State wildlife officials said Tuesday they're taking urgent steps to protect Minnesota's deer population after 12 additional white-tailed deer from a defunct Beltrami County deer farm tested positive for chronic wasting disease.

Officials said they're quarantining five additional herds across the state and building a fence around a site where deer were illegally dumped in Beltrami County to prevent the spread of the always-fatal neurological disease affecting deer and elk.

A herd in Hennepin County and one in Kanabec County were quarantined Thursday.

Three other herds in Mille Lacs, Morrison and Mower counties that received animals from the Kanabec County herd were quarantined on Friday.

The Board of Animal Health is working to identify and test animals in all potentially infected herds. It is also investigating possible violations of animal health laws.

All 54 in the Beltrami County herd were killed by the U.S. Department of Agriculture earlier this month. The deer were then tested to see how many on the farm were carrying CWD.

Dreamstime • TNS, Star Tribune

Of the 12, nine were found to have been born on the Beltrami County farm and three others were moved to the farm from other herds. The other herds are considered exposed since there's a possibility the animals could have caught the disease before moving, according to a news release from the Minnesota Board of Animal Health on Tuesday.

The Beltrami County herd was initially quarantined in October 2020 after it received animals from an exposed herd in Winona County. A doe tested positive for CWD after over a year of moving out from the exposed herd, according to the release.

During an inspection, officials found the owner illegally dumped several deer and fawn carcasses on county-managed land — posing a threat to deer in the wild.

Now, herds in at least eight Minnesota counties have been quarantined to minimize the spread. Herds in Winona, Houston and Beltrami counties were quarantined before this latest round was announced.

A herd in the state's most southeasterly region, Houston County, had a least one deer that tested positive for CWD in October. The enclosure was double-fenced and it had only imported animals from two Minnesota herds. It exported one of the animals to a location in Wisconsin.

That herd was killed in January, and 10 of the 49 deer tested positive for CWD.

The Minnesota Department of Natural Resources will also test hunted deer in the fall to see if CWD has spread to wildlife populations.

Alex Chhith • 612-673-4759