Fig. 1
From: An evaluation of the Zambia influenza sentinel surveillance system, 2011–2017
Influenza sentinel surveillance implemented at six surveillance sites in Zambia, 2011–2017. A: years of implementation of influenza surveillance by sentinel site (solid line: sentinel sites situated in Lusaka Province; dashed line: sentinel sites situated in Copperbelt Province). B: monthly number of influenza-positive specimens among patients with influenza-like illness (ILI) or severe acute respiratory illness (SARI)