ELLSWORTH, Iowa — Iowa poultry producers are preparing for the worst of avian influenza, as many are tightening biosecurity measures to prevent the deadly bird virus from entering or escaping their farms.

"I wash my car at least three times a week and have a bottle of disinfectant in the car to spray my shoes every time I set foot home or leave," said Sheila Larson, director of membership services for the Iowa Turkey Federation (ITF), who raises 200,000 turkeys annually near Ellsworth. She said her family is limiting traffic on the farm, such as having packages dropped off at another location.

Iowa ranks ninth in turkey production nationwide, with the state’s 130 turkey farmers raising more than 11 million birds annually, according to the ITF. Iowa also had 59.6 million laying hens as of Feb. 1, according to the USDA.

For Katie Olthoff, ITF communications specialist and a turkey farmer from Stanhope, Iowa’s first confirmed case of highly pathogenic avian influenza April 14 wasn’t a surprise, given the impact it’s already had on other states. But she is optimistic it won’t spread further because of farmer actions, the spring migratory season coming to an end and warmer temperatures, which helps kill pathogens.

"It can be really devastating," said Olthoff, whose family raises more than 100,000 turkeys. "There’s not much more we can do to prevent it than what we’re doing now."

The H5N2 avian influenza virus was first detected in Iowa April 14 in a flock of 27,000 turkeys on an Osceola commercial farm in Buena Vista County, located within the Mississippi Flyway (migratory path for birds), where this specific strain of avian influenza had been identified last year.

On April 20, Northey ordered about 3.8 million chickens on Sunrise Farms in Harris – all of which were confirmed infected with H5N2 – to be destroyed, to control the spread of the disease. On April 23, avian influenza was confirmed on a commercial farm with 34,000 turkeys in Sac County, which is adjacent to the first infected farm.

On April 27, the Iowa Department of Agriculture and Land Stewardship (IDALS) reported five new probable cases confirmed positive for H5N2: a pullet farm in Osceola County with an estimated 250,000 birds and two O’Brien County commercial laying operations – one with an estimated 240,000 infected birds, and another with 98,000.

The two other cases of avian influenza reported April 27 were in Sioux County – the first on a commercial laying operation with an estimated 1.7 million infected birds; and the second, also commercial, with an estimated 3.8 million.

On April 29, IDALS reported four new probable cases confirmed positive. The first three were in Buena Vista County: a turkey farm with an estimated 50,000 birds; a turkey farm that has experienced increased mortality (the total number is pending); and a commercial laying operation with an estimated 63,000 birds. The fourth case was a Kossuth County chicken breeder farm with an estimated 19,000 infected birds. On April 30, IDALS reported five new cases in commercial poultry farms: three in Buena Vista County, one in Sioux County (a commercial laying operation with 3.7 million birds) and one in Clay County (a commercial laying operation that has experienced increased mortality – an estimate on the number of birds is pending).

State officials have quarantined the premises and nearby facilities would be investigated for more possible cases, said Iowa Agriculture Secretary Bill Northey.

Iowa has approximately 60 million laying hens, which produced about 16.5 billion eggs in 2014 – or one out of every five in the United States, according to the Iowa Egg Council.