A news story was circulating a few months ago—a woman in Australia came into the hospital with abdominal pain. She was increasingly forgetful and struggling with depression. Her doctors were stumped for over a year. What was causing her symptoms? Turns out she had a three-inch parasitic worm living in her brain. They took it out, and she recovered.How do doctors crack cases like this? How do you even know to check for a brain worm? This is the specialty of Dr. Joe DeRisi. When doctors run into a diagnostic dead end they call him. In his world, brain worms aren’t even that rare. (Ask him about brain-eating amoebas.)Guest host Flora Lichtman talks with Dr. DeRisi, professor of biochemistry and biophysics at the University of California, San Francisco’s School of Medicine and president of the Chan Zuckerberg BioHub San Francisco, about his fascinating work solving some of the most vexing medical mysteries, and how it may even help detect the next pandemic-inducing pathogen.  To stay updated on all-things-science, sign up for Science Friday's newsletters.Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.