Phylogenetic analysis of NS gene of avian influenza viruses (H9N2) isolated from chicken in Iran during 2007–2011

Norouzian, Hassan; Chashmi, Hessam Emadi; Nazari, Z; Marandi, M Vasfi

doi:10.3906/vet-1311-11

Cited by 3 publications

(3 citation statements)

References 54 publications

(83 reference statements)

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“…The aim of the present study was to perform sequencing and phylogenetic analysis of 10 viruses to determine the molecular evolution and genetic variation of the HA and NA genes of H9N2 viruses. The topologies of HA and NA phylogenetic trees were very similar to each other and all the Iranian viruses fell into G1 sub-lineage in agreement with previous studies (Bashashati et al, 2013;Norouzian et al, 2014;Bahari et al, 2015). On the basis of phylogenetic analysis, the Iranian HAs are classified into four branches whereas NA genes fall into five categories.…”

Section: Discussionsupporting

confidence: 87%

Ongoing genetic evolution of H9N2 avian influenza viruses in Iranian industrial poultry farms

Bashashati

mojahedi

Roudsari

et al. 2020

AVet

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Despite the use of wide-scale vaccination programmes against the H9N2 virus, enzootic outbreaks of H9N2 avian influenza (AI) have often occurred and caused serious nationwide economic losses, particularly in broiler chickens. In this study, the haemagglutinin (HA) and neuraminidase (NA) genes of nine recent H9N2s and a common vaccine strain were fully sequenced and compared with other representative Iranian viruses. Phylogenetic analysis revealed that all Iranian viruses were grouped into the G1 sub-lineage with different clusters in which recent isolates (2014–2017) formed a distinct cluster compared to the vaccine group (1998–2004). All Iranian H9N2s exhibited low pathogenicity AI connecting peptide feature with an R/KSSR motif. Amino acid 226, located in the 220 loop of the receptor binding site, was leucine among the recent Iranian viruses, a characteristic of human influenza viruses. With an overall gradual increase in the genetic diversity of H9N2s, Bayesian skyline plots of Iranian HA and NA genes depicted a fluctuation and a relative stable situation, respectively. It is recommended to apply constant surveillance to assess any increase in viral human adaptation and evolutionary changes in circulating field H9N2s. Moreover, antigenic characterisation of the prevailing H9N2 viruses seems to be necessary for evaluating the possible antigenic drift from the vaccine strain.

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Section: Discussionsupporting

confidence: 87%

Ongoing genetic evolution of H9N2 avian influenza viruses in Iranian industrial poultry farms

Bashashati

mojahedi

Roudsari

et al. 2020

AVet

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“…Another study conducted in the southern region of Pakistan found that 28 out of 50 samples tested positive for avian influenza subtype H9N2 because the birds showed respiratory signs and symptoms that were significantly associated to AIV infection (Ahmed et al, 2009). According to Norouzian et al (2014), the H9N2 subtype of avian influenza (AI) virus was isolated from backyard poultry farms in Iran between 2010 and 2011 and was associated with significant mortality and respiratory problems (Norouzian et al, 2014).…”

Section: Resultsmentioning

confidence: 99%

Seroprevalence and associated risk factors of avian influenza virus subtype H9N2 in backyard poultry of Peshawar Pakistan

Rehman

Khan

Rantam³

et al. 2021

J. Indonesian Trop. Anim. Agric.

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The current study was conducted to estimate the serological prevalence and risk factors associated with the transmission of avian influenza subtype H9N2 among backyard poultry from different villages of semi-arid climate district Peshawar Pakistan between January to May 2019. In total, 240 blood samples of healthy backyard poultry older than two months were collected from 30 different villages of district Peshawar. A predesigned questionnaire was used to collect the data related to risk factors. Se-rum samples were tested through the haemagglutination inhibition (HI) test further confirmed by the micro-neutralizing test (MN). Antibody body titer ≤ 8 considered negative for prevalence of H9N2. In order to classify risk factors, Chi-square and Logistic regression analyses were performed. Out of 240, 150 were found to be positive. The overall seroprevalence was 62.5%, mean antibody titer for avian influenza virus in all villages was 6.8 and (95%) confidence interval ranges from 35.33 to 51.70% re-spectively. The high prevalence of antibodies to avian influenza viruses in bird serum emphasizes that avian influenza plays an important role in the respiratory infections of backyard chickens in the area, and possibly throughout Pakistan. In order to avoid the introduction of H9N2, biosecurity initiatives, surveillance, monitoring systems, and to some extent, vaccinations are useful tools.

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“…The H9N2 influenza viruses circulate widely in domestic poultry across many countries ( 40 – 44 ). The H9N2 viruses isolated in China form multiple genotypes ( 21 , 41 ) and were the source of the internal genes of the novel H7N9 viruses and the H10N8 viruses that have infected humans in China ( 22 , 45 , 46 ).…”

Section: Discussionmentioning

confidence: 99%

Characterization of Clade 7.2 H5 Avian Influenza Viruses That Continue To Circulate in Chickens in China

Liu

Zeng

Chen

et al. 2016

J Virol

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The H5N1 avian influenza viruses emerged in Southeast Asia in the late 20th century and have evolved into multiple phylogenetic clades based on their hemagglutinin (HA)-encoding genes. The clade 7.2 viruses were first detected in chickens in northern China in 2006, and vaccines specifically targeted to the clade were developed and have been used in poultry in China since 2006. During routine surveillance and disease diagnosis, we isolated seven H5 viruses between 2011 and 2014 that bear the clade 7.2 HA genes. Here, we performed extensive studies to understand how the clade 7.2 H5 viruses have evolved in chickens in China. Full genome sequence analysis revealed that the seven viruses formed two subtypes (four H5N1 viruses and three H5N2 viruses) and four genotypes by deriving genes from other influenza viruses. All of the viruses had antigenically drifted from the clade 7.2 viruses that were isolated in 2006. Pathogenicity studies of four viruses, one from each genotype, revealed that all of the viruses are highly pathogenic in chickens, but none of them could replicate in ducks. The four viruses exclusively bound to avian-type receptors and replicated only in the turbinates and/or lungs of mice; none of them were lethal to mice at a dosage of 106 50% egg infective doses (EID50). Our study indicates that although the clade 7.2 viruses have not been eradicated from poultry through vaccination, they have not become more dangerous to other animals (e.g., ducks and mice) and humans.IMPORTANCE Animal influenza viruses can acquire the ability to infect and kill humans. The H5N1 viruses have been a concern in recent decades because of their clear pandemic potential. We sorted H5N1 influenza viruses into different phylogenetic clades based on their HA genes. The clade 7.2 viruses were detected in chickens in several provinces of northern China in 2006. Vaccines for these viruses were subsequently developed and have been used ever since to control infection of poultry. Here, we analyzed the genetic and biologic properties of seven clade 7.2 viruses that were isolated from chickens between 2011 and 2014. We found that after nearly 9 years of circulation in chickens, the clade 7.2 viruses still exclusively bind to avian-type receptors and are of low pathogenicity to mice, suggesting that these H5 viruses pose a low risk to human public health.

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Phylogenetic analysis of NS gene of avian influenza viruses (H9N2) isolated from chicken in Iran during 2007–2011

Cited by 3 publications

References 54 publications

Ongoing genetic evolution of H9N2 avian influenza viruses in Iranian industrial poultry farms

Ongoing genetic evolution of H9N2 avian influenza viruses in Iranian industrial poultry farms

Seroprevalence and associated risk factors of avian influenza virus subtype H9N2 in backyard poultry of Peshawar Pakistan

Characterization of Clade 7.2 H5 Avian Influenza Viruses That Continue To Circulate in Chickens in China

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