Risa Bandou, Ryohei Hirose
, Takaaki Nakaya, Hajime Miyazaki, Naoto Watanabe, Takuma Yoshida, Tomo Daidoji, Yoshito Itoh, and Hiroshi Ikegaya
Figure 1. Decrease in titers of influenza virus on plastic (A, C) and the human skin (B, D) surfaces as a function of time. Various subtypes of influenza viruses (A, B) and recombinant viruses (C, D) were targeted. Each virus (2.0 × 105 FFUs) was mixed with 2 µL of phosphate-buffered saline and applied on each surface. Each surface was incubated in a controlled environment (temperature 25°C, humidity 45%–55%) for 0–24 h. The virus on the surface was then recovered in 1 mL of medium and titrated to calculate the titer of virus remaining on the surface. For each condition, 3 independent experiments were performed; results are expressed as mean + SD of the mean. Dotted horizontal lines represent detection limit titers; data below this limit were omitted. Data are shown for H5N1-Ky, A/crow/Kyoto/53/04 (H5N1); H5N1-Eg, A/chicken/Egypt/CL6/07 (H5N1); H7N9, A/Anhui/1/23 (H7N9); H5N3, A/duck/Hong Kong/820/80 (H5N3); H5N9, A/turkey/Ontario/7732/66 (H5N9); H3N2, a clinical strain (H3N2); H1N1-PR8, A/Puerto Rico/8/1934 (H1N1); and H1N1-Ok-pdm, A/Osaka/64/2009 (H1N1). A/crow/Kyoto/53/04 (H5N1) was recombined with the neuraminidase or hemagglutinin gene of AdDuck/Hong Kong/820/80 (H5N3), and the recombinant viruses were designated as rH5N1-H5N3-NA or rH5N1-H5N3-HA, respectively. In addition, A/Duck/Hong Kong/820/80 (H5N3) was recombined with the neuraminidase, nonstructural protein, matrix protein, or hemagglutinin gene of A/crow/Kyoto/53/04 (H5N1), and the recombinant viruses were designated as rH5N3-H5N1-NA, rH5N3-H5N1-NS, rH5N3-H5N1-M, or rH5N3-H5N1-HA. FFU, focus-forming unit.