Second Moose Tests Positive for Chronic Wasting Disease in Libby Area

More than 60 deer have also tested positive for the fatal disease

By Beacon Staff
A bull moose in Northwest Montana. Image from Adobe Stock

A second moose has tested positive for chronic wasting disease in the Libby area, according to Montana Fish, Wildlife and Parks (FWP).

In addition to the two moose, 61 white-tailed deer and one mule deer from the Libby area have tested positive for chronic wasting disease (CWD), which is a fatal disease that can affect the nervous system of mule deer, white-tailed deer, elk and moose. Wildlife officials say the disease could result in large-scale population declines for infected herds.

A hunter harvested the bull moose during the last week of general hunting season near Fawn Creek southeast of Libby within the Libby CWD Management Zone near its southeastern boundary.

FWP collected a sample from the moose on Dec. 1 at the Libby Sampling Station on U.S. Highway 2 and submitted it for testing to the Veterinary Diagnostic Lab at Colorado State University in Fort Collins, Colorado. The lab identified it to be suspected of CWD infection on Jan. 14 and confirmed the positive detection on Jan. 17 with a second test.

CWD was first detected in the Libby area in the spring of 2019 after a white-tailed deer tested positive. It marked the first time the disease had been detected west of the Continental Divide in Montana. It was first found in wild deer east of the divide in Montana in October 2017.

In response to the disease’s discovery in Northwest Montana, FWP established the Libby CWD Management Zone, spanning a 10-mile radius around town, and began surveillance efforts to identify the prevalence and distribution of the disease. Surveillance efforts included sampling road-killed and symptomatic animals, deer trapped in the urban center of town and hunter harvests of deer, elk and moose inside the management zone. More than 950 samples have been collected and tested inside the zone.

The first moose to test positive was harvested approximately half a mile outside the northwestern corner of the Libby CWD Management Zone in late October. The rest of the positive detections, including all 62 deer, have occurred within the management zone, with a majority near the urban center of town, according to FWP.

The estimated prevalence of CWD in the Libby urban area, identified as the Libby Survey Area, is approximately 13 percent. In the greater Libby CWD Management Zone, the estimated prevalence is nearly 4 percent.

“FWP is working with the City of Libby as it considers an urban deer management plan that would reduce the density of deer in the Libby Survey Area and hopefully reduce the prevalence and spread of CWD,” FWP Region 1 Wildlife Manager Neil Anderson said.

During the 2020 hunting season-setting process, FWP is proposing an over-the-counter either-sex white-tailed deer B license for both the archery and general hunting seasons that would only be valid inside the Libby CWD Management Zone. This license would increase overall harvest of white-tailed deer within the management zone with the goal of reducing the spread of CWD. Public input is open until Jan. 27, and the Fish and Wildlife Commission will review the proposal at its February meeting.

Animals infected with CWD may appear completely healthy. At the terminal stages of the disease, CWD symptoms include poor body condition, excessive salivation and drooling, drooping head and ears, disoriented behavior and decreased sociability.

Transmission most commonly occurs through direct contact between cervids, as well as shed in urine, feces, saliva, blood and antler velvet from infected cervids. Carcasses of infected cervids may serve as a source of environmental contamination as well and can infect other cervids that come into contact with the carcass.

There is no known transmission of CWD to humans or other animals, including pets or livestock. The Centers for Disease Control and Prevention (CDC) recommends that hunters harvesting a deer, elk or moose from an area where CWD is known to be present have their animal tested for CWD prior to consuming the meat, and to not consume the meat if the animal tests positive.

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