Bird flu found in Iowa cattle for first time

A highly transmissible avian flu has infected dairy cattle of an O’Brien County herd in far northwest Iowa, according to state agriculture officials.

It is the first detection of bird flu in Iowa cattle and follows recent discoveries of the virus in poultry flocks in nearby counties.

Cows usually recover from the infections within two weeks, but highly pathogenic avian influenza is often fatal for domestic chickens and turkeys. Infected flocks are destroyed to prevent the virus’ spread.

“Poultry producers and dairy farmers should immediately take steps to harden their biosecurity defenses, limit unnecessary visitors and report symptomatic birds or cattle to the Department (of Agriculture and Land Stewardship),” Mike Naig, the state’s agriculture secretary, said Wednesday.

Naig said unspecified “additional response steps” are forthcoming from the department.

Iowa has about 850 dairy farms that range in size from 25 to 10,000 cows. A typical dairy has about 250.

Iowa is the 10th state with a confirmed infection in dairy cattle. The virus was first identified in Texas cattle in March, where it had festered for months as a mysterious illness. Wild birds are believed to be the source of the initial infections.

Since then, the virus has been found in more than 80 herds, including in faraway states such as South Dakota. The long distance spread has been attributed to the movement of infected cattle to new herds — which has since been restricted by the U.S. Department of Agriculture — but the virus has also spread among local herds in those states, possibly via farm workers, veterinarians and equipment.