51�Թ�

In the past three years, outbreaks of bird flu, formally called highly pathogenic avian influenza, in wild animals spilled over to dairy cows and poultry, infecting several dozen humans and even killing one American.

Department of Agriculture continues to log confirmed reports of highly pathogenic avian influenza in poultry flocks, and a quick look at its tracker confirms that there is a hell of a lot of bird flu out there.

But highly pathogenic avian influenza is aptly named because of what it does to birds, including chickens.

There have been probable cases of highly pathogenic avian influenza viruses, including H5N1 — but, crucially, not the same H5N1 that is circulating now — being passed from one human to another in a very limited way.

A study found that 95% of documented cases of mild avian influenza evolving into severe strains occurred in commercial poultry operations.