Emergence of equine influenza virus H3Nx Florida clade 2 in Arabian racehorses in Egypt.

Autor: Ahmed BM; Department of Virology, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt., Bayoumi MM; Department of Virology, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt.; Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, LA1 4YG, UK., Farrag MA; Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia., Elgamal MA; Department of Virology, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt., Daly JM; One Virology, Wolfson Centre for Global Virus Research, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire, LE12 5RD, UK., Amer HM; Department of Virology, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt. hamoamer@cu.edu.eg.
Jazyk: angličtina
Zdroj: Virology journal [Virol J] 2022 Nov 12; Vol. 19 (1), pp. 185. Date of Electronic Publication: 2022 Nov 12.
DOI: 10.1186/s12985-022-01917-9
Abstrakt: Background: Equine influenza is an important cause of respiratory disease in equids. The causative virus; EIV, is highly variable and can evolve by accumulation of mutations, particularly in the haemagglutinin (HA) gene. Currently, H3N8 is the sole subtype circulating worldwide with Florida clade 1 (FC1) is most prevalent in the Americas and FC2 in Asia and Europe. In Egypt, EIV was detected in two occasions: subtype H7N7 in 1989 and subtype H3N8 (FC1) in 2008. No data is available on the circulation pattern of EIV during the last decade despite frequent observation of suspected cases.
Methods: Twenty-two nasal swabs were collected from vaccinated and non-vaccinated horses showing respiratory signs suggestive of EIV infection in 2017-18. Three additional swabs were retrieved during a national race event in January 2018 from Arabian mares with high fever, gait stiffness and dry cough. Samples were screened by RT-qPCR and HA1 domain of the hemagglutinin gene was amplified and sequenced for sequence and phylogenetic analysis.
Results: RT-qPCR screening revealed that only the 3 samples from the race were positive with cycle thresholds ranging from 16 to 21 indicating high viral load. Isolation attempts in hen's eggs were unsuccessful. Sequence analysis of the HA1 domain gene has revealed two identical nucleotide sequences, while the third contained 3 synonymous mutations. Phylogenetic analysis clustered study sequences with recent FC2 sequences from Europe. Amino acid alignments revealed 14 and 13 amino acid differences in the study sequences compared to A/equine/Egypt/6066NANRU-VSVRI/08 (H3N8) and A/equine/Kentucky/1997 (H3N8), respectively, available as EIV vaccines in Egypt. Nine amino acids were different from A/equine/Richmond/1/2007 (H3N8), the recommended FC2 vaccine strain by the world organization of animal health expert surveillance panel (OIE-ESP), two of which were unique to the Egyptian sequences while the remaining 7 changes were shared with the FC2-144V subgroup detected in the United Kingdom from late 2015 to 2016.
Conclusions: The study represents the first reported detection of FC2-144V related EIV from Arabian mares in Egypt, and probably from the entire middle east region. The presented information about EIV epidemiology and spread may require reconsideration of the vaccine strains used in the national vaccination programs.
(© 2022. The Author(s).)
Databáze: MEDLINE
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