In Larimer County, Colorado, 16-year old Taylor Gaes passed away as a result of the septicemic plague, the rarest and most lethal form of the plague, according to the Center for Disease Control and Prevention. Via ABC News:
Gaes — a sophomore at Poudre High School — began experiencing flu-like symptoms after pitching at a baseball game on June 4, Katie O’Donnell from the Larimer County Department of Health and Environment said.
An investigation into Gaes’ death is still ongoing by the Department of Health and Environment, the U.S. Centers for Disease Control and the State Health Department. However, Gaes is thought to have been bitten by an infected flea on his family’s ranch, O’Donnell said.
“This form of the plague is extremely rare because the bacteria goes right to the bloodstream. It’s just the third case in the past 30 years that we’ve seen,” O’Donnell said.
The symptoms of the septicemic plague include "fever, chills, extreme weakness, abdominal pain, shock, and possibly bleeding into the skin and other organs," according to the CDC. It's transmitted, often, through flea bites, or contact with "contaminated fluid or tissue."
According to Dr. Lee Riley, a professor of epidemiology at UC Berkeley, there's a reason most of the plague cases in the United States occur in Colorado and the surrounding states, and it has much to do with the specific physical conditions of the region. Because of the confluence of the dry desert areas allowing bacteria to thrive in the soil and the concentration of rodents in that region of the country (rodents are known to be particularly susceptible to carrying the plague, though it's unclear why), the conditions are (relatively) rife for the spreading of the plague.
Because those conditions are so specific, though, there's hardly any chance the plague returns in any real way to anywhere in the United States.
"It's extremely unusual in the United States," Riley told Fusion. "You need the right set of conditions for it to happen. It's just not likely to spread."
Michael Rosen is a reporter for Fusion based out of Oakland.