The worst recent bird flu outbreak in the US happened in 2015, when more than 230 farms in 15 states had outbreaks.
Iowa agriculture officials announced two more bird flu outbreaks in commercial flocks on Tuesday that will require the killing of more than 1.5 million hens and turkeys.
One of the new outbreaks will lead to the killing of 1.5 million chickens at an egg-laying farm in Guthrie County, about 60 miles (97km) west of Des Moines. The other was at a turkey farm in Hamilton County, about 65 miles (105km) north of Des Moines, where 28,000 birds will be killed.
After they are killed, birds typically are buried in compost pits on the farms.
Iowa State Veterinarian Dr Jeff Kaisand said it appears the infections are coming from migrating wild birds.
The United States Department of Agriculture says 17 states have had outbreaks in commercial or private outdoor flocks this year. The virus has been found in wild birds in at least 25 states.
With the addition of the new Iowa cases, the US poultry industry has had to kill more than 15.6 million chickens and 1.3 million turkeys since January 1. In Iowa alone, infections have been found in seven commercial flocks and two backyard flocks.
Iowa’s agriculture secretary, Mike Naig, said the situation could worsen since the spring migration is likely to continue for a few more months. Much depends on the weather and improved biosecurity on farms, he said.
Naig said it’s too soon to estimate the economic loss this year.
“It’s a difficult time for poultry producers, not just those that have an infected site,” he said.
Food prices are already high because of inflation and supply chain problems, and if the bird flu outbreak expands to enough farms, chicken, turkey, and egg prices could climb higher.
Health officials say they don’t know of any people who have caught the bird flu in the US, and the disease doesn’t present an immediate public health concern. The virus can spread from infected birds to people, but such infections are rare and haven’t led to sustained outbreaks among humans.
The worst recent bird flu outbreak in the US happened in 2015, when more than 230 farms in 15 states had outbreaks leading to the killing of more than 50 million birds. The total economic loss was valued at $3.3bn, according to research published in 2019 by a group of Iowa State University scientists.
In 2015, cases didn’t surface in Iowa until mid-April. This year the first Iowa case was confirmed on March 1.