Implications of migratory and exotic birds and the mosquito community on West Nile virus transmission

Abstract

Background

Vector-borne diseases like West Nile virus (WNV) pose a global health challenge, with rising incidence and distribution. Culex mosquitoes are crucial WNV vectors. Avian species composition and bird community diversity, along with vector communities, influence WNV transmission patterns. However, limited knowledge exists on their impact in southwestern Spain, an area with active WNV circulation in wild birds, mosquitoes, and humans.

Methods

To address this, we conducted a comprehensive study investigating the contributions of migratory and exotic bird species to WNV transmission and the influence of mosquito community composition.

Results

Analysing 1194 serum samples from 44 avian species, we detected WNV antibodies in 32 samples from 11 species, four for the first time in Europe. Migratory birds had higher WNV exposure likelihood than native and exotic species, and higher phylogenetic diversity in bird communities correlated with lower exposure rates. Moreover, in 5859 female mosquitoes belonging to 12 species, we identified WNV competent vectors like Cx. pipiens s.l. and the Univittatus subgroup. Birds with WNV antibodies were positively associated with competent vector abundance, but negatively with overall mosquito species richness.

Conclusions

These findings highlight the complex interactions between bird species, their phylogenetics, and mosquito vectors in WNV transmission. Understanding these dynamics will help to implement effective disease control strategies in southwestern Spain.

Keywords:

• Arbovirus
• Culex mosquitoes
• evenness
• phylogenetic diversity
• serology
• vector-borne diseases

Acknowledgments

We are grateful to Francisco Javier Oficialdegui and Gonzalo Cidoncha for their help in the fieldwork. We also appreciate the technical support provided by SAIUEx with the molecular analyses (financed by UEx, Junta de Extremadura, MICINN, FEDER, and FSE).

Ethical approval

Bird trapping was carried out with all necessary permits with the current regional and national laws of Spain. Bird and mosquito sampling on private land and in private residential areas was conducted with all the necessary permits and consent from the owners. Methods were evaluated and approved by the institutional Commission of Bioethics of University of Extremadura (CBUE 49/2019) and by Junta de Extremadura Local Government (87/2019) and (CN0055/19/ACA).

Authors’ contribution

MF, SM, FdL were involved in development of the study design. MF, SM, CM-R, AM, IHC, JAO collected the samples; MF, SM, CM-R, DB-B carried out the entomological identification; DB-B, FG-C performed the ELISA assays; PA-S, EP-R, FL performed the VNT analyses. MF conducted the statistical analyses and wrote the first draft of the manuscript; FdL, AM, EF and MAJ-C contributed to the reagents/materials/analysis tools. All authors read, contributed to, and approved, the final manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data supporting the conclusions of this review are available in the supporting information of this article.

Additional information

Funding

This study was funded by Ayudas Fundación BBVA a Equipos de Investigación Científica 2019 (PR (19_ECO_0070)), line of action LA4 which is part of the R+D+I program in the Biodiversity Area financed by the FEDER Extremadura 2021-2027 Operational Program of the Recovery, Transformation and Resilience Plan from the Consejería de Economía e Infraestructura of the Junta de Extremadura and the European Regional Development Fund, a Way to Make Europe (IB20089 project), and by the Spanish Ministry of Science and Innovation (PID2022-142803OA-I00 project). MF was partially financed by a grant from the Asociación Española de Ecología Terrestre (Ayuda a proyectos de investigación en ecología liderados por jóvenes investigadores, AEET-SIBECOL Call 2020), and she is currently supported by a Ramón y Cajal postdoctoral contract (RYC 2021-031613-I) from the Spanish Ministry of Science and Innovation (MICINN), and by a 2023 Leonardo Grant for Researchers and Cultural Creators (BBVA Foundation). SM was supported by CSIC’s Global Health Platform (PTI Salud Global). CMR is funded by a FPU grant from the Ministry of Universities of Spain (reference: FPU20/01039). FG-C was supported by “Ayudas a la Formación Investigador Predoctoral 2018” Formative contract (PD18056) from the Extremadura regional government. The BBVA Foundation accepts no responsibility for the opinions, statements and contents included in the project and/or the results thereof, which are entirely the responsibility of the authors.