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UW Seeks Better Brucellosis Control Through Vaccine Development, Vaccination Practices

Written by Steve Miller

By Steve Miller, University of Wyoming Extension


College of Agriculture and Natural Resources scientists at the University of Wyoming are hopeful their brucellosis studies will result in improved control of the disease.

Brucellosis can cause elk, bison and cattle to abort fetuses. The organism can also be transmitted to humans, which may result in a severe disease called undulant fever.

“We have essentially eradicated the disease from livestock but occasionally get a disease spillover from elk transmitting the organism to cattle,” said Bruce Hoar, UW brucellosis research coordinator.

One method of control is through vaccinations.

“The currently licensed vaccine protects 60-70 percent of animals in the herd, leaving 30-40 percent vulnerable, and, because of that, there is a need for improved vaccines. That is what a team of researchers at the University of Wyoming has been involved in for a number of years,” he said.

Gerry Andrews, associate professor in the Department of Veterinary Sciences and a medical microbiologist, has developed unique vaccines.

“These have been tested in a mouse model of brucellosis,” said Hoar. “They are in the early stages of development, but we are very hopeful this will lead to a better vaccine for cattle.”

Another effort is to simply vaccinate with more doses of the current vaccine, called RB51, said veterinary science assistant professor Jeff Adamovicz.

“We recently completed a study in cattle and have promising results that show multiple doses of RB51 vaccine reduced abortions in cattle and may also reduce the risk of transmission,” he said. “We hope to pursue a recommendation to change the vaccination practices in Wyoming based on our findings.”

Modeling the risk of brucellosis transmission and developing economically feasible ranching practices are also an important part of the overall goal of reducing impacts to Wyoming ranchers, according to Brant Schumaker, assistant professor in the Department of Veterinary Sciences, and Dannele Peck, associate professor in the Department Agricultural and Applied Economics.

The work of the Wyoming Game and Fish Department is also critical in helping to break disease transmission, said Hoar. In northwestern Wyoming, 20-40 percent of elk will test positive for exposure to the bacterium on a blood test. Most recently, seropositive elk have been found in Big Horn County, raising concerns about the potential for spread to local cattle, although no evidence of transmission has been found in this area, said Hoar.

Hoar says the university has a well-qualified team for brucellosis research, and they hope to apply for grant funding that was identified in the most recent farm bill to help in their efforts.

“Our long-term goal is to develop vaccines and vaccine strategies that will enhance our ability to control the potentially devastating effects that this disease could cause to Wyoming cattle and wildlife,” he said.