Intra-Abdominal Dermatophytic Pseudomycetoma in a Persian Cat

Invasive Fungal Infections and Oomycoses in Cats: 1. Diagnostic approach

CLINICAL RELEVANCE

In contrast to superficial fungal infections, such as dermatophytosis, invasive fungal infections (IFIs) are characterised by penetration of tissues by fungal elements. Disease can spread locally within a region or can disseminate haematogenously or via the lymphatics. The environment is the most common reservoir of infection. Since fungal spores are airborne, indoor cats are also susceptible to IFIs. Some environmental fungi are ubiquitous and present globally, while others are endemic or hyperendemic within specific geographic regions. Zoonotic pathogens include Microsporum canis, Sporothrix schenckii and Sporothrix brasiliensis.

AIM

In the first of a two-part article series, the approach to the investigation of feline IFIs and oomycoses is reviewed. As well as tips for diagnosis, and information on the ecological niche and distribution of fungal pathogens, the review covers clinical presentation of the most common IFIs, including cryptococcosis, histoplasmosis, blastomycosis, coccidioidomycosis, sporotrichosis, phaeohyphomycosis, aspergillosis and dermatophytic pseudomycetoma, as well as the oomycoses pythiosis, lagenidiosis and paralagenidiosis. In Part 2, the spectrum of activity, mechanisms of action, pharmacokinetic and pharmacodynamic properties and adverse effects of antifungal drugs are reviewed, and the treatment and prognosis for specific IFIs and oomycoses are discussed.

EVIDENCE BASE

The review draws on published evidence and the authors' combined expertise in feline medicine, mycology, dermatology, clinical pathology and anatomical pathology.

Eumycetoma and disseminated phaeohyphomycosis in a Sumatran tiger

A 16-y-old female Sumatran tiger (Panthera tigris sumatrae) was evaluated for hyporexia. Examination revealed chronic kidney disease and a large subcutaneous axillary mass with draining tracts that contained numerous small black grains. Histologic examination revealed the presence of intralesional fungal hyphae. Persistent hyporexia and pyogranulomatous disease, as well as progressive cachexia and azotemia occurred despite treatment, and euthanasia was performed. Disseminated phaeohyphomycosis was diagnosed on postmortem examination, additionally affecting various lymph nodes, the nasal cavity, mesenteric adipose tissue, abdominal aorta, pericardium, and kidney. Fungal culture from a deep-tissue sample isolated a pure growth of Curvularia sp., a dematiaceous opportunistic fungus able to cause eumycetomas and/or phaeohyphomycosis. Phaeohyphomycosis is a rare but emerging condition, not previously reported as disseminated disease in an exotic carnivore, to our knowledge. Aggressive systemic antifungal treatment was unsuccessful, likely complicated by diagnostic challenges and concurrent renal disease. The presence of a swelling with abundant grains exiting draining tracts should direct clinicians to the diagnosis of a mycetoma, warranting early and aggressive treatment.

Diagnosis and treatment of dermatophytosis in dogs and cats.: Clinical Consensus Guidelines of the World Association for Veterinary Dermatology

BACKGROUND

Dermatophytosis is a superficial fungal skin disease of cats and dogs. The most common pathogens of small animals belong to the genera Microsporum and Trichophyton. It is an important skin disease because it is contagious, infectious and can be transmitted to people.

OBJECTIVES

The objective of this document is to review the existing literature and provide consensus recommendations for veterinary clinicians and lay people on the diagnosis and treatment of dermatophytosis in cats and dogs.

METHODS

The authors served as a Guideline Panel (GP) and reviewed the literature available prior to September 2016. The GP prepared a detailed literature review and made recommendations on selected topics. The World Association of Veterinary Dermatology (WAVD) provided guidance and oversight for this process. A draft of the document was presented at the 8th World Congress of Veterinary Dermatology (May 2016) and was then made available via the World Wide Web to the member organizations of the WAVD for a period of three months. Comments were solicited and posted to the GP electronically. Responses were incorporated by the GP into the final document.

CONCLUSIONS

No one diagnostic test was identified as the gold standard. Successful treatment requires concurrent use of systemic oral antifungals and topical disinfection of the hair coat. Wood's lamp and direct examinations have good positive and negative predictability, systemic antifungal drugs have a wide margin of safety and physical cleaning is most important for decontamination of the exposed environments. Finally, serious complications of animal-human transmission are exceedingly rare.

Invasive Microsporum canis causing rhinitis and stomatitis in a cat

Microsporum canis is a pathogenic fungus that typically causes dermatophytosis in cats. This report describes a cat with a Microsporum canis infection causing invasive fungal rhinitis that extended through the hard palate, resulting in adjacent stomatitis. Treatment with itraconazole and terbinafine resolved the infection.

Successful treatment of an intra-pelvic fungal pseudomycetoma causing constipation and hypercalcaemia in a Persian cat

This case report describes the successful treatment of a Persian cat diagnosed with intra-abdominal fungal pseudomycetoma causing hypercalcaemia and constipation due to an extra-luminal mechanical obstruction of the colon. Treatment included surgical excision, supportive care and itraconazole for 6 months.

Dermatophytosis in cats: ABCD guidelines on prevention and management

OVERVIEW

Dermatophytosis, usually caused by Microsporum canis, is the most common fungal infection in cats worldwide, and one of the most important infectious skin diseases in this species. Many adult cats are asymptomatic carriers. Severe clinical signs are seen mostly in kittens or immunosuppressed adults. Poor hygiene is a predisposing factor, and the disease may be endemic in shelters or catteries. Humans may be easily infected and develop a similar skin disease.

INFECTION

Infectious arthrospores produced by dermatophytes may survive in the environment for about a year. They are transmitted through contact with sick cats or healthy carriers, but also on dust particles, brushes, clothes and other fomites.

DISEASE SIGNS

Circular alopecia, desquamation and sometimes an erythematous margin around central healing ('ringworm') are typical. In many cats this is a self-limiting disease with hair loss and scaling only. In immunosuppressed animals, the outcome may be a multifocal or generalised skin disease.

DIAGNOSIS

Wood's lamp examination and microscopic detection of arthrospores on hairs are simple methods to confirm M canis infection, but their sensitivity is relatively low. The gold standard for detection is culture on Sabouraud agar of hairs and scales collected from new lesions.

DISEASE MANAGEMENT

In shelters and catteries eradication is difficult. Essential is a combination of systemic and topical treatments, maintained for several weeks. For systemic therapy itraconazole is the drug of choice, terbinafine an alternative. Recommended topical treatment is repeated body rinse with an enilconazole solution or miconazole with or without chlorhexidine. In catteries/shelters medication must be accompanied by intensive decontamination of the environment.

VACCINATION

Few efficacy studies on anti-M canis vaccines (prophylactic or therapeutic) for cats have been published, and a safe and efficient vaccine is not available.

Intra-abdominal actinomycetoma in a cat

A 5-year-old, female Ragdoll cat was diagnosed with an intra-abdominal mycetoma involving the ileocaecal region. Diagnosis was obtained via histopathological examination following surgical resection of the mass and an ileocolic anastomosis. The initial surgery was complicated by lymphangiectasia, chylous abdominal effusion and mild bacterial leakage from the anastomosis site. A second, exploratory laparotomy was performed to augment the anastomosis with serosal patching and omentalisation and to investigate a cystic structure observed on follow-up abdominal ultrasound. Initial amoxycillin clavulanate (Clavulox; Pfizer Animal Health) therapy was ineffective, but clindamycin (Antirobe; Pfizer Animal Health) proved successful in resolving the infection. Abdominal actinomycetoma in the cat may be an under-diagnosed condition due to its close resemblance to neoplastic disease. Standard diagnostic and therapeutic regimens are commonly ineffective in Actinomyces species infections. Surgical resection along with adjunctive, long-term, selective antimicrobial therapy is effective and prognosis is good for localised lesions.

Mycologic disorders of the skin

Cutaneous tissue can become infected when fungal organisms contaminate or colonize the epidermal surface or hair follicles. The skin can be a portal of entry for fungal infection when the epithelial barrier is breached or it can be a site for disseminated, systemic fungal disease. The two most common cutaneous fungal infections in small animals are dermatophytosis and Malassezia dermatitis. Dermatophytosis is a superficial cutaneous infection with one or more of the fungal species in the keratinophilic genera Microsporum, Trichophyton, or Epidermophyton. Malassezia pachydermatis is a nonlipid dependent fungal species that is a normal commensal inhabitant of the skin and external ear canal in dogs and cats. Malassezia pachydermatis is the most common cause of Malassezia dermatitis. The diagnosis and treatment of these cutaneous fungal infections will be discussed.

Pulmonary hyalohyphomycosis caused byFusariumspp in a Kemp's ridley sea turtle (Lepidochelys kempi): an immunohistochemical study

AIM

To describe the microscopic and immunohistochemical findings in a case of pulmonary hyalohyphomycosis in a Kemp's ridley sea turtle (Lepidochelys kempi).

METHODS

Samples of lung, liver and kidney from a stranded, dead Kemp's ridley sea turtle were routinely processed for histopathological studies. Two monoclonal antibodies that reacted specifically with antigens of Aspergillus spp and the Mucorales (Zygomycetes) group, and a panel of polyclonal antibodies raised against Aspergillus fumigatus, Candida albicans, Geotrichum candidum, Fusarium solani, and Scedosporium apiospermum were used for immunohistochemical or immunofluorescence staining.

RESULTS

Histologically, a severe multifocal granulomatous pneumonia associated with fungal infection was diagnosed. All hyphae were identified as Fusarium spp because a strong and uniform reactivity was obtained only with a heterologously-absorbed polyclonal antibody raised against somatic antigens of Fusarium solani.

CONCLUSIONS

Fusarium spp should be included in the differential diagnosis of mycotic pneumonia in Kemp's ridley sea turtles.

CLINICAL RELEVANCE

This is the first report of a pulmonary mycotic infection in a sea turtle diagnosed using immunohistochemistry. Wildlife rehabilitators and pathologists should be aware of the availability of immunohistochemical techniques for identifying fungi in sea turtles.

Intestinal candidiasis in a loggerhead sea turtle (Caretta caretta): an immunohistochemical study

Post mortem examination of a juvenile loggerhead sea turtle (Caretta caretta) stranded in the Canary Islands revealed a fishing-line in the small intestine. Histologically, severe necrotic enteritis, multiple haemorrhages, and marked oedema of the intestinal submucosa were observed. Yeast cells and fungal hyphae were seen in the lamina propria of the intestinal mucosa and in the connective tissue of the submucosa. Because fungal cultures were not taken at the time of necropsy, an immunohistochemical study was performed in order to identify the fungus involved. Specific monoclonal and heterologously absorbed polyclonal antibodies served as the primary reagents for identification of aspergillosis, candidiasis, fusariosis, geotricosis, scedosporiosis, and zygomycosis, using an indirect immunofluorescence staining technique. The fungal elements were strongly stained only by a polyclonal antibody against Candida albicans and a monoclonal antibody against C. albicans. There are no known previous reports of Candida sp. causing skin disease or systemic mycotic infection in sea turtles.