Low‐pathogenicity avian influenza

Pérez, Daniel R.; Wit, Janneke

doi:10.1002/9781118924341.ch11

Cited by 5 publications

(4 citation statements)

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“…However, the H9 subtype was first discovered in North America, associated with an LPAI outbreak in turkeys in February 1966 in northern Wisconsin in the United States (Smithies et al 1969;Homme and Easterday 1970). Details of this and other LPAI H9 outbreaks in poultry in the United States, particularly in the main turkey-production states of Minnesota and Wisconsin, have been extensively covered elsewhere (Halvorson et al 1983(Halvorson et al , 1997Halvorson 2009;Perez and de Wit 2016).…”

Section: S Carnaccini and Dr Perezmentioning

confidence: 99%

“…These studies have allowed identification of a number of molecular markers associated with mammalian adaptation, transmission, and virulence (mostly in the mouse model). Details about these studies has been previously summarized (Perez and de Wit 2016). In this work, two updated tables summarize these findings: Table 3 contains general markers of avian and mammalian host tropism and airborne transmission found in H9 IAVs, and Table 4 contains virulence markers found in H9N2 strains but tested in the context of other IAV subtypes with zoonotic potential.…”

Section: Clinical Signs Pathology and Interspecies Transmissionmentioning

confidence: 99%

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H9 Influenza Viruses: An Emerging Challenge

Carnaccini

Pérez

2019

Cold Spring Harb Perspect Med

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Influenza A viruses (IAVs) of the H9 subtype are enzootic in Asia, the Middle East, and parts of North and Central Africa, where they cause significant economic losses to the poultry industry. Of note, some strains of H9N2 viruses have been linked to zoonotic episodes of mild respiratory diseases. Because of the threat posed by H9N2 viruses to poultry and human health, these viruses are considered of pandemic concern by the World Health Organization (WHO). H9N2 IAVs continue to diversify into multiple antigenically and phylogenetically distinct lineages that can further promote the emergence of strains with pandemic potential. Somewhat neglected compared with the H5 and H7 subtypes, there are numerous indicators that H9N2 viruses could be involved directly or indirectly in the emergence of the next influenza pandemic. The goal of this work is to discuss the state of knowledge on H9N2 IAVs and to provide an update on the contemporary global situation.

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Section: S Carnaccini and Dr Perezmentioning

confidence: 99%

Section: Clinical Signs Pathology and Interspecies Transmissionmentioning

confidence: 99%

H9 Influenza Viruses: An Emerging Challenge

Carnaccini

Pérez

2019

Cold Spring Harb Perspect Med

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“…In those cases, illness or death is most often from respiratory damage, especially if accompanied by secondary bacterial infections. This is especially the case when co-infections occur as is seen in the areas with H9N2 and IBV infections (Perez & De Wit, 2017). Some LPAI strains have the capacity to spread systematically, replicating and causing damage in the kidney (Shinya et al, 1995;Ziegler et al, 1999;Mosleh et al, 2009), pancreatic acinar epithelium (Shinya et al, 1995), oviduct (Ziegler et al, 1999;Bonfante et al, 2018), and other organs with epithelial cells having trypsin-like enzymes (Swayne et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

Major difference in clinical outcome and replication of a H3N1 avian influenza strain in young pullets and adult layers

et al. 2020

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In this study, we investigated the pathogenicity, replication and tropism of the low pathogenic avian influenza (LPAI) strain A/chicken/Belgium/460/2019(H3N1) in adult SPF layers and young SPF males. The inoculated hens showed 58% mortality and a 100% drop in egg production in the second week post inoculation. The high viral loads in the cloacal samples coincided with the period of the positive immunohistochemistry of the oviduct, acute peritonitis and time of mortality, suggesting that the replication of H3N1 in the oviduct was a major component of the onset of clinical disease and increased level of excretion of the virus. In the inoculated young birds, the clinical signs were very mild with the exception of one bird. The results suggest that the time of replication of the virus was much shorter than in the adult layers; some of the young males did not show any proof of being infected at all. To conclude, the results of the study in young birds confirmed the intravenous pathogenicity test results but also showed that the clinical signs in adult layers were very severe. Based on the mortality without a bacterial component, complete drop of egg production and post mortem findings, this H3N1 strain is a moderately virulent strain, the highest category for LPAI strains. It is important to realize that if HPAI did not exist, this moderately virulent H3N1 virus would most likely to be considered as a very virulent virus.

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“…H9 LPAIVs have spread in poultry populations worldwide since the 1990s [27]. Notably, H9N2 subtype LPAIVs have been circulating in poultry in Asia and the Middle East, causing decreases in egg-laying rates and feeding efficiency, and are sometimes associated with high mortality especially in chickens due to co-infection with other viruses and bacteria [9,18,29]. Furthermore, the N1 NA and the internal protein gene segments of the first human H5N1 HPAIV isolate in Hong Kong in 1997 were derived from H6N1 and H9N2 LPAIVs, which were prevalent in poultry at that time [28].…”

Section: Introductionmentioning

confidence: 99%