Deadly fungal meningitis cases nearly double as CDC rushes to find exposed

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. 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.

The fungus

The other complexity of the outbreak is the fungus itself. Fusarium solani is a common environmental fungus found in soil, organic matter, and water. It can lurk in healthcare facilities and in sink faucet aerators. But it doesn't often cause infections; meningitis cases from F. solani are rare. They're sometimes seen in immunocompromised people, who may inhale the spores and develop an infection that slowly spreads to their spinal cord or brain. If the source of the infections in Matamoros was poor practices from an anesthesiologist, the contaminated medicine may have been grossly contaminated, containing multiple microorganisms. And for whatever reason, F. solani is the one environmental contaminant that's able to establish an infection, Chiller speculated. Most fungal pathogens prefer temperatures cooler than normal human body temperature, which creates a hurdle for many fungal infections in warm-blooded mammals. In fact, some scientists speculate that the demise of nonavian dinosaurs could have been hastened by a bloom of fungal pathogens at the end of the Cretaceous Period, favoring the rise of mammals. Amid ongoing climate change, fungal adaption to rising temperatures is a real concern, and it's a fear explored in science fiction. For now, F. solani is still a rare cause of infection, and even when it's injected directly into people's spines, the infection is elusive and mercurial—which can make it difficult to treat. For those potentially exposed, the recommended testing involves lumbar punctures to check spinal fluid, even if there are no symptoms. But "the fungus itself isn't hanging out in that fluid; it's getting into the tissues," Chiller said. "It's wedging itself into the meninges and into the brain." PCR tests, which probe for genetic snippets of the pathogen, usually don't pick it up.  And as it digs into tissue, it can lay low for months. "Fungi can be very indolent for a while, so it can sort of smolder, but then it can boom, then it can move rapidly," Chiller said. He recalled seeing fungal meningitis cases that manifested a year after an exposure. In the current outbreak, officials have seen cases with symptoms occurring as long as 102 days after the cosmetic surgery, Chiller said. That means treatment and case designation have been aggressive. For people who may have been exposed, the strategy is to treat at any hint of inflammation in the spinal fluid. "If you [went to] one of those clinics and you had epidural anesthesia, and you have five white cells—which is a very low number in your CSF [cerebrospinal fluid]—then we're going to call you a probable case. We're not going to mess [around]," he said. Health officials in Mexico handed the CDC and state health officials a list of patients they think were treated at the two clinics. Chillers said investigators are tracking those people down and talking with them about who else might have gone with them for procedures. US-based investigators have also been able to reach recruiters who gather Americans to go down to clinics in Mexico for cosmetic procedures, gaining information about potential exposures that way. "I think we've got a pretty complete list now," Chiller said. For those not affected by the current outbreak, Chiller advises people to "just know where you're going to get healthcare. I mean really know what that institution does, how its practices are," he said, adding that things like this can also happen in the US. The people who have died in the outbreak so far are young, otherwise healthy women, who had procedures that were elective, he noted. "And it's just tragic."