Via Emerging Infectious Diseases: Historic Prevalence and Distribution of Avian Influenza Virus A(H7N9) among Wild Birds. Like the report mentioned just below, this suggests our newest afflictions are very new indeed. The abstract:
We examined 48 published studies for which sample sizes could be ascertained to determine the historic prevalence of influenza A(H7N9) virus in wild bird populations and reviewed GenBank data to further establish its distribution. Low prevalence (0.0093%) in Asia suggests > 30,000 samples would be required to detect the H7N9 subtype in wild birds.
