Story highlights A local public health official laments death of teenager with such a bright future

Naegleria fowleri, often found in fresh water, can cause an infection that destroys the brain

Of the 133 documented cases of infection, 130 people died

(CNN) The fatal brain-eating amoeba has struck once again, this time claiming the life of a 14-year-old star athlete.

Michael John Riley Jr. had been just days away from starting his freshman year of high school. The Houston teen, who qualified for the Junior Olympics three times in track, was swimming with his cross-country team on August 13 at Sam Houston State Park.

That's when Michael encountered the Naegleria fowleri amoeba. Within days, the teen's bad headache turned into a total loss of brain function. He died Sunday.

Dr. Umair Shah said the Harris County, Texas, health department, which he heads, learned of Micheal's case a few days earlier on August 22. His agency soon became one of many -- including the hospital, the state and U.S. Centers for Disease Control and Prevention -- involved in the case, trying to pin down the source of his illness and get the word out to the public and health professionals.

Naegleria fowleri are rare, Shah points out. But they can be found waters, especially those that are warm and still.