Feline Sporothrix spp. detection using cell blocks from brushings and fine‐needle aspirates: Performance and comparisons with culture and histopathology

Abstract

Background: Sporotrichosis is an emerging zoonotic mycosis that presents as a cutaneous lymphatic or disseminated disease, caused by fungi from the Sporothrix schenkii (S schenkii) clinical clade. Its importance is growing, primarily due to an outbreak that occurred in Brazil, affecting mainly cats and people.Objectives: In Brazil, an S schenkii diagnosis is often made using cultures, which allows genus identification and sufficient growth to perform molecular biology testing.Despite its advantages, fungal cultures are slow to develop and can delay public health measures, highlighting the importance of developing additional diagnostics techniques.Methods: Cell block cytology (CBLC) is an older method that regained importance after liquid-based cytology (LBC) was introduced, and it has been previously and successfully applied to veterinary diagnostics. We aimed to standardize and compare CBLC from cervical brush exfoliation of open wounds and fine-needle aspirates with culture and immunohistochemistry of skin biopsies for sporotrichosis in cats, as a novel method.Results: For this purpose, we selected 40 cats with skin lesions suspected of having sporotrichosis in Guarulhos city, São Paulo state, Brazil. We achieved 97.5% and 95% positivity using CBLC and culture, respectively, and 100% of feline skin biopsies were positive for Sporothrix spp on histopathology/immunohistochemistry. Conclusions:Cell block cytology is an efficient and rapid tool to diagnose sporotrichosis in cats, particularly during epidemics.

The threat of emerging and re-emerging pathogenic Sporothrix species

“…These structures measure 3-5 lm in diameter and 5-9 lm in length and are surrounded by a clear halo. Recently, Gonsales et al reported the high sensitivity (97.5%) of using cell block cytology (imprint) as an efficient and rapid tool for diagnosing sporotrichosis in cats, particularly during epidemics [214].…”

Direct PCR of lesions suggestive of sporotrichosis in felines

“…Cases of human sporotrichosis have been reported in 14 of 26 Brazilian states, and the southern and southeast regions of Brazil have the highest incidence of human cases . According to Pereira et al (2014), sporotrichosis is considered a neglected disease and was a serious public health problem in Rio de Janeiro; from 1997 to 2011, 4118 human cases diagnosed at the INI/FIOCRUZ (Instituto Nacional de Infectologia Evandro Chagas/ Fundação Oswaldo Cruz), the main reference center for the treatment of this ringworm in Brazil (Silva et al, 2013;Gremião et al, 2015). In the last 3 years the city of Guarulhos has registered more than 1500 cases in cats, resulting in a status of "compulsory notification".…”

“…The definitive diagnosis depends on the isolation of the etiologic agent in culture (Silva et al, 2015). Other methodologies proposed for diagnosis are cytopathology (Pereira et al, 2011), histopathology (Miranda et al, 2013), serology (Fernandes et al, 2011), species determination by polymerase chain reaction of fungal isolation (Rodrigues et al, 2015) and cell block cytology (Gonsales et al, 2019). The aim of this study was to detect and identify the species of Sporothrix in cats with lesions from an endemic area and for whom sporotrichosis was part of the differential diagnosis (city of Guarulhos) and compare this method with the reference methodology, fungal culture, considering the following variables: type of injury (dry or wet) and treatment status of the cat (being treated or not treated) at the time of sampling.…”

Development and evaluation of a multiplex qPCR assay for rapid diagnostics of emerging sporotrichosis

“…There were 9 (12.9%) dry lesions and 61 (87.1%) wet lesions regarding the type of injury. Sixteen (22.9%) cats had already started treatment with itraconazole at the time of sampling, one of the cats had 1 week of treatment, and the others had months of treatment (ranging from 2 to 9 months) (Gonsales et al., 2019; Gonsales et al, 2020). Lesion samples for culture and PCR were collected with sterile swabs.…”