Thomas Besser, DVM, Ph.D., Dipl. ACVM, a veterinary professor at Washington State University, has been named the Rocky Crate DVM and Wild Sheep Foundation Endowed Chair in Wild Sheep Disease Research.
Dr. Besser succeeds Subramaniam Srikumaran, BVSc, Ph.D., who held this position since its beginning in 2004.
“I am honored to be appointed to Dr. Crate’s chair,” Besser said. “Pneumonia is a very nasty disease that has severely limited the recovery of bighorn sheep in the western U.S. We’ve learned a lot about the disease in the past few years, and I am looking forward to trying new approaches to preventing the disease in bighorn herds that haven’t yet been affected, and in limiting the damage in herds that have. We are getting ready to start clinical trials that may lead to effective, manageable approaches for all parties, including domestic sheep producers.”
Besser’s work on pneumonia in bighorn sheep ranges from basic investigations of the infectious process and immunity, to development of practical approaches to management of both domestic sheep and bighorn sheep to alleviate the disease, according to the university.
“For decades, people smarter than I pursued a vaccine for controlling organisms that seemingly cause a fatal pneumonia in wild sheep with little success,” he said. “It now appears that for a long list of reasons, a vaccine strategy for wild sheep is not the best way to control the agent that starts the disease process, a bacteria named Mycoplasma ovipneumoniae. We call this bacterium, ‘Movi’ for short.
“In just the last five years, we’ve come to understand this complex disease process much better, and now I think we are now at the point where we can begin to try out some possible solutions. That progress is specifically why I took this position now instead of retiring this year.”
Movi is found in most domestic sheep flocks and causes few problems there, except in weaned lambs which can develop a similar, but much milder, pneumonia, Besser said.
Experiments have shown that contacts between domestic sheep carrying Movi and bighorn sheep nearly always result in fatal bighorn sheep pneumonia. However, similar contacts with domestic sheep that don’t carry Movi do not trigger epidemic pneumonia. Besser plans to develop efficient ways to eliminate Movi from domestic sheep flocks, in order to greatly reduce or eliminate the risk of pneumonia if contact with bighorn sheep occurs.
“This year, we are working with the University of Idaho Sheep Center to see if we can eliminate Movi from part of their domestic sheep flock,” Besser said. “As long as domestic sheep carry Movi, they represent a significant risk to bighorn sheep they might contact, so it would be a great help if domestic sheep flocks near bighorn ranges would work to eliminate Movi from their animals.
“I am also working with wildlife agency biologists and veterinarians to try to eliminate the carriers of Movi from affected wild sheep populations, to stop the on-going pneumonia losses they often experience.”