Sensitivity of cytopathological examination in the diagnosis of feline sporotrichosis

Abstract

Sporotrichosis is caused by Sporothrix schenckii. The cat is the animal species most affected by this mycosis and plays an important role in the zoonotic transmission of this disease. The definitive diagnosis is made by isolation of the fungus in culture; however, cytopathological examination is frequently used in cats. Medical records from cats treated at Instituto de Pesquisa Clínica Evandro Chagas/Fiocruz, Rio de Janeiro, Brazil, between 2004 and 2006 were reviewed. Criteria for inclusion were a diagnosis by isolation of S schenckii in culture and cytopathological examination of the same lesion as that used for collection of the culture material. Eight hundred and six cats were included in the study. Yeast-like structures suggestive of S schenckii were observed in 636 cases. The sensitivity of the method was 78.9%. Its practicality, low cost and sensitivity validate cytopathology as a safe technique for the presumptive diagnosis of sporotrichosis in cats.

Fig 1

Photomicrograph of impression smear from ulcerated skin lesion in cat with sporotrichosis showing numerous cigar-shaped to oval or round budding yeast-like organisms fulfilled with blue cytoplasm with a single round pink nucleus surrounded by a non-staining cell wall within macrophages and extracellularly (Quick Panoptic stain, 100×).

Fig 2

Feline sporotrichosis: ulcer on the bridge of the nose.