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Published on: September 6, 2011
A Cautionary Tale of Exophiala spinifera Infection in Two Cats: Case Reports and Literature Review
Maryann D Makosiej1, Stephanie Anderson2, Mandy A Womble3
1Department of Comparative Pathobiology, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts, USA, tufts.edu.
Abstract:
This case series reports two independent cases of Exophiala spinifera infection in adult male neutered domestic cats, both referred following misdiagnosis. To date, only six cases associated with this organism have been reported in domestic cats, excluding those described herein. These also represent the first documented cases of E. spinifera infection in cats in the United States. In both cases, a definitive etiologic diagnosis could not be made by cytology, histology, or fungal culture. Moreover, histologic features did not allow for clear classification of the lesions as phaeohyphomycosis or chromoblastomycosis. Ultimately, accurate identification of the fungal pathogen was achieved through molecular diagnostic testing, rather than conventional mycologic or microscopic methods. These cases underscore the importance of molecular diagnostics and inter-institutional collaboration in the accurate identification of dematiaceous fungi, such as E. spinifera, particularly given their variable clinical and pathological presentations.
Insights
Two domestic cats in the US were diagnosed with Exophiala spinifera infection after misdiagnosis. Molecular diagnostics were crucial for identifying this rare fungal pathogen, highlighting its importance in veterinary medicine.
Area of Science:
- Veterinary Mycology
- Infectious Diseases in Animals
- Fungal Pathogenesis
Background:
- Exophiala spinifera is a dematiaceous fungus rarely reported in domestic cats.
- Previous cases are limited, with few documented instances globally.
- Accurate diagnosis of fungal infections in felines can be challenging.
Purpose of the Study:
- To report two novel cases of Exophiala spinifera infection in domestic cats in the United States.
- To highlight the diagnostic challenges associated with this fungal pathogen.
- To emphasize the utility of molecular diagnostics for identifying dematiaceous fungi.
Main Methods:
- Case series reporting two independent feline infections.
- Evaluation of diagnostic methods including cytology, histology, and fungal culture.
- Application of molecular diagnostic testing for definitive pathogen identification.
Main Results:
- Two adult male neutered domestic cats presented with misdiagnosed infections.
- Conventional diagnostic methods (cytology, histology, culture) were inconclusive.
- Molecular diagnostics successfully identified Exophiala spinifera as the causative agent.
- Histologic features did not clearly differentiate between phaeohyphomycosis and chromoblastomycosis.
Conclusions:
- Molecular diagnostics are essential for accurate identification of Exophiala spinifera in cats.
- Variable clinical and pathological presentations necessitate advanced diagnostic approaches.
- Inter-institutional collaboration aids in identifying rare fungal pathogens.
