Avian Influenza Viruses in Wild Land Birds in Northern Vietnam

Thinh, Tien Vu; Gilbert, Martin; Bunpapong, Napawan; Amonsin, Alongkorn; Nguyen, Dung Tien; Doherty, Paul F.; Huyvaert, Kathryn P.

doi:10.7589/0090-3558-48.1.195

Cited by 13 publications

(5 citation statements)

References 18 publications

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“…The positive rate that we detected in Central Africa’s wild birds is consistent with surveillance elsewhere in the Old World Tropics. For example, infection rates in passerines at tropical sites in northern Vietnam and southern China range from 2.3-6.6% [32, 33], which is within the confidence limits of our estimates for Central Africa (1.57-7.95%).…”

Section: Discussionsupporting

confidence: 81%

Seasonality dynamics of avian influenza occurrences in Central and West Africa

Fuller

Ducatez

Njabo

et al. 2014

Preprint

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SUMMARY Understanding seasonal cycles of viruses originating in wildlife can provide insight into their likelihood of persistence in animal populations and inform policies to limit spillover to human populations. Avian influenza virus (AIV) is an important zoonotic agent causing seasonal occurrence of avian influenza (AI) in wild birds in temperate areas. Although the seasonality of AIV transmission in tropical birds is largely unknown, peaks of influenza activity in human populations in the tropics coincide with the rainy season. To assess the seasonality of AI in tropical birds, from 2010-14, we sampled 40,099 birds at 32 sites in Central Africa (Cameroon, Central African Republic, Congo-Brazzaville, and Gabon) and West Africa (Benin, Côte d’Ivoire, and Togo). Although AIV was not isolated by egg culture, in Central Africa, detection rates by real-time RT-PCR were 3.57% for passerine songbirds and 8.74% for Anatid ducks. RT-PCR positivity in resident birds increased when Palearctic migrants arrived in Central Africa. At sampling sites with two annual wet seasons, the positive rate in wild birds was greatest during the big rainy season in September – October. This study provides the first evidence that AI is present in Central African birds and identifies environmental factors associated with cases.

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Section: Discussionsupporting

confidence: 81%

Seasonality dynamics of avian influenza occurrences in Central and West Africa

Fuller

Ducatez

Njabo

et al. 2014

Preprint

View full text Add to dashboard Cite

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“…Our studies did not quantify very low levels of virus RNA in the swabs by real-time PCR which was not used in the analyses; moreover, the quantitative results for virus infectivity shown in Figure 1 could not be applied to the low titres of viable virus propagated from swabs from crows since virus was only detected after a blind passage (Table 2). It is known that crows are susceptible to H5N1 avian influenza virus infection [25,41-50], but, to our knowledge, no experimental infection has been reported describing the levels of virus shedding and transmission from H5N1 infected crows to naïve contact crows or chickens. Evidence for widespread prevalence of H9N2 viruses in house sparrows and crows is only limited [14,16], but six H9N2 viruses collected from sparrows in 2005 and 2006 have been described, and the HA genes have been characterised (Zhu,W.…”

Section: Discussionmentioning

confidence: 99%

Infectivity and transmissibility of H9N2 avian influenza virus in chickens and wild terrestrial birds

Iqbal

Yaqub

Mukhtar

et al. 2013

Vet Res

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Genetic changes in avian influenza viruses influence their infectivity, virulence and transmission. Recently we identified a novel genotype of H9N2 viruses in widespread circulation in poultry in Pakistan that contained polymerases (PB2, PB1 and PA) and non-structural (NS) gene segments identical to highly pathogenic H7N3 viruses. Here, we investigated the potential of these viruses to cause disease and assessed the transmission capability of the virus within and between poultry and wild terrestrial avian species. Groups of broilers, layers, jungle fowl, quail, sparrows or crows were infected with a representative strain (A/chicken/UDL-01/08) of this H9N2 virus and then mixed with naïve birds of the same breed or species, or different species to examine transmission. With the exception of crows, all directly inoculated and contact birds showed clinical signs, varying in severity with quail showing the most pronounced clinical signs. Virus shedding was detected in all infected birds, with quail showing the greatest levels of virus secretion, but only very low levels of virus were found in directly infected crow samples. Efficient virus intra-species transmission was observed within each group with the exception of crows in which no evidence of transmission was seen. Interspecies transmission was examined between chickens and sparrows and vice versa and efficient transmission was seen in either direction. These results highlight the ease of spread of this group of H9N2 viruses between domesticated poultry and sparrows and show that sparrows need to be considered as a high risk species for transmitting H9N2 viruses between premises.

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“…Vietnam is also part of the East Asia-Australasian flyway and Thinh et al [ 35 ] showed avian influenza A viruses including H5 and H6, and H9 subtypes were isolated from wild migratory birds in Vietnam. Indeed, a live poultry movement network between Vietnam and other neighboring countries revealed the epidemiological links for AIV importation to Vietnam [ 36 ].…”

Section: Discussionmentioning

confidence: 99%

Reassortant Highly Pathogenic H5N6 Avian Influenza Virus Containing Low Pathogenic Viral Genes in a Local Live Poultry Market, Vietnam

Lee

et al. 2021

Curr Microbiol

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Sites of live poultry trade and marketing are hot spots for avian influenza virus (AIV) transmission. We conducted active surveillance at a local live poultry market (LPM) in northern Vietnamese provinces in December 2016. Feces samples from the market were collected and tested for AIV. A new reassorted AIV strain was isolated from female chickens, named A/chicken/Vietnam/AI-1606/2016 (H5N6), and was found to belong to group C of clade 2.3.4.4 H5N6 highly pathogenic (HP) AIVs. The neuraminidase gene belongs to the reassortant B type. The viral genome also contained polymerase basic 2 and polymerase acidic, which were most closely related to domestic-duck-origin low pathogenic AIVs in Japan (H3N8) and Mongolia (H4N6). The other six genes were most closely related to poultry-origin H5N6 HP AIVs in Vietnam and had over 97% sequence identity with human AIV isolate A/Guangzhou/39715/2014 (H5N6). The new reassorted AIV isolate A/chicken/Vietnam/AI-1606/2016 (H5N6) identified in this study exemplifies AIVs reassortment and evolution through contact among wild birds, poultry farms, and LPMs. Therefore, active surveillance of AIVs is necessary to prevent potential threats to human and animal health.

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Avian Influenza Viruses in Wild Land Birds in Northern Vietnam

Cited by 13 publications

References 18 publications

Seasonality dynamics of avian influenza occurrences in Central and West Africa

Seasonality dynamics of avian influenza occurrences in Central and West Africa

Infectivity and transmissibility of H9N2 avian influenza virus in chickens and wild terrestrial birds

Reassortant Highly Pathogenic H5N6 Avian Influenza Virus Containing Low Pathogenic Viral Genes in a Local Live Poultry Market, Vietnam

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