Volume 12, Number 4—April 2006
Perspective
Human Influenza Surveillance: the Demand to Expand
Figure 1

Figure 1. Global influenza surveillance for the 2004–2005 season Respiratory samples were collected from persons with febrile respiratory illness worldwide. Approximately 15% of samples were influenza positive. Note that only some of the type A viruses were subtyped. Data are from the Centers for Disease Control and Prevention website (http://www.cdc.gov/flu/weekly/weeklyarchives2004-2005/04-05summary.htm).