Philadelphia health officials say a goose found next to Carroll Park in West Philadelphia had highly infectious bird flu.

Avian flu is a common illness among birds, but it can spread to humans and other mammals. The virus is shed through excretions, such as saliva and feces. Exposure to sick or dead animals is the primary way humans contract bird flu, according to the CDC.

Georgia, the top US chicken-producing state, confirmed its second recent case of bird flu in a commercial poultry flock, putting exports of the meat at risk.