Monitoring Avian Influenza A(H7N9) Virus through National Influenza-like Illness Surveillance, China
Figure 2. . Percentage of hospital visits attributed to influenza-like illness, China, April 2, 2012–May 6, 2013. Hospital visits were made to sentinel surveillance hospitals in 7 southern provinces (SP) and 3 northern provinces/municipalities (NM, NP) with confirmed human cases of avian influenza A(H7N9) virus infection. Arrows indicate March 31, 2013, the date the first human case of influenza A(H7N9) virus infection was reported.