Experts suspect avian flu spreads from farm to farm or by the wind

ST. PAUL - Scientists have not yet been able to figure out how the highly pathogenic H5N2 avian influenza is being spread, but some are worried that it is moving from farm to farm and being carried by the wind.
A recent report based on epidemiological studies of the infections to date could not determine how the disease is being spread, Dr. Bill Hartmann, state veterinarian and director of the Minnesota Board of Animal Health, told reporters Wednesday during a conference call.
However, he said veterinarians working with turkey producers suspect that some “lateral” or farm-to-farm transmission is occurring. They also suspect that winds are possibly carrying the virus.
Hartmann cautioned that the veterinarians are speaking from their “gut feeling,’’ and that there is no evidence to confirm this.
The relatively high number of infected farms in Stearns and Kandiyohi counties is one of the reasons that the veterinarians suspect farm-to-farm transmission is occurring, Hartmann said. He also cautioned that these two counties also have the largest number of turkey farms, and that alone may explain the number of infected sites.
Hartmann said there have been cases where a flock in one barn on a multi-barn site has been infected and isolated in hopes that the flocks in the other barns would not need to be euthanized. Despite the effort, the virus has reached the other barns, he said.
If the winds carry the virus, producers could add filters to barns. That would be very expensive. Consequently, only barns holding breeding birds would likely be outfitted with the filters, Hartmann said.