Midwestern chicken and egg producers are on heightened alert this week following an outbreak of avian influenza on a Tennessee farm, with some stepping up security measures.

Iowa and Nebraska are far from Tennessee, but chickens and turkeys here could be vulnerable because the virus can be transmitted from wild birds migrating north.

“Because of the location of our farms in the Mississippi flyway, we will increase the monitoring of and security measures for our flocks,” said Jonathan Spurway, vice president at Rembrandt Foods. The Spirit Lake, Iowa, company makes egg products for use in food manufacturing and food service kitchens.

Spurway said the company is limiting traffic and visits to its facilities, which is one of the steps experts advise egg producers to take to avoid the spread of disease.

The Tennessee case was the first this year, and the virus hasn’t been detected in Nebraska or Iowa.

But producers don’t want a repeat of 2015, when the country’s worst animal disease outbreak resulted in the death of about 50 million birds, with estimated losses totaling nearly $1.6 billion, according to the U.S. Department of Agriculture.

Midwestern egg producers suffered some of the biggest losses. Farms in Iowa, the nation’s top egg-producing state, lost 31.5 million poultry. In Nebraska, nearly 5 million poultry were destroyed, all in Dixon County, where Post Holdings subsidiary Michael Foods has operations.