Abstract
In early 2009, a novel influenza A (H1N1) virus appeared in Mexico and rapidly disseminated worldwide. Little is known about the phylogeny and evolutionary dynamics of the H1N1 strain found in Saudi Arabia. Nucleotide sequencing and bioinformatics analyses were used to study molecular variation between the virus isolates. In this report, 72 hemagglutinin (HA) and 45 neuraminidase (NA) H1N1 virus gene sequences, isolated in 2009 from various regions of Saudi Arabia, were analyzed. Genetic characterization indicated that viruses from two different clades, 6 and 7, were circulating in the region, with clade 7, the most widely circulating H1N1 clade globally in 2009, being predominant. Sequence analysis of the HA and NA genes revealed a high degree of sequence identity with the corresponding genes from viruses circulating in the South East Asia region and with the A/California/7/2009 strain. New mutations in the HA gene of pandemic H1N1 (pH1N1) viruses, that could alter viral fitness, were identified. Relaxed-clock and Bayesian Skyline Plot analyses, based on the isolates used in this study and closely related globally representative strains, indicated marginally higher substitution rates than the type strain (5.14×10-3 and 4.18×10-3 substitutions/nucleotide/year in the HA and NA genes, respectively). The Saudi isolates were antigenically homogeneous and closely related to the prototype vaccine strain A/California/7/2009. The antigenic site of the HA gene had acquired novel mutations in some isolates, making continued monitoring of these viruses vital for the identification of potentially highly virulent and drug resistant variants.
Highlights
In early 2009, a novel influenza A (H1N1) virus appeared in Mexico and rapidly disseminated worldwide
J Infect Dev Ctries 2017; 11(1):81-88. doi:10.3855/jidc.9259 (Received 03 August 2016 – Accepted 19 September 2016). Influenza virus strains such as H1N1 and H5N1, are a major concern for both public health and the global economy, with outbreaks in recent decades resulting in major socio-economic damage because of lost productivity and the medical costs of infection
All but one of the HA genes from the Saudi isolates grouped into a cluster that was identified as clade 7 (Figure 1A)
Summary
In early 2009, a novel influenza A (H1N1) virus appeared in Mexico and rapidly disseminated worldwide. Results: In this report, 72 hemagglutinin (HA) and 45 neuraminidase (NA) H1N1 virus gene sequences, isolated in 2009 from various regions of Saudi Arabia, were analyzed. The antigenic site of the HA gene had acquired novel mutations in some isolates, making continued monitoring of these viruses vital for the identification of potentially highly virulent and drug resistant variants. Influenza virus strains such as H1N1 and H5N1, are a major concern for both public health and the global economy, with outbreaks in recent decades resulting in major socio-economic damage because of lost productivity and the medical costs of infection. NA removes the sialic acid residues from the surfaces of infected cells, allowing the virus progeny to be released from the cell and to infect other cells [5]
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