Detection of a Novel Reassortant H9N9 Avian Influenza Virus in Free-Range Ducks in Bangladesh

Wild aquatic birds are the primary natural reservoir for influenza A viruses (IAVs). In this study, an A(H9N9) influenza A virus (A/duck/Bangladesh/44493/2020) was identified via routine surveillance in free-range domestic ducks in Bangladesh. Phylogenetic analysis of hemagglutinin showed that the H9N9 virus belonged to the Y439-like lineage. The HA gene had the highest nucleotide identity to A/Bean Goose (Anser fabalis)/South Korea/KNU 2019-16/2019 (H9N2). The other seven gene segments clustered within the Eurasian lineage.

Download Full-text

Assessment of exposure to influenza A viruses in pigs between weaning and market age

Veterinary Research ◽

10.1186/s13567-021-00927-9 ◽

2021 ◽

Vol 52 (1) ◽

Author(s):

Juliana Bonin Ferreira ◽

Zvonimir Poljak ◽

Robert Friendship ◽

Éva Nagy ◽

Greg Wideman ◽

...

Keyword(s):

Influenza A ◽

Production Systems ◽

Influenza A Viruses ◽

Ha Gene ◽

Testing Strategies ◽

Common Causes ◽

Nasal Swabs ◽

Antibody Titers ◽

2009 H1n1 ◽

Low Prevalence

AbstractInfluenza A viruses (IAVs) are common causes of respiratory infection in pigs. The objective of this study was to characterize the circulation of IAVs between weaning and market age on the basis of development of antibody response and molecular epidemiology of detected viruses. Two batches of weaned pigs were followed in the nursery and finisher barns with a sample of 81 and 75 pigs. Nasal swabs and blood samples were collected from individual pigs for virological and serological analyses. A H3N2 subtype virus, of cluster IV, was detected in Study 1, with a maximum of 97.9% identity to HA gene of viruses previously isolated in Ontario. In Study 2, a H1N1 subtype virus, of 2009 H1N1 pandemic lineage, was detected, with a maximum of 97.8% identity to HA gene of viruses previously isolated in Ontario. On the basis of HA gene, it was observed that pigs were being detected with the same virus over time. The existence of antibody titers for IAV other than the isolated one confirmed that more than one subtype can circulate in the same population. In Study 1, pigs with higher numbers of IAV detection had lower serological titers for the same virus that was confirmed to circulate in the nursery (P < 0.01). Thorough knowledge of all endemic viral strains is fundamental for development of infection and disease control, particularly in complex production systems. This may include consideration of sampling and testing strategies which could detect circulation of all IAV variants, even if they have low prevalence.

Download Full-text

Cooperation between the Hemagglutinin of Avian Viruses and the Matrix Protein of Human Influenza A Viruses

Journal of Virology ◽

10.1128/jvi.76.4.1781-1786.2002 ◽

2002 ◽

Vol 76 (4) ◽

pp. 1781-1786 ◽

Cited By ~ 40

Author(s):

Christoph Scholtissek ◽

Jürgen Stech ◽

Scott Krauss ◽

Robert G. Webster

Keyword(s):

Influenza A Virus ◽

Influenza A ◽

Matrix Protein ◽

Gene Products ◽

Human Influenza ◽

Influenza A Viruses ◽

M Gene ◽

Human Virus ◽

Ha Gene ◽

M Proteins

ABSTRACT To analyze the compatibility of avian influenza A virus hemagglutinins (HAs) and human influenza A virus matrix (M) proteins M1 and M2, we doubly infected Madin-Darby canine kidney cells with amantadine (1-aminoadamantane hydrochloride)-resistant human viruses and amantadine-sensitive avian strains. By using antisera against the human virus HAs and amantadine, we selected reassortants containing the human virus M gene and the avian virus HA gene. In our system, high virus yields and large, well-defined plaques indicated that the avian HAs and the human M gene products could cooperate effectively; low virus yields and small, turbid plaques indicated that cooperation was poor. The M gene products are among the primary components that determine the species specificities of influenza A viruses. Therefore, our system also indicated whether the avian HA genes effectively reassorted into the genome and replaced the HA gene of the prevailing human influenza A viruses. Most of the avian HAs that we tested efficiently cooperated with the M gene products of the early human A/PR/8/34 (H1N1) virus; however, the avian HAs did not effectively cooperate with the most recently isolated human virus that we tested, A/Nanchang/933/95 (H3N2). Cooperation between the avian HAs and the M proteins of the human A/Singapore/57 (H2N2) virus was moderate. These results suggest that the currently prevailing human influenza A viruses might have lost their ability to undergo antigenic shift and therefore are unable to form new pandemic viruses that contain an avian HA, a finding that is of great interest for pandemic planning.

Download Full-text

Isolation of influenza A viruses from domestic ducks in Malaysia

Veterinary Record ◽

10.1136/vr.118.5.130 ◽

1986 ◽

Vol 118 (5) ◽

pp. 130-130

Author(s):

I. Aini ◽

A. Ibrahim

Keyword(s):

Influenza A ◽

Influenza A Viruses ◽

Domestic Ducks

Download Full-text

No gene communication of HA gene between the human H3N2 and H1N1 pandemic 2009 influenza A viruses

Journal of Infection ◽

10.1016/j.jinf.2019.04.014 ◽

2019 ◽

Vol 79 (2) ◽

pp. 174-187

Author(s):

Xuejuan Shen ◽

Zhiqing Pu ◽

David M. Irwin ◽

Yongyi Shen

Keyword(s):

Influenza A ◽

H1n1 Pandemic ◽

Influenza A Viruses ◽

Ha Gene

Download Full-text

Pathogenicity and Vaccine Efficacy of Different Clades of Asian H5N1 Avian Influenza A Viruses in Domestic Ducks

Journal of Virology ◽

10.1128/jvi.01176-08 ◽

2008 ◽

Vol 82 (22) ◽

pp. 11374-11382 ◽

Cited By ~ 55

Author(s):

Jeong-Ki Kim ◽

Patrick Seiler ◽

Heather L. Forrest ◽

Alexey M. Khalenkov ◽

John Franks ◽

...

Keyword(s):

Influenza Virus ◽

Avian Influenza ◽

Influenza A ◽

Preventive Strategy ◽

Complete Protection ◽

Influenza A Viruses ◽

Symptomatic Infection ◽

Domestic Ducks ◽

Virus Challenge ◽

H5n1 Influenza

ABSTRACT Waterfowl represent the natural reservoir of all subtypes of influenza A viruses, including H5N1. Ducks are especially considered major contributors to the spread of H5N1 influenza A viruses because they exhibit diversity in morbidity and mortality. Therefore, as a preventive strategy against endemic as well as pandemic influenza, it is important to reduce the spread of H5N1 influenza A viruses in duck populations. Here, we describe the pathogenicity of dominant clades (clades 1 and 2) of H5N1 influenza A viruses circulating in birds in Asia. Four representatives of dominant clades of the viruses cause symptomatic infection but lead to different profiles of lethality in domestic ducks. We also demonstrate the efficacy, cross-protectiveness, and immunogenicity of three different inactivated oil emulsion whole-virus H5 influenza vaccines (derived by implementing reverse genetics) to the viruses in domestic ducks. A single dose of the vaccines containing 1 μg of hemagglutinin protein provides complete protection against a lethal A/Duck/Laos/25/06 (H5N1) influenza virus challenge, with no evidence of morbidity, mortality, or shedding of the challenge virus. Moreover, two of the three vaccines achieved complete cross-clade or cross-subclade protection against the heterologous avian influenza virus challenge. Interestingly, the vaccines induce low or undetectable titers of hemagglutination inhibition (HI), cross-HI, and/or virus neutralization antibodies. The mechanism of complete protection in the absence of detectable antibody responses remains an open question.

Download Full-text

Emergence of influenza A viruses

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2001.0997 ◽

2001 ◽

Vol 356 (1416) ◽

pp. 1817-1828 ◽

Cited By ~ 154

Author(s):

R. J. Webby ◽

R. G. Webster

Keyword(s):

Intermediate Host ◽

Influenza A ◽

Influenza Viruses ◽

Human Populations ◽

Aquatic Bird ◽

Intermediate Hosts ◽

Aquatic Birds ◽

Influenza A Viruses ◽

Bird Populations ◽

Human Viruses

Pandemic influenza in humans is a zoonotic disease caused by the transfer of influenza A viruses or virus gene segments from animal reservoirs. Influenza A viruses have been isolated from avian and mammalian hosts, although the primary reservoirs are the aquatic bird populations of the world. In the aquatic birds, influenza is asymptomatic, and the viruses are in evolutionary stasis. The aquatic bird viruses do not replicate well in humans, and these viruses need to reassort or adapt in an intermediate host before they emerge in human populations. Pigs can serve as a host for avian and human viruses and are logical candidates for the role of intermediate host. The transmission of avian H5N1 and H9N2 viruses directly to humans during the late 1990s showed that land-based poultry also can serve between aquatic birds and humans as intermediate hosts of influenza viruses. That these transmission events took place in Hong Kong and China adds further support to the hypothesis that Asia is an epicentre for influenza and stresses the importance of surveillance of pigs and live-bird markets in this area.

Download Full-text

Influenza viruses: transmission between species

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1980.0021 ◽

1980 ◽

Vol 288 (1029) ◽

pp. 439-447 ◽

Cited By ~ 9

Keyword(s):

Influenza A ◽

Direct Evidence ◽

Swine Influenza ◽

Indirect Evidence ◽

Preliminary Evidence ◽

Influenza Viruses ◽

Surface Proteins ◽

Aquatic Birds ◽

Influenza A Viruses ◽

Wide Range

The only direct evidence for transmission of influenza viruses between species comes from studies on swine influenza viruses. Antigenically and genetically identical Hsw1N1 influenza viruses were isolated from pigs and man on the same farm in Wisconsin, U.S.A. The isolation of H3N2 influenza viruses from a wide range of lower animals and birds suggests that influenza viruses of man can spread to the lower orders. Under some conditions the H3N2 viruses can persist for a number of years in some species. The isolation, from aquatic birds, of a large number of influenza A viruses that possess surface proteins antigenically similar to the viruses isolated from man, pigs and horses provides indirect evidence for inter-species transmission. There is now a considerable body of evidence which suggests that influenza viruses of lower animals and birds may play a role in the origin of some of the pandemic strains of influenza A viruses. There is no direct evidence that the influenza viruses in aquatic birds are transmitted to man, but they may serve as a genetic pool from which some genes may be introduced into humans by recombination. Preliminary evidence suggests that the molecular basis of host range and virulence may be related to the RNA segments coding for one of the polymerase proteins (P3) and for the nucleoprotein (NP).

Download Full-text

Matrix Gene of Influenza A Viruses Isolated from Wild Aquatic Birds: Ecology and Emergence of Influenza A Viruses

Journal of Virology ◽

10.1128/jvi.78.16.8771-8779.2004 ◽

2004 ◽

Vol 78 (16) ◽

pp. 8771-8779 ◽

Cited By ~ 78

Author(s):

Linda Widjaja ◽

Scott L. Krauss ◽

Richard J. Webby ◽

Tao Xie ◽

Robert G. Webster

Keyword(s):

North American ◽

Influenza A ◽

Delaware Bay ◽

Influenza Viruses ◽

Aquatic Birds ◽

Influenza A Viruses ◽

M Gene ◽

Matrix Gene ◽

Distinct Lineage ◽

Wild Waterfowl

ABSTRACT Wild aquatic birds are the primary reservoir of influenza A viruses, but little is known about the viruses' gene pool in wild birds. Therefore, we investigated the ecology and emergence of influenza viruses by conducting phylogenetic analysis of 70 matrix (M) genes of influenza viruses isolated from shorebirds and gulls in the Delaware Bay region and from ducks in Alberta, Canada, during >18 years of surveillance. In our analysis, we included 61 published M genes of isolates from various hosts. We showed that M genes of Canadian duck viruses and those of shorebird and gull viruses in the Delaware Bay shared ancestors with the M genes of North American poultry viruses. We found that North American and Eurasian avian-like lineages are divided into sublineages, indicating that multiple branches of virus evolution may be maintained in wild aquatic birds. The presence of non-H13 gull viruses in the gull-like lineage and of H13 gull viruses in other avian lineages suggested that gulls' M genes do not preferentially associate with the H13 subtype or segregate into a distinct lineage. Some North American avian influenza viruses contained M genes closely related to those of Eurasian avian viruses. Therefore, there may be interregional mixing of the two clades. Reassortment of shorebird M and HA genes was evident, but there was no correlation among the HA or NA subtype, M gene sequence, and isolation time. Overall, these results support the hypothesis that influenza viruses in wild waterfowl contain distinguishable lineages of M genes.

Download Full-text