Canine rhinitis caused by an uncommonly-diagnosed fungus, Scedosporium apiospermum

Abstract

A Golden Retriever cross was presented with a four week history of violent sneezing and licking at the nasal planum. Nasal mycosis was diagnosed and Aspergillus sp. presumed the causative agent, until culture, PCR and DNA sequencing showed that Scedosporium apiospermum, an uncommonly diagnosed, yet emerging, fungal pathogen, was the agent responsible. Debridement of the fungal plaques and systemic itraconazole therapy resulted in complete resolution of clinical disease. We discuss the current literature on S. apiospermum, review its clinical significance and question the validity of its ‘complex’ taxonomy.

Disseminated Scedosporium apiospermum infection in a Maremmano-Abruzzese sheepdog

“…It is important to remark that in our case, the dog did not show any anamnestic, clinical, radiographic, ultrasound or hematological evidence of concurrent disease, and no specific predisposition of Maremmano-Abruzzese sheep dogs has been described so far. Therefore, as reported in humans, Scedosporium apiospermum could also act as a primary pathogen in young and apparently healthy dogs [2,3].…”

“…The diagnosis of Scedosporium apiospermum infection is often time-consuming, challenging and complicated by the numerous clinical and morphologic similarities to other fungal granulomatous diseases, such as aspergillosis and fusariomycosis [3,9]. Notably, the systemic form described herein was initially diagnosed as poisoning by clinicians; this interim diagnosis was deduced only because of the acute progression of the clinical signs and the presence of sudden neurological signs, as no poison bait was found by the owner, and was finally excluded by toxicological examinations.…”

“…There has been a steady increase in the infection rates of this species in both immunocompromised and immunocompetent hosts, which acts as an opportunistic or primary pathogen. In addition, the high degree of intrinsic antifungal resistance makes these infections difficult to manage [2][3][4].…”

“…Scedosporiosis in dogs has often associated with localized infections (i.e. nasal infection, eumycetoma, or keratomycosis) [1,3,[6][7][8][9][10], but in rare cases, it has been associated with disseminated infections [11].…”

“…and Fusarium spp. infections, making the diagnosis challenging [3,12]. Sporulation in culture is required for fungal identification, but even confusion with other morphologically similar species is possible, and in most cases, the etiological agent is identified by molecular methods [12,13].…”