The Emergence of Cat-Transmitted Sporotrichosis Driven by Sporothrix brasiliensis in Piauí, Brazil

In Brazil, the emergence of feline sporotrichosis, a neglected subcutaneous mycosis primarily transmitted by cats and caused by the fungus Sporothrix brasiliensis, has been monitored via molecular tools. This approach underscores the geographic expansion of this disease and highlights the critical role of molecular surveillance in understanding its epidemiology and guiding public health interventions. We investigated three domestic cats (Felis catus) with multiple skin lesions in Picos, Piauí, Brazil. The cats were examined, and samples were collected for laboratory diagnosis, including cytological evaluation, fungal culture, and molecular characterisation. The molecular analysis involved a one-tube multiplex probe-based qPCR assay for the diagnosis of Sporothrix species, mating-type determination, and amplified fragment length polymorphism (AFLP, EcoRI-GA/MseI-AG) to assess genetic similarity and potential origin. All three cats were diagnosed with sporotrichosis caused by the hypervirulent S. brasiliensis. A probable case of zoonotic transmission has been reported in a 12-year-old girl who developed Parinaud oculoglandular syndrome after contact with one of the cats with sporotrichosis. The molecular analysis revealed that the cat isolates were MAT 1-2 and formed a single cluster according to the AFLP analysis, suggesting direct transmission (cat-cat) and a potential founder effect. The isolates were also closely related to strains from Pernambuco and Southeast Brazil, indicating a possible introduction from these regions. Identifying S. brasiliensis in Piauí emphasises the need for increased awareness and control measures to prevent further spread. The predominance of the MAT1-2 idiomorphs and the genetic similarity among outbreak isolates suggest clonal expansion, which could have significant implications for public health and veterinary practices. Considering its zoonotic potential and environmental adaptability, a One Health approach is crucial for managing and controlling the spread of cat-transmitted sporotrichosis.