Iowa’s bird flu death toll this fall has surpassed last year

By Jared Strong

Another massive flock of egg-laying hens in Iowa was recently found to be infected by a very transmissible and deadly version of avian flu, which has pushed the total number of affected birds this fall beyond last year’s casualties for the same time period.

The recent detection of avian influenza was in a flock of about 1.6 million birds in Sioux County, according to the Iowa Department of Agriculture and Land Stewardship. Humans are seldom infected by the virus, but it can spread quickly in domestic flocks and is lethal to the birds. Entire flocks are culled to prevent the virus from spreading.

That incident more than doubled the total affected Iowa birds since mid-October. Infected sites now total 15 — ranging from backyard flocks to immense commercial chicken operations — with nearly 3 million birds.

That is more than double the number of detections in October, November and December of last year in Iowa, which affected about 2.5 million birds. The final virus confirmation last year happened Dec. 12.

The death toll is largely driven by the type of facility that is infected. Iowa is the nation’s leading egg producer, and those chicken flocks can number in the millions. Commercial turkey flocks often have tens of thousands of birds. The smallest flock affected this fall — a backyard group of different species — had 23.

The virus is often transmitted to domestic flocks by wild, migrating birds that can be asymptomatic.

While the infections in Iowa this fall have been worse than last year, the state largely escaped infections during the spring migration, which was devastating last year. The total number of affected birds in 2022 in Iowa was about 16 million.

That led to the state’s lowest annual egg production in more than a decade, according to U.S. Department of Agriculture data. Iowa produced about 12.2 billion eggs in 2022. That was down from 15 billion the year before and from a high of 17 billion in 2019.

Iowa’s second-lowest production total in recent years was in 2015, when there was also a widespread avian flu outbreak. That year the state produced 12.7 billion eggs.

This year, production has rebounded but will be short of 2021, before the latest outbreaks. Through October, Iowa has produced about 11.4 billion eggs this year and has averaged more than a billion each month, according to USDA data.

The other virus detections in Iowa this fall include:

— Nov. 15: A mixed-species backyard flock in Benton County with about 86 birds.
— Nov. 13: A game bird hatchery in Kossuth County with about 13,000 pheasants, quail and chukars.
— Nov. 13: A mixed-species backyard flock in Cerro Gordo County with about 75 birds.
— Nov. 10: A commercial egg-laying facility in Taylor County with about 1.2 million chickens.
— Nov. 10: A backyard mixed species flock in Jones County with 23 birds.
— Nov. 7: A game bird farm in Kossuth County with about 8,576 pheasants, peafowl and chickens.
— Nov. 3: A commercial chicken breeding facility in Hamilton County with about 15,000 birds.
— Nov. 3: A duck farm with a backyard mixed species flock in Clay County with about 7,361 birds.
— Nov. 3: A duck farm in Clay County with about 8,270 birds.
— Nov. 3: A duck farm in Clay County with about 1,700 birds.
— Oct. 31: A commercial turkey flock in Buena Vista County with about 30,000 birds.
— Oct. 23: A commercial turkey flock in Pocahontas County with about 47,500 birds.
— Oct. 23: A backyard flock in Guthrie County with about 50 birds.
— Oct. 20: A commercial turkey flock in Buena Vista County with about 50,000 birds.