Assessing West Nile virus (WNV) and Usutu virus (USUV) exposure in bird ringers in the Netherlands: a high-risk group for WNV and USUV infection?

Chiara de Bellegarde de Saint Lary, Louella M.R. Kasbergen*, Patricia C.J.L. Bruijning-Verhagen, Henk van der Jeugd, Felicity Chandler, Boris M. Hogema, Hans L. Zaaijer, Fiona R.M. van der Klis, Luisa Barzon, Erwin de Bruin, Quirine ten Bosch, Marion P.G. Koopmans, Reina S. Sikkema, Leo G. Visser

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Introduction: In 2020, the first Dutch West Nile virus (WNV) infected birds were detected through risk-targeted surveillance of songbirds. Retrospective testing of patients with unexplained neurological disease revealed human WNV infections in July and August 2020. Bird ringers are highly exposed to mosquito bites and possibly avian excrements during ringing activities. This study therefore investigates whether bird ringers are at higher risk of exposure to WNV and Usutu virus (USUV). Methods: Dutch bird ringers were asked to provide a single serum sample (May – September 2021) and to fill out a survey. Sera were screened by protein microarray for presence of specific IgG against WNV and USUV non-structural protein 1 (NS1), followed by focus reduction virus neutralization tests (FRNT). Healthcare workers (2009–2010), the national immunity cohort (2016–2017) and blood donors (2021) were used as control groups without this occupational exposure. Results: The majority of the 157 participating bird ringers was male (132/157, 84%) and the median age was 62 years. Thirty-seven participants (37/157, 23.6%) showed WNV and USUV IgG microarray signals above background, compared to 6.4% (6/94) in the community cohort and 2.1% (2/96) in blood donors (p < 0.01). Two seroreactive bird ringers were confirmed WNV or USUV positive by FRNT. The majority of seroreactive bird ringers travelled to EU countries with reported WNV human cases (30/37, 81%) (p = 0.07). No difference was observed between bird ringers with and without previous yellow fever vaccination. Discussion: The higher frequency of WNV and/or USUV IgG reactive bird ringers indicates increased flavivirus exposure compared to the general population, suggesting that individuals with high-exposure professions may be considered to complement existing surveillance systems. However, the complexity of serological interpretation in relation to location-specific exposure (including travel), and antibody cross-reactivity, remain a challenge when performing surveillance of emerging flaviviruses in low-prevalence settings.

Original languageEnglish
Article number100533
JournalOne Health
Publication statusPublished - Jun 2023

Bibliographical note

Funding Information:
NWO: This work is part of the research programme One Health PACT with project number 109986, which is (partly) financed by the Dutch Research Council (NWO) . RS and MK received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 874735 (VEO project).

Publisher Copyright: © 2023 The Authors


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