Climate change projections of West Nile virus infections in Europe: Implications for blood safety practices

Jan C. Semenza, Annelise Tran, Laura Espinosa, Bertrand Sudre, Dragoslav Domanovic, Shlomit Paz

Research output: Contribution to journalArticlepeer-review


Background: West Nile virus (WNV) is transmitted by mosquitoes in both urban as well as in rural environments and can be pathogenic in birds, horses and humans. Extrinsic factors such as temperature and land use are determinants of WNV outbreaks in Europe, along with intrinsic factors of the vector and virus. Methods: With a multivariate model for WNV transmission we computed the probability of WNV infection in 2014, with July 2014 temperature anomalies. We applied the July temperature anomalies under the balanced A1B climate change scenario (mix of all energy sources, fossil and non-fossil) for 2025 and 2050 to model and project the risk of WNV infection in the future. Since asymptomatic infections are common in humans (which can result in the contamination of the donated blood) we estimated the predictive prevalence of WNV infections in the blood donor population. Results: External validation of the probability model with 2014 cases indicated good prediction, based on an Area Under Curve (AUC) of 0.871 (SD = 0.032), on the Receiver Operating Characteristic Curve (ROC). The climate change projections for 2025 reveal a higher probability of WNV infection particularly at the edges of the current transmission areas (for example in Eastern Croatia, Northeastern and Northwestern Turkey) and an even further expansion in 2050. The prevalence of infection in (blood donor) populations in the outbreak-affected districts is expected to expand in the future. Conclusions: Predictive modelling of environmental and climatic drivers of WNV can be a valuable tool for public health practice. It can help delineate districts at risk for future transmission. These areas can be subjected to integrated disease and vector surveillance, outreach to the public and health care providers, implementation of personal protective measures, screening of blood donors, and vector abatement activities.

Original languageEnglish
Article number28
Pages (from-to)125-136
JournalEnvironmental Health: A Global Access Science Source
StatePublished - 2016

Bibliographical note

Funding Information:
The study was funded by ECDC including the publication charges and several co-authors (JCS, LE, BS, DD) are employed by ECDC. The authors declare no financial competing interests. The opinions in this paper reflect that of the authors and not necessarily that of ECDC. This article has been published as part of Environmental Health Volume 15 Suppl 1, 2016: Healthy-Polis: Challenges and Opportunities for Urban Environmental Health and Sustainability. The full contents of the supplement can be found at

Publisher Copyright:
© 2016 Semenza et al.


  • Arbovirus
  • Blood safety
  • Blood supply
  • Climate change
  • Environmental determinants
  • Epidemiology
  • Remote sensing
  • Risk maps
  • Surveillance
  • Temperature
  • West Nile fever
  • West Nile virus

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis


Dive into the research topics of 'Climate change projections of West Nile virus infections in Europe: Implications for blood safety practices'. Together they form a unique fingerprint.

Cite this