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. 2025 Apr 25:46:1607444.
doi: 10.3389/phrs.2025.1607444. eCollection 2025.

Effect of Climate Change on West Nile Virus Transmission in Italy: A Systematic Review

Antonio Lorenzon  1 , Michele Granata  1 , Pietro Verzelloni  1 , Luigi Tommasi  1 , Lucia Palandri  1 , Marcella Malavolti  1 , Annalisa Bargellini  1 , Elena Righi  1 , Marco Vinceti  1   2 , Stefania Paduano  1 , Tommaso Filippini  1   3
Affiliations

Effect of Climate Change on West Nile Virus Transmission in Italy: A Systematic Review

Antonio Lorenzon et al. Public Health Rev. .

Abstract

Objectives: West Nile Virus (WNV) infection prevalence is increasing in recent years in Europe, particularly in Italy. Such increase has been related to climate and environmental factors. Our review aims to assess the relation between climate change-related factors and the spread of WNV in Italy.

Methods: We conducted a literature search across four online databases until 22 January 2025, using as search terms WNV, its vectors, and climate change.

Results: Out of 282 unique articles, we included 29 eligible papers published between 2011-2025, most of them assessing distribution of the main WNV vector (Culex pipiens) and epidemiology of the infection in relation to climate/environmental factors. We found a positive strong association of WNV transmission with temperature and agricultural land use. Associations with other environmental variables also emerged, but they were either weak or inconsistent.

Conclusion: Despite some inconsistencies in the results, likely due to heterogeneity in study methodologies and interactions of environmental variables, review findings indicate that some climate change-related factors favor WNV spread through its vectors in Italy, in line with exploratory observations obtained on the entire Europe.

Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD42023430636, identifier CRD42023430636.

Keywords: Culex pipiens; West Nile virus; arbovirus; climate change; mosquito.

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Conflict of interest statement

The authors declare that they do not have any conflicts of interest.

Figures

FIGURE 1
FIGURE 1
PRISMA flow chart of the inclusion process (systematic review, Italy, 2011–2025).
FIGURE 2
FIGURE 2
Geographical distribution of studies. The whole Italian territory was considered in six works (systematic review, Italy, 2011–2025).
FIGURE 3
FIGURE 3
Graphical summary of the emerged associations. The size of the circles represents the number of studies evaluating each factor, while the x-axis shows the percentage of times an association emerged (100% means that an association was found in all the studies). Within the circle is the proportion in the sign of associations: grey for positive, black for negative (systematic review, Italy, 2011–2025).
See this image and copyright information in PMC

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