Report: Spread of bird flu could be related to high wind

The spread of avian flu in Minnesota appears to be related to several high wind events in March and April, according to a report from the U.S. Department of Agriculture.

More than 9 million birds in Minnesota's commercial and domestic poultry flocks have died during the 2015 avian influenza outbreak sweeping the western half of the United States.

The report is far from definitive, calling for further study and saying the USDA can't point to a single statistically significant pathway for the current spread of bird flu.

However, it raises the possibility that the virus traveled on airborne dust or other particles from infected to non-infected farms. Researchers found clusters of new bird flu cases appearing in hard-hit Kandiyohi and Stearns counties about a week after each of several periods of high winds.

In a separate finding, the report said the bird flu virus can take to the air. Viable influenza virus was found in some air samples taken from infected barns.

The report also said that human and machinery traffic between infected and non-infected farms was a likely cause of some virus transmission.