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oai:recercat.cat:20.500.12327/30432025-10-22T11:31:33Zcom_2072_4428com_2072_4427col_2072_487898

Neuropathogenesis of a highly pathogenic avian influenza virus (H7N1) in experimentally infected chickens Chaves, Aida J. Busquets, Núria Valle, Rosa Rivas, Raquel Serra Gironella, Joan Dolz, Roser Ramis, Antonio Darji, Ayub Majó, Natàlia Producció Animal Sanitat Animal In order to understand the mechanism of neuroinvasion of a highly pathogenic avian influenza virus (HPAIV) into the central nervous system (CNS) of chickens, specific pathogen free chickens were inoculated with a H7N1 HPAIV. Blood, cerebrospinal fluid (CSF), nasal cavity and brain tissue samples were obtained from 1 to 4 days postinoculation (dpi) of infected and control chickens. Viral antigen topographical distribution, presence of influenza A virus receptors in the brain, as well as, the role of the olfactory route in virus CNS invasion were studied using different immunohistochemistry techniques. Besides, viral RNA load in CSF and blood was quantified by means of a quantitative real-time reverse transcription-polymerase chain reaction. Viral antigen was observed widely distributed in the CNS, showing bilateral and symmetrical distribution in the nuclei of the diencephalon, mesencephalon and rhombencephalon. Viral RNA was detected in blood and CSF at one dpi, indicating that the virus crosses the blood-CSF-barrier early during infection. This early dissemination is possibly favoured by the presence of Siaa2,3 Gal and Siaa2,6 Gal receptors in brain vascular endothelial cells, and Siaa2,3 Gal receptors in ependymal and choroid plexus cells. No viral antigen was observed in olfactory sensory neurons, while the olfactory bulb showed only weak staining, suggesting that the virus did not use this pathway to enter into the brain. The sequence of virus appearance and the topographical distribution of this H7N1 HPAIV indicate that the viral entry occurs via the haematogenous route, with early and generalized spreading through the CSF. 2025-10-22T11:31:33Z 2025-10-22T11:31:33Z 2025-10-22T11:31:33Z 2011-10-07 info:eu-repo/semantics/article Chaves, Aida J, Núria Busquets, Rosa Valle, Raquel Rivas, Júlia Vergara-Alert, Roser Dolz, Antonio Ramis, Ayub Darji, and Natàlia Majó. 2011. “Neuropathogenesis of a Highly Pathogenic Avian Influenza Virus (H7N1) in Experimentally Infected Chickens.” Veterinary Research 42 (1): 106. doi: 10.1186/1297-9716-42-106 0928-4249 http://hdl.handle.net/20.500.12327/3043 https://doi.org/10.1186/1297-9716-42-106 eng Veterinary Research EC/FP6/44098/EU/Molecular factors and mechanisms of transmission and pathogenicity of highly pathogenic Avian Influenza Virus/EUROFLU http://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess Attribution 4.0 International BMC