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WORLAND – Ranchers, farmers, veterinarians and curious community members gathered Thursday to learn what brucellosis abortus is, how it is transmitted, the types of animals, both wild and domesticated, who are affected by it, the danger to humans and what is being done to keep it under control and to hopefully eradicate it.

University of Wyoming veterinarian and brucellosis expert Bruce Hoar explained during a WESTI (Wyoming Extension's Strategically and Technologically Informative) Ag Days, presentation at the Worland Community Center Complex that brucellosis was first discovered in 1887 by David Bruce when he was studying a disease of soldiers on the island Malta and it was originally called Malta fever. In 1897 a veterinarian by the name of Bernhard Bang isolated Brucella abortus, therefore it is also called Bang's disease.

Hoar stated that the disease probably arrived in the United States when European cattle were first imported into the United States. Since then it has gotten into the wild bison and elk in the greater Yellowstone area. It was first isolated in bison in 1917 and in elk in 1930.

In bison, elk and cattle the disease affects the reproductive organs causing abortions (miscarriages) after the fifth month of pregnancy. "So in cows what you typically see is reproductive failure; it causes abortions and that abortion is usually after the fifth month of pregnancy. The cow herself generally does not show clinical signs, so a cow walking in a pasture, you cannot really tell by looking at her whether she has brucellosis or not. An infected animal is not infectious to another. Those bison up in Yellowstone maybe half, a quarter, whatever percent have brucellosis, they can walk around and they are not a risk to anybody else until they have an abortion. Usually cows will only abort once but sometimes will abort a second calf and sometimes even a third calf. After a cow aborts they develop some protective immunity that protects them from future abortion but it's not 100 percent. Few infected cows ever recover from infection. Basically, once you identify a positive cow you're going to assume that she is positive forever and ever," Hoar said.

While animals don't transfer the disease to each other, the aborted fetus along with the fluids, etc., are the primary way the disease is spread. "Transition occurs after a cow has an abortion and somebody else comes along and sniffs or licks or chews on that placenta," Hoar stated. He added that when another cow eats the infected grass or sniffs the aborted fetus, the cow becomes infected. "The bacteria is quite hardy it can survive in the appropriate environment for up to 100 days. So a nice warm environment, a cow has an abortion out in the pasture that bacteria can last for quite some time. So the next cow comes along and ingests that bacteria, the bacteria goes into regional lymph nodes, they swallow it so it goes up into the tonsils first then it spreads throughout the body and winds up in the uterus, the placenta and the udder and that's where it causes the damage that you see with abortions."

While predators do not get the disease, they can spread it. If a cow aborts in the pasture and a coyote chews on that, the coyote won't get sick but the coyote could carry off the fetal membrane to the next pasture and cause infection that way, Hoar said.

Hoar stated that the disease is an infectious zoonotic disease which means that it can be transferred from animals to humans. "Not only does it cause disease in animals but also a very significant disease in humans," Hoar stated.

The primary way that humans get the disease is through handling infected animals, transmitted through abrasions in the skin and by ingesting unpasteurized dairy products. "You may have read earlier this fall there was a hunter, most likely infected by dressing an infected elk that got brucellosis, so it can be a concern to people hunting. There are other possibilities where he got that infection but chances are it was an infected elk. In the United States now the primary way is through unpasteurized milk or dairy products," Hoar stated. He added that at one time the disease was a huge issue for veterinarians handling fetuses and calving cows.

The symptoms in humans are much different than the symptoms in animals. The disease does not attack human reproductive organs instead causes a long list of symptoms including sweats, headache, back pain, anorexia, myalgia, fevers that go up and down, arthritis, chronic fatigue and depression. "There is no treatment that are successful in animals, treatment in people can be successful but it takes a long, long time with a lot of antibiotics so it's not a nice disease, not something you want to get," Hoar stated.

The disease has been somewhat under control for a long time dropping from 124,000 infected domestic cattle herds in the United States in 1956 to only three known infected herds today, one in Idaho and two in Montana. Cow producers use the RB51 vaccine to protect their animals which has 70 percent effectiveness but the disease seems to be re-emerging. Hoar stated that two cases have recently been found in Wyoming, one in Park County and one in Sublette County and both cases appear to have been caused by wild elk.

Diseased wild elk have been found in the Big Horn Mountains in four different hunt areas. "Between 2002 and 2016 there have been nine elk that have been identified as seropositive, that means that they have been exposed to brucellosis, we don't know for sure if they are carrying the organism but they have certainly been exposed. Elk hunt areas 39, 40 and 41 and then in 2016 we had one bull elk show up in hunt area 49 as positive with brucellosis," Hoar stated.

The Brucellosis Coordination Team (BCT) established in 2004 by governor Freudenthal, which consists of ranchers, outfitters, sportsmen, conversationalists, state and federal land managers and domestic and wildlife health managers are working hard to eradicate the disease in both domestic and wild animals. Specific requirements have been issued for vaccination of cattle, change of ownership and movement of herds to help prevent the spread of the disease and new testing is being currently worked on. Wyoming Game and Fish is also working to eradicate the disease by radio collaring cow elk to learn more about their movements and learn if an elk is found to be diseased where the infection may have occurred.

While brucellosis is a significant threat to humans, the meat is safe to eat since the disease is not usually found in the muscle tissue and cooking temperatures kill the bacteria. Wyoming Livestock Board assistant state veterinarian Thach Wilson stated if hunters take the proper safety procedures, such as wearing gloves when dressing an elk and bison there should be nothing to worry about.