Here's how scientists think it's sneaking into the well-guarded spinal cord and brain of a healthy person:
—The steroid injected near the spine reduces inflammation, one of the immune system's defenses against contamination.
—The mold grows quietly until enough accumulates for it to burrow a tiny hole, or abscess, into the lining of the spinal canal, said Dr. William Schaffner of Vanderbilt University. Reaching the spinal fluid inside offers a direct pathway to the brain.
—The fungus' color signals how intractable it is. Brown-black molds produce melanin, the same chemical that helps human skin tan. It guards against the sun's mold-killing ultraviolet rays — and inside people, it fends off both antifungal drugs and other immune-system attacks, Casadevall said.
The good news: Black mold is treatable with a drug named voriconazole, with far fewer side effects than the older treatment initially recommended when the outbreak began.
Still, Kauffman cautioned doctors to carefully monitor patients because differences in metabolism can make levels surge in the bloodstream, causing hallucinations, confusion, nausea and occasionally liver damage. On the flip side, their bodies may process the drug too quickly to battle the fungus. Plus, voriconazole can interact badly with a list of other common medications.
"It's not clear" how long to treat but at least three months is advised, Kauffman said. It begins with intravenous infusions that are hard to administer outside of a hospital. Then once the patient is stable enough, pills can be used.