As studies continue, photos released by WGFD show the aftermath: a haunting winter landscape littered with dead pronghorn.
“While reported M. bovis outbreaks causing mortality in wildlife are rare, this is not the first occurrence of M. bovis being linked to pronghorn mortalities in Wyoming,” offers Wyoming Game and Fish (WGFD) wildlife disease specialist Hank Edwards via press release.
WGFD is estimating approximately 200 pronghorn have died in less than a month due to what is believed to be an outbreak of Mycoplasma Bovis (M. bovis). Preliminary lab results identify it as the pathogen responsible. Word is still out on the event becoming a full-blown outbreak, however.
Since mid-February, the southern end of the Mesa south of Pinedale has been hit hardest:
While the aftermath is clear, WGFD is unsure of the source.
“The source of infection of the M.bovis and the ability to predict the duration and the geographic distribution of this outbreak in pronghorn is unknown at this time,” their press release cites.
WGFD also notes that Mycoplasma bovis should not be confused with Mycobacterium bovis. The latter M. bovis is what causes tuberculosis in cattle. “They are two unrelated bacteria that cause very different diseases,” the department explains.
As for Mycroplasma bovis, the pathogen enters the upper respiratory tract. There, it can reside without symptoms then spread through nasal secretions. It is a cause of mastitis, arthritis, pneumonia, and other diseases in wildlife. In livestock, it causes bovine respiratory disease (BRD), Zoetis cites.
The disease can be chronic and fatal for both wild and domestic animals. For those that survive, irreversible lung damage is common.
Disease Outbreaks in Wyoming Pronghorn Becoming Prevalent
In 2019, the first reported cases of pneumonia in pronghorns occurred this same time of year. The same would crop up in 2020 – both near Gillette, WY. At least 460 animals were infected.
“Those outbreaks started at a similar time in mid-February and then tapered down by the beginning of April,” WGFD notes.
Currently, Wyoming Game and Fish officials continue to monitor for M. bovis across the state. Right now, the outbreak seems to be local to Gillette. The bacteria isn’t causing significant mortality in other Wyoming wildlife populations (outside of pronghorn) in Wyoming.
Thankfully, this pathogen isn’t affecting domestic pets such as horses, dogs or cats and is not a human health risk, WGFD assures the public. But preventing spread is still a priority.
To do so, local Game and Fish personnel will periodically remove carcasses and euthanize dying pronghorn. This is only possible in “relatively accessible areas,” however. Disturbance to other healthy wintering pronghorn is a concern, too. So intervention will remain minimal while officials do what they can to “reduce the prevalence of this pathogen on the landscape.”
