Pathogenic Fungus Found in Wild Animals Transmitted by Domestic Cat Scratches

A pathogenic fungus known to spread from domestic cats to humans, Sporothrix brasiliensis, has been identified in wild animal populations, according to research reported by Phys.org on June 11, 2026. This discovery indicates the fungus has established a reservoir in wildlife, which may increase the risk of zoonotic transmission and complicate efforts to control the spread of the infection in urban and rural areas.

The fungus causes sporotrichosis, a disease characterized by skin lesions and, in severe cases, systemic infection. While the condition was historically associated with soil and plant matter, the S. brasiliensis strain is highly virulent and spreads efficiently between mammals through scratches and bites.

For years, public health officials focused on domestic cats as the primary vectors for this specific strain. The new findings reported by Phys.org show that the pathogen is now present in wild fauna, suggesting the fungus can persist in the environment independently of domestic pet populations.

How does the fungus spread to humans?

Sporotrichosis enters the body through traumatic inoculation. This happens when the fungus is pushed into the skin through a break, such as a scratch, bite, or puncture wound. According to the reporting, the S. brasiliensis strain is particularly aggressive in its transmission from cats to humans.

In humans, the infection typically begins as a small, painless bump, often on the hand or arm. Over time, this nodule may ulcerate. In many cases, the fungus spreads along the lymphatic vessels, creating a characteristic chain of nodules that move up the limb from the original site of infection.

The discovery of the fungus in wild animals adds a new layer to this transmission cycle. It means humans could potentially be exposed to the pathogen through contact with wild animals, not just household pets.

Why is S. brasiliensis different from other Sporothrix species?

Not all sporotrichosis is the same. The Sporothrix schenckii complex contains several species, and they differ significantly in how they infect hosts. A comparison of these strains reveals a shift in how the disease behaves.

Traditional sporotrichosis, often called rose gardener’s disease, is caused by S. schenckii. This species is typically found in sphagnum moss, hay, and rose bushes. It is generally an environmental infection where the human is the accidental host.

In contrast, S. brasiliensis is highly zoonotic. It doesn’t just wait in the soil; it actively circulates among animal populations. According to the research, this strain is more virulent than its cousins, leading to more severe lesions and a higher rate of transmission between animals and people.

What happens when a fungus enters the wild?

The presence of S. brasiliensis in wild animals creates what scientists call a sylvatic cycle. This means the fungus can move between wild species without needing a domestic bridge.

This development makes eradication nearly impossible. When a disease is limited to domestic pets, veterinarians and health officials can use targeted vaccination, treatment, and confinement to stop an outbreak. Once the fungus enters the wild population, those controls no longer work.

Wild animals can act as a permanent source of infection. They can carry the fungus into new territories, potentially introducing the pathogen to areas where it was previously unknown. This increases the geographic footprint of the disease.

What are the public health implications?

The expansion of the fungal reservoir requires a shift in how health agencies monitor zoonotic threats. Monitoring can no longer be limited to veterinary clinics and domestic pet shelters.

Public health risks increase for people who live near wild habitats or work in forestry and wildlife management. These individuals may be exposed to the fungus through scratches from wild cats or other infected mammals without realizing the risk exists.

Medical professionals must also remain vigilant about the origin of the infection. If a patient presents with sporotrichosis but has no contact with domestic cats or rose bushes, the possibility of exposure to wildlife is now a verified clinical consideration.

Treatment for sporotrichosis typically involves antifungal medications, such as itraconazole. However, the virulence of the S. brasiliensis strain often requires longer treatment courses and more intensive monitoring to ensure the infection is completely cleared from the system.