Erin Ross Nov 20
SaveSave story
Why experts are quietly concerned about bird flu
Chickens on a farm chicken on the outskirts of Shanghai, China, on April 3, 2013. Photo: Gillian Wong / AP

Global health officials are quietly ratcheting up concern about H7N9 bird flu, per the New York Times. "The number of human infections reported in [this epidemic] is almost as many as were reported during the previous four epidemics combined," notes the CDC of this years' flu season, though they believe this is due to increased spread among birds, not improved human transmission.

The bottom line: This particular lineage of H7N9 has long been "ranked as the influenza virus with the highest potential pandemic risk," according to the CDC. But there isn't yet a pandemic, and there might never be one. H7N9 could continue to be a small, regional problem like another influenza virus known as H5N1 has, or it could spread (comparatively) harmlessly, like H1N1/swine flu. Regardless, those who study the disease are watching it closely.