Prairie dogs may be source of area plague

Since a woman in La Plata County tested positive for bubonic plague last week, San Juan Basin Health Department investigators have raced to identify the origin of her disease.

The Health Department announced Thursday its team of investigators had discovered the likely source: a burrow of prairie dogs in western La Plata County ridden with plague-positive fleas.

Joe Fowler, an epidemiologist with San Juan Basin, said health officials could not name the burrow’s precise location, citing the patient’s right to privacy.

The last time a human came down with bubonic plague in La Plata County was 2006, according to the Centers for Disease Control and Prevention.

The woman was treated and released Aug. 8.

Whenever there are outbreaks of dangerous infectious diseases such as bubonic plague, smallpox and Ebola, containment only partially depends on infected patients’ receiving adequate medical care. To prevent further transmission, public health officials also have to do old-fashioned detective work to ascertain the disease’s etiology, tracing the path of infection it blazed – traveling from host to host, jumping between species – back to its earliest origin.

In a phone interview Thursday, Fowler said almost 10 San Juan Basin Health employees had worked to track down the vector of last week’s report of bubonic plague with help from experts and laboratories at the Colorado Department of Health and Environment. Working with information provided by the plague patient, investigators eventually narrowed in on the burrow of plague positive, flea-infested prairie dogs as probable exposure source.

It’s impossible right now to determine the number of infected prairie dogs, Fowler said.

But he said humans had to be cautious.

“The main message here is that in summertime in Colorado, plague can occur at any place and time. Plague is endemic to our area, and everybody in La Plata County – no matter where they live – has to take precautions,” he said.

Twice in history, bubonic plague has ravaged the human species, killing between 75 million to 200 million people in the 1300s, wiping out as much as 60 percent of Europe’s entire population.

With the advent of antibiotics, the threat posed to humans by plague, once glaring, has dimmed.

The disease is still deadly, however. Since 1957, Colorado has seen a total of 64 cases of human plague: In nine cases – 14 percent – the disease proved fatal.

So far this year in Colorado, four other cases of human plague have been identified in Adams County. Two rodents, a dog and a dozen flea samples also have tested positive for plague, according to San Juan Basin Health Department.

According to Joe Lewandowski, spokesman with Durango Parks and Wildlife, since bubonic plague landed in North America around 1900, prairie dogs have failed to develop any resistance to it.

Bubonic plague regularly wipes out whole colonies.

In a June interview, Lewandowski said Colorado Parks and Wildlife researchers are studying different options to vaccinate prairie dogs against bubonic plague.

The Health Department is imploring residents to be vigilant: Don’t approach or sleep with animals; Expel rodents from your residence.Remember, plague lurks in fleas. Do everything within your power to keep them from biting you and your pets.

cmcallister@durangoherald.com