Wild bird infections and the ecology of avian influenza viruses

2016 ◽  
pp. 153-176 ◽  
Author(s):  
David E. Stallknecht ◽  
Justin D. Brown
2008 ◽  
Vol 89 (4) ◽  
pp. 949-957 ◽  
Author(s):  
Min-Suk Song ◽  
Taek-Kyu Oh ◽  
Ho Jin Moon ◽  
Dai-Woon Yoo ◽  
Eun Ho Lee ◽  
...  

To determine the genetic origins of novel H3 avian influenza viruses of chickens and ducks in Korea, genetic characterization of H3 avian influenza viruses isolated from live poultry markets and migratory aquatic birds in South Korea during 2004–2006 was conducted. Phylogenetic analysis revealed that at least four novel genotypes of H3N2 and two genotypes of H3N6 avian influenza viruses were co-circulating in backyard poultry of Korea. The viruses were reassortants between H9N2 viruses of Korean chickens and unknown influenza viruses of migratory birds. Genetic comparison of H3 viruses from live bird markets with those from wild bird isolates revealed that certain gene segments of wild bird isolates are related closely to those of Korean group H9N2 viruses isolated from live poultry markets in 2003. Furthermore, animal-challenge studies demonstrated that the pathogenicity of certain avian H3 influenza viruses was altered due to reassortment, leading to H3 avian influenza viruses in Korea that can potentially expand their host range to include mammals. These studies emphasize the continuing need to monitor backyard poultry at live poultry markets to better understand interspecies transmission and the emergence of novel influenza viruses that have the potential to infect humans.


2003 ◽  
Vol 27 ◽  
pp. 107-114 ◽  
Author(s):  
M.A. De Marco ◽  
E. Foni ◽  
L. Campitelli ◽  
E. Raffini ◽  
M. Delogu ◽  
...  

2021 ◽  
Vol 9 (4) ◽  
pp. 864
Author(s):  
Marina Gulyaeva ◽  
Maria Alessandra De Marco ◽  
Ganna Kovalenko ◽  
Eric Bortz ◽  
Tatiana Murashkina ◽  
...  

Avian influenza viruses (AIVs) are maintained in wild bird reservoirs, particularly in mallard ducks and other waterfowl. Novel evolutionary lineages of AIV that arise through genetic drift or reassortment can spread with wild bird migrations to new regions, infect a wide variety of resident bird species, and spillover to domestic poultry. The vast continental reservoir of AIVs in Eurasia harbors a wide diversity of influenza subtypes, including both highly pathogenic (HP) and low pathogenic (LP) H7 AIV. The Caspian Sea region is positioned at the intersection of major migratory flyways connecting Central Asia, Europe, the Black and Mediterranean Sea regions and Africa and holds a rich wetland and avian ecology. To understand genetic reservoirs present in the Caspian Sea region, we collected 559 cloacal swabs from Anseriformes and other species during the annual autumn migration periods in 2017 and 2018. We isolated two novel H7N3 LPAIV from mallard ducks whose H7 hemagglutinin (HA) gene was phylogenetically related to contemporaneous strains from distant Mongolia, and more closely Georgia and Ukraine, and predated the spread of this H7 LPAIV sublineage into East Asia in 2019. The N3 neuraminidase gene and internal genes were prototypical of AIV widely dispersed in wild bird reservoirs sampled along flyways connected to the Caspian region. The polymerase and nucleoprotein segments clustered with contemporaneous H5 HPAI (clade 2.3.4.4b) isolates, suggesting the wide dispersal of H7 LPAIV and the potential of this subtype for reassortment. These findings highlight the need for deeper surveillance of AIV in wild birds to better understand the extent of infection spread and evolution along spatial and temporal flyways in Eurasia.


Pathogens ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 163 ◽  
Author(s):  
Marjolein J. Poen ◽  
Ron A. M. Fouchier ◽  
Richard J. Webby ◽  
Robert G. Webster ◽  
Mohamed E. El Zowalaty

Avian influenza viruses are pathogens of global concern to both animal and human health. Wild birds are the natural reservoir of avian influenza viruses and facilitate virus transport over large distances. Surprisingly, limited research has been performed to determine avian influenza host species and virus dynamics in wild birds on the African continent, including South Africa. This study described the first wild bird surveillance efforts for influenza A viruses in KwaZulu-Natal Province in South Africa after the 2017/2018 outbreak with highly pathogenic avian influenza virus H5N8 in poultry. A total of 550 swab samples from 278 migratory waterfowl were tested using real-time RT-PCR methods. Two samples (0.7%) were positive for avian influenza virus based on the matrix gene real-time RT-PCR but were negative for the hemagglutinin subtypes H5 and H7. Unfortunately, no sequence information or viable virus could be retrieved from the samples. This study shows that avian influenza viruses are present in the South African wild bird population, emphasizing the need for more extensive surveillance studies to determine the South African avian influenza gene pool and relevant local host species.


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