Researchers have recently identified Sporothrix brasiliensis, a fungus linked to skin infections, in Uruguay. The discovery was triggered by infections in people, pets, and local wildlife associated with cats.
This single finding suggests that a more challenging fungal threat is now establishing itself in South America.
Cats and Sporothrix brasiliensis
In the Maldonado and Rocha departments along Uruguay’s southeastern coast, a notice from the Institute of Hygiene confirmed the presence of this fungus in cats and other animals, as well as in humans.
Elisa Cabeza from the Universidad de la Republica (Udelar) connected these cases directly to Sporothrix brasiliensis.
Her research team found additional sick cats in both departments that had no link to an initial adopted kitten, indicating that the fungus might be spreading locally.
This broadens the concern, shifting from a household issue to a puzzling question about how efficiently cats can transmit this fungus.
Why cats amplify Sporothrix brasiliensis
Infected cats often have open sores that host a considerable amount of the fungus, particularly around their noses, faces, mouths, and paws.
If a human’s skin is pierced by claws, teeth, or fluids from these wounds, the fungus can enter and start to grow.
A recent review mentioned that cats can transfer a significant quantity of yeast-like cells through scratches, bites, or contact with their discharge.
Street cats, which tend to roam freely and can get into fights, facilitate ongoing transmission of the fungus across neighborhoods without anyone realizing.
A body-heat switch
Outside of a host, this fungus exists as branching threads, but it transforms into a yeast form when exposed to body heat.
This change is critical as the smaller yeast form more readily colonizes damaged skin and proliferates within living tissue.
This adaptation, known as dimorphism, allows for a temperature-driven shift between two forms, supporting the fungus’s survival in various environments.
This versatility is part of why the organism can endure in the environment and continue infecting mammals it encounters.
Sporothrix brasiliensis symptoms
Sporotrichosis, the skin infection in humans, usually begins with a red bump that eventually ruptures after a scratch.
As it spreads through drainage channels beneath the skin, additional bumps may appear in a line.
Cats often exhibit persistent wounds, crusted areas, and hair loss, particularly on their faces and heads, and may sometimes have red, watery eyes.
Though rare, the infection can occasionally extend beyond the skin and drainage channels, which underscores the importance of swiftly addressing any initial lesions.
How doctors confirm the cat fungus
To confirm the infection, doctors typically examine tissues from a sore microscopically or culture the fungus.
This confirmation is crucial since these sores can be misdiagnosed as bacterial infections, leading to ineffective antibiotic treatments.
“The infection is treatable,” Dr. Cabeza pointed out. Common antifungal medications are effective, but treatment can extend over weeks or months, and managing sick cats poses additional challenges.
Who faces trouble
Young children, the elderly, and individuals with weakened immune systems are at the highest risk of severe outcomes if the fungus infiltrates their bodies.
Rare instances can involve severe reactions affecting joints, lungs, or the protective lining of the brain, complicating treatment options.
Udelar researchers have cautioned that this fungus can severely impact children under two and older adults, emphasizing the need for prompt diagnosis.
Following the cat fungus trail
In Argentina, a report from 2024 connected two human cases to shared contact with sick cats.
The World Health Organization has stated that this situation has led to significant and ongoing outbreaks in Brazil and nearby South American countries.
They noted that over the past decade, affected regions have reported more than 11,000 human cases.
The movement of cats, whether legal or otherwise, is increasingly significant; even one infected animal can spread a resilient fungal strain across borders.
Uruguay’s old pattern
Historically, sporotrichosis in Uruguay was mainly linked to contact with soil, plants, or armadillos, rather than cats.
According to a Udelar review, there were 157 diagnosed cases over 38 years, with 128 stemming from armadillo scratches during hunting activities.
This previous pattern explains why the emergence of the new cat-associated transmission route is causing significant concern among healthcare professionals.
It indicates that Uruguay is not simply experiencing a rise in the same illness but is facing a new transmission method.
Control gets harder
Controlling the situation is challenging due to street cats, many of which go undiagnosed, untreated, or are left outdoors while their wounds are still open.
A study discovered the fungus in droplets expelled by infected cats when they sneeze, broadening the concerns beyond mere scratches and bites.
To effectively manage this epidemic, public health initiatives require coordination among animal care, medical services, and community reporting.
Without this collaborative approach, each untreated cat could prolong the outbreak long after the first human infections resolve.
What this changes
The identification of this fungus in Uruguay indicates that a pathogen once mainly associated with Brazilian outbreaks is now becoming more established across southern South America.
Timely diagnosis, appropriate treatment for both pets and humans, and enhanced control of feral cats will determine if these warnings remain localized or spread further.
The study has been published in Medical Mycology Case Reports.
