INDIANAPOLIS – No H5N1 was found in unpasteurized milk from Grade A dairies in Indiana during two rounds of testing for the virus, according to the Indiana State Board of Animal Health (BOAH).

In March 2024, cases of highly pathogenic avian influenza (HPAI) were found in dairy cows in Texas. The source was wild birds, BOAH said in a release. Since then, H5N1 has been confirmed on more than 1,000 dairy farms in 18 states, the agency noted. After H5N1 was found in some unpasteurized milk, USDA announced the National Milk Testing Strategy (NMTS) late last year. The strategy is a five-stage program with a goal to eliminate the disease from the U.S. dairy cattle population, BOAH said.

To date, BOAH said no dairy cattle have tested positive for the virus in Indiana.

In the initial round of NMTS testing (March 12-April 14), milk from all 660 of the state’s Grade A dairies was tested, Denise Derrer Spears, BOAH public information director, told Farm World. During the second round (April 17-May 2), milk from 98 percent of the grade A dairies was tested, BOAH said. The NMTS calls for three rounds of testing.

The state is in the second stage of the strategy, she said. Milk samples are screened by the Indiana Animal Disease Diagnostic Laboratory. Non-negatives samples will be sent to the USDA’s National Veterinary Services Laboratories for confirmation, BOAH said.

“During the stage 2 testing process, if the virus is confirmed on a farm, Indiana moves to stage 3,” Spears explained. “A confirmed finding triggers additional epidemiologic investigation of the identified farm, as well as a Restricted Movement Order to limit movement of lactating dairy cattle off the property for at least 30 days. A 10-km surveillance zone will be established. All Grade A dairies in the surveillance zone will undergo active surveillance – testing every 28 days until the confirmed herd tests negative.

“Commercial poultry premises located within the surveillance zone will also undergo testing every 28 days. We know that other states have experienced H5N1 spill-over from dairies to poultry farms.”

If Indiana gets through the three rounds of testing required in stage 2 of the NMTS with no confirmed cases of H5N1 in milk, the state will move to stage 4 of the strategy.

“(In stage 4), the number of farms tested drops to a risk-based, statistical sample (instead of all eligible farms) for another three months,” Spears pointed out. “If Indiana continues to demonstrate an absence of virus, we can move to stage 5.”

Stage 5 indicates what USDA calls “demonstrating freedom from H5N1 in U.S. dairy cattle.” The agency said it will work with states to begin periodic sampling and testing to illustrate long-term absence of the virus from the national herd.

Spears said dairy farmers should practice high levels of biosecurity, including being aware of all movements on and off their farms of people, equipment and animals.

“USDA’s epidemiologists have found that much of the farm-to-farm spread of the H5N1 virus in dairies has been tied to sharing equipment (tractors, vehicles, manure spreaders, etc.) between farms,” she said. “Human traffic, including employees who work on multiple farms, is another risk factor for carrying virus particles from one site to another.

“No one should have cow contact or enter cow areas unless they need to. And those who do should wear clean or dedicated clothing and footwear. This includes regular farm visitors, such as feed delivery and milk haulers.”

Anyone bringing new lactating cattle onto a farm should isolate and observe the herd additions before introducing them to the herd to ensure animals are free of clinical signs, Spears said.

Consumers should know the milk they buy at the grocery store is safe, as pasteurization has been proven to kill any H5N1 that may be present, she said.

Nationally, cases of H5N1 in dairy cows have slowed in recent months, according to the USDA’s Animal and Plant Health Inspection Service. In the 30 days ending May 6, there were 49 cases in three states – Arizona, California and Idaho. The peak period for new cases was October through December, Spears said.

As for HPAI in poultry, Indiana hasn’t had a case of the virus in a commercial flock since March 28. The Indiana Department of Natural Resources continues to monitor the wild-bird population, she said, adding the agency’s most recent report identified H5N1-positive birds in Noble and Porter counties.

‘We are hopeful that the worst is behind us as migration season comes to an end,” she said. “Remember, the virus is still circulating in the environment and wild-bird populations know no boundaries and don’t practice biosecurity. Controlling as many factors as possible goes a long way.”

Since the HPAI outbreak began in poultry in the state in February 2022, more than 8.5 million commercial egg layers, turkeys, ducks and non-commercial birds have been destroyed, according to BOAH.

For biosecurity information and resources, visit https://securemilksupply.org.