GoKawiilWASHINGTON — Microbiologists are used to looking at gross pictures and hearing scary statistics. So when a moderator of a session on emerging fungal infections at the ASM Microbe meeting uttered the words “somewhat terrifying,” it caught my attention. He was referring to a sexually transmitted skin infection that is becoming increasingly drug resistant. But what came next was even more horrifying to me.
Medical mycologist Shawn Lockhart stepped to the podium and began describing a fungal disease that attacks cats, causing oozing skin ulcers and worse, and spreads to humans. It isn’t yet in the United States … that officials know of. But the disease, caused by Sporothrix brasiliensis, has sickened and killed thousands of cats and infected more than 11,000 people and at least 200 dogs in South America since its emergence in Brazil in the 1990s.
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“What we have right now is this ginormous ongoing outbreak of Sporothrix brasiliensis in Brazil,” Lockhart, a senior adviser at the U.S. Centers for Disease Control and Prevention, said June 7. The fungus has spread beyond Brazil to cats, dogs and people in Paraguay, Chile, Argentina and most recently Uruguay.
“It’s just a matter of time” until the fungus reaches the United States, Lockhart told me after the session. “We’re waiting.”
Here’s why he’s so concerned.
He worries about the fungus spreading in big cities such as Istanbul and Bangkok where “cats are just everywhere,” and in rural areas in the United States where large populations of farm cats roam freely. “All it takes is one traveler [from South America] bringing their cat with them, and it can emerge anywhere,” Lockhart said during the presentation. “This is something we are very, very worried about.”
Sporothrix brasiliensis infections cause oozing skin ulcers in cats (an infected feline shown). Without treatment the infection can spread to the lungs and throughout the body, even killing the cat. H. Montenegro et al/BMC Veterinary Research, 2014
Infected cats develop skin ulcers and nodules and swollen lymph glands. If the infection isn’t treated with antifungal drugs, it can become a respiratory disease and spread throughout the body. “Without treatment, it’s 100 percent fatal, and even with treatment, it has a pretty high fatality rate,” Lockhart said. In people, it causes painful skin ulcers. If untreated, the disease can also be severe and may kill those who have weakened immune systems.
Risk of contagion is complicated because symptoms don’t always show up right away. Two members of a family who moved from Brazil to the United Kingdom developed the disease three years after the move, health authorities reported in 2022. One of the family’s two cats turns out to have been infected with Sporothrix brasiliensis. A vet who treated the cat was also infected.
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