ARS | Publication request: PATHOGENESIS AND VIRULENCE FACTORS ASSOCIATED WITH HIGHLY VIRULENT H5 AVIAN INFLUENZA A VIRUSES IN MICE

Submitted to: International Congress of Virology
Publication Type: Abstract Only
Publication Acceptance Date: July 10, 1999
Publication Date: N/A

Technical Abstract: In 1997, highly virulent H5N1 avian influenza A viruses were recovered from poultry and humans in Hong Kong (HK). The factors involved in this transmission to mammals are not fully understood and the potential risk of other highly virulent avian influenza A viruses infecting and causing disease in mammals is not known. HK-origin and non-HK-origin highly virulent H5 avian influenza A viruses were analyzed for their ability to cause pathogenesis and disease in BALB/c mice. All the avian influenza (AI) viruses caused mild to severe lesions in the respiratory tract of mice. The most severe and widespread lesions were in the lungs of the A/ck/HK/220/97, A/ck/HK/728/97, and A/HK/156/97 infected mice while no lesions or mild lesions were evident with A/ck/Scotland/59 and A/ck/Queretaro/7653-20/95 AI viruses. The A/tk/England/91 and A/ck/Italy/330/97 AI viruses were intermediate, producing mild-to-moderate respiratory tract lesions. A significant and rapid reduction in body weight and body temperature was observed in mice infected with the HK AI viruses with 75-100% mortality 6-8 dpi. Mice infected with England/91 demonstrated clinical signs of disease at 4 dpi; however, no deaths occurred and the mice quickly recovered from infection. Two virulent avian influenza viruses, Queretaro/95 and HK/220 were successfully mated in order to identify virulence genes. Several genetic reassortants have been analyzed for their pathogenicity in mice.