Surveillance for Chinese bird flu will be difficult

They reviewed 48 avian influenza surveillance studies in Asia, Europe, Africa, the Americas and Australia, estimating an H7N9 prevalence of 0.01% in wild birds.

“We estimate that >30,000 birds would have to be sampled to detect one bird that was H7N9-positive with a 95% probability,” the authors said.

They advised continuing risk-based surveillance, saying that ruling out wild birds as a continuing source of infection for domestic birds or humans “will be critical to