Fungal flora on cutaneous and mucosal surfaces of cats infected with feline immunodeficiency virus or feline leukemia virus

Malassezia dermatitis in dogs and cats

Malassezia are members of the mycobiome of dogs and cats. In the presence of an underlying disease, these yeasts can proliferate, attach to the skin or mucosa to induce a secondary Malassezia dermatitis, otitis externa or paronychia. Since allergic dermatitis is one of the most common underlying causes, diagnostic investigation for allergy is often indicated. Cats may suffer from various other underlying problems, especially where Malassezia dermatitis is generalised. Malassezia dermatitis in dogs and cats is chronic, relapsing and pruritic. Direct cytology from dermatological lesions and the ear canal, showing "peanut-shaped" budding yeasts, facilitates a rapid and reliable diagnosis. Topical treatment includes antiseptic and antifungal azole-based products. Systemic treatment with oral antifungals is indicated only in severe or refractory disease. Identification and treatment of the underlying cause is essential for an optimal response. In this evidence-based narrative review, we discuss the clinical presentation of Malassezia dermatitis in dogs and cats, underlying comorbidities, and diagnostic considerations. Treatment is discussed in light of emerging evidence of antifungal resistance and the authors' clinical experience.

Antifungal susceptibility profile of yeasts isolated from the oral cavity of cats

BACKGROUND

Microorganisms living in the oral cavity play an important role in health and disease of the host. Cats are susceptible to oral infections, and it is documented that fungi in the oral cavity could impact these infections. Antifungal resistance has been increasing in recent years.

OBJECTIVES

This study was designed to identify yeast isolates from the oral cavity of healthy cats and to evaluate their antifungal susceptibility pattern.

METHODS

Oral specimens were collected from 60 cats and cultured at 37°C for 10 days. Yeasts were isolated and identified. Their antifungal susceptibility pattern was determined according to CLSI M44-A.

RESULTS

Three yeast genera were isolated, including Candida spp (55.5%), Rhodotorula spp (33.3%) and Hanseniaspora spp (11.1%). Antifungal susceptibility profiling showed that, apart from a dose-dependent effect of itraconazole, Hanseniaspora spp was susceptible to all seven drugs studied. The Candida species were susceptible to all drugs except ketoconazole (sensitivity 80%) and caspofungin (sensitivity 40%). In R. glutinis and R. minuta, 100% sensitivity was observed for amphotericin B, posaconazole, ketoconazole and voriconazole.

CONCLUSIONS

The results suggest that, in comparison with humans and other animals, cats have a different oral mycoflora in terms of species, number and diversity. However, these isolates have similar susceptibility patterns to those seen in isolates from other animals and humans. More studies should be done to further characterize the oral mycobiota of cats and its role in oral infections.

Diseases associated with feline leukemia virus and feline immunodeficiency virus infection: A retrospective study of 1470 necropsied cats (2010-2020)

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are retroviruses affecting cats worldwide, and the prevalence of infection varies considerably according to the geographic area. We retrospectively described FIV- and FeLV-associated diseases in a population of 1470 necropsied cats, of which 396 (26.9%) were infected with FeLV, 199 (13.5%) with FIV, and 134 (9.1%) with FeLV and FIV concomitantly. Cats infected with FeLV (OR 3.4) and co-infected with FeLV and FIV (OR 1.9) were more likely to have neoplasms. The diagnosis of lymphoma and leukemia was higher in cats infected with FeLV (OR 3.9 and 19.4, respectively) and coinfected with FeLV and FIV (OR 1.9 and 19.3, respectively). The odds of diagnosing bacterial diseases were higher in cats coinfected with FeLV and FIV (OR: 2.8), whereas the odds of viral diseases were higher in those infected with FeLV (OR: 2.8), with 2.2 times more diagnoses of feline infectious peritonitis. Neoplastic and infectious diseases in FIV-infected cats did not differ significantly from those in uninfected cats. According to our results, a high prevalence of retroviral infections was observed in southern Brazil, mainly in relation to FeLV. Infected cats were significantly younger than uninfected cats. The main causes of death associated with FeLV infection and FeLV and FIV coinfection were neoplastic and infectious diseases. In contrast, FIV infection was not associated with any specific condition.

Malassezia: Zoonotic Implications, Parallels and Differences in Colonization and Disease in Humans and Animals

Malassezia spp. are commensals of the skin, oral/sinonasal cavity, lower respiratory and gastrointestinal tract. Eighteen species have been recovered from humans, other mammals and birds. They can also be isolated from diverse environments, suggesting an evolutionary trajectory of adaption from an ecological niche in plants and soil to the mucocutaneous ecosystem of warm-blooded vertebrates. In humans, dogs and cats, Malassezia-associated dermatological conditions share some commonalities. Otomycosis is common in companion animals but is rare in humans. Systemic infections, which are increasingly reported in humans, have yet to be recognized in animals. Malassezia species have also been identified as pathogenetic contributors to some chronic human diseases. While Malassezia species are host-adapted, some species are zoophilic and can cause fungemia, with outbreaks in neonatal intensive care wards associated with temporary colonization of healthcare worker’s hands from contact with their pets. Although standardization is lacking, susceptibility testing is usually performed using a modified broth microdilution method. Antifungal susceptibility can vary depending on Malassezia species, body location, infection type, disease duration, presence of co-morbidities and immunosuppression. Antifungal resistance mechanisms include biofilm formation, mutations or overexpression of ERG11, overexpression of efflux pumps and gene rearrangements or overexpression in chromosome 4.

Novel approach of dermatophytosis eradication in shelters: effect of Pythium oligandrum on Microsporum canis in FIV or FeLV positive cats

Background

Shelters and similar facilities with a high concentration and fluctuation of animals often have problems with various infections, which are usually difficult to solve in such environments and are very expensive to treat. This study investigated the eradication of Microsporum canis, the widespread cause of zoonotic dermatophytosis in shelters, even in immunosuppressed feline leukaemia virus or feline immunodeficiency virus positive cats.

Results

Our study showed the increased effectiveness of an alternative topical therapy for affected animals using the mycoparasitic fungus Pythium oligandrum, which is gentler and cheaper than the standard systemic treatment with itraconazole, and which can also be easily used as a preventative treatment. A decrease in the number of M. canis colonies was observed in cats treated with a preparation containing P. oligandrum 2 weeks after the start of therapy (2 cats with P-1 score, 2 cats with P-2 score, 5 cats with P-3 score) compared with the beginning of the study (9 cats with P-3 score = massive infection). The alternative topical therapy with a preparation containing P. oligandrum was significantly more effective compared with the commonly used systemic treatment using itraconazole 5 mg/kg in a 6-week pulse. After 16 weeks of application of the alternative topical therapy, the clinical signs of dermatophytosis were eliminated throughout the whole shelter.

Conclusion

The complete elimination of the clinical signs of dermatophytosis in all cats indicates that this therapy will be useful for the management and prevention of zoonotic dermatophytosis in animal shelters.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-03001-w.

A prospective epidemiological, clinical, and clinicopathologic study of feline leukemia virus and feline immunodeficiency virus infection in 435 cats from Greece

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are retroviruses causing significant morbidity and mortality in cats. The aim of this study was to describe the epidemiological, clinical and clinicopathologic aspects of FeLV and FIV infections in different populations of cats in Greece, including client-owned cats, stray cats and cats who live in catteries. A total of 435 cats were prospectively enrolled. Serological detection of FeLV antigen and FIV antibody was performed using a commercial in-house ELISA test kit. The results showed that 17 (3.9 %) and 40 (9.2 %) of the 435 cats were positive for FeLV antigen and FIV antibody, respectively, whereas 5 (1.1 %) had concurrent infection with FeLV and FIV. Factors that were associated with FeLV antigenemia, based on multivariate analysis, included vomiting, rhinitis, infection with FIV, neutropenia, decreased blood urea nitrogen and increased serum cholesterol and triglyceride concentrations. Factors associated with FIV seropositivity included male gender, older age, outdoor access, weight loss, fever, gingivostomatitis, skin lesions and/or pruritus and hyperglobulinemia. Various clinical signs and laboratory abnormalities were found to be significantly associated with retroviral infections, suggesting that current guidelines to test all sick cats should be followed, taking into particular consideration the high-risk groups of cats found in this study.

Comparison of subclinical dermatophyte infection in short- and long-haired cats

Background and Aim

Long-haired cats may have an increased risk of dermatophytosis due to insufficient grooming and their thick hair coat trapping fungal spores. The prevalence of subclinical dermatophytosis in long-haired cats was evaluated using fungal culture and Wood's lamp test. Hematology and blood chemistry results were compared between cats negative and positive for dermatophytosis.

Materials and Methods

A total of 127 cats (median age, 3 years [range, 10 months-10 years]) without feline leukemia virus or feline immunodeficiency virus infection were classified into short-haired (n=64) and long-haired (n=63) groups. Hair samples were cultured on a fungal culture medium (dermatophyte test medium, enhanced sporulation agar, and Sabouraud agar).

Results

The prevalence of dermatophytosis in short-haired and long-haired cats was 6.25% (95% confidence interval [CI], 2.15-12.28) and 34.92% (95% CI, 22.94-46.90), respectively. The odds of long-haired cats having dermatophytosis were 8.05 (95% CI, 2.44-33.97) times greater than that in short-haired cats. The number of positive dermatophytosis found in domestic short-haired cats (2/50, 4.0%) was significantly lower than that in Persian cats (17/47, 36.17%; p<0.001) and long-haired mixed breed cats (3/7, 42.86%; p=0.011). The overall sensitivity and specificity of the Wood's lamp test for diagnosing Microsporum canis infection were 37.5% (95% CI, 21.2-57.3%) and 96.1% (95% CI, 90.4-98.5%), respectively. Cats with dermatophytosis had significantly lower hematocrit and serum albumin levels than cats without dermatophytosis.

Conclusion

Subclinical dermatophytosis was more common in long-haired cats; therefore, dermatophyte examinations should be performed routinely.

Biology, diagnosis and treatment of Malassezia dermatitis in dogs and cats Clinical Consensus Guidelines of the World Association for Veterinary Dermatology

BACKGROUND

The genus Malassezia is comprised of a group of lipophilic yeasts that have evolved as skin commensals and opportunistic cutaneous pathogens of a variety of mammals and birds.

OBJECTIVES

The objective of this document is to provide the veterinary community and other interested parties with current information on the ecology, pathophysiology, diagnosis, treatment and prevention of skin diseases associated with Malassezia yeasts in dogs and cats.

METHODS AND MATERIAL

The authors served as a Guideline Panel (GP) and reviewed the literature available prior to October 2018. The GP prepared a detailed literature review and made recommendations on selected topics. The World Association of Veterinary Dermatology (WAVD) Clinical Consensus Guideline committee provided guidance and oversight for this process. The document was presented at two international meetings of veterinary dermatology societies and one international mycology workshop; it was made available for comment on the WAVD website for a period of six months. Comments were shared with the GP electronically and responses incorporated into the final document.

CONCLUSIONS AND CLINICAL IMPORTANCE

There has been a remarkable expansion of knowledge on Malassezia yeasts and their role in animal disease, particularly since the early 1990's. Malassezia dermatitis in dogs and cats has evolved from a disease of obscurity and controversy on its existence, to now being a routine diagnosis in general veterinary practice. Clinical signs are well recognised and diagnostic approaches are well developed. A range of topical and systemic therapies is known to be effective, especially when predisposing factors are identified and corrected.

Development of enzyme immunoassays (ELISA and Western blot) for the serological diagnosis of dermatophytosis in symptomatic and asymptomatic cats

Dermatophytosis is the most common fungal infection in cats worldwide and plays an important role in both animal and human health due to their high zoonotic potential. Effective screening is a strong preventive measure and the fungal culture is quite useful but requires full laboratorial experience and it takes a long time to obtain the result. A rapid and accurate screening test for dermatophytosis in cats is crucial for the effective control of disease outbreaks. The aim of this study was to develop and evaluate the diagnostic efficacy of enzyme immunoassays (ELISA and Western blot [WB]) for the rapid and precise diagnosis of dermatophytosis in cats. Seventy cats of various ages were divided into three groups: S (symptomatic, n = 20), AS (asymptomatic, n = 30), and N (negative, n = 20). All animals were submitted to fungal culture and blood samples for carrying out the serological tests. A significant difference (P < 0.05) was found between IgG-specific levels of sera of Microsporum canis positive and negative animals. There was no statistic difference between groups symptomatic and asymptomatic. The ELISA test showed sensitivity of 94% and specificity of 75%. Receiver operating characteristic (ROC) analysis also showed higher diagnostic accuracy (AUC 0.925). The WB technique detected 13 bands, and the 50 kDa protein was considered the most immunogenic protein, observing reactivity in 83.3% in the symptomatic group and 66.6% in the asymptomatic group. The study concluded that ELISA and WB were useful tools to reliably detect cats that have been exposed to M. canis.

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.

Cutaneous Hypersensitivity Dermatoses in the Feline Patient: A Review of Allergic Skin Disease in Cats

Feline allergic skin disease presents a unique set of challenges to the veterinary practitioner. Although there is some similarity to what is seen in the allergic canine patient, cutaneous hypersensitivity dermatoses in cats can manifest with strikingly different clinical signs, treatment options and outcomes, and secondary complications/disease entities. Additionally, less is known about the pathogenesis of feline allergic skin diseases, particularly "feline atopic syndrome" when compared to dogs or people. This article aims to review what is currently known in regards to allergic skin disease in the feline patient, with focus on non-flea, non-food hypersensitivity dermatitis.

Comparative study of aural microflora in healthy cats, allergic cats and cats with systemic disease

Twenty healthy cats (group 1) with clinically normal ears, 15 cats with systemic disease (group 2) and 15 allergic cats (group 3) were included in a prospective study. The experimental unit was the ear. A clinical score was established for each ear canal after otoscopic examination. Microbial population was assessed on cytological examination of smears performed with the cotton-tipped applicator smear technique. Fungal population was significantly more prominent in allergic cats ( P <0.001) and in diseased cats compared with healthy cats ( P <0.02). Bacterial population was significantly higher in allergic cats than in healthy cats ( P <0.001) and cats suffering from systemic disease ( P <0.001). Bacterial overgrowth was also higher in cats with systemic disease than healthy cats. In cats from group 2, only fungal overgrowth was associated with otitis severity. In group 3, only bacterial overgrowth was associated with otitis severity.

Granulomatous rhinitis due to Candida parapsilosis in a cat

A 9-year-old female spayed Domestic Medium Hair cat presented to the referring veterinarian with a 2-week history of sneezing, which progressed to swelling over the nasal planum. The cat had been under veterinary care for inflammatory bowel disease and had been treated with 1.25 mg/kg prednisolone once a day for approximately 1 year. On physical examination, an approximately 2–3 mm diameter, round polypoid pink soft-tissue mass was protruding slightly from the right nostril. Through histologic examination of representative sections from the mass, there was a severe diffuse infiltrate of epithelioid macrophages and neutrophils that surrounded frequent 15–20 µm yeast organisms. A Grocott methenamine silver stain revealed the presence of pseudohyphae in addition to the previously noted yeast forms. Real-time polymerase chain reaction (PCR) for Cryptococcus neoformans, Ajellomyces dermatitidis (syn. Blastomyces dermatitidis), Coccidioides immitis, Ajellomyces capsulatus (syn. Histoplasma capsulatum), Malassezia spp., and Candida spp. was performed on the paraffin-embedded sample. The PCR for Candida spp. was positive; the product was then sequenced and was determined to be consistent with Candida parapsilosis. Following the PCR diagnosis and prior to treatment of the infection, C. parapsilosis was cultured from a nasal swab. The infection in the cat in the current report was considered opportunistic and secondary to immunosuppression, following treatment for the inflammatory bowel disease.

Dermatophytosis in Cats

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.

Isolation of Sporothrix schenckii from the claws of domestic cats (indoor and outdoor) and in captivity in São Paulo (Brazil)

Sporotrichosis is a subcutaneous mycosis and is also a zoonosis (sapro- and anthropozoonosis). The objective of the present study was to determine the occurrence of sporotrichosis in domestic cats and in wild or exotic felines in captivity through the isolation of Sporothrix spp. from claw impressions in a culture medium. The samples included 132 felines, of which 120 (91.0 %) were domestic cats, 11 (8.3 %) were wild felines, and one (0.7 %) was an exotic felid. Twenty-one (17.5 %) were outdoor cats. Of the total, 89 (67.4 %) had contact with other animals of the same species. It was possible to isolate Sporothrix schenckii from the claws of one (0.7 %) of the felids probed; this animal exhibited generalised sporotrichosis and had infected a female veterinarian. The potential pathogenic agents Microsporum canis and Malassezia pachydermatis were isolated in 12.1 and 5.3 % of the animals, respectively. The following anemophilous fungi, which were considered to be contaminants, were also isolated: Penicillium sp. (28 or 21.2 %), Aspergillus sp. (13 or 9.8 %), Rhodotorula sp. (5 or 3.8 %), Candida sp. (5 or 3.8 %), Trichoderma sp. (1 or 0.7 %), and Acremonium sp. (1 or 0.7 %). Due to the low magnitude of occurrence (0.7 %) of Sporothrix in feline claws, the potential of the cats evaluated in this study to be sources of infection in the city of São Paulo is considerably low.

[Phospholipase and proteinase production by Malassezia pachydermatis isolated in dogs with and without otitis]

BACKGROUND

Malassezia pachydermatis is part of the skin microbiota of dogs and cats. M. pachydermatis has been associated with external otitis and seborrhoeic dermatitis, reported more often in dogs than in cats. When the physical, chemical or immunological mechanisms of the skin are altered, M. pachydermatis could act as a pathogen. Thus, several virulence factors, such as the ability to produce esterase, lipase, lipoxygenase, protease, chondroitin sulphatase, and hyaluronidase, have been studied.

AIMS

In the present study, we aim to identify the phospholipase activity measured at pH 6.3, and the proteinase activity measured at pH 6.3 and pH 6.8 (pH from ears of dogs with external otitis) of M. pachydermatis strains isolated from dogs with and without external otitis.

METHODS

The phospholipase activity was measured using a semi-quantitative method with egg yolk, and the proteinase activity with a semi-quantitative method using bovine serum albumin agar. The study was performed on 96 isolates of M. pachydermatis, 43 isolated from dogs without clinical symptoms of otitis, and 52 isolated from dogs with otitis.

RESULTS

In our study, 75.8% of the isolates showed phospholipase activity at pH 6.3, and 81 and 97.9% of them showed proteinase activity measured at pH 6.3 and 6.8, respectively. A higher phospholipase activity was detected in strains isolated from dogs with otitis. The proteinase activity was increased at a pH of 6.8 (97.9%) in comparison to a pH of 6.3 (81%).

CONCLUSIONS

Our results suggest that the phospholipase activity may play an important role in the invasion of host tissues in chronic canine otitis cases. The proteinase activity results obtained in this study suggest that a reduction in the pH of the treatment may improve its efficacy in the resolution of M. pachydermatis otitis.

Generalized dermatitis associated with Malassezia overgrowth in cats: A report of six cases in France

We recently observed six cases of generalized dermatitis associated with Malassezia overgrowth in cats presented to the Veterinary College of Alfort, France. Elevated numbers of yeasts were observed in lesional skin by cytology and culture. Skin lesions occurred on the face, ventral neck, abdomen and ear canals and were characterized by some degree of alopecia, erythema and crusting. In most cases, pruritus was intense. The species M. pachydermatis was systematically isolated.

Malassezia pachydermatis and M nana predominate amongst the cutaneous mycobiota of Sphynx cats

Carriage of Malassezia species yeasts in healthy Sphynx cats was compared with that in Devon Rex cats (DRC), Cornish Rex cats (CRC) and domestic shorthair (DSH) cats. Swab samples from the external ear, anus and claw folds, and contact plate samples from the axillae and groins, were incubated on modified Dixon's agar at 32°C for 7 days. Malassezia species were isolated from all 18 Sphynx cats; M pachydermatis accounted for 118/140 isolates. Of 20 isolates of M nana, 16 were recovered from the ear canal. M slooffiae was isolated from the claw fold of one cat and the left groin of another. The high counts of M pachydermatis obtained from the axillae, groins and claw folds of the Sphynx cats exceeded those of healthy DSH, CRC and DRC; axillary populations were comparable to those of seborrhoeic DRC. These data support recent reports of high Malassezia species colonisation in Sphynx cats.

Cutaneous mycoflora and CD4:CD8 ratio of cats infected with feline immunodeficiency virus

This study was designed to compare cutaneous mycoflora isolation and CD4+:CD8+ ratio in feline immunodeficiency virus (FIV)-infected cats with that in FIV-uninfected cats. Sixty cats were examined. Twenty-five were FIV-infected cats and 35 were FIV-uninfected cats. All 60 cats were FeLV-negative. Fungi were speciated and immunophenotyping of peripheral CD4+ and CD8+ T lymphocytes was performed. At least one fungal colony was isolated from 22/25 (88%) FIV-infected cats. Among the FIV-uninfected cats fungal colonies were recovered from 13/35 (37%) specimens. Dermatophytes were recovered from 2/25 (8%) FIV-infected cats (one Microsporum gypseum, one Microsporum canis) and 3/35 (8.5%) FIV-uninfected cats ( M gypseum). Malassezia species was the most commonly isolated organism from both groups of cats (51.6%). Malassezia species was more commonly isolated from FIV-infected cats than FIV-uninfected cats (84% vs 28.6%). The CD4+ to CD8+ lymphocyte ratio for FIV-infected cats was significantly lower than the CD4+ to CD8+ ratio in the FIV-uninfected cats. The CD4+ to CD8+ lymphocyte ratio for FIV-infected cats with cutaneous overall fungal isolation was significantly lower than the CD4:CD8 lymphocyte ratio in the FIV-infected cats but without cutaneous fungal isolation. We can conclude that immunologic depletion due to retroviral infection might represent a risk factor to cutaneous fungal colonization in cats.

Lufenuron no tratamento da dermatofitose em gatos?

Em função de controvérsias sobre a eficácia do lufenuron no tratamento da dermatofitose causada por Microsporum canis, o efeito da droga foi avaliado em 46 gatos (30 com lesões cutâneas e 16 portadores assintomáticos) atendidos no Hospital Veterinário da Universidade Federal Rural do Rio de Janeiro, Brasil. O diagnóstico foi estabelecido através da lâmpada de Wood, da cultura fúngica e, adicionalmente, na maioria dos animais sintomáticos, pela avaliação histopatológica da pele. Os animais foram tratados com 120mg/kg de lufenuron, a cada 21 dias (quatro doses); a droga mostrou-se eficaz no tratamento de 29 dos 30 felinos que apresentaram a forma clínica da dermatofitose, bem como no de todos os animais assintomáticos. O único felino que não teve cura clínica completa havia recebido várias doses de dexametasona antes do inicio do tratamento. Em um animal gestante, foram utilizadas duas doses do lufenuron e não foi observada qualquer alteração clínica e morfológica nos filhotes. Nenhum dos animais tratados teve qualquer reação adversa ao medicamento. Vinte dias após o último tratamento, o exame micológico resultou negativo em 45 dos felinos estudados (98%). Embora o lufenuron tenha o custo um pouco mais elevado do que o do cetoconazol, é uma droga que apresenta praticidade e margem de segurança bem maiores. Vale ressaltar que o sucesso do tratamento está diretamente relacionado à correta utilização da droga, assim como a perfeita higienização do ambiente e dos utensílios dos animais.

Intranasal infusion of clotrimazole for the treatment of nasal aspergillosis in two cats

CASE DESCRIPTION

2 cats (13 and 11 years old) were evaluated to determine the cause of nasal discharge of varying duration (4 days and 5 months, respectively).

CLINICAL FINDINGS

Computed tomography revealed marked turbinate destruction and soft tissue densities in the nasal passages. Histologic examination of nasal specimens revealed chronic active inflammation and branching fungal hyphae consistent with Aspergillus spp. Fungal culture of nasal specimens resulted in growth of Aspergillus spp. Testing yielded negative results for antibodies against Aspergillus spp.

TREATMENT AND OUTCOME

Both cats were anesthetized and treated with a 1-hour intranasal infusion of clotrimazole. Recovery from the procedure was uncomplicated, and both cats had complete resolution of clinical signs.

CLINICAL RELEVANCE

Little information is available on the treatment of nasal aspergillosis in cats, and the prognosis for affected animals is considered poor. The procedure for local intranasal infusion of clotrimazole in 2 cats was described here. Results and follow-up monitoring for both cats suggested that this may be a safe, effective, and durable treatment for cats with nasal aspergillosis.

Cutaneous carriage of Malassezia species in healthy and seborrhoeic Sphynx cats and a comparison to carriage in Devon Rex cats

Cutaneous carriage of Malassezia species yeast was investigated in 32 Sphynx cats, and in 10 domestic shorthair (DSH) cats. Samples for mycological culture were taken using contact plates and swabs at seven sites in each cat (left and right axillae and groin, left ear, claw fold on left front paw and the interdigital palmar web of the left front paw). Malassezia species were isolated from 26/32 Sphynx cats (81%) and from 0/10 DSH control cats. In five cases Malassezia species yeasts were isolated at a single site, in the remaining 21 Sphynx cats at multiple sites. A total of 73 Malassezia species isolates were made, of which 68 were Malassezia pachydermatis and five were lipid-dependent Malassezia. Five out of the 32 Sphynx had greasy seborrhoea, and all seborrhoeic cats had M pachydermatis isolated from their skin, at multiple sites. None of the 32 Sphynx had Malassezia species isolated from the ears. The difference in population sizes between Sphynx and DSH cats was significant (P≤0.05) for the axillae, groins and claw fold. The difference in frequency of isolation was significant (P≤0.05) for the axillae and right groin. The level of cutaneous carriage of Malassezia species in Sphynx was similar to that previously reported for Devon Rex cats (DRC) [Åhman S, Perrins N, Bond R. Carriage of Malassezia species yeasts in healthy and seborrhoeic Devon Rex cats. Med Mycol 2007; 45: 449–455]. The poor recovery of Malassezia species from ears in both Sphynx and DRC, has clinical implications for dermatological sampling in these breeds.

Malassezia spp. overgrowth in allergic cats

A series of 18 allergic cats with multifocal Malassezia spp. overgrowth is reported: atopic dermatitis was diagnosed in 16, an adverse food reaction in another and one was euthanized 2 months after diagnosis of Malassezia overgrowth. All the cats were otherwise healthy and those tested (16 out of 18) for feline leukaemia or feline immunodeficiency virus infections were all negative. At dermatological examination, multifocal alopecia, erythema, crusting and greasy adherent brownish scales were variably distributed on all cats. Cytological examination revealed Malassezia spp. overgrowth with/without bacterial infection in facial skin (n = 11), ventral neck (n = 6), abdomen (n = 6), ear canal (n = 4), chin (n = 2), ear pinnae (n = 2), interdigital (n = 1) and claw folds skin (n = 1). Moreover, in two cats Malassezia pachydermatis was isolated in fungal cultures from lesional skin. Azoles therapy alone was prescribed in seven, azoles and antibacterial therapy in eight and azoles with both antibacterial and anti-inflammatory therapy in three of the cats. After 3-4 weeks of treatment, substantial reduction of pruritus and skin lesions was observed in all 11 cats treated with a combined therapy and in five of seven treated solely with azoles. Malassezia spp. overgrowth may represent a secondary cutaneous problem in allergic cats particularly in those presented for dermatological examination displaying greasy adherent brownish scales. The favourable response to treatment with antifungal treatments alone suggests that, as in dogs, Malassezia spp. may be partly responsible for both pruritus and cutaneous lesions in allergic cats.

Prevalence of Malassezia spp. yeasts in feline nail folds: a cytological and mycological study

Malassezia spp. yeasts are commensal organisms of mammal and avian skin, but little is known about their presence on the skin of healthy cats. The purposes of this study were to evaluate the prevalence of Malassezia spp. yeasts in feline nail folds and to identify the different species. Forty-six cats of different breeds were evaluated by cytological examination, and Malassezia spp. yeasts were seen in 61% of them. Yeasts were found in 100% of Devon Rex cats [mean 8.63/oil immersion field (high-power field - HPF)]. Conversely, only 42% of cats of other breeds (domestic short-haired and Persian) were positive (mean 0.59/HPF). Twenty-one cats of different breeds were subsequently evaluated by fungal culture. Malassezia pachydermatis was isolated from 52%, M. furfur from 38%, and M. sympodialis from 9.5% of the cats. More than one species was observed in eight of 21 cats, six of which were Devon Rex. Malassezia spp. yeasts are common inhabitants of feline nail folds, especially in Devon Rex cats, and the presence of a high number of yeasts on cytology correlates with the clinical observation of brown, greasy material in the nail folds. M. pachydermatis and two lipid-dependent species were isolated from both Devon Rex cats and cats of other breeds.

Carriage ofMalassezia spp.yeasts in healthy and seborrhoeic Devon Rex cats

Skin and anal mucosal carriage of Malassezia spp. yeasts was investigated in 21 healthy Devon Rex cats (DRC) and in 9 seborrhoeic DRC using swabs and contact plates. M. pachydermatis was isolated from 26 cats and lipid-dependent Malassezia spp. isolates were recovered from the claw fold of 5 healthy and 3 seborrhoeic DRC. The frequencies of isolation and population sizes of M. pachydermatis in the axillae, left groin and claw fold in seborrhoeic DRC significantly exceeded (P<0.05) those of healthy animals. The frequencies of isolation and population sizes of M. pachydermatis in the axillae and groin in both groups of DRC, and the frequencies of isolation and population sizes of M. pachydermatis in the claw fold of the seborrhoeic DRC, exceeded those of healthy Domestic short-haired cats. Using polymerase chain reaction--restriction enzyme analyses (PCR-REA) based on amplification of the large subunit rRNA gene, all eight lipid-dependent isolates had profiles that were indistinguishable from that of M. slooffiae CBS 7956. These data indicate that DRC are frequently colonized by M. pachydermatis and that the claw folds may also be colonized by M. slooffiae. The pathogenic significance of the high Malassezia spp. counts in the seborrhoeic DRC should now be determined.

Carriage ofMalasseziaspp. yeasts in cats with diabetes mellitus, hyperthyroidism and neoplasia

The frequencies of isolation and population sizes of Malassezia spp. on skin and at mucosal sites in 16 cats with diabetes mellitus, 20 cats with hyperthyroidism and 8 cats with neoplasia did not vary significantly from those of healthy cats when measured with the use of contact plates and a swab technique. M. pachydermatis was isolated from nine sites in one cat with feline paraneoplastic alopecia and pancreatic adenocarcinoma, two cats with diabetes mellitus and five cats with hyperthyroidism. A polymerase chain reaction-restriction enzyme analysis (PCR-REA) method that differentiated the 11 species of Malassezia spp was used to identify the lipid-dependent isolates that were obtained from two cats with diabetes mellitus, two cats with hyperthyroidism and one cat with multicentric lymphoma. Six isolates had PCR-REA patterns that were indistinguishable from M. slooffiae CBS 7956 and three matched M. nana CBS 9557. Our data suggests that skin and mucosal counts of Malassezia spp. are not routinely increased in cats with diabetes mellitus or hyperthyroidism but we report a further example of an association between feline paraneoplastic alopecia and Malassezia spp. proliferation. To the authors' knowledge, this is the first report of the isolation of M. slooffiae from feline skin.

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.

Use of Posaconazole in the Management of Invasive Orbital Aspergillosis in a Cat

Orbital infection with Aspergillus fumigatus was diagnosed in a Persian cat that was presented with chronic third eyelid protrusion and exophthalmos. Evidence of nasal, sinus, or disseminated aspergillosis was not detected in this cat. Complete surgical excision of diseased tissues was not possible during orbital exenteration, and infection subsequently extended into the tissues of the oral cavity. Oral therapy with itraconazole and parenteral therapy with amphotericin B were ineffective in resolving the infection. Oral therapy with a novel triazole, posaconazole, was curative.

Immunomodulation and immunodeficiency

This article briefly reviews the concepts of immunodeficiency and immunomodulation as they relate to selected skin diseases in the dog and cat. Immunodeficiency states are uncommon and may be associated with a subnormal or down-regulated immune system, including humoral deficiencies, such as IgA, and abnormal lymphocyte or neutrophil function. Establishing a causal relationship between a skin disease and presumed immunodeficient state has been difficult due to the rarity of such conditions, and the limited nature of the techniques used to characterise the immune system response. Severe combined immunodeficiency in dogs is a well characterised primary immunodeficiency state involving lymphocytes; retrovirus infection in cats may lead to an acquired immunodeficient state with some association with certain dermatological conditions although it remains unclear that infection is causally linked with disease. Immunomodulation usually implies stimulating the immune system along a beneficial pathway. Such a therapeutic approach may involve a wide variety of agents, for example intravenous immunoglobulin. There are few randomised controlled trials with veterinary patients that unequivocally demonstrate beneficial responses to immunomodulatory agents. Interferons are cytokines of major interest in human and veterinary medicine for their antiviral, anti-tumour and immunomodulatory effects. The advent of veterinary-licensed products containing recombinant interferon may enable demonstration of the efficacy of interferons for conditions such as canine papillomatosis and feline eosinophilic granuloma complex. Canine pyoderma has been treated with a number of presumed immunomodulatory agents with limited success. With more detailed knowledge of the pathogenesis of pyoderma it may be possible to develop efficacious immunomodulators.

Fungal rhinitis and sinusitis in three cats

Localized infection of the nasal or paranasal cavities caused by Aspergillus spp or Penicillium spp was diagnosed in 3 cats. Clinical signs included chronic mucopurulent nasal discharge, epistaxis, and mandibular lymphadenopathy. Rhinoscopic and diagnostic imaging findings were compatible with severe inflammation of the nasal mucosa and destruction of the turbinates. Fungal plaques were observed rhinoscopically in 2 cats, and histologic examination of biopsy specimens revealed fungal colonies with surrounding inflammatory infiltrates in all 3. Results of fungal culture were negative for all 3 cats. Results of serum immunoelectrophoresis for antibodies against Aspergillus spp were positive in 2 cats. Treatment with itraconazole was effective in controlling clinical signs in 1 cat, but hepatotoxicosis developed. A single intranasal infusion of clotrimazole subsequently led to long-term resolution of clinical signs in this cat. Localized aspergillosis-penicilliosis is clinically indistinguishable from other pathologic conditions of the nasal and paranasal cavities in cats and should be considered when examining cats with chronic nasal discharge.

Candida spp. urinary tract infections in 13 dogs and seven cats: predisposing factors, treatment, and outcome

Records from 20 animals (13 dogs, seven cats) with Candida spp. urinary tract infections were reviewed. Six Candida spp. were isolated; Candida albicans was the most common isolate. Concurrent diseases or nonantifungal drugs administered within 1 month of isolation included antibiotics (n=16), corticosteroids (n=6), diabetes mellitus (n=4), nonurogenital neoplasia (n=3), and noncandidal urogenital disease (n=14). All animals had sources of local or systemic immune compromise that likely predisposed to infection. Of five animals with resolution of infection, three did not receive specific antifungal treatment. The authors conclude that correction of predisposing conditions is likely critical for management of Candida spp. urinary tract infection.

Pathological and clinical aspects of the diseases caused by Malassezia species

From veterinary point of view Malassezia pachydermatis has the greatest significance. It has been standing in the focus of interest since the early 1990s, mostly because of the frequency of otitis externa and dermatitis caused by this yeast in dogs. This is the only lipid-independent species in the genus Malassezia. It can be found in very large proportion on the skin of healthy animals, but can be isolated in much greater number from diseased dogs. It often causes illness together with other pathogens (e.g. Staphylococcus intermedius). Some breeds are predisposed. In addition to the treatment of the accidental concurrent diseases, therapy consists of systemic and/or topical antimicrobial treatment. Ketoconazole is used most frequently. Malassezia pachydermatis plays also a role in the skin disorders of other carnivores. It has little zoonotic potential, it can be dangerous to immunocompromised humans. The other Malassezia species have little veterinary importance, although M. sympodialis and M. globosa were isolated from asymptomatic animals (mostly cats) and from mixed infections.

Cerebral phaeohyphomycosis caused by Cladosporium spp. in two domestic shorthair cats

Two domestic shorthair cats presented for clinical signs related to multifocal central nervous system dysfunction. Both cats had signs of vestibular system involvement and anisocoria, and one had generalized seizure activity. Cerebrospinal fluid analysis revealed a neutrophilic pleocytosis with protein elevation in one cat and pyogranulomatous inflammation in the second. Electroencephalography and brain-stem auditory-evoked potentials in the first cat confirmed cerebral cortical and brain-stem involvement. Euthanasia was performed in both cats, and postmortem diagnoses of phaeohyphomycosis secondary to Cladosporium spp. were made based on histopathology and fungal culture in both cats.

Retrospective study: the presence of Malassezia in feline skin biopsies. A clinicopathological study

Malassezia spp. dermatitis, a rare disorder in cats, has previously been associated with immune suppression and internal malignancies. This study evaluates the presence and importance of Malassezia spp. in feline biopsy specimens submitted for histopathological examination. Five hundred and fifty haematoxylin and eosin-stained skin biopsy specimens received for histopathological examination between January 1999 and November 2000 were reviewed. Fifteen (2.7%) submissions contained Malassezia organisms in the stratum corneum of the epidermis or follicular infundibulum. Eleven of 15 cats presented with an acute onset of multifocal to generalized skin lesions. All 11 cats were euthanized or died within 2 months of the onset of clinical signs. Seven cats had dermatopathological changes and clinical signs supportive of paraneoplastic alopecia, and three cats had an interface dermatitis suggestive of erythema multiforme or thymoma-associated dermatosis. Histopathological changes were nonspecific in one cat that was euthanized 2 weeks following onset of severe pruritus and alopecia. In three cats, Malassezia spp. were found in localized sites (two chin, one footpads) and appeared inconsequential to their overall health status. One cat had Malassezia spp. in association with cutaneous demodicosis. These findings suggest that Malassezia yeast in dermatopathological specimens from multifocal or generalized lesions should prompt a thorough clinical work-up for internal neoplasia.