Animal influenza virus surveillance

Diagnosis and clinic-pathological findings of influenza virus infection in Brazilian pigs

“…Even though there was evidence of influenza A virus circulation in pigs in Brazil before 2009 (Cunha et al 1978, Brentano et al 2002, Mancini et al 2006, the introduction of the pandemic H1N1 virus (Schaefer et al 2011) appear to have led to more pronounced clinical signs, gross, and microscopic lesions in that species. Although influenza is a low mortality and fast recovery illness, the elevated morbidity leads to considerable economic impact due to the reduced food intake and consequential time increase to achieve slaughter weight (Fouchier et al 2003). Thus, influenza presents a threat to the swine industry and it is essential to know its epidemiologic, clinical, and pathologic characteristics, so as to establish accurate diagnosis methods and develop efficient vaccines.…”

Genetic Evolution of Swine Influenza A (H3N2) Viruses in China from 1970 to 2006

“…However, influenza has serious consequences in pigs due to the increased time needed to attain slaughter weight (5). The primary clinical manifestations of influenza virus infection in pigs are fever and acute respiratory distress (nasal discharge, coughing, and dyspnea).…”

“…The reassortment events responsible for the 1957 and 1968 pandemic viruses might have occurred in an animal that served as a mixing vessel. Pigs are susceptible to both human and avian influenza viruses and have been proposed to be intermediate hosts for the generation of pandemic influenza viruses through reassortment or adaptation to the mammalian host (5,8,22). Thus, the human influenza pandemic strains of 1957 and 1968 might have been generated in pigs (5).…”

“…Pigs are susceptible to both human and avian influenza viruses and have been proposed to be intermediate hosts for the generation of pandemic influenza viruses through reassortment or adaptation to the mammalian host (5,8,22). Thus, the human influenza pandemic strains of 1957 and 1968 might have been generated in pigs (5). In this study, we report that double-reassortant and triple-reassortant H3N2 swine influenza viruses emerged in pigs in China, and this finding might raise further concerns about whether these viruses will become established in pigs in China and whether they will become a significant pandemic threat.…”

Opinion of the Scientific Panel on Animal Health and Welfare (AHAW) related with the vaccination against avian influenza of H5 and H7 subtypes in domestic poultry and captive birds

“…To our knowledge, H5N3 virus is the only HPAI virus isolated from wild birds (dead tern) in South Africa in 1961, without known links to an outbreak from domestic poultry (Becker, 1966). During monitoring programmes performed on the American (Hinshaw et al, 1986;Webster et al, 1992;Hanson et al, 2003;Krauss et al, 2004) and European continents (Sinnecker et al, 1983;Süss et al, 1994;Fouchier et al, 2003a;De Marco et al, 2004;Fouchier et al, 2003b) before 2002, HPAI viruses have never been isolated from wild birds, suggesting that HPAI viruses could eventually not maintain themselves in wild birds only.…”