Figure 1From: Improving global influenza surveillance: trends of A(H5N1) virus in Africa and AsiaCumulative number of A(H5N1) hemagglutinin genes sequenced in Asian and African countries and reported to influenza surveillance networks between 2003 and 2011 approximates a power law distribution (nonlinear power law regression, R2 = 0.9066 and Kolmogorov-Smirnov test P < 0.0001 for lower, middle, and upper quartiles).Back to article page