"He had an amazing personality. He was kind, courageous, very outgoing, warm-hearted," Ethan Conyers told KMGH.
That was Ethan Conyers talking to Newsy's partners at KMGH about his friend Taylor Gaes, who died June 8.
Health officials now say the 16-year-old's cause of death was the septicemic plague, which he most likely contracted from fleas.
The National Institutes of Health reports this form of the plague is similar to the bubonic plague in that it's most often caused by either rodent or flea bites.
A Larimer County Health and Environment spokesperson told KUSA Taylor reported feeling ill before he died.
"Sometimes they just show flu-like symptoms, which is what Taylor had. It's very hard to know a difference between running a fever and having some general aches and pains and having plague, which is exactly the case with Taylor," Katie O'Donnell said.
Now, if a person is diagnosed properly within 24 hours of symptoms appearing and immediately started on antibiotics, the plague is treatable.
"One of the challenges, though, here is that because it is so rare, it's often overlooked or not diagnosed at all," medical contributor Dr. Holly Phillips told CBS.
The Centers for Disease Control and Prevention said there are only an average of seven reported cases of the plague every year, and they're most commonly reported in the southwestern U.S., in states like Arizona and Colorado, where Taylor lived.
In fact, The Coloradoan reports the last time there was a confirmed case of the plague in Larimer County was in 1999.