Five more states, including Ohio, now have confirmed cases of the Highly Pathogenic Avian Influenza (HPAI), which has claimed the lives of millions of mostly commercial turkeys.

Some affected states like Indiana, where the virus first turned up earlier this year, are easing restrictions after not discovering a new case for a month.

Indiana State Department of Animal Health spokesperson Denise Derrer Spears said the six commercial poultry farms that had infected birds in the state are still prohibited from restocking. Those farms, under USDA guidelines, must finish a thorough cleaning and disinfecting of their operations before they can bring in more birds. “It takes a while to complete that process,” she said.

Control zones have been lifted, though, on farms within a six-mile radius of where the infected birds in Indiana were discovered.

Spears said poultry farms without infected birds can still operate in control zones but must obtain a special permit and meet certain benchmarks in keeping out infection for the restrictions to be lifted.

Despite progress, she said poultry farmers aren’t out of the woods yet, as states like Iowa and South Dakota are being hit hard most recently by the virus.

Spears said the flu appears to spread mostly from wild migratory birds, which are still in flight toward their destinations. “They’re still very much in migration mode right now,” she said.

According to USDA, the only case in Ohio was confirmed March 29 and involved a small backyard flock in Franklin County. The other states with their first confirmed cases were North Carolina, North Dakota, Massachusetts and Wyoming.

Backyard flocks were involved in those cases, except in North Carolina, where infections were found on a farm with more than 32,000 commercial turkeys outside Raleigh, according to USDA.

On March 1, the first confirmed case in Iowa involved a backyard flock. Two weeks later, the virus was discovered at a farm containing 5.3 million commercial layer chickens in Buena Vista County. Two of the most recent infected farms in Iowa housed 1.4 million commercial layer chickens in Guthrie County and more than 250,000 commercial pullet chickens in Franklin County.

About two dozen mostly commercial turkey farms with nearly 800,000 birds combined in South Dakota have had cases confirmed since March 20.

According to USDA, Kentucky hasn’t seen a new case since February, when the virus was discovered at a commercial broiler chicken farm in Fulton County and commercial turkey operation in Webster County. About 300,000 birds at those farms in the western part of the state were euthanized.

The cases in Kentucky resulted in a control zone extending to poultry farms in Obion County, which is across the border in Tennessee. The control zone for Obion County was lifted on March 22.

So far, no confirmed cases of the flu have turned up in Tennessee.

“Despite numerous detections across the U.S. this year, HPAI has not been detected in a domestic Tennessee poultry flock to this point and we aim to keep it that way,” said State Veterinarian Dr. Samantha Beaty.

Animal health authorities in Kentucky and Tennessee worked together on developing an emergency response to address the virus and restore trade.

Beaty said now is not the time for producers to let their guards down because the risk of infection remains and the virus in birds spreads rapidly. “It’s critical that poultry owners remain vigilant of their flocks and immediately report sudden illness or death,” she said.

In Michigan, there have been just two confirmed cases, both involving backyard flocks. The first was near Kalamazoo on Feb. 23 and the second a month later in Macomb County, according to USDA.

This strain of avian influenza is not considered a risk to human health or a food safety concern. According to experts, poultry and eggs from infected birds are safe to eat when handled and cooked properly. However, all birds at farms where the virus surfaces are euthanized to keep them out of the food chain as a precaution, USDA said.