Nine turkey farms in Minnesota have been infected with bird flu.

Kansas, Missouri, South Dakota and Arkansas have all reported bird flu outbreaks on turkey farms as well, but Minnesota has been hit the hardest by H5N2. Minnesota is the country's largest turkey-producing state.

The H5N2 virus spreads quickly amongst poultry through droppings or nasal discharge. It's believed the current outbreak was spread by migratory birds who showed no symptoms. Sick birds do not enter the food stream and are, instead, composted on-site.

Birds are vaccinated for bird flu, but this particular strain is new the United States. H5N2 is not infecting humans.

Read More:

• Eighth Minnesota turkey farm hit with bird flu (StarTribune)
• Talking turkey: Deadly bird flu strain keeps popping up on turkey farms in top turkey state (U.S. News & World Report)