A rare bacterial pneumonia disease has taken out at least 500 antelope south of Pinedale, and that number is likely to rise as more bodies are uncovered from snowmelt.
The disease is called Mycoplasma bovis. It is typically seen in cattle or bison exhibiting often as an arthritis – but for antelope, it is really rare and exhibits more pneumonia-like symptoms. In fact, Wyoming has only seen one other outbreak before starting in 2019 near Gillette, where it inevitably took out about 460 animals. The herd has recovered since spring 2020.
The Wyoming Game and Fish Department (WGFD) discovered the disease in the Sublette antelope herd in February, and it seems to be pretty deadly. Once an antelope contracts the disease, they seem to die quickly. On a county road south of Pinedale, one can see bunches of dead antelope, with some still alive, but lying down and coughing – barely hanging on.
“We don't know if this disease is simply going to burn out in the population, because they're so susceptible,” Hank Edwards, WGFD disease specialist, said. “Or if there's going to be animals that continue to live with the disease, and they'd be able to pass on the disease to other susceptible antelope.”
Edwards said they are taking blood samples and looking at old samples to better understand the disease. Something of particular interest is whether any of the antelope contracted the disease prior to the winter, as this might help them understand whether the severe winter made the disease worse for the animals.
“So if they picked up this bug, say in February, and they started to die, it's hard to say that it's the winter that caused it,” Edwards said. “On the other hand, if they picked it up in October, or sometime over the summer, then maybe we could say it's probably the winter that helped lead to their demise.”
Edwards said he hopes this is the last the state sees of the disease, but the fact that there has been two outbreaks in just the last five years in the state gives him concern for the future.
“Given this is the second outbreak that we've seen, I really wouldn't be surprised to see it again somewhere else in the state or even in the same locations of Pinedale and Gillette,” he said.
He hopes that moving out of winter will give the Pinedale herd some reprieve.
“Our hope is that as the snow melts and forage becomes available that these animals are able to build up their energy reserves,” he said.
Due to the heavy snowfall this year, experts believe there will be a lot of vegetation.
Radio collar data shows that about 50 percent of the Sublette herd could succumb to starvation from this winter and disease. Prior to this winter, the herd was at about 40,000 animals.
