The Czech Republic has reported an outbreak of the highly pathogenic H5N1 strain of avian influenza, or bird flu, on a poultry farm, the World Organisation for Animal Health (WOAH) said on Monday.

This year in the United States, 14 people have tested positive for avian influenza, or bird flu. Nine of those became infected after coming into contact with poultry, and four got the virus from exposure to dairy cows. The source of the remaining, most recent case remains a mystery.

A patient in Missouri who was hospitalized after an infection with bird flu had the H5N1 strain of the virus, the US Centers for Disease Control and Prevention confirmed Friday.

In a disclosure that can't eliminate the possibility that bird flu may have spread from one human to another for the first time, U.S. health officials have reported that a person who lived with a Missouri resident infected with H5N1 became sick the same day.