Super Fungus in Brazil Is Evolving Faster in Cities and Spreading Through Cats

A dangerous fungal outbreak in Brazil is evolving rapidly—and cats are helping it spread. According to a new study published in Mycology and highlighted by Tsinghua University Press, the fungus Sporothrix brasiliensis is now showing unusually high genetic diversity, especially in polluted urban areas. Researchers believe city Pollution may be speeding up its evolution.

This fungus causes sporotrichosis, a skin and lymphatic disease that can occasionally affect internal organs. What makes this outbreak different is how easily it spreads from cats to humans. Infected cats can transmit the fungus through scratches, bites, or even contact with bodily fluids. Since the late 1990s, the outbreak has grown from Rio de Janeiro into a widespread epidemic across Brazil and even into neighboring countries.

Dr. Anderson Messias Rodrigues of the Federal University of São Paulo led the research, supported by the São Paulo Research Foundation (FAPESP). His team studied over 100 fungal samples and found 79 genetic variants of the fungus. They discovered signs of rapid adaptation, possibly linked to urban pollutants like benzene and toluene. These chemicals may act as stressors, selecting for fungal strains that are more resistant and more aggressive.

The good news? The study identified new molecular targets that could improve diagnosis, vaccines, and treatments. But the rapid spread of S. brasiliensis, combined with its resistance to antifungal medications, makes this a serious public health concern—especially for communities with high stray cat populations and limited access to veterinary care.

This research adds to the growing body of evidence that environmental pollution doesn’t just harm air and water—it may also be helping harmful pathogens evolve. Read the full study here.

If you care about animals, public health, or clean urban environments, consider supporting local spay/neuter programs, avoiding products that pollute, and choosing cruelty-free, plant-based lifestyles. It all adds up.

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