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Soltész Z, Erdélyi K, Bakonyi T, Barna M, Szentpáli-Gavallér K, Solt S, Horváth É, Palatitz P, Kotymán L, Dán Á, Papp L, Harnos A, Fehérvári P. West Nile virus host-vector-pathogen interactions in a colonial raptor. Parasit Vectors 2017; 10:449. [PMID: 28962629 PMCID: PMC5622512 DOI: 10.1186/s13071-017-2394-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 09/19/2017] [Indexed: 11/12/2022] Open
Abstract
Background Avian host species have different roles in the amplification and maintenance of West Nile virus (WNV), therefore identifying key taxa is vital in understanding WNV epidemics. Here, we present a comprehensive case study conducted on red-footed falcons, where host-vector, vector-virus and host-virus interactions were simultaneously studied to evaluate host species contribution to WNV circulation qualitatively. Results Mosquitoes were trapped inside red-footed falcon nest-boxes by a method originally developed for the capture of blackflies and midges. We showed that this approach is also efficient for trapping mosquitoes and that the number of trapped vectors is a function of host attraction. Brood size and nestling age had a positive effect on the number of attracted Culex pipiens individuals while the blood-feeding success rate of both dominant Culex species (Culex pipiens and Culex modestus) markedly decreased after the nestlings reached 14 days of age. Using RT-PCR, we showed that WNV was present in these mosquitoes with 4.2% (CI: 0.9–7.5%) prevalence. We did not detect WNV in any of the nestling blood samples. However, a relatively high seroprevalence (25.4% CI: 18.8–33.2%) was detected with an enzyme-linked immunoabsorbent assay (ELISA). Using the ELISA OD ratios as a proxy to antibody titers, we showed that older seropositive nestlings have lower antibody levels than their younger conspecifics and that hatching order negatively influences antibody levels in broods with seropositive nestlings. Conclusions Red-footed falcons in the studied system are exposed to a local sylvatic WNV circulation, and the risk of infection is higher for younger nestlings. However, the lack of individuals with viremia and the high WNV seroprevalence, indicate that either host has a very short viremic period or that a large percentage of nestlings in the population receive maternal antibodies. This latter assumption is supported by the age and hatching order dependence of antibody levels found for seropositive nestlings. Considering the temporal pattern in mosquito feeding success, maternal immunity may be effective in protecting progeny against WNV infection despite the short antibody half-life measured in various other species. We conclude that red-footed falcons seem to have low WNV host competence and are unlikely to be effective virus reservoirs in the studied region.
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Affiliation(s)
- Zoltán Soltész
- Lendület Ecosystem Services Research Group, MTA Centre for Ecological Research, Vácrátót, Hungary. .,Hungarian Natural History Museum, Budapest, Hungary.
| | - Károly Erdélyi
- National Food Chain Safety Office, Veterinary Diagnostic Directorate, Budapest, Hungary
| | - Tamás Bakonyi
- Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, Budapest, Hungary.,Viral Zoonoses, Emerging and Vector-Borne Infections Group, Institute of Virology, University of Veterinary Medicine, Vienna, Austria
| | - Mónika Barna
- Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, Budapest, Hungary
| | | | - Szabolcs Solt
- MME/BirdLife Hungary, Red-footed Falcon Conservation Working Group, Budapest, Hungary
| | - Éva Horváth
- MME/BirdLife Hungary, Red-footed Falcon Conservation Working Group, Budapest, Hungary
| | - Péter Palatitz
- MME/BirdLife Hungary, Red-footed Falcon Conservation Working Group, Budapest, Hungary
| | | | - Ádám Dán
- National Food Chain Safety Office, Veterinary Diagnostic Directorate, Budapest, Hungary
| | - László Papp
- Hungarian Academy of Sciences, Biological Section, Budapest, Hungary
| | - Andrea Harnos
- Department of Biomathematics and Informatics, University of Veterinary Medicine, Budapest, Hungary
| | - Péter Fehérvári
- Hungarian Natural History Museum, Budapest, Hungary.,Department of Biomathematics and Informatics, University of Veterinary Medicine, Budapest, Hungary
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