A fungus called Cryptococcus gattii can cause life-threatening infections, especially in people with compromised immune systems. One-third of AIDS-related deaths are thought to be caused by the fungus.
But though people in Southern California have been getting sick from C. gatti for years, nobody knew how.
"We had a good idea that the fungus was going to be associated with trees," says , a postdoctoral fellow at Duke University who studies C. gatti. “We just didn’t know what trees.”
And she didn’t have the time to find out.
But someone did: Elan Filler, a 7th grader who was looking for a science fair project. Her dad, , an infectious disease specialist at the University of California, Los Angeles, ran into , Springer’s advisor, at a conference, and told him about Elan. Heitman told Springer.
Elan Filler and Springer connected on email and figured out a plan. Soon Elan was making her way around greater Los Angeles, swabbing tree trunks and growing out the fungus in Petri dishes. None of the eucalyptus trees in the first batch she gathered tested positive for C. gattii, so she expanded her tests to include more types of trees.
Springer analyzed the genetic fingerprints of fungi in the samples that Elan sent to North Carolina.
Bingo! C. gattii from three trees, Canary Island pine, New Zealand pohutukawa and American sweet gum, matched almost exactly with C. gattii from infected patients. And the tree samples matched not just those from recent patients but from people who were sick 10 to 12 years ago. Thus this strain of C. gattii has been causing health problems in California for at least that long.
The were published Thursday in PLOS Pathogens.
The Canary Island pine is one tree species that hosts a fungus that causes disease in humans.