BATON ROUGE, La. (AP) — Authorities say Louisiana’s first case of a slow-developing but always lethal deer disease has been confirmed in a deer killed in Tensas Parish.

Chronic wasting disease, or CWD, is a highly infectious disease spread by malformed proteins called prions, like those that cause mad cow disease and the related human infection called Creutzfeldt-Jacob disease.

Tensas Parish is located along the Mississippi River, just south of Vicksburg and Tallulah and west of Port Gibson and Claiborne County. It does not share a regular land border with Warren County, where two deer with CWD have been found since December, but deer have been known to swim across the river.

The Louisiana Department of Wildlife and Fisheries did not say how far from the state line the deer was shot.

“This is what we have feared,” LDWFP Secretary Jack Montoucet said. “We will count on the diligence of our hunters, property owners, deer processors and taxidermists in monitoring and helping to control the spread of CWD.”

To keep deer from gathering together and making infection easier, supplemental feeding, including salt and mineral licks, is now banned in Tensas, Franklin and Madison parishes, the department said Friday. A ban on exporting deer carcasses from those parishes was also installed, effective immediately, and will remain in place until further notice.

Authorities have heightened surveillance in Tensas Parish since 2018, when an infected deer was found in Issaquena County, Mississippi. Two more cases were diagnosed in Warren County, Mississippi, during the 2021-22 hunting season, the department said Thursday.

Both Wildlife and Fisheries and the Louisiana Department of Agriculture and Forestry sent out news releases Friday saying that the National Veterinary Services Laboratory had confirmed the case.

Agriculture Commissioner Mike Strain reminded owners of penned herds that inspection, population control, and record-keeping are needed to ensure the health of such herds

“It will take diligence from all parties to help control the spread of CWD in Louisiana; this includes our permitted deer pen licensees,” he said.

Louisiana’s first case was confirmed less than a month after Alabama’s.

Symptoms can include weight loss up to emaciation, salivation, frequent drinking and urination, lack of coordination, circling and lack of fear of people.

It was first identified in a Colorado research herd in the 1960s. It has since been found in wild deer, elk and moose in at least 27 states, two Canadian provinces and other countries, according to the U.S. Centers for Disease Control and Prevention.

Although no human cases have been reported, the CDC and the World Health Organization recommend against eating infected deer.