Colorado health officials reported this weekend that a healthy 16-year-old boy’s sudden death earlier this month was caused by a rare strain of plague.

High school star athlete Taylor Gaes was believed to have contracted the septicemic plague from fleas on a dead rodent or other animal he came in contact with on his family’s ranch in rural Cherokee Park, northwest of Fort Collins, Fox 31 said Saturday.

Septicemic plague occurs when bacteria enters the bloodstream directly. It is highly fatal and very rare in humans.

The Larimer County Health Department warned people who attended a memorial service for Taylor on the ranch to be extra vigilant should they come down with flu-like symptoms.

“There is a small chance that others might have been bitten by infected fleas, so anyone who was on the family’s land in the last 7 days should seek medical attention immediately if a fever occurs,” the agency said.

Taylor suddenly became ill and died June 8, a day after his 16th birthday. Friends thought he had a bad case of the flu.

The Denver Post reported that in the U.S. only 7 people contract plague each year. The last confirmed case in Larimer County was in 1999.

Bubonic plague is the most common form of the disease among humans, the Fort Collins Coloradoan reported. Bubonic plague can be successfully treated when diagnosed promptly, the paper said.

At 15, Taylor was the starting first baseman and No. 2 pitcher for the Poudre High School varsity baseball team.

The Post said that although only a sophomore, Taylor, who stood 6 foot, 4 inches, and 210 pounds, was already being considered an excellent college baseball prospect.

“We often talk about Taylor’s potential as an athlete, but he was much more than that," Poudre baseball coach Russell Haigh told the Post. “He was a good friend to all of our players. He was a special young man.”