Funguses commonly cause superficial skin diseases in cats but are responsible for severe and often fatal systemic infections. The most common and least pathogenic fungus which affects cats is Microsporum canis, causing Ringworm.
Other fungi are cultured included Aspergillus spp, Penicillium spp, Cladosporium spp, Scopulariopsis spp and lipophilic yeasts of the genus Malassezia spp. Paronychia is usually caused by Malassezia spp yeast.
Cats infected with FIV or FeLV may have a greater diversity of cutaneous and mucosal mycoflora than noninfected cats. However, infected cats may be no more likely than noninfected cats to expose humans to zoonotic fungi such as Cryptococcus spp and Microsporum spp. A greater diversity of fungal genera was isolated from retrovirus-infected cats, and Malassezia spp were more commonly recovered from these cats, compared with noninfected cats.
Antifungal therapy must address the causative organism, the organ(s) involved and the susceptibility of the fungus to the particular drug chosen.
| Skin | Systemic |
| Microsporum canis (skin) | Cryptococcus spp |
| Microsporum gypseum (skin) | Coccidioides spp |
| Trichophyton mentagrophytes (skin) | Cytauxzoon felis |
| Trichophyton rubrum (nasal cavity) | Aspergillosis (Neosartorya spp, Aspergillus flavus, A. fumigatus) (naso-orbital abscesses) |
| Malassezia spp (otitis externa / otitis media / paronychia) | Histoplasma spp (Histoplasma capsulatum) |
| Trichosporon spp (nasal cavity) | Phaeohyphomycosis – opportunistic dematiaceous fungi |
| Prototheca spp (algae in nasal cavity) | Penicillium spp (naso-orbital abscesses) |
| Aphanoascus fulvescens (commensal) | Sporotrichosis spp |
| Chrysosporium parvum (keratinolytic) | Rhinosporidium spp (cause tumour-like growths resembling nasopharyngeal polyps) |
| Candida spp | Blastomyces dermatitidis |
| Microsphaeropsis spp | Scopulariopsis spp |
| Colletotrichum spp | Mucor amphibiorum |
| Pythium spp – naso-orbital abscesses | |
| Encephalitozoon spp, Microsporidium spp |
References
1. August, JR (2006) Consultations in Feline Internal Medicine, Vol 5. Elsevier Saunders