UW researches brucellosis vaccine

Brucellosis is a bacterial disease known to cause elk, bison and cattle to abort their fetuses with abortions associated with higher risk of transmission. While most of the U.S. is free of bovine brucellosis, the disease is endemic in bison and elk in the Greater Yellowstone Area, occasionally spilling over to cattle herds in northwestern Wyoming and adjoining parts of Idaho and Montana. 

                  Researchers at the University of Wyoming (UW) have been working to eradicate brucellosis for over 15 years. 

Brucella vaccines

                  According to UW scientists studying the disease, the brucellosis vaccination has been an integral part of eradicating the disease from domestic cattle populations. 

                  “While vaccination of cattle with Brucella abortus strain RB51 does reduce abortions, it does not necessarily prevent infection,” states an article written by UW Associate Professor in Veterinary Sciences Gerry Andrews and Brucellosis Research Coordinator Bruce Hoar. “Also, currently available vaccines are not appropriate for use in bison or elk.” 

                  While UW researchers have applied modern methods with the goal of producing a vaccine which protects more than one species of potential hosts of the disease, scientists across the country have been working to find a solution for more that a decade. 

                  “These microorganisms have a propensity to colonize their animal hosts, survive for long periods of time and remain dormant,” Andrews and Hoar say. “The characteristic hallmark of Brucella abortus in mammals is chronic infection. The ideal pathogen would not necessarily cause disease.” 

                  “Epidemiological studies on Brucella abortus bear this out, as it has been difficult to numerically correlate pathogenic outcomes with infection in natural host populations such as cattle and/or wild herding animals, like elk,” the article continues. 

UW research history

                  Research to develop brucellosis vaccines began at UW in 2005. Scientists worked to create a vaccine which gives animals immunity by targeting virulence components or factors which evoke disease. 

                  “In a pivotal study at UW, a laboratory methodology known as in-vivo-induced antigen technology (IVIAT) successfully identified novel Brucella abortus genes expressed during infection in elk. Some of these genes were also found to be common to brucellosis infection in cattle,” note Andrews and Hoar. 

                  The scientists also recognized long-term infection of Brucella abortus in the host animal was likely due to the animal’s suppressed immune response to the pathogen, thanks to inflammation caused by the Brucella enzyme, Mdh. 

                  In 2009, researchers tested the ability to isolate protein components of Brucella found in E. coli to use in a variety of vaccine formulations. Another study suggested using cellular components, but not complete cells, of Brucella abortus could stimulate strong immune response against the pathogen. In 2014, UW filed a patent for the continued use and development of these potential vaccines. 

                  A partnership with researchers at Colorado State University in 2016 has resulted in steps towards a potential vaccine using Brucella abortus cell components. 

                  “Variation between molecular components of the various Brucella species could lead to development of tests which differentiate between several different infections species of Brucellae,” states the article. “More importantly, these findings may contribute to increase specificity and sensitivity of a rapid field assay for Brucella abortus under development at UW.” 

Vaccine alternatives

                  Most recently, novel live vaccine platforms against brucellosis have been explored at UW, according to Andrews and Hoar. 

                  “The probiotic bacterium, lactococcus, has been examined for use as a carrier of Brucella genes to colonize the mammalian gastrointestinal tract and consequently immunize the animal host against Brucella infection. These ongoing experiments represent the potential for another alternative to the traditional live Brucella-based vaccine for cattle,” the article notes. 

                  Although brucellosis continues as a problem in the northeastern part of Wyoming and surrounding areas, researchers using gene discovery methods and nontraditional vaccine platforms have a better chance at understanding the microorganism’s biology and therefore, the end goal of multi-species vaccines and disease eradication. 

                  Information in this article was sourced from an article written by Gerry Andrews and Bruce Hoar found at uwagnews.com. Averi Hales is the editor of the Wyoming Livestock Roundup. Comments on this article can be sent to roundup@wylr.net.