Ahmed BM, Bayoumi MM, Farrag MA, Elgamal MA, Daly. Emergence of equine influenza virus H3Nx Florida clade 2 in Arabian racehorses in Egypt. Virol J. 2022 Nov 12;19(1):185
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.
- Bidirectional movement of emerging H5N8 avian influenza viruses between Europe and Asia via migratory birds since early 2020 2 days ago
- Household Transmission of Influenza A Viruses in 2021-2022 3 days ago
- Effects of ambient temperature on influenza-like illness: A multicity analysis in Shandong Province, China, 2014-2017 3 days ago
- Highly pathogenic avian influenza A(H5N1) virus infection in farmed minks, Spain, October 2022 4 days ago
- Infectivity and transmissibility of an avian H3N1 influenza virus in pigs 4 days ago