Plague

A flyer published by San Miguel County health officials will be posted in recreation areas around Trout Lake and San Bernardo.  (Courtesy image)

Say the word plague and grim medieval images might come to mind. Plague masks, population devastation, hysteria — banish those thoughts now. Thanks to modern medicine, which treats the infection with antibiotics, the likelihood of the bubonic plague  — the bacterium Yersinia pestis — wiping out 30 to 60 percent of the population (as it did in Europe from 1346-1353) is exceedingly slim. But, fleas carried by critters such as mice, rats, squirrels and rabbits, can carry the bacterium, which can, in turn, infect our pets. And while it’s true a bite from an infected flea can pass along the plague to humans, again, it’s highly treatable. Officials have announced a second incidence of an infected domestic cat, this one in the Norwood area. There is no need for alarm, they say, but instead remind the public to take preventative measures to protect pets.

County health department officials announced Friday that the Norwood cat was hospitalized, tested, and treated for the bacterium and is now recovering well. The first reported case earlier this week, was of a cat in the San Bernardo area. That cat, too, is on the mend and doing well. According to the news release, no fleas were found during treatment and those who handled the cat did not experience high-risk exposures though they will monitor for symptoms for the next week.

The takeaway message, said the Animal Hospital’s Dr. Steve Smolen is one of taking preventative measures.

“The main thing from our perspective is, for cats, keeping them inside,” Smolen said. “Letting them outside is a hazard.”

For dogs, he said, “keep them on a leash,” though he allowed that, “no one wants to do that.”

However, by not letting your dog run free, she won’t be able to investigate a prairie dog hole or chase down a field mouse, potentially coming in contact with any fleas that animal might be harboring. 

“Prevention is the key,” he said, and encouraged pet owners to get their animals treated for flea and tick prevention.

The news release, issued by San Miguel County public health, noted that, while not unknown, the presence of plague is not prevalent. 

“This is one of a few instances of the plague in domestic and wild animals so far this summer across the state of Colorado though there have been no human cases to-date,” the release stated.

It went on to state that plague has been present in Colorado since at least the 1940s and is most frequently discovered among rodents in the summer months. Domestic animals can be infected with the plague when the infection spills over from rodent populations. It can be transmitted by infected animal tissue, such as an animal carcass, fluid or respiratory droplets spread through coughing or sneezing. Plague is most often spread to people through a bite from an infected flea. While there is no human vaccine for plague, it can be treated successfully with antibiotics when caught early. “Throughout the summer, as you and your pets enjoy being active outdoors, it’s important to keep an eye out for disease and infections,” said Public Health Director Grace Franklin. “If you or your pets have contact with fleas, wild animals, or rodents, please monitor for symptoms throughout the season. When caught early, the plague is highly treatable.” 

The first reported infection occurred in San Bernardo at 9,400 feet in elevation. The county health department is currently working with regional campgrounds to watch for dead rodents, fleas, and other possible signs of disease prevalence. 

What’s interesting, Smolen noted, is that not long ago, fleas and tick-borne diseases were almost non-existent at altitude. He points to climate change with its accompanying warmer temperatures, as a culprit in why he’s observed more ticks and fleas at this altitude.

“It’s absolutely climate-related,” he said. “For instance, there never used to be as many ticks. Climate has something to do with this.”

Still, there’s no reason for the kind of anxiety he’s hearing from some of his clients.

“There’s nothing to be alarmed about,” Smolen said. 

In his six years in Telluride, there have been just three cases of plague in the area, two of those his clinic successfully treated. The third case was treated elsewhere. But still, it appears flea and tick season is not just confined to the summer months. A January 2021 editorial on the PetMD website agrees with Smolen.

“Someday, in the not-so far off future, we may be calling flea and tick season flea and tick year,” wrote Geoff Williams, one of the website’s contributing veterinarians. “The problem? As the climate heats up, it's become less unusual to find record-hot days in traditionally cold months like November and December, which means that ticks and fleas are finding the world a more hospitable place and our dogs, cats and small animals (like rabbits) have better odds of catching diseases spread by fleas and ticks.”

Smolen urges common sense thinking.

“There are ways to prevent these things,” he said. “It’s serious, but let’s keep it in perspective.”

Bubonic plague symptoms in cats include swollen lymph nodes, fever, inflammation, depression, vomiting, dehydration, diarrhea, enlarged tonsils, and anorexia. The head and neck area will swell considerably. In humans the symptoms include swollen or tender lymph nodes, shortness of breath, pain in the abdomen or muscles, fever, chills and fatigue. 


If you or someone you know has been in contacted with an infected rodent, wild or domestic animal and is experiencing symptoms of the plague, please contact your primary care physician right away. If you do not see a local physician, please reach out directly to San Miguel County Public Health by emailing publichealth@sanmiguelcountyco.gov