Jessica J. Talbot

Computed tomographic features of feline sino-nasal and sino-orbital aspergillosis

Feline upper respiratory tract aspergillosis (URTA) occurs as two distinct anatomical forms, namely, sino-nasal aspergillosis (SNA) and sino-orbital aspergillosis (SOA). An emerging pathogen, Aspergillus felis, is frequently involved. The pathogenesis of URTA, in particular the relationship between the infecting isolate and outcome, is poorly understood. In this study, computed tomography was used to investigate the route of fungal infection and extension in 16 cases (SNA n = 7, SOA n = 9) where the infecting isolate had been identified by molecular testing. All cases had nasal cavity involvement except for one cat with SNA that had unilateral frontal sinus changes. There was a strong association between the infecting species and anatomic form (P = 0.005). A. fumigatus infections remained within the sino-nasal cavity, while cryptic species infections were associated with orbital and paranasal soft-tissue involvement and with orbital lysis. Cryptic species were further associated with a mass in the nasal cavity, paranasal sinuses or nasopharynx. Orbital masses showed heterogeneous contrast enhancement, with central coalescing hypoattenuating foci and peripheral rim enhancement. Severe, cavitated turbinate lysis, typical of canine SNA, was present only in cats with SNA. These findings support the hypothesis that the nasal cavity is the portal of entry for fungal spores in feline URTA and that the route of extension to involve the orbit is via direct naso-orbital communication from bone lysis. Additionally, a pathogenic role for A. wyomingensis and a sinolith in a cat with A. udagawae infection are reported for the first time.

Disseminated Scedosporium prolificans infection in a Labrador retriever with immune mediated haemolytic anaemia

Disseminated scedosporiosis is rare in dogs and is usually reported in German Shepherds with suspected heritable immunodeficiency. This is the first report of disseminated scedosporiosis due to Scedosporium prolificans in a Labrador retriever dog that was receiving immunosuppressive drug therapy for treatment of immune-mediated haemolytic anaemia. Despite cessation of immunosuppressive medications and an initial response to aggressive treatment with voriconazole and terbinafine the dog developed progressive disease with neurological signs necessitating euthanasia six months from diagnosis.

Azole resistance in canine and feline isolates of Aspergillus fumigatus.

Azole resistance is an emerging cause of treatment failure in humans with aspergillosis. The aim of this study was to determine if azole resistance is emerging in Aspergillus fumigatus isolates from canine and feline sino-nasal aspergillosis cases. Susceptibilities of isolates collected between 1988 and 2014 from 46 dogs and 4 cats to itraconazole, posaconazole, voriconazole, fluconazole and ketoconazole were assessed using Sensititre YeastOne microdilution trays; and to enilconazole and clotrimazole, following the CLSI M38-A2 standard. For the majority of isolates MICs were high for ketoconazole, low for enilconazole and clotrimazole, and less than established epidemiological cut-off values for itraconazole, posaconazole and voriconazole. One canine isolate from 1992 had multiazole resistance and on Cyp51A gene sequencing a mutation associated with azole resistance (F46Y) was detected. There is no evidence of emerging azole resistance among A. fumigatus isolates from dogs and cats and topical azole therapy should be effective against most isolates.

Detection of Aspergillus-specific antibodies by agar gel double immunodiffusion and IgG ELISA in feline upper respiratory tract aspergillosis

Feline upper respiratory tract aspergillosis (URTA) is an emerging infectious disease. The aims of this study were: (1) to assess the diagnostic value of detection of Aspergillus-specific antibodies using an agar gel double immunodiffusion (AGID) assay and an indirect immunoglobulin G (IgG) ELISA; and (2) to determine if an aspergillin derived from mycelia of Aspergillus fumigatus, Aspergillus niger and Aspergillus flavus can be used to detect serum antibodies against cryptic Aspergillus spp. in Aspergillus section Fumigati. Sera from cats with URTA (group 1: n = 21) and two control groups (group 2: cats with other upper respiratory tract diseases, n = 25; group 3: healthy cats and cats with non-respiratory, non-fungal illness, n = 84) were tested. Isolates from cats with URTA comprised A. fumigatus (n = 5), A. flavus (n = 1) and four cryptic species: Aspergillus felis (n = 12), Aspergillus thermomutatus (Neosartorya pseudofischeri, n = 1), Aspergillus lentulus (n = 1) and Aspergillus udagawae (n = 1). Brachycephalic purebred cats were significantly more likely to develop URTA than other breeds (P = 0.013). The sensitivity (Se) of the AGID was 43% and the specificity (Sp) was 100%. At a cut-off value of 6 ELISA units/mL, the Se of the IgG ELISA was 95.2% and the Sp was 92% and 92.9% for groups 2 and 3 cats, respectively. Aspergillus-specific antibodies against all four cryptic species were detected in one or both assays. Assay Se was not associated with species identity. Detection of Aspergillus-specific antibodies by IgG ELISA has high Se and Sp for diagnosis of feline URTA.

Discovery of Aspergillus frankstonensis sp. nov. during environmental sampling for animal and human fungal pathogens

Invasive fungal infections (IFI) due to species in Aspergillus section Fumigati (ASF), including the Aspergillus viridinutans species complex (AVSC), are increasingly reported in humans and cats. The risk of exposure to these medically important fungi in Australia is unknown. Air and soil was sampled from the domiciles of pet cats diagnosed with these IFI and from a nature reserve in Frankston, Victoria, where Aspergillus viridinutans sensu stricto was discovered in 1954. Of 104 ASF species isolated, 61% were A. fumigatus sensu stricto, 9% were AVSC (A. felis-clade and A. frankstonensis sp. nov.) and 30% were other species (30%). Seven pathogenic ASF species known to cause disease in humans and animals (A. felis-clade, A. fischeri, A. thermomutatus, A. lentulus, A. laciniosus A. fumisynnematus, A. hiratsukae) comprised 25% of isolates overall. AVSC species were only isolated from Frankston soil where they were abundant, suggesting a particular ecological niche. Phylogenetic, morphological and metabolomic analyses of these isolates identified a new species, A. frankstonensis that is phylogenetically distinct from other AVSC species, heterothallic and produces a unique array of extrolites, including the UV spectrum characterized compounds DOLD, RAIMO and CALBO. Shared morphological and physiological characteristics with other AVSC species include slow sporulation, optimal growth at 37°C, no growth at 50°C, and viriditoxin production. Overall, the risk of environmental exposure to pathogenic species in ASF in Australia appears to be high, but there was no evidence of direct environmental exposure to AVSC species in areas where humans and cats cohabitate.

Sinonasal aspergillosis in a British Shorthair cat in the UK

Case summary A 13-year-old, castrated male, British Shorthair cat presented for investigation of chronic, intermittent, bilateral epistaxis and stertor. CT revealed severe asymmetric bilateral intranasal involvement with extensive turbinate lysis, increased soft tissue attenuation and lysis of the sphenopalatine bone and cribriform plate. On retroflexed pharyngoscopy, a plaque-like mass occluded the choanae. Rostral rhinoscopic examination revealed extensive loss of nasal turbinates, necrotic tissue and mucosal fungal plaques in the left nasal cavity. The right nasal cavity was less severely affected. The nasal cavities were debrided extensively of plaques and necrotic tissue. Aspergillus fumigatus was isolated on fungal culture, and species identity was confirmed using comparative sequence analysis of the partial β-tubulin gene. On histopathology of nasal biopsies, there was ulcerative lymphoplasmacytic and neutrophilic rhinitis, and fungal hyphae were identified on nasal mucosa, consistent with a non-invasive mycosis. The cat was treated with oral itraconazole after endoscopic debridement, but signs relapsed 4.5 months from diagnosis. Residual left nasal fungal plaques were again debrided endoscopically and oral posaconazole was administered for 6 months. Fourteen months from diagnosis, the cat remains clinically well with mild intermittent left nasal discharge secondary to atrophic rhinitis. Relevance and novel information This is the first case of rhinoscopically confirmed sinonasal aspergillosis to be diagnosed in a cat in the UK. Endoscopic confirmation of resolution of infection is useful in cases where mild nasal discharge persists after treatment.

Identification of pathogenic Aspergillus isolates from captive birds in Australia

Abstract Aspergillosis is a major cause of severe respiratory disease in birds. The prevalence of cryptic section Fumigati and other non‐Aspergillus fumigatus species as causative agents is unknown. Species identity was determined in 30 isolates from affected birds from zoos, pet birds and poultry by PCR of the ITS1‐5.8S‐ITS2 and partial &bgr;‐tubulin genes. The most prevalent isolate was A. fumigatus sens. str. in 87% (26) cases. Other Aspergillus species were identified in 13% (4) cases, including A. restrictus (1), A. flavus sens. str. (2), and A. nidulans‐clade (1). This is the first report of A. restrictus causing avian disease.

Gastrointestinal granuloma due to Candida albicans in an immunocompetent cat.

Abstract A 3.5 year-old cat was admitted to the University of Melbourne Veterinary Teaching Hospital for chronic vomiting. Abdominal ultrasonography revealed a focal, circumferential thickening of the wall of the duodenum extending from the pylorus aborally for 3cm, and an enlarged gastric lymph node. Cytology of fine-needle aspirates of the intestinal mass and lymph node revealed an eosinophilic inflammatory infiltrate and numerous extracellular septate acute angle branching fungal-type hyphae. Occasional hyphae had globose terminal ends, as well as round to oval blastospores and germ tubes. Candida albicans was cultured from a surgical biopsy of the duodenal mass. No underlying host immunodeficiencies were identified. Passage of an abrasive intestinal foreign body was suspected to have caused intestinal mucosal damage resulting in focal intestinal candidiasis. The cat was treated with a short course of oral itraconazole and all clinical signs resolved.

Type III hemifacial microsomia in a kitten

The case described herein presented with craniofacial malformations resembling hemifacial microsomia (HFM), a congenital disorder described in humans. To our knowledge, this is the first reported case of HFM in a domestic cat.

Long term survival of a dog with disseminated Aspergillus deflectus infection without definitive treatment

Canine disseminated fungal infection by Aspergillus species carries a guarded to grave prognosis as they often rapidly progress and are refractory to treatment with many euthanased soon after diagnosis. This case report describes a 2.5 year old female spayed German Shepherd Dog diagnosed with disseminated Aspergillus deflectus infection for which definitive treatment was declined by the owners. With only palliative management the dog survived three years and two months before succumbing to chronic kidney disease.