Felis ISSN 2398-2950


Contributor(s): Vanessa Barrs, Rhea Morgan


  • Two forms of aspergillosis are reported most commonly in the cat (upper respiratory tract aspergillosis (URTA), disseminated invasive aspergillosis (DIA)).
  • URTA is an emerging mycosis of cats worldwide, and can be divided into two anatomic forms: sino-nasal aspergillosis (SNA) where disease is restricted to the sino-nasal cavity, and sino-orbital aspergillosis (SOA), the more common and aggressive form, with additional orbital involvement.
  • CauseAspergillus spp (most commonly Aspergillus felis, A. fumigatus and A. niger  in URTA. The Aspergillus spp that cause DIA are largely unknown because most cases have been diagnosed at post-mortem from histologic findings only. Infection by spores (condia), usually inhaled.
  • Signs: SNA - sneezing, nasal discharge, epistaxis, stertor; SOA - exophthalmos (usually unilateral), 3rd eyelid prolapse, exposure keratitis, conjunctival hyperemia, oral mass or ulcer in ipsilateral pterygopalatine fossa, paranasal soft-tissue swelling, nasal signs may not be present at time of presentation for a retrobulbar mass; disseminated disease - vomiting, diarrhea, lethargy, cachexia, renal failure, and respiratory disease.
  • Diagnosis: URTA - combination of serology (ELISA to detect Aspergillosis-specific IgG), diagnostic imaging findings, visualization of fungal plaques on endoscopy, cytological or histological detection of hyphae in tissue biopsies, fungal culture. PCR and sequencing is required for correct idenitifcation to species level in most cases; most frequently made post-mortem with disseminated disease.
Print off the owner factsheet Feline fungal disease (aspergillosis) Feline fungal disease (aspergillosis) to give to your client.



  • SNA: usually Aspergillus fumigatus  Aspergillus fumigatus  or A. niger, occasionally other species in Aspergillosis fumigatus complex, eg A. lentulus.
  • SOA: usually Aspergillus felisA. udagawae, or other species in A. fumigatus complex.
  • Disseminated disease: largely unknown. A. fumigatus was cultured from two cats with mycotic pneumonia, and A. nidulans from one cat with mycotic cystitis.

Predisposing factors



URT aspergillosis

  • Inhalation of fungal spores    →   local infection of the nasal cavity and paranasal sinuses.
  • Infection can be non-invasive, similar to canine SNA, where fungal colonies maintain close contact with nasal mucosa but fungal hyphae do not penetrate into cells. Such infections remain restricted to the sino-nasal cavity. SOA is always invasive, where fungal hyphae are found within tissues.

Disseminated aspergillosis

  • Inhalation of fungal spores   →    association with immunocompromised state   →    pulmonary infection   →    hematogenous dissemination to eye, kidneys, intestines, liver, spleen, lymph nodes, brain.


  • Since the saprophytic fungi that cause aspergillosis are disseminated widely in nature, both URTA and DIA occur in cats worldwide    →   inhalation of fungal spores.
  • Disease usually occurs in young to middle-aged cats (median 6.5 y) but can occur in cats of any age.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Barrs V R, Talbot J J (2014) Feline aspergillosis. Vet Clin North Am Sm Anim Pract 44 (1), 51-73 PubMed.
  • Barrs V R, Beatty J A, Dhand N K et al (2014) Computed tomographic features of feline sino-nasal and sino-orbital aspergillosis. Vet J 201 (2), 215-22 PubMed.
  • Barrs V R, van Doorn T M, Houbraken J et al (2013) Apergillus felis sp. nov., an emerging agent of invasvie aspergillosis in humans, cats and dogs. PLoS One (6), e64871 PubMed.
  • Hartmann K, Lloret A, Pennisi M G et al (2013) Aspergillosis in Cats: ABCD guidelines on preventions and management. J Feline Med Surg 15 (7), 605-610 PubMed.
  • Barrs V R, Halliday C, Martin P et al (2012) Sinonasal and sino-orbital aspergillosis in 23 cats: aetiology, clinicopathologic features and treatment outcomes. Vet J 191 (1), 58-64 PubMed.

Other sources of information

  • Sykes J E (2014) Aspergillosis. In: Sykes J E Canine and Feline Infectious diseases. Elsevier, p 633.