The fungus behind an outbreak of dangerous nervous system infections in U.S. residents who underwent cosmetic procedures in Matamoros, Mexico, has been identified.
The culprit is Fusarium solani, a fungal species found in the environment whose genus has been tied to eye infections and fungal meningitis in the past, the Centers for Disease Control and Prevention (CDC) announced Thursday (June 1).
Investigations into the outbreak suggest that many more people may have been exposed to the disease-causing fungus than have been initially identified. The CDC is therefore advising anyone who had a medical or surgical procedure done under epidural anesthesia at the affected clinics — River Side Surgical Center and Clinica K-3 — between Jan. 1 and May 13, 2023 to be tested for possible meningitis at their nearest emergency room.
The outbreak has affected people in multiple U.S. states, three of whom have died — two with probable cases of the disease and one with a confirmed case, the CDC reported. In total, 547 people in the U.S., Mexico and Canada had procedures done this year at the affected clinics in Matamoros and therefore may have been exposed to F. solani, according to the World Health Organization.
Last month, CDC officials reported that five people in Texas had been hospitalized, and one of whom had died, due to suspected fungal meningitis, in which a fungus triggers inflammation in the protective membranes covering the brain and spinal cord. All of the patients had recently undergone cosmetic procedures under epidural anesthesia in Matamoros, Mexico.
Investigators learned that these patients had been treated at two clinics in Matamoros, called River Side Surgical Center and Clinica K-3. Both clinics were closed on May 13, the CDC website states.
Now, more possible meningitis cases have been flagged and three U.S. labs and the Mexican national laboratory have confirmed that they detected F. solani in the cerebrospinal fluid (CSF) — fluid surrounding the brain and spinal cord — of patients receiving follow-up care in Mexico or the U.S. All the cases have been tied to the two aforementioned clinics.
In 2006, fungi in the genus Fusarium were linked to an outbreak of an eye infection called fungal keratitis that was associated with a type of contact lens solution. More recently, Fusarium caused a health-care-associated outbreak of meningitis in Durango, Mexico, according to the June 1 CDC alert. More than 4 in 10 patients who developed meningitis in that outbreak died.
Sometimes, patients with fungal meningitis have few or no symptoms at first, which can make the condition tricky to treat.
"Early detection and treatment of fungal meningitis" — which involves high-dose antifungal medications — "is critical to improving patient outcomes, particularly because patients whose symptoms are initially mild or absent may quickly worsen without treatment," the CDC alert states.
Because early treatment is so important, the CDC went on to identify additional patients who'd received epidural anesthesia at the two clinics and are therefore at risk of fungal meningitis. In total, they've found 212 residents in 25 U.S. states and jurisdictions who match that description. "Among these patients, 14 suspected, 11 probable, and two confirmed U.S. cases have been diagnosed," the alert says.
Diagnosing fungal meningitis requires an MRI of the brain and a lumbar puncture, or spinal tap, to test the patient's CSF for the fungus and for signs of immune cell activity that would point to infection. Fungal meningitis is not contagious and infected people cannot spread the fungus to others.
The CDC and state and local health departments are currently working to contact all U.S. residents who may have been exposed, as the Mexican Ministry of Health has provided a list of people who were treated at the associated clinics. Officials are simultaneously working to identify people who may have been missed on that initial list.
Patients who had procedures done at the River Side Surgical Center or Clinica K-3 this year should be tested for meningitis regardless of whether they're showing symptoms of the disease, which can include headache, stiff neck, nausea, vomiting, light sensitivity and altered mental status, the CDC advises.
For more information about what to do if you are at risk, visit the CDC website.
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Nicoletta Lanese is the health channel editor at Live Science and was previously a news editor and staff writer at the site. She holds a graduate certificate in science communication from UC Santa Cruz and degrees in neuroscience and dance from the University of Florida. Her work has appeared in The Scientist, Science News, the Mercury News, Mongabay and Stanford Medicine Magazine, among other outlets. Based in NYC, she also remains heavily involved in dance and performs in local choreographers' work.