Cases have nearly doubled in a deadly outbreak of fungal meningitis linked to tainted cosmetic surgeries in Matamoros, Mexico, the Centers for Disease Control and Prevention reported this week.

To date, there have been 34 cases identified in the outbreak: 18 suspected, 10 probable, and six confirmed. That's up from just 18 cases—nine suspected, nine probable, zero confirmed—late last month. The death toll from the cases has risen from two to four since then. The CDC is investigating 172 other people who are thought to have been exposed.

Health officials in the US and Mexico suspect that the infections stem from cosmetic procedures, including liposuction, that involved epidural anesthesia, a component of which may have been contaminated with the fungus Fusarium solani. The US cases are linked to procedures performed from January 1, 2023, to May 13 at two specific clinics in Matamoros, which sits across the border from Brownsville, Texas. Both clinics—River Side Surgical Center and Clinica K-3—have since been shuttered by Mexican health officials, who have also closed other area clinics amid the investigation.

Even with all the links so far, health officials are still struggling to nail down the source and those infected. The outbreak highlights both the dangers of cut-rate surgical procedures in facilities with little oversight and the lethal vagaries of what happens when fungi make their way into people's spinal cords and brains.

The source

Despite knowing the clinics, the procedures, and the drugs used in the cases, health officials are skeptical that they'll ever be able to confirm the source of the fungus. "It's not like you can go to the clinic and find the meds on the shelf and go test them," Dr. Tom Chiller, Mycotic Diseases Branch chief for the CDC, told Ars.

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In Mexico, anesthesiologists procure their own drugs and bring them into clinics, Chiller explained. To track down a contamination problem, "you got to find the anesthesiologist and find out where they bought [the drugs] from and more than likely, they're gone, because they've used them already," he said.

Chiller emphasized that the Mexican authorities—who have jurisdiction over the outbreak investigation, not the CDC—are doing their best and being open with the CDC. But he highlighted the significant challenges they face. The city of Matamoros is in the state of Tamaulipas, which is heavily influenced by cartels.

So far, Chiller said, the authorities there are skeptical that the source of the infection is the anesthetic medicine itself. It's "a pretty common anesthetic that's widely distributed across Mexico," he said. If it were contaminated during manufacturing, "they think they would be seeing signals other places." But the anesthetic drug is mixed with morphine before being injected into people's spinal columns, he noted. And the morphine may be the source. It's in short supply and hard to get in Mexico right now, he said. One hypothesis Mexican officials have is that the morphine may be coming from black or gray markets while being sold as legitimate.

In addition to bad morphine, another hypothesis is bad practices. "If the anesthesiologists are bringing their medicines in and they're accessing these vials multiple times, or they're just doing poor practices, they could contaminate a vial, and then that vial could be reused multiple times," he noted.

That was thought to be the cause of a fungal meningitis outbreak last year in Durango, Mexico. That outbreak mostly affected women having epidurals during cesarean section births in private hospitals. The cases were also Fusarium solani infections. The outbreak resulted in 80 cases and 39 deaths as of the latest outbreak update on June 6. Whether or not the outbreak in Durango is linked to the one stemming from Matamoros is an open question, Chiller said.