At least seven people have died and 91 have fallen ill in the United States in a worsening meningitis outbreak tied to a contaminated drug, updated figures showed Sunday.
Cases have been identified in nine states, with the hardest-hit being Tennessee, where 32 people have been diagnosed with the fungal infection and three have died, the Centers for Disease Control and Prevention said.
Michigan is the second-most infected state, with 20 cases and two deaths, so far. Cases have also been noted in a vast region spanning Florida, Maryland and Minnesota.
In its latest bulletin, the CDC urged doctors to "actively contact" any patients who received doses of the potentially contaminated steroid injection—typically used to treat back pain—as far back as May 21.
The public health agency said symptoms of fungal meningitis, which has a very long incubation period, include fever, new or worsening headaches, neck stiffness, sensitivity to light, new weakness or numbness, increasing pain, redness or swelling of the injection site.
The rare infection—which inflames the protective membranes covering the brain and spinal cord—often goes undetected until it is too late because its flu-like symptoms can be mild at first. But meningitis is not contagious in this form.
Early detection and treatment—requiring a hospital stay to administer intravenous anti-fungal medications—can prevent permanent damage.
An initial investigation found that Tennessee clinicians who administered the contaminated drug "had no way of knowing" there was anything wrong with it and found "no lapses" in their standards, according to the state's health commissioner John Dreyzehner.
"The evidence indicates this is a product issue," he told reporters on Friday.
A multi-state investigation is underway to determine the cause of the outbreak, but the Food and Drug Administration said it had detected a fungal contaminant in a sealed vial of the drug produced by the New England Compounding Center in Massachusetts.
While further testing is required to confirm it was the source of the outbreak, the company has issued a voluntary recall of all of its products and shut down all operations.
Officials posted a list of the 75 health care facilities that received lots of the contaminated drug at: www.cdc.gov/hai/outbreaks/meningitis-facilities-map.html
Explore further: Rare US fungal meningitis outbreak grows; 5 dead (Update)