Why Do Prairie Dogs in Colorado Have the Plague?

Photo credit: photo by yasa - Getty Images
Photo credit: photo by yasa - Getty Images

From Popular Mechanics

  • Prairie dogs in parts of the Rocky Mountain Arsenal Wildlife Refuge are infected with the Plague, leading to officials closing portions of the refuge.

  • The burrows are being treated with insecticide aimed to kill the fleas that carry and spread the Plague to other animals and humans.

  • While some of the refuge has since reopened to the public, certain areas still remain closed until Labor Day weekend.


Yeah, the Plague is still a thing—refer to the prairie dogs who recently contracted the deadly disease. The U.S. Fish and Wildlife Service reports that Portions of the Rocky Mountain Arsenal National Wildlife Refuge in Colorado have been closed due to an outbreak though some of the refuge re-opened on the morning of August 17.

The refuge was closed towards the end of July as a "precautionary measure" and after coordinating with "local, state, and federal partners—including health officials—we are confident that conditions at the refuge support reopening to the public," Fish and Wildlife said in a statement.

The Denver suburb of Commerce City has been affected by the infected prairie dogs and areas around the city will stay closed up until Labor Day weekend reports CNN.

Currently, the prairie dogs are under watch and their burrows have been treated with an insecticide powder to kill the fleas.

"There is still evidence of fleas in the hiking and camping areas, which could put people and pets at risk, so those areas will remain closed," John M. Douglas, Jr., the Executive Director of the Tri-County Health Department, told CNN.

What is the Plague?

The Plague is caused by Yersinia pestis, a bacteria that easily moves between fleas and rodents and can even infect larger predators who prey on diseased animals.

According to the CDC, it's likely that the Plague bacteria "circulate at low rates within populations of certain rodents without causing excessive rodent die-off." In turn, the rodents that don't die from Plague act as "reservoirs for the bacteria," which is how it easily moves between animals and even people.

Colorado State University notes that "not all fleas effectively transmit Plague. Those that do become infective days or weeks after ingesting blood from a plague-infected rodent."

CSU researchers found that once a flea has fed from an infected host, the Plague bacteria reproduces within the flea's digestive tract and typically ends up killing the flea by creating a blockage in its gut.

Since the Plague organism also is lethal to the flea, due to the gut obstruction, fleas often die before they can transmit the disease. However, an effect of the bacteria blocking the gut is that the infected flea becomes starved and thus more actively bites and seeks a host. Fleas capable of transmitting the disease usually do so in the course of biting; less commonly, the Plague organisms are transmitted when scratching the flea feces into bites or wounds.

How To Avoid the Plague

Today, the Plague is rare—between one and 17 cases are reported annually in the U.S with the average being around seven reported cases. Some precautions to keep you plague-free include wearing mosquito and insect repellant when outdoors and avoiding contact with wildlife—even if it's a cute little prairie dog.

The CDC also recommends removing piles of rocks, leaves, and wood where rodents can burrow, wearing gloves when handling wildlife, and using flea control products on pets to keep the whole family safe.

The chances of surviving the Plague are better if you seek treatment as soon as possible.

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