Twice, bubonic plague, caused by the rodent-borne bacterium Yersinia pestis, has killed large swathes of Earth’s human population.
But with the dawn of antibiotics after 1940, the threat posed to humans by plague has faded.
For Southwest Colorado’s prairie dogs, however, the Black Death has remained a deadly foe. A single prairie dog’s infection routinely wipes out whole colonies.
“It’s the same thing that hit Europe,” said Joe Lewandowski, public information officer for Colorado Parks and Wildlife’s southwest region.
He said it’s important to emphasize that because plague is an imported pathogen, arriving in North America around 1900, prairie dogs haven’t been able to develop an immunity to it.
“Prairie dogs have no defense against it,” Lewandowski said. “That’s why when the bacteria is carried on some flea, and it infects a prairie dog, it can wipe out a whole colony.”
Within human society, prairie dogs don’t enjoy the same status as elephants or Labradors, eliciting feelings of conservationist passion and love. But according to a Colorado Parks and Wildlife news release, prairie dogs play a vital role in the ecosystem of Southwest Colorado.
“In some situations prairie dogs can be seen as pests, but they are critical in the environment and help to promote survival of numerous other species such as burrowing owls, badgers and raptors,” said Dan Tripp, a wildlife disease researcher with Colorado Parks and Wildlife, in the release.
But the dynamics of the disease may finally be changing in the wild. After researchers dabbled with dusting fleas with insecticide – an effective but expensive treatment, they are newly encouraged by one potential treatment, the oral sylvatic plague vaccine, Tripp said.
Developed by the U.S. Geological Survey’s National Wildlife Health Center, the vaccine – which is still in the experimental stage – works well in the laboratory.
The vaccine’s delivery mechanism is wily: It’s administered in a cube flavored with peanut butter, a food apparently as alluring to prairie dogs as humans. The bait-cubes also contain a red dye that sticks to the prairie dogs’ coats, allowing researchers to track which prairie dogs have taken the bait.
This is only the second year the vaccine has been tested in the field in Colorado. Parks and Wildlife said longer-term monitoring will be needed to determine its efficacy.
“So far, we’re encouraged by the results, and we are optimistic that the vaccine will be effective in limiting future plague outbreaks,” Tripp said in the release.
In the Gunnison area, four prairie dog colonies are being used to test this new vaccine. Two colonies will receive the bait, while the other two will serve as control groups and receive no treatment.
In Teller County the test is also being conducted on two colonies. Colonies typically include 50 to 100 individuals.
“We’re not attempting to upset nature’s balance with these treatments,” Tripp said. “We are working to restore balance in the environment and reduce the risk of major plague outbreaks in prairie dog colonies. We lose a lot of resilience in the environment when we lose prairie dogs.”
cmcallister@durangoherald.com
