مسح ودراسة النماط الجزينية لفيروس الانفلونزا A بين الفلسطينيين
Date
2017-01-03
Authors
ميسون صادق ياسين البكري
maysoon sadek yaseen Al Bakri
Journal Title
Journal ISSN
Volume Title
Publisher
AL-Quds University
جامعة القدس
جامعة القدس
Abstract
Influenza A virus (IAV) causes significant mortality, morbidity, and financial burden throughout
the world. IAV is a negative, single-stranded, and segmented RNA virus of the
Orthomyxoviridae family. IAV subtypes are determined based on its two surface glycoproteins,
hemagglutinin (HA) and neuraminidase (NA). H1N1 and H3N2 are the major circulating
subtypes among humans. Frequent genotyping of IAV strains throughout the influenza season is
crucial for the identification of circulating subtypes and subsequently the choice of the H3N2 and
H1N1 subtypes’ lineages to be included in the annually prepared vaccine cocktail. Sequencing
and identification of circulating subtypes in the region continues to be less frequent and less
intensive than in other parts of the world, despite increasing interest and efforts made ever since
the swine H1N1 outbreak in 2009. This work presents the first comprehensive study on IAV
circulating in Palestine. 200 Nasopharyngeal aspirate (NPA) samples were collected between
February 10th and May 5th, 2015 from participants suffering from mild to severe symptoms of
upper respiratory infections and were screened for the presence of IAV using RT-PCR assays
amplifying the HA and NA gene regions. 50 samples (25%) tested positive for IAV, 24 (48%)
were identified as H1N1, and 26 (52%) were identified as H3N2 subtype, respectively. Infection
with H1N1 occurred mainly in April, while H3N2 infections were mainly detected in March.
Most IAV infections in children younger than 6-year-old were attributed to subtypes H3N2,
while H1N1 was responsible for most infections in adults older than eighteen-year-old.
Hundred-fifteen sequences of the HA and NA genes were successfully analyzed. These
sequences belong to 23 IAV positive Palestinian IAV samples. The percent identity of thesequences among Palestinian isolates was higher than that between Palestinian isolates and
GenBank-archived reference sequences. 14, 15, 22 and 6 non-synonymous substitutions were
detected in the Palestinian H1, N1, H3 and N2 genes, including novel ones, respectively. Some
of these amino acid substitutions localized to the antigenic sites, T202S and Q180K in H1 gene,
T144A and L173S in H3 gene. Such substitutions in the antigenic sites may affect the hostimmune
response. Other substitutions located at the receptor binding sites, such as T228A in H3
gene, may affect viral binding activity to host cell receptor, and subsequently its virulence and
host species barrier.None of the substitutions detected in this work were associated with drug resistance or fatal
outcomes. Phylogenetic analysis revealed that Palestinian H1N1 and H3N2 were not closely
related to those regionally circulating strains and clustered closer to international, rather nonregional
strains. The results of this study are significant in providing the first insight into the
genetic properties of the HA and NA genes of the influenza A viruses circulating in Palestine.
Finally, this study provides evidence of the efficacy of the seasonal influenza vaccine 2014-2015
in Palestine.
Description
Keywords
الكيمياء الحيوية والاحياء الجزيئية , Biochemistry & Molecular Biology