Bird flu reemerges in Midwest states amid southward bird migration

There are large amounts of migratory birds flying south for the winter, and they are apparently bringing with them a renewed threat of deadly, highly transmissible avian influenza.

There has not been a confirmed infection among Iowa’s domestic birds since early May, but two dead, wild geese in eastern Iowa had the disease in early September, and three ducks shot by hunters in western Iowa in the middle of that month also had it, according to U.S. Department of Agriculture data.

Further, commercial turkey flocks in Nebraska, North and South Dakota, and Wisconsin, have had outbreaks of the virus in recent weeks, and its presence has been confirmed in states coast to coast.

“We are certainly aware of the cases showing up in other states and are monitoring the situation closely,” said Don McDowell, a spokesperson for the Iowa Department of Agriculture and Land Stewardship. “Because migration is beginning again and given that this is caused by migratory and wild birds, it would not be unexpected that there could be additional cases this fall.”

The virus wreaked havoc in Iowa for about two months earlier this year, which led to the culling of about 13.4 million birds. The state had far fewer flocks affected than other states such as Minnesota, but Iowa’s flocks were massive — two included at least 5 million egg-laying chickens apiece.

Colorado and Nebraska have the next-highest death tolls from the virus, at 4.7 and 5 million birds, respectively. It is common practice to kill all the birds of infected flocks to prevent the spread of the disease.

Iowa implemented new procedures after the last bird flu outbreak in 2014-2015, which affected more than 30 million of its birds. Mainly, the state sought to isolate outbreaks by killing and disposing of infected birds on-site if possible.

The goal was to prevent transmissions of the disease from one site to another, which was a problem identified with the outbreaks seven years ago. Mike Naig, the state’s secretary of agriculture, has said those efforts were successful.

This year’s outbreak is approaching the death toll of 2014-2015. So far, about 47 million birds have been culled, compared with more than 50 million in the last outbreak, most of which were in Iowa. The state’s birds count for less than a third of this year’s victims.

What’s different is this year’s second round of infections. Confirmed cases of deadly avian influenza ceased in June 2015 in the United States. This year, the virus reemerged in late August and led to the culling of 6.1 million birds in September. More than half of them were from one Ohio egg-laying facility, the USDA reported.

“We are continually reminding and encouraging poultry farmers, egg producers, and those with backyard flocks to remain vigilant and focused with their biosecurity,” McDowell said. “If someone suspects they may have affected birds, they should immediately contact the Iowa Department of Agriculture and Land Stewardship.”

Wild birds that carry the disease can often be asymptomatic and shed the virus in their feces and other bodily fluids. The virus can be transmitted directly to domestic birds or by contaminated food, water or a worker’s clothing.

On Wednesday, more than 450 million birds were predicted to be migrating south through the United States, according to the BirdCast forecast by Colorado State University and the Cornell Lab of Ornithology. The highest intensities of migration were likely in the Midwest.

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