Understanding the Complex Pathobiology of High Pathogenicity Avian Influenza Viruses in Birds

Persistence of highly pathogenic avian influenza virus (H7N1) in infected chickens: feather as a suitable sample for diagnosis

“…HPAIV causes multisystemic disease with high viraemia levels in poultry, where virus is detected not only in respiratory and enteric organs but also in internal organs (Spickler et al, 2008;Starick & Werner, 2003;Swayne & Beck, 2005). In susceptible poultry species, HPAIV infection leads to severe depression and high morbidity and mortality rates (Spickler et al, 2008;Swayne, 2007), causing important economic losses Tiensin et al, 2005).…”

“…Such information may form a basis for control measures during AIV outbreaks and/or limit AIV circulation, which is a risk factor in the generation of new reassortant viruses with other AIV strains from other animals such as swine or even humans. Infectious AIV has already been found in different tissues of infected chickens (Serena Beato et al, 2006;Starick & Werner, 2003;Swayne, 2007), ducks (Tumpey et al, 2002), turkeys , swans and geese (Brown et al, 2008), and detected in the muscles of infected chickens (Swayne & Beck, 2005), turkeys (Toffan et al, 2008), ducks and quails (Antarasena et al, 2006). HPAIV has also been detected in commercial frozen duck carcasses of retained slaughter batches (Harder et al, 2009), which has increased concern about the food safety of poultry products by its zoonotic implications.…”

“…Fragmented information on HPAIV detection and isolation from the tissues of infected chickens already exists (Serena Beato et al, 2006, 2009Spickler et al, 2008;Starick & Werner, 2003;Swayne, 2007, Swayne & Beck, 2005; however, complete studies on HPAIV detection in several samples during active infection as well as at different times post-mortem (p.m.) have not been carried out. In addition, most recent studies have focused on the H5N1 strain (Swayne, 2006) and little information is currently available on the detection and persistence of other HPAIV subtypes in animal tissues.…”

Infectious and Lethal Doses of H5N1 Highly Pathogenic Avian Influenza Virus for House Sparrows (Passer Domesticus) and Rock Pigeons (Columbia Livia)

“…21,25,27 The frequency of interspecies transmission of H5N1 HPAI virus in Southeast Asia is the result of a wide host range and an extensive interface between humans, domestic animals, and wildlife. This large interface serves as a constant and significant risk for virus spillover into nonreservoir hosts, such as humans or wildlife, and makes eradication difficult, if not impossible, in endemic areas.…”

MicroRNAs in the immune organs of chickens and ducks indicate divergence of immunity against H5N1 avian influenza

“…The results were in agreement with the clinical manifestations of the two avian species with H5N1 HPAIV infection. Experimentally, HPAI viruses typically produce a servere and systemic disease with high mortality in chickens and other gallinaceous birds [26]. In addition to the severe and consistent gross lesions including splenomegaly and pulmonary oedema and congestion, histologically, moderate to severe lymphoid depletion with apoptosis to necrosis in remaining lymphocytes were observed in the spleen, thymus and bursa of Fabricius of H5N1-HPAIV-infected chickens [27].…”