Phylogenetic Analysis of Influenza A Viruses (H6N8, H1N8, H4N2, H9N2, H10N7) Isolated from Wild Birds, Ducks, and Ostriches in South Africa from 2007 to 2009

Abolnik, Célia; Gerdes, Gertruida Hermanna; Sinclair, M.; Ganzevoort, Boto W.; Kitching, James P.; Burger, Christina E.; Romito, Marco; Dreyer, Magdeline; Swanepoel, Stefan; Cumming, Graeme S.; Olivier, Adriaan

doi:10.1637/9094-878109-digest.1

Cited by 7 publications

(9 citation statements)

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“…H9N2 influenza viruses have been widely reported to infect mammals, including pigs and humans (Abolnik et al, 2010;Butt et al, 2010;Cong et al, 2007;Sun et al, 2010;Xu et al, 2007); there is evidence that a large number of people have been infected with H9N2 viruses, in particular poultry workers (Coman et al, 2013;Jia et al, 2009;Wang et al, 2009). H9N2 virus infections in humans showed typical human flu-like symptoms, which can easily go undetected or unreported (Butt et al, 2005;Lin et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

PA-X is a virulence factor in avian H9N2 influenza virus

Gao

Sun

et al. 2015

Journal of General Virology

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H9N2 influenza viruses have been circulating worldwide in multiple avian species, and regularly infect pigs and humans. Recently, a novel protein, PA-X, produced from the PA gene by ribosomal frameshifting, was demonstrated to be an antivirulence factor in pandemic 2009 H1N1, highly pathogenic avian H5N1 and 1918 H1N1 viruses. However, a similar role of PA-X in the prevalent H9N2 avian influenza viruses has not been established. In this study, we compared the virulence and cytopathogenicity of H9N2 WT virus and H9N2 PA-X-deficient virus. Loss of PA-X in H9N2 virus reduced apoptosis and had a marginal effect on progeny virus output in human pulmonary adenocarcinoma (A549) cells. Without PA-X, PA was less able to suppress co-expressed GFP in human embryonic kidney 293T cells. Furthermore, absence of PA-X in H9N2 virus attenuated viral pathogenicity in mice, which showed no mortality, reduced progeny virus production, mild-to-normal lung histopathology, and dampened proinflammatory cytokine and chemokine response. Therefore, unlike previously reported H1N1 and H5N1 viruses, we show that PA-X protein in H9N2 virus is a pro-virulence factor in facilitating viral pathogenicity and that the pro-or antivirulence role of PA-X in influenza viruses is virus strain-dependent.

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Section: Introductionmentioning

confidence: 99%

PA-X is a virulence factor in avian H9N2 influenza virus

Gao

Sun

et al. 2015

Journal of General Virology

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“…Although some intriguing data exist from South Africa (such as the finding that precursors to pathogenic AIV strains are introduced to and possibly moved between ostrich farms by Egyptian Geese Alopochen aegyptiacus; e.g. see Abolnik et al, 2010;Sinclair et al, 2005), little relevant research has been carried out in most southern African countries.…”

Section: Introductionmentioning

confidence: 99%

The Ecology of Influenza A Viruses in Wild Birds in Southern Africa

et al. 2011

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Avian influenza viruses (AIVs) are pathogens of global concern, but there has been little previous research on avian influenza in southern Africa and almost nothing is known about the dynamics of AIVs in the region. We counted, captured and sampled birds regularly at five sites, two in South Africa (Barberspan and Strandfontein) and one in each of Botswana (Lake Ngami), Mozambique (Lake Chuali) and Zimbabwe (Lakes Manyame and Chivero) between March 2007 and May 2009. The South African and Zimbabwean sites were visited every 2 months and the sites in Botswana and Mozambique every 4 months. During each visit we undertook 5-7 days of standardised bird counts followed by 5-10 days of capturing and sampling water-associated birds. We sampled 4,977 birds of 165 different species and completed 2,503 half-hour point counts. We found 125 positive rRT-PCR cases of avian influenza across all sites. Two viruses (H1N8 and H3N8) were isolated and additional H5, H6 and H7 strains were identified. We did not positively identify any highly pathogenic H5N1. Overall viral prevalence (2.51%) was similar to the lower range of European values, considerable spatial and temporal variation occurred in viral prevalence, and there was no detectable influence of the annual influx of Palearctic migrants. Although waterbirds appear to be the primary viral carriers, passerines may link wild birds and poultry. While influenza cycles are probably driven by the bird movements that result from rainfall patterns, the epidemiology of avian influenza in wild birds in the subregion is complex and there appears to be the possibility for viral transmission throughout the year.

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“…9N2 influenza viruses have been circulating worldwide in multiple avian species and occasionally transmitted to mammalian species, including humans and pigs (1)(2)(3)(4)(5), posing a significant threat to public health. Regarded as an epicenter of pandemic influenza viruses, China is home to the endemic BJ/94-like H9N2 influenza viruses, which continue to undergo rapid evolution by drift mutations and/or reassortment (4,5).…”

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confidence: 99%

Amino Acid 316 of Hemagglutinin and the Neuraminidase Stalk Length Influence Virulence of H9N2 Influenza Virus in Chickens and Mice

Sun

Tan

Wei

et al. 2013

J Virol

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e H9N2 influenza viruses with an A316S substitution in hemagglutinin (HA) and a shorter neuraminidase (NA) stalk have become predominant in China. The A316S was shown to increase HA cleavage efficiency when combined with short stalk NA, and the short stalk NA improved NA enzyme activity and release of virus from erythrocytes. Single mutations or combinations of these mutations strengthened the virulence of H9N2 virus in chickens and mice.

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Phylogenetic Analysis of Influenza A Viruses (H6N8, H1N8, H4N2, H9N2, H10N7) Isolated from Wild Birds, Ducks, and Ostriches in South Africa from 2007 to 2009

Cited by 7 publications

References 0 publications

PA-X is a virulence factor in avian H9N2 influenza virus

PA-X is a virulence factor in avian H9N2 influenza virus

The Ecology of Influenza A Viruses in Wild Birds in Southern Africa

Amino Acid 316 of Hemagglutinin and the Neuraminidase Stalk Length Influence Virulence of H9N2 Influenza Virus in Chickens and Mice

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