Elk-to-cattle transmission confirmed

by Cat Urbigkit

The second session of the Wyoming Brucellosis Task Force opened Thursday in Lander with Dr. Don Montgomery of the University of Wyoming's Department of Veterinary Science explaining that research indicates that the recent outbreak of brucellosis in a Sublette County cattle herd appears to have come from infected elk on the adjacent Muddy Creek elk feedground.

Montgomery said that Dr. Betsy Bricker of the National Animal Disease Center did the testing, and found when comparing brucella taken from a beef cow to a nearby elk cow: "This is a very close match between the cow and the elk isolate. ... The elk and cattle isolates from Muddy Creek are as close as she's ever come to date" to documenting elk-to-cattle transmission.

Montgomery noted that within the brucella genome, there are certain loci with hypervariable regions that are very susceptible to mutation, as was evident in the comparison tests.

Dr. Arnold Gertonson of the U.S. Animal and Plant Health Inspection Service noted that even the mutation in the genome was similar. The chance of such a similar mutation from two different brucella isolates would be very remote.

Dr. Donal O'Toole of the Wyoming State Veterinary Laboratory said with the testing that has been conducted, Bricker couldn't say that the isolates are an exact match.

"This is the most compelling evidence she's aware of, of transmission from elk to cattle," O'Toole said. "It does look like this is definitely, from these preliminary data, that it came from elk to the cattle."