Volume 13, Number 9—September 2007
Dispatch
Reduced Sensitivity of Influenza A (H5N1) to Oseltamivir
Figure
![Sensitivity of clade 1 and clade 2 influenza A (H5N1) viruses to zanamivir, oseltamivir, and 4-amino-Neu5Ac2en in a MUNANA-based enzyme inhibition assay (Sigma, Saint Louis, MO, USA). Viruses were grown in allantoic fluid and irradiated for testing sensitivities of their neuraminidases. Plots are the mean values for inhibition of enzyme activity for each drug concentration of all isolates from that country and year; bars represent standard deviations of values for all isolates from that group. A) Sensitivity to zanamivir; B) sensitivity to oseltamivir; C) sensitivity to 4-amino-Neu5Ac2en.](/eid/images/07-0164-F1.jpg)
Figure. Sensitivity of clade 1 and clade 2 influenza A (H5N1) viruses to zanamivir, oseltamivir, and 4-amino-Neu5Ac2en in a MUNANA-based enzyme inhibition assay (Sigma, Saint Louis, MO, USA). Viruses were grown in allantoic fluid and irradiated for testing sensitivities of their neuraminidases. Plots are the mean values for inhibition of enzyme activity for each drug concentration of all isolates from that country and year; bars represent standard deviations of values for all isolates from that group. A) Sensitivity to zanamivir; B) sensitivity to oseltamivir; C) sensitivity to 4-amino-Neu5Ac2en.
1Isolates tested were the following: A/Mississippi/3/2001 wt, A/Mississippi/3/2001 H274Y; A/quail/Kelantan/6309/2004, A/chicken/Kelantan/5858/2004, A/quail/Vietnam/007B/2004, A/duck/Vietnam/007A/2004, A/chicken/Vietnam/0024/2004, A/chicken/Vietnam/0023/2004 A/chicken/Vietnam/0018/2004, A/chicken/Vietnam/0015/2004, A/chicken/Vietnam/0010/2004, A/chicken/Vietnam/008/2004; A/chicken/Cambodia/Siem Reap/77B/2004, A/chicken/Cambodia/Siem Reap/76/2004, A/chicken/Cambodia/Takeo/45/2004, A/chicken/Cambodia/Kandal/23/2004, A/chicken/Cambodia/Pong Peay/1B/2004, A/chicken/Cambodia/Pong Peay/1A/2004, A/goose/Cambodia/Kandal/2005, A/chicken/Cambodia/Kandal/3/2005, A/chicken/Cambodia/Kandal/2/2005, A/chicken/Cambodia/Kandal/1/2005, A/chicken/Indonesia/Wates/130/2005, A/chicken/Indonesia/Wates/126/2005, A/chicken/Indonesia/Wates/83/2005, A/chicken/Indonesia/Wates/80/2005, A/chicken/Indonesia/Wates/77/2005, A/chicken/Indonesia/Wates/1/2005.