ST. PAUL, Minn. (AP) - Poultry farmers in Minnesota are cautiously watching the spread of bird flu in Europe and Asia.

The World Health Organization is on "high alert" because the virus has been found in 40 countries around the world since last fall and is spreading quickly.

Michael Osterholm, director of the University of Minnesota's Center for Infectious Disease Research and Policy, says the spring waterfowl migration will increase the risk of the virus coming to Minnesota. Outbreaks in 2015 devastated over 100 Minnesota farms and cost the state economy over $500 million.

Rembrandt Foods owner Glen Taylor says his company, one of the nation's largest egg producers, has taken steps to keep out any new virus. Supply trucks that may visit other poultry farms are strictly controlled, and employees unload at an entrance gate if possible.