The U.S. Centers for Disease Control and Prevention said it now counted 419 cases in 19 states: 409 cases of fungal meningitis and 10 joint infections. At least 30 people have died.
For a map of cases by state, click here.
The outbreak has been linked to contaminated vials of methylprednisolone acetate, an injectable steroid used to treat back and joint pain. Sealed vials of the steroid, made by the New England Compounding Center in Framingham, Mass., contained exserohilum rostratum, a fungus found in soil and plants.
For a full list of clinics receiving the recalled lots of spinal steroid injections, click here.
It's not clear how the fungus landed in the pharmacy's ostensibly sterile vials, some of which were shipped to clinics without sterility testing, according to an inspection by the Massachusetts Department of Public Health. Floor mats near sterile drug-mixing areas were "visibly soiled with assorted debris," and a leak from a nearby boiler created an "environment susceptible to contaminant growth," according to the report.
The pharmacy has recalled all of its products and shut down operations.
Unlike drug manufacturers, which are regulated by the U.S. Food and Drug Administration, compounding pharmacies are overseen by state boards of pharmacy. The deadly meningitis outbreak has prompted calls for stricter regulation.
"The [New England Compounding Center] has a history of problems, some of which were documented in an FDA warning letter in 2006," the House subcommittee on Oversight and Investigation said in a statement announcing a Nov. 14 congressional hearing on the outbreak. "We want to know what went wrong at this facility, the views and actions of its regulators, and that steps can be taken to ensure such an outbreak never happens again."
FDA commissioner Dr. Margaret Hamburg is set to testify at the hearing.
Meningitis affects the membranous lining of the brain and spinal cord. Early symptoms of fungal meningitis -- including headache, fever, dizziness, nausea, sensitivity to light, stiff neck, weakness or numbness, slurred speech and pain, and redness or swelling at the injection site -- can take more than a month to appear.
The longest duration from the time of injection to the onset of symptoms in the current outbreak is 42 days, according to the CDC. The tainted steroids were recalled 39 days ago.
Fungal meningitis is diagnosed through a spinal tap, which draws cerebrospinal fluid from the spine that can be inspected for signs of the disease. Once detected, it can be treated with high doses of intravenous antifungal medications.
Unlike bacterial meningitis, fungal meningitis is not transmitted from person to person and only people who received the steroid injections are thought to be at risk.