For Immediate Release
September 10, 2007
CONTACT: Steve Merritt
Public Information Officer
Montana Department of Livestock
406-444-9431
Sheep in Musselshell County must stay in Musselshell County
Sheep producers in Musselshell County are not allowed to transport sheep anywhere within or beyond county lines for the next 30 days because of a recent possible outbreak of bluetongue.
State Veterinarian Dr. Marty Zaluski authorized the hold order today, Monday, September 10, in an effort to reduce potential transmission of the virus.
About 100 sheep in Musselshell County have died within the past two weeks. Severalinitially tested positive for the virus in a screening test and when whitetail deer were tentatively diagnosed, too, Zaluski decided to protect other livestock with the hold order.
“I implemented this hold as a general precaution after the state laboratory provisionally diagnosed bluetongue in a flock,” Zaluski said. “The sheep from this flock had clinical signs and death loss that is consistent with bluetongue, but we still need to confirm that diagnosis. Also, several deer in Musselshell County tested positive for bluetongue.”
Confirmation of the test results are expected this week. Bluetongue, Epizootic hemorrhagic disease (EHD) and other diseases look similar on screening tests so more specific tests are required before bluetongue can be confirmed.
“Samples from the infected Musselshell deer have been taken to the National Veterinary Services Lab in Ames, Iowa, and they are working on identifying this particular serotype,” Zaluski said.
Sheep, whitetail deer and antelope are especially susceptible to bluetongue; the virus often causes death if these species are exposed. Cattle, goats, mule deer and elk also can contract the disease, but rarely show symptoms and are a much lower risk in spreading the disease, said Zaluski. Humans are not susceptible.
Bluetongue commonly spreads by biting gnats, especially in late summer and early fall. Zaluski wants to limit movement of infected sheep so gnats will not have the opportunity to bite an infected sheep and then bite a healthy sheep, spreading the disease.
Vaccines have been developed for bluetongue, but no antibiotics exist for the virus. However, infected animals often develop secondary bacterial infections and those infections can be treated with antibiotics.
Once the national lab identifies the specific serotype in this potential outbreak, Musselshell County sheep producers might have the opportunity to vaccinate their sheep. However, the vaccination is not widely available and it takes two to three weeks before the vaccine effectively increases immunity.
“We’re going to have a frost sometime soon and that would lower the risk of spreading the disease just as well this year,” Zaluski said.
Common symptoms of bluetongue include a crusty, swollen muzzle, lesions or bleeding in the mouth or on the skin and, sometimes, lameness. In sheep, the mouth can become swollen and have bloody blisters inside. Those red or dirty blue-colored blisters give the disease its name—bluetongue. Livestock producers should look for the following signs of the disease:
- Depression with heavy breathing or panting;
- High fever;
- Open sores on the tongue, mouth, or nostrils;
- Redness of the skin, face, neck, and possibly body;
- Lameness accompanied by an engorged reddish–blue area around the base of the horns and on the coronary bands of the feet;
- Loss of condition and muscular weakness;
- Loss of wool.
Livestock owners are the first line of defense against the spread of the virus. Producers should inspect their flocks and herds frequently for suspicious signs and report any such symptoms to their local veterinarian.
For more than 25 years, the presence of bluetongue viruses in the United States has blocked the export of U.S. cattle, sheep, and goats to many major world markets, including Australia, New Zealand, and the European Union. Canada accepts U.S. cattle, but requires rigorous testing before the animals may cross the border.
“Montana has not had a major outbreak in the 15 years that I’ve been here,” said Montana Veterinary Diagnostic Lab director Dr. Bill Layton. “We’ve had serological evidence that it is out there, but this outbreak was a bit of a surprise.”
Bluetongue was first recognized in South Africa in the late 1800s, but it was not until the early 1900s that it was described in detail. The disease was reported in Cyprus in 1943 and subsequently in Israel, Turkey, Spain, Portugal, Pakistan, India, and the United States during the 1950s. In the United States, the disease is most prevalent in the southern and southwestern States.
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