In up to 10% of cases, usually involving elderly or immunocompromised people, the fungus can enter the bloodstream and cause destructive illnesses. “The fungus can affect any organ or system, including the bones, joints, lungs, throat, brain. It can cause a kind of meningitis,” Freitas says. “If this happens, it is very, very severe, and the death rate is high.”

Brazil has seen an explosion of the fungus in recent years. “Cats are spreading this disease among themselves, but also to humans at an alarmingly high rate,” Smith says.

From 1998 to 2001, fewer than 180 people, concentrated around Rio de Janeiro, fell sick with the disease. In recent years, thousands of people across the country are infected annually, Smith says.

The disease is now even infecting people in remote villages in the Amazon, Freitas says, and has emerged in other countries too. Cases of Sporothrix brasiliensis have been steadily sprouting up across South America in countries including Argentina, Paraguay, and Chile. Uruguay experienced its first outbreak of the disease in 2025, and Peru reported its first case this year, Smith says. “It’s just a matter of time before it ends up in the United States” and beyond, he says.