MILWAUKEE — Farms stricken with a deadly pig virus must report outbreaks as part of a new program to help monitor and possibly control the spread of the disease, the federal government announced Friday.

Porcine epidemic diarrhea has killed millions of pigs in 27 states since showing up in the U.S. last May, with Illinois, Iowa, Minnesota and North Carolina being hit hardest. The disease has been blamed for recent increases in bacon and pork prices. Farmers have struggled to control the virus, because little is known about how it spreads and there is not yet a federally approved vaccine.

The U.S. Department of Agriculture said it would step up efforts by requiring farms to report infections and labs to report positive tests from submitted tissue and fecal samples. Farms that suffer an outbreak also will have to participate in a program to help control the spread of the disease; details of that program have not yet been worked out.

Previously, the USDA and the nation’s pork industry tracked PED with voluntary reports from the labs.

The USDA said Friday it would commit $5 million to fight the disease, boosting the $1.7 million research effort already begun by the pork industry. It also will require farmers to report cases of a similar disease, swine delta coronavirus.

“Today’s actions will help identify gaps in biosecurity and help us as we work together to stop the spread of these diseases and the damage caused to producers, industry and ultimately consumers,” Agriculture Secretary Tom Vilsack said in statement.

Believed to be from China, PED poses the most risk to newborn piglets, who die from dehydration. It does not infect humans or other animals.

Dr. Paul Sundberg, vice president of science and technology for the National Pork Board, said the new reporting requirements would provide better information on how many farms have been infected by PED and where. They also set a model for how similar diseases could be handled.

“The issue of accuracy of information is a really important one for the future of PED as well as other diseases,” Sundberg said. “The issue of being able to analyze data to control disease, and to analyze data, you have to have good data.”