Evolutionary analysis of HA and NS1 genes of H5N1 influenza viruses in 2004-2005 epidemics
Related Experiment Video
Updated: Jul 15, 2026

Monitoring Influenza Virus Survival Outside the Host Using Real-Time Cell Analysis
Published on: February 20, 2021
Massimo Ciccozzi1, Stefania Montieri, Marzia Facchini
1Department of Infectious, Parasitic and Immunomediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, Rome 00161, Italy.
Abstract:
H5N1 avian influenza viruses circulating in early 2004 in eastern Asia appeared to be under strong purifying selection, except for the hemagglutinin (HA) and nonstructural 1 (NS1) genes, where few amino acid positions were found under positive selection pressure. To evaluate whether the widespread circulation of the H5N1 viruses in the following years was accompanied by a change in the evolution of the HA and NS1, phylogenetic and positive selection analyses were performed on 89 HA and 57 NS1 sequences. Results showed that the number of HA positively selected sites decreased compared to 2004; no selection pressure for NS1 was found. These findings suggest a possible change in the adaptation of the H5N1 virus to birds.
More Related Videos
Related Concept Videos
Viral Mutations
Influenza
Leaky Scanning
Inhibitors Of Virion Release
Viral Recombination
Single Nucleotide Polymorphisms-SNPs

