Two cases of dermatophytic pseudomycetoma in the dog: an immunohistochemical study

Two cases of canine dermatophytic pseudomycetoma resulting in subcutaneous nodules resembling those previously reported in Persian cats are described. Culture performed from one nodule yielded dark yellow colonies consistent with Microsporum canis. Immunohistochemistry, using rabbit anti-M. canis, demonstrated specific binding to fungal elements in paraffin sections. The specificity of the antiserum was further tested by an agar gel immunodiffusion assay using a soluble extract from a feline isolate of M. canis as antigen. The antiserum did not cross-react with an Aspergillus fumigatus antigen. These are the first two reported cases of canine dermatophytic pseudomycetoma and immunohistochemical staining supported the diagnosis.     

"Carry-on" dermal baggage: a nodule from a dog. Pyogranulomatous inflammation with intralesional fungal agents

A 2-year-old intact female Australian Cattle Dog presented with a 1-cm diameter nonexudative dermal nodule on the medial aspect of the right thigh. Fine-needle aspiration revealed pyogranulomatous inflammation and many ovoid, 2-4 microm diameter, thin-capsulated, basophilic bodies that appeared to be fungal spores or yeast. Results of CBC, serum chemistry panel, lymph node palpation, and radiographs were unremarkable. Excisional biopsy and histopathology revealed pyogranulomatous folliculitis, furunculosis, and perifolliculitis. Rare fungal hyphae and spore forms were intimately associated with, and occasionally within, hair shafts. A morphologic diagnosis of dermatophytosis was made and Microsporum canis infection was confirmed by fungal culture. M canis is a common infectious agent found within the follicles and superficial keratin layers of canine skin. The kerion-type clinical presentation observed in the dog of this case is uncommonly observed with M canis. Additionally, the cytologic finding of multiple arthroconidia without hyphae is unusual. In the absence of hyphae, M canis arthroconidia may be confused with other fungal yeast bodies; therefore close scrutiny of a cytologic sample for arthroconidia associated with keratin, hair fragments, or hyphal structures is recommended.     

Dysgonic strain of Microsporum canis pseudomycetoma in a Domestic Long-hair cat

A 4-year-old Domestic Long-hair cat was presented with two large non-painful, ulcerated and suppurative lesions over the flanks. Histopathology and cytology were consistent with fungal pyogranulomatous inflammation. Culture of tissue yielded a dysgonic strain of Microsporum canis. The cat was treated successfully by staged en bloc resections of the lesions, followed by oral ketoconazole, then oral terbinafine. This is the first reported case of dermatophytic pseudomycetoma in a Domestic Long-hair cat in Australia.     

Pseudomycetoma caused by Microsporum canis in a Persian cat: lack of response to oral terbinafine.

An eight-year-old neutered female Persian cat with a four-year history of relapsing skin disease, characterised by ulcerated nodules with a yellow granular discharge, was examined. A diagnosis of granulomatous dermatitis and panniculitis (pseudomycetoma) caused by Microsporum canis was made on the basis of history, clinical signs, histopathological examination of skin biopsy specimens and culture of macerated tissue. Because previous therapy, comprising repeated surgical excision and the administration of griseofulvin and itraconazole, had not been successful, terbinafine was administered for an eight-month period. However, lesions progressed despite this treatment and the cat was euthanased.     

Canine nodular dermatophytosis (kerion): 23 cases

Dermatophytosis is a common zoonotic disease, and one of its clinical presentations in the dog is nodular dermatophytosis (kerion). Because the infection is located within the dermis, routine diagnostic tests such as a Wood's lamp examination, microscopic examination of hair shafts for fungal elements and fungal culture can yield negative results. In such cases, histopathological examination with routine and special stains (periodic acid-Schiff, Gomori methenamine silver) is required to confirm the diagnosis. Nodular dermatophytosis in 23 dogs of different breed, age and sex with single or multiple nodules is described. Twelve dogs had a single nodule, and 11 dogs showed multiple lesions. Wood's lamp examination was negative in all cases. Microscopic examination of plucked hairs showed arthrospores in 8 of 23 cases. Skin scrapings in mineral oil looking for arthrospores and/or hyphae were positive in 12 cases. Impression smears of exudates were diagnostic in 21 of 23 cases (91%), showing arthrospores within fragments of hair shafts or free among neutrophils and macrophages (pyogranulomatous inflammation). Histopathology was performed in two cases. Fungal culture was positive for Microsporum canis in 16 dogs and for Microsporum gypseum in one dog. In six cases, the causative agent was not identified by fungal culture. All dogs were treated with systemic antifungal therapy and in eight cases with concurrent antibiotic therapy. Nodular dermatophytosis resolved in all dogs with the prescribed treatments within 4 to 8 weeks. Transmission to people or other pets in the home was not found.     

Imaging diagnosis--sublumbar pseudomycetoma in a Persian cat.

A 6-year-old Persian cat was examined for constipation, anorexia, and vomiting that was subsequently found to be due to a pseudomycetoma originating from the descending colon and sublumbar region, and causing mechanical obstruction of the colon and rectum. Multiple discrete hyperechoic foci likely representing fungal grains within the lesion gave the mass a coarse echotexture on ultrasound and was supportive of the diagnosis and computed tomography allowed delineation the extent of the mass. A pseudomycetoma is a granulomatous/pyogranulomatous reaction that surrounds dermatophytic fungal hyphae. Definitive diagnosis of a dermatophytic pseudomycetoma requires identification of the etiologic agent by cultivation or immunohistochemical staining. A pseudomycetoma should be included in the differential diagnosis for an abdominal mass in a Persian cat, especially is accompanied by the sonographic findings noted above.     

IMAGING DIAGNOSIS—SUBLUMBAR PSEUDOMYCETOMA IN A PERSIAN CAT

A 6-year-old Persian cat was examined for constipation, anorexia, and vomiting that was subsequently found to be due to a pseudomycetoma originating from the descending colon and sublumbar region, and causing mechanical obstruction of the colon and rectum. Multiple discrete hyperechoic foci likely representing fungal grains within the lesion gave the mass a coarse echotexture on ultrasound and was supportive of the diagnosis and computed tomography allowed delineation the extent of the mass. A pseudomycetoma is a granulomatous/pyogranulomatous reaction that surrounds dermatophytic fungal hyphae. Definitive diagnosis of a dermatophytic pseudomycetoma requires identification of the etiologic agent by cultivation or immunohistochemical staining. A pseudomycetoma should be included in the differential diagnosis for an abdominal mass in a Persian cat, especially is accompanied by the sonographic findings noted above.     

Nannizziopsis guarroi infection in 2 Inland Bearded Dragons (Pogona vitticeps): clinical,cytologic, histologic,and ultrastructural aspects

Chrysosporium‐related infections have been increasingly reported in reptiles over the last 2 decades. In this report, we describe clinical, cytologic, histopathologic, and ultrastructural aspects of Chrysosporium‐related infection in 2 Inland Bearded Dragons (Pogona vitticeps). Case 1 was presented for an enlarging raised lesion over the left eye and multiple additional masses over the dorsum. Case 2 was submitted to necropsy by the referring veterinarian for suspected yellow fungus disease. Impression smears of the nodules in case 1 revealed granulomatous to pyogranulomatous inflammation and many septate, variably long, 4–10 μm wide, often undulated hyphae, and very rare conidia. Postmortem impression smears of the superficial lesions of case 2 contained large numbers of solitary conidia and arthroconidia and low numbers of hyphae with similar morphology to case 1. Histopathology of the 2 cases revealed severe, multifocal, chronic, ulcerative, nodular pyogranulomatous dermatitis, with myriad intralesional septate hyphae, and arthroconidia. Fungal culture and molecular sequencing in both cases indicated infection with Nannizziopsis guarroi.     

Dermatophyte granulomas caused by Trichophyton mentagrophytes in a dog

Multiple, dermal and subcutaneous nodules developed in a young female Manchester Terrier dog that had a chronic history of superficial dermatophytosis. Skin biopsy specimens of the nodules revealed granulomatous inflammation in the deep dermis and subcutis with branching fungal organisms. Cultures of multiple biopsy specimens from the nodules all yielded Trichophyton mentagrophytes. The lesions in this dog were similar to granulomatous dermatophytosis, a skin disease that has been reported in Persian cats and one Yorkshire Terrier dog.     

An evaluation of the clinical, cytological, infectious and histopathological features of feline acne

Clinical, cytological, microbial and histopathological features of feline acne were investigated in 22 cats referred or volunteered to a veterinary dermatology practice in the south-west region of the USA. For comparison, same parameters were evaluated in five unaffected pet cats. Additionally, all cats were evaluated by immunohistochemistry (IHC) for the presence of feline calicivirus (FCV) and feline herpes virus (FHV-1) in acne lesions. The age of onset of acne in affected cats ranged from 6 months to 14 years with a median of 4 years. The most common dermatologic lesions were comedones (73%), alopecia (68%), crusts (55%), papules (45%) and erythema (41%). Pruritus was reported in 35% of the affected cats. Cytological evidence of Malassezia pachydermatitis was present on 4/22 (18%) of affected cats. Microsporum canis was isolated from a single affected cat. Bacteria were isolated from 10 of the 22 (45%) affected cats; coagulase-positive staphylococci and alpha-haemolytic streptococci were most common. Histopathological features included lymphoplasmacytic periductal inflammation (86%), sebaceous gland duct dilatation (73%), follicular keratosis with plugging and dilatation (59%), epitrichial gland occlusion and dilatation (32%), folliculitis (27%), pyogranulomatous sebaceous adenitis (23%) and furunculosis (23%). In one affected cat from a household with five cats, simultaneously having feline acne, FCV antigen was detected in the biopsy of the chin by IHC. Chin tissue samples from all other affected cats, as well as the five healthy cats, were negative by IHC for FCV and FHV-1 antigens.     

Dermatophytic pseudomycetomas in four cats

The aim of this retrospective study was to describe the clinical characteristics and treatment of four cats with dermatophytic pseudomycetoma. Four Persian cats, one female and three males, with age ranging from 1.4 to 5 years, were diagnosed with dermatophytic pseudomycetoma by histological examination and fungal culture. Wood's lamp examination revealed positive fluorescence of hairs in all four cats. Characteristic skin lesions consisted of multifocal, raised, firm and nodular to dome-shaped lesions varying in size from 1 to 8 cm in diameter, with ulcers or fistulas in some of the lesions. One cat was treated and cured with 3 months of oral itraconazole; lesions completely regressed, and at the time of writing there has been no recurrence. One cat was treated with surgical excision alone, and recurrence of lesions occurred after a disease-free interval of 15 months. Two cats were treated with surgical excision and systemic itraconazole therapy. Itraconazole therapy was started 1-2 months before surgery and continued for 3 months after surgery. Surgical margins were wide in both cats, and underlying adipose tissue and/or deeper fascia was removed. One cat relapsed, but had a disease-free interval of 18 months. The other cat has been disease free for 32 months. This case series suggests that aggressive, wide surgical excision and concurrent oral itraconazole are highly beneficial in treating dermatophytic pseudomycetoma in cats.     

Bilateral orbital and nasal aspergillosis in a cat

A 12-year-old, 4 kg, castrated male Persian cat was referred with a 2-month history of sneezing and bilateral mucopurulent nasal discharge. Rhinoscopically acquired nasal biopsies at this time revealed bilateral lymphoplasmacytic rhinitis. A tapering dose of oral prednisone caused the complete remission of the clinical signs, but 2 months after discontinuation of the therapy, the rhinitis recurred and the OD became exophthalmic. Computed tomography showed a soft tissue mass in both sides of the nasal cavity, both frontal sinuses, the right orbit, and to a lesser extent the left orbit. A fine needle aspirate of the right orbit revealed pyogranulomatous inflammation and Aspergillus spp. hyphae. Repeat nasal biopsy demonstrated multi-focal necrosis and a mixed inflammatory cell process which now included macrophages and scattered septate fungal hyphae. A few days later the cat became bilaterally blind and a contrast enhancing lesion involving the optic chiasm was found on magnetic resonance imaging. Despite a poor prognosis, therapy consisted of exenteration of the right orbit and trephination of both frontal sinuses before the planned initiation of medical antifungal therapy. Unfortunately, the cat died of cardiac arrest intraoperatively. Aspergillus fumigatus was cultured from both orbits at necropsy. Orbital aspergillosis has been rarely reported in cats and its relationship with lymphoplasmacytic rhinitis is unclear. In this patient lymphoplasmacytic rhinitis or previous antibiotic/corticosteroid therapy may have allowed secondary fungal invasion of the nasal mucosa and subsequently both orbits and the brain. Alternatively, Aspergillus infection may have preceded the lymphoplasmacytic rhinitis.     

Evaluation of topically applied enilconazole for the treatment of dermatophytosis in a Persian cattery

Many Persian catteries have long-standing dermatophyte infections and are particularly difficult to treat. Enilconazole is a topical antifungal agent that has demonstrated good efficacy in recent studies. Twenty-two Persian cats naturally infected with Microsporum canis in a breeding cattery were treated with topical 0.2% enilconazole and monitored for 180 days. The treatments were repeated every 3 days for a total of eight applications. All the cats improved clinically and became culture negative by day 28. By day 180, four cats had developed clinical dermatophytosis and all cats had positive fungal cultures. In this study, topical 0.2% enilconazole was generally well tolerated but may have caused hypersalivation, idiopathic muscle weakness and slightly elevated serum alanine aminotransferase (ALT) concentrations. This study suggests that enilconazole may be used safely with little risk to the young, aged and gravid animals.     

Isolation of Microsporum canis from the hair coat of pet dogs and cats belonging to owners diagnosed with M. canis tinea corporis

Microsporum canis has been frequently isolated from human cases of tinea capitis and tinea corporis. The infection may be acquired from infected animals with cutaneous lesions but also from asymptomatic carriers or from the environment. As asymptomatic M. canis carriers are considered to be a critical factor in the epidemiology of dermatophytosis in humans, this study investigated the relationship between the presence of dermatophytes on the hair coats of dogs and cats without cutaneous lesions and the occurrence of the disease in their respective owners. A total of 136 dogs and 248 cats were sampled from January 1999 to January 2005. Seventy-eight animals (22 dogs and 56 cats) belonged to individuals affected by tinea corporis caused by M. canis and 306 (114 dogs and 192 cats) to individuals without dermatophytosis. Age, sex, breed, habitat and season were recorded for each animal and examined as potential risk factors. Dermatophytes were isolated from 20.5% of the dogs and 28.2% of the cats. Microsporum canis was isolated from 36.4% of dogs cohabiting with owners diagnosed with tinea corporis but it was never isolated from dogs whose owners had no lesions. By contrast, M. canis was isolated from 53.6% of cats cohabiting with owners diagnosed with tinea corporis and from 14.6% of cats whose owners had no signs of the disease. These results clearly indicate that both cats and dogs should be considered as a major source of pathogenic dermatophytes for humans even when they do not present clinical signs of dermatophytosis.     

Subcutaneous Botryomycosis Due to Bibersteinia trehalosi in a Texas Longhorn Steer

A 3-year-old Texas Longhorn steer had a long history of progressive swelling of the soft tissues of the jaw and neck. At necropsy, multifocal to coalescing dermal and subcutaneous pyogranulomas were surrounded by fibrous tissue. Microscopically, the pyogranulomas contained aggregates of gram-negative coccobacilli surrounded by Splendore-Hoeppli material and were separated by bands of fibrovascular tissue (botryomycosis). Phylogenetic analysis of multilocus sequence-typing data revealed that the bacteria recovered in pure culture from swabs of submandibular tissue were most closely related to Bibersteinia [Pasteurella] trehalosi. The bacterial colonies were immunohistochemically reactive with a rabbit polyclonal anti-Pasteurella class C acid phosphatase antibody. Botryomycosis is a pyogranulomatous inflammation caused by a variety of nonbranching, nonfilamentous bacteria that elicit the formation of Splendore-Hoeppli material. This case of botryomycosis is unique for its association with Bibersteinia trehalosi.     

Miconazole/chlorhexidine shampoo as an adjunct to systemic therapy in controlling dermatophytosis in cats

A 2 per cent miconazole/2 per cent chlorhexidine shampoo was used in two groups of Persian cats infected with Microsporum canis. In the first group, the cats were treated with griseofulvin alone while, in the second, griseofulvin was used with the shampoo. The clinical signs of the cats were scored on a scale of 1 to 4 for seborrhoea, ease of epilation of hair and the extent of primary lesions, to try to give an overall impression of hair coat condition. The speed of resolution of the infection was assessed in terms of time to mycological cure. Samples were taken from the environment of both groups to assess the degree of environmental contamination at the end of treatment. No statistically significant difference was found between the two groups for time to mycological cure, although the lesion scores in the second group decreased significantly more quickly than those of the first group. Additionally, no dermatophytes were cultured from the environment in the second group at the end of the study.     

Environmental detection of Microsporum canis arthrospores in the households of infected cats and dogs

Microsporum canis is the dermatophyte most frequently recovered from canine and feline ringworm cases. The household environment can be contaminated both by symptomatic animals and through asymptomatic M canis carriage, resulting in a potential human health risk. The load of M canis arthrospores was determined in households harbouring infected pets, in order to evaluate the infectivity of the animals versus the environment. The environments inhabited by 30 symptomatic animals (21 cats and 9 dogs) infected by M canis were examined by sampling both surfaces and indoor air. The surfaces were examined by means of contact plates; the air sampling was performed with a Sas super-100 AIR SAMPLER (PBI, Italy). Environmental contamination was detected in all households with cats, while only four out of nine houses harbouring dogs were found positive. The frequence of isolation in each sampling, and the results in terms of colony forming units per plate in the different houses appeared to be quite homogeneous. Heavily infected environments harboured kittens only. Infected owners were observed in eight households, in all of which at least one infected cat was present. No history of human dermatophytosis in households harbouring dogs was found. On the basis of our results, infected cats appear to cause substantial environmental contamination, and provoke a substantial presence of viable airborne fungal elements. Dogs seem to be of lower importance in the spread of M CANIS: they contaminated surfaces, but they never contaminated the air. The results of this study confirm the potential leading role of the feline species in the environmental spread of M canis.     

健康猫被毛真菌菌相

定量检测了４０只临床健康猫的被毛真菌菌相,从３１只猫被毛上共分离出１１个属１７５株真菌,主要为交链孢霉属、芽枝孢霉属、犬小孢子菌和曲霉属等。皮肤病病原菌２个属３个种,包括犬小孢子菌、红色毛癣菌和石膏样毛癣菌。     

Cerebral phaeohyphomycosis in a dog

Cerebral phaeohyphomycosis was diagnosed in a 9-year-old spayed dog that had a series of epileptic convulsions a day before death. About 6 weeks before her death, she had been treated for severe demodectic mange. During this period, persistent leukopenia, lymphocytopenia, and thrombocytopenia were found by blood analyses. At necropsy, multiple large pyogranulomatous lesions were found in the cerebrum and meninges. Dematiaceous fungi with brown, branching, septate hyphae and budding yeasts were found within tissue cells and in the necrotic areas.