Pox Americana

The sudden die-off of a colony of prairie dogs in Fremont County, Colorado, in July alerted knowledgeable local residents that something was amiss.

Residents in Florence, a town of about 3,800 people in southeastern Fremont County, alerted county health officials, who were aware a sudden rodent die-off could be a signal for the plague, in this case bubonic, which attacks the lymph nodes.

Sid Darden, the Fremont County Environmental Health Department sanitarian, collected fleas from the carcasses of the rodents, and those fleas tested positive for plague.

“We received an email regarding a possible die-off on Monday,” Sid Darden said in an interview with LifeZette.

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Plague is scary, but this outbreak happened no more than a mile from the United States Penitentiary Administrative Maximum Facility at Florence, Colorado, known as ADX Florence, Supermax. It’s also called the Alcatraz of the Rockies, inspiring sci-fi scenarios of bubonic plague sweeping a maximum security hold of hardened criminals.

“Plague is endemic in Colorado, and there are always reports of positive plague activity somewhere in Colorado, every year,” Darden said.

“Precautions were taken, using insect repellant with DEET for example, and one of the samplers wore protective coveralls,” he said. “We collected fleas for testing on Wednesday. We had the results by Friday.” The results were positive for bubonic plague.

The devastation at the prairie dog colony was nearly total, evoking images of what the plague has done to Asia and Europe over the centuries.

Related: Legionnaire’s Outbreak

“Plague naturally tends to eliminate or significantly reduce a prairie dog colony,” Darden said.

But where medieval societies would throw plague-ridden bodies on carts and burn them, these prairie dogs were left where they died. “The prairie dogs die down in the burrows, so there are rarely any accessible carcasses that are even visible,” he said.

The prairie dog die-off occurred in a sparsely populated area. The nearest human is “probably a quarter of a mile away,” Darden said.

“There was no quarantine other than the posting of the warning signs,” he said. “Most of the signs are still up.”

The Centers for Disease Control and Prevention said plague is transmitted “usually through the bite of infected rodent fleas.”

“Less common exposures include handling infected animal tissues (hunters, wildlife personnel), inhalation of infectious droplets from cats or dogs with plague, and, rarely, contact with a pneumonic plague patient,” according to the CDC.

These days, human deaths from plague are rare. The CDC says 80 cases of plague have been confirmed in people since 2000. Of those 80 cases, eight people died.

One person in Fremont County died of plague in the mid-1990s, and Darden said he remembers four human cases of plague since he started working in the county in 1987.

Plague has afflicted humanity since biblical times. In 1 Samuel 5:6 of the Hebrew Bible, the Philistines of Ashdod were punished with plague for stealing the Ark of the Covenant from the Children of Israel. The Philistine city is overrun with mice, which brought plague and death to a large segment of the population.

The plague has been isolated and controlled. It no longer kills millions.

From there, human history can be divided into three plague pandemics: The first spread plague from Egypt to the Mediterranean from 541 to 750. The second plague pandemic is also known as The Black Death. Plague killed millions as it spread from central Asia to the Mediterranean and Europe. The third plague pandemic ran from 1866 to the 1960s, spreading from China to India and the West Coast of the United States.

Plague also has been used as a biological weapon as far back as ancient China and medieval Europe. The Japanese used it as a weapon in World War II. The Russians and Americans developed plague weapons after World War II.

Through the 20th century and into the 21st century, the plague has been isolated and controlled. It no longer kills millions. To protect against it, health experts say it’s best to avoid touching any wild rodents, dead or alive. They also encourage using insect repellent and flee control for pets.

Still, health officials are always on the lookout for signs of plague — like the die-off of a once-thriving prairie dog community.