16(4):599.
doi: 10.3390/v16040599.

Circulation of West Nile Virus and Usutu Virus in Europe: Overview and Challenges

Yannick Simonin  1
Affiliations
Review

Circulation of West Nile Virus and Usutu Virus in Europe: Overview and Challenges

Yannick Simonin. Viruses. .

Abstract

West Nile Virus (WNV) and Usutu Virus (USUV) are both neurotropic mosquito-borne viruses belonging to the Flaviviridae family. These closely related viruses mainly follow an enzootic cycle involving mosquitoes as vectors and birds as amplifying hosts, but humans and other mammals can also be infected through mosquito bites. WNV was first identified in Uganda in 1937 and has since spread globally, notably in Europe, causing periodic outbreaks associated with severe cases of neuroinvasive diseases such as meningitis and encephalitis. USUV was initially isolated in 1959 in Swaziland and has also spread to Europe, primarily affecting birds and having a limited impact on human health. There has been a recent expansion of these viruses' geographic range in Europe, facilitated by factors such as climate change, leading to increased human exposure. While sharing similar biological traits, ecology, and epidemiology, there are significant distinctions in their pathogenicity and their impact on both human and animal health. While WNV has been more extensively studied and is a significant public health concern in many regions, USUV has recently been gaining attention due to its emergence in Europe and the diversity of its circulating lineages. Understanding the pathophysiology, ecology, and transmission dynamics of these viruses is important to the implementation of effective surveillance and control measures. This perspective provides a brief overview of the current situation of these two viruses in Europe and outlines the significant challenges that need to be addressed in the coming years.

Keywords: Usutu Virus; West Nile Virus; arboviruses.

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Conflict of interest statement

The author declares no conflicts of interest.

Figures

Figure 1
Figure 1
WNV and USUV transmission cycle involves birds (amplifying hosts) and mosquitoes (vectors). Infection can spread to humans and a diverse range of vertebrates, which are generally considered incidental or “dead-end” hosts.
Figure 2
Figure 2
Distribution of WNV and USUV in Europe. Countries reporting only USUV: Belgium, Luxembourg, Poland, Serbia, Switzerland, United Kingdom. Countries reporting only WNV: Bulgaria, Portugal. Countries reporting both WNV and USUV: Austria, Croatia, the Czech Republic, France, Germany, Greece, Hungary, Italy, Netherlands, Slovakia, Slovenia, Spain.
Figure 3
Figure 3
Distribution of different lineages of USUV in Europe in humans, mosquitoes, and birds.
See this image and copyright information in PMC

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