More than two months after a St. Michael family lost their 16-year-old daughter, her loved ones finally know what claimed her life on a hot July morning, just blocks away from her home while on a run.

Robin and DuWayne Olson take a walk to visit the spot where their daughter collapsed each day, straightening up the flowers and remembering the girl who grew up with a passion for soccer.

They told FOX 9 News that Michaela Olson had battled breathing problems for four years before her death. Doctors treated her for asthma for three years, but it turns out she never had it. In April, she was diagnosed with vocal chord dysfunction -- but that couldn't be fatal.

The soon-to-be high school junior was training for her upcoming soccer season when she collapsed on her route. At first, many people thought her death was heat-related, but the Olsons didn't believe it for a minute.

After 10 weeks of waiting, they finally know what killed the well-liked teen who hoped to become a pediatrician. Michaela died from coronary artery vasculitis brought on fibrosing mediastinitis associated with pulmonary histoplasmosis.

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Essentially, a fungus that is commonly found in the soil has airborne spores that can be breathed into lungs.

Michaela's lungs had scar tissue inside that the fungus attached to. As it grew, it got into her blood stream and caused a lymph node near her heart to swell, along with her coronary arteries. Eventually, the swelling got so severe that blood could no longer pass through.

Though there is no way to avoid the fungus, a doctor at HCMC told FOX 9 News it's easy to diagnose, but is commonly mistaken for asthma.

Most people who get it never know it because the body usually can conquer the spores, and death is extremely rare.

"Something in Michaela's body just reacted differently to it than most people," her father said.

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