Inactivation and morphological changes of avian influenza virus by copper ions


The infectivity of the H9N2 virus to MDCK cells was time-dependently inhibited by Cu2+ at concentrations of 2.5–250 μM. In 25 μM Cu2+ solution, the virus titer decreased by approximately 3 and 4 log within 3 and 6 h, respectively. Compared to Cu2+, Zn2+ was much less effective in virus inactivation. The H9N2 virus hemagglutinin activity was not affected by 2.5–250 μM Cu2+. The H9N2 virus neuraminidase (NA) activity was drastically reduced by 25 mM Cu2+, marginally reduced by 250 μM Cu2+, and not affected by 25 μM Cu2+. Thus, we found that copper ions suppress the infectivity of influenza virus at lower concentrations at which neither NA nor hemagglutination inhibition occurs. Electron microscopic analysis revealed morphological abnormalities of the Cu2+-treated H9N2 virus. Additional studies should be undertaken to clarify the mechanism underlying the antiviral effect of copper ions on influenza virus.

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This work was partially supported by grants from the Program of Founding Research Centers for Emerging and Reemerging Infectious Diseases, and by grant-in aid for Exploratory Research (19659115), MEXT Japan.

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Correspondence to H. Ogawa.

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Horie, M., Ogawa, H., Yoshida, Y. et al. Inactivation and morphological changes of avian influenza virus by copper ions. Arch Virol 153, 1467 (2008).

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  • Influenza
  • Influenza Virus
  • CuCl2
  • CuSO4
  • Virus Titer