The Michigan Department of Health and Human Services and the Centers for Disease Control and Prevention (CDC) announced on Tuesday, June 25, an unprecedented study on human blood in hopes that it may provide answers on how to fight the H5N1 virus. The agencies will conduct research on the blood of farm workers to see if they carry H5N1 antibodies. Researchers will also look to see if workers exposed to infected cows have asymptomatic infections.

The research could shed light on whether farm workers are spreading the virus through contact with infected raw milk on their clothes or skin, or whether infected humans can spread the virus to other animals, according to scientists involved in the study.

Dairy farmers have previously been reluctant to do testing. Last week, Michigan offered to pay 20 dairy farms up to $28,000 each to participate in research. The money would be in addition to funds the federal government is offering.

Additionally, the U.S. Food and Drug Administration announced on Tuesday that it’s launching another round of testing on dairy products, sampling more than 150 products, like raw milk cheeses, cream cheese, ice cream and butter. The additional testing is to shore up gaps in any research the agency may have missed the first time.

The agency’s initial testing showed that some commercial milk and other dairy products contained the remnants of H5N1, but said pasteurization made the products safe to consume.

The latest testing also comes following recent studies on infected milk, in which researchers used a process similar to the flash pasteurization method — the most common process to pasteurize commercial milk in the United States — and found that the process may not fully neutralize all of the virus remnants in milk.

However, scientists cautioned that experiments did not replicate the full flash pasteurization process, including a pre-heating step, and maintained that more research is needed to verify results. An FDA spokesperson said the agency’s studies will be closer to the method used in commercial milk processing.

The testing of farm workers in Michigan comes after two farm workers in the state tested positive for the virus in May.

Meanwhile, efforts across the world are being launched to defend against the virus. Finland announced plans on Wednesday to vaccinate vulnerable populations against bird flu, which would make it the first country to do so.