Immediate and residual antifungal activity of compounds used for whole body and adjuvant topical therapy against Microsporum canis: an in vitro study

BACKGROUND

Topical antifungal therapy is recommended to disinfect hairs of dermatophyte-infected animals.

OBJECTIVE

To determine the immediate and residual (24, 48 and 72 h) antifungal activity of commonly used products for focal (n = 11) and whole body application (n = 3).

ANIMALS

Hair samples from naturally infected kittens.

METHODS AND MATERIALS

Immediate antifungal activity was assessed using isolated infected spores. In a more robust challenge, toothbrushes containing whole infected hairs were repeatedly treated with products until culture-negative. Residual activity was determined by treating 0.04 g of uninfected hair with test products, allowing hairs to dry and then plating hairs onto fungal culture plates inoculated with Microsporum canis. Residual activity was assessed at 24, 48 and 72 h post-treatment.

RESULTS

All products showed good efficacy against isolated infected spores. Two products required three treatments to disinfect whole infected hairs (miconazole 0.2% and ketoconazole 0.15%); all other products were efficacious after one treatment. For each product residual activity at 24, 48 and 72 h was similar. For the whole body products, lime sulfur and enilconazole showed residual activity, but as expected none was detected for 2% miconazole nitrate/ 2% chlorhexidine shampoo. For focal therapy products, residual activity was detected for clotrimazole 1%, terbinafine 1%, miconazole at 0.2, 1 or 2% (with or without chlorhexidine), climbazole 0.5% with chlorhexidine gluconate, and ketoconazole 1% with chlorhexidine gluconate. A ketoconazole 0.15% with 0.15% chlorhexidine gluconate showed no residual activity.

CONCLUSIONS AND CLINICAL IMPORTANCE

Findings support twice weekly application of enilconazole and lime sulfur, and application of adjuvant focal topical therapy daily or every other day.

Mechanical washing of pet food bowls is effective for Microsporum canis decontamination

BACKGROUND

Dermatophyte lesions are common on the face of animals and pet food bowls can become contaminated by direct contact with the facial lesions. Owners are concerned about appropriate decontamination and yet worried about exposing pets to disinfectant residues.

OBJECTIVE

To determine the efficacy of mechanical cleaning alone for decontamination of contaminated pet food dishes.

METHODS AND MATERIALS

An isolated infective spore suspension of Microsporum canis was used to experimentally contaminate metal (n = 4), plastic (n = 4) and glass (n = 4) pet food bowls. The experiment was repeated twice, first with just the spore suspension, and then with a mixture of spore suspension and canned pet food. The bowls were soaked in hot water (34°C) with a generic dish soap in a sink for two minutes, scrubbed using a dishwashing brush until visibly clean or for 2 min, rinsed, allowed to air-dry and then cultured. Fungal culture samples were collected using disposable dust cloths. Environmental fungal cultures were obtained from the sink after routine mechanical cleaning with a sudsy detergent.

RESULTS

No environmental contamination was detected. The results of both experiments were similar. All bowls (n = 24) were fungal culture positive for M. canis before washing and all were completely decontaminated with mechanical washing alone.

CONCLUSIONS AND CLINICAL IMPORTANCE

Mechanical washing alone can decontaminate pet food bowls exposed to naturally infective material. Dishes should be soaked in hot sudsy water to loosen organic debris, scrubbed until visibly clean and then rinsed. Owners should wear dishwashing gloves for personal protection.

One vs two negative fungal cultures to confirm mycological cure in shelter cats treated for Microsporum canis dermatophytosis: a retrospective study

OBJECTIVES

The aim of this study was to determine how often one negative fungal culture (FC) was indicative of mycological cure (MC) when compared with two negative consecutive FCs in cats treated for Microsporum canis dermatophytosis.

METHODS

In this retrospective study, weekly FC data from shelter cats treated for M canis dermatophytosis were reviewed.

RESULTS

Complete records from 371 cats were reviewed. The first negative FC was indicative of MC in 335 (90.3%) cats. In this group, all cats were otherwise healthy and either had obvious lesions (n = 237) or no lesions or evidence of resolving lesions (n = 98). In the 36 cats in which the first negative culture was not indicative of MC, there were two clinical subgroups. The first consisted of healthy but lesional cats (n = 19) that had one negative FC within the first 3 weeks of treatment followed by one or more positive FCs. The most likely explanation was sampling error. These cats went on to cure and the next negative FC was indicative of MC. In the second clinical group, cats were lesional but had concurrent medical problems (n = 17). These cats showed an initial good response to treatment (lesion resolution and an initial negative FC). However, this negative FC was followed by at least one strongly positive FC (>10 colony-forming units/plate) before proceeding to cure. These cats took the longest time to cure (mean 11 weeks; range 8-28 weeks). MC occurred after resolution of the concurrent health issues. There was very good agreement between using one negative FC vs two negative FCs for the determination of MC in healthy cats (kappa = 0.903).

CONCLUSIONS AND RELEVANCE

In cats where there has been high compliance with environmental cleaning, as well as topical and systemic treatment recommendations, two consecutive negative FCs may not be necessary to determine MC. The first negative FC in an otherwise healthy cat is likely indicative of MC. Good sampling technique is needed to avoid false-negative FC results.

Trichophyton species and Microsporum gypseum infection and fomite carriage in cats from three animal shelters: a retrospective case series

OBJECTIVES

The goal of this retrospective case series was to report on the clinical aspects of confirmed Trichophyton species and Microsporum gypseum infections in cats from three animal shelters.

METHODS

This was an observational retrospective study. Fungal culture and treatment data from three animal shelters was retrospectively reviewed to identify cats with dermatophytosis caused by Trichophyton species or M gypseum.

RESULTS

Among the three shelters only four cats were diagnosed with M gypseum dermatophytosis. With respect to Trichophyton species infections, there were six cases identified and treated in a 1 year period in one shelter, 13 cases over 13 years in the second shelter and 27 cases over 5 years in the third shelter. Four cases of M gypseum dermatophytosis were treated in the third shelter. Young cats were most commonly infected and the disease was most commonly diagnosed in the fall and winter months. Lesions were inflammatory and found predominantly on the head and neck. There was a rapid response to treatment in all cases; mean (n = 20) and median (n = 17) days to mycological cure were calculated from available data. Fungal culture data revealed fomite carriage without clinical evidence of infection for Trichophyton species (n = 43) cats and M gypseum (n = 37) cats.

CONCLUSIONS AND RELEVANCE

There is a paucity of clinical information about non-Microsporum canis dermatophytosis in shelter cats. This study data shows that Trichophyton species and M gypseum infections do occur but are uncommon. Based upon the rapid response to conventional treatment, these infections do not represent a treatment challenge, as most cats reached mycological cure within 3 weeks.

Decontamination of 70 foster family homes exposed to Microsporum canis infected cats: a retrospective study

BACKGROUND

Dermatophytosis is a superficial fungal skin disease of animals. A key part of treatment is cleaning and disinfection of the environment to prevent false-positive results due to fomite carriage. Furthermore, there is a perception in the lay literature that decontamination of homes is difficult or impossible.

CLINICAL SUMMARY

Data from a 10 year period identified 70 foster family homes where Microsporum canis infected cats had lived for varying periods of time. Mechanical debris was removed from the rooms housing the cats, the areas cleaned with over-the-counter household detergents, rinsed and hard surfaces disinfected with 1:100 concentration household bleach or accelerated hydrogen peroxide. Thirty-eight homes were completely decontaminated after one cleaning post removal or cure of the cat. Of the remaining homes, decontaminated was achieved after one (n=28), two (n=2) or three (n=1) additional cleanings. Complete decontamination was not possible in one home; the foster family was admittedly noncompliant. There was no evidence of disease transmission to other animals or people.

CONCLUSIONS

Environmental decontamination is not difficult in homes exposed to M. canis and can be accomplished with established procedures.

Evaluation of incubation time for Microsporum canis dermatophyte cultures

Objectives The goal of this study was to determine how frequently Microsporum canis was isolated after 1, 2 and 3 weeks of incubation on dermatophyte culture medium either from untreated cats or cats during treatment. Methods This was an observational retrospective study. Toothbrush fungal culture results were examined from two data pools: untreated cats with suspect skin lesions and weekly fungal cultures from cats being treated for dermatophytosis. Results Results from 13,772 fungal cultures were reviewed and 2876 (20.9%) were positive for M canis. Of these, 2800 were confirmed as positive within 14 days of incubation and only 76 (2.6%) required >14 days for confirmation of M canis. In pretreatment specimens, 98.2% (1057/1076) of M canis isolates were recovered within 14 days of incubation in specimens from cats not known to have received prior antifungal treatment. For cats receiving treatment, 96.8% (1743/1800) of M canis isolates were recovered within 14 days of incubation. Of the 57 cultures that required >14 days for finalization, 21 required extra incubation time because cultures were grossly abnormal, 12 had concurrent contaminant growth delaying microscopic confirmation and 24 had no growth in the first 14 days. Of these 24, 19 had 1-2 colony-forming units (cfu)/plate and the remaining five plates had 5 to >10 cfu/plate, all with abnormal morphology. Conclusions and relevance The findings of this study show that it is not necessary to hold pretreatment or post-treatment fungal cultures for 21 days before finalizing cultures for no growth. Growth requiring >14 days had grossly abnormal morphology.

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.

Use of a commercial qPCR assay in 52 high risk shelter cats for disease identification of dermatophytosis and mycological cure

BACKGROUND

qPCR is used to test for dermatophytosis.

OBJECTIVES

To determine the clinical usefulness of a commercial qPCR for confirming dermatophytosis in lesional cats, and the clinical usefulness of the qPCR Microsporum spp. and/or M. canis assay for confirming mycological cure.

ANIMALS

Fifty two shelter cats with skin lesions.

METHODS

qPCR testing of toothbrush fungal culture samples of lesions.

RESULTS

qPCR and fungal culture (FC) matched in 49 of 52 cats. The qPCR correctly identified 45 of 46 and two of four cats with M. canis and Trichophyton spp. infections, respectively. qPCR correctly identified two cats as not infected. No evidence of cross reactivity was noted. The Microsporum spp. qPCR assay was positive in 45 of 46 (97.8%) of infected cats. Results were positive on both Microsporum spp. and M. canis assays in 29 of 45 cats. No cat had a positive qPCR result for M. canis alone. Mycological cure was defined as two negative fungal cultures. There were 92 negative FC from the 46 treated cats and qPCR assay for Microsporum spp. and M. canis was negative in 68 of 92 (73.1%) and 79 of 92 (85.9%) samples, respectively. The number of cats correctly identified with mycological cure via qPCR was 30 of 46 (65.2%) and 39 of 46 (84.8%) cats for the Microsporum spp. and M. canis assays, respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

The commercial qPCR assay was a reliable test for confirming disease. The qPCR Microsporum spp. assay was more useful for initial disease confirmation; while the qPCR M. canis assay was more useful for determining mycological cure.

Decontamination of carpet exposed to Microsporum canis hairs and spores

Objectives The objective of this study was to evaluate the efficacy of vacuuming and three carpet cleaning methods for the removal of Microsporum canis spores and hairs from experimentally contaminated carpets. Methods Sterile Berber carpeting was artificially contaminated with naturally infective M canis hairs and spores. Carpet swatches were vacuumed for 10 s, 30 s and 60 s, and then cultured. Three carpet cleaning methods were evaluated on area rugs experimentally contaminated with infective material: a beater brush carpet shampooing, beater brush carpet shampooing post-disinfectant application and hot water extraction. Home cleaning products labeled as having efficacy against Trichophyton species were used in addition to 1% potassium peroxymonosulfate. Carpets were cultured at 24 h, 48 h and 7 days after cleaning. Good efficacy was no detectable spores at post-cleaning culture. Results All pretreatment carpet samples were culture positive for M canis (>300 colony-forming units [cfu]/site). Vacuuming did not decontaminate carpets but did remove intact hairs. Spores were not detected by wipe samples after two washings with an upright beater brush carpet shampooer or pretreatment with a disinfectant prior to carpet shampooing. Carpets cleaned with one hot water extraction technique had a decrease from 300 cfu/site to a mean of 5.5 cfu/site at 24 and 48 h post-cleaning and 2 cfu/site at day 7. The use of disinfectants was associated with odor, even when dry, and permanent discoloration. Hot water extraction cleaning was associated with the fastest drying time and no discoloration. Conclusions and relevance Carpets exposed to M canis can be disinfected via carpet shampooing or hot water extraction cleaning. Vacuuming of carpets is recommended to remove infective hairs. For homes, exposed carpeting can be decontaminated by routine washing with a carpet shampooer (twice) or hot water extraction. Use of pretreatment with a disinfectant is recommended when a high level of overall decontamination is needed in an animal facility with necessary carpeted surfaces (eg, entryway carpet mats).

In vitro efficacy of shampoos containing miconazole, ketoconazole, climbazole or accelerated hydrogen peroxide against Microsporum canis and Trichophyton species

Objectives

The objective was to evaluate the antifungal efficacy of shampoo formulations of ketoconazole, miconazole or climbazole and accelerated hydrogen peroxide wash/rinse against Microsporum canis and Trichophyton species spores.

Methods

Lime sulfur (1:16)-treated control, enilconazole (1:100)-treated control, accelerated hydrogen peroxide (AHP 7%) 1:20 and a 1:10 dilution of shampoo formulations of miconazole 2%, miconazole 2%/chlorhexidine gluconate 2–2.3%, ketoconazole 1%/chlorhexidine 2%, climbazole 0.5%/chlorhexidine 3% and sterile water-untreated control were tested in three experiments. In the first, a suspension of infective spores and hair/scale fragments was incubated with a 1:10, 1:5 and 1:1 dilution of spores to test solutions for 10 mins. In the second, toothbrushes containing infected cat hair in the bristles were soaked and agitated in test solutions for 10 mins, rinsed, dried and then fungal cultured (n = 12×). In the third, a 3 min contact time combined with an AHP rinse was tested (n = 10×). Good efficacy was defined as no growth.

Results

Water controls grew >300 colony-forming units/plate and all toothbrushes were culture-positive prior to testing. For the suspension tests, all test products showed good efficacy. Miconazole 2%, ketoconazole 1% and AHP showed good efficacy after a 10 min contact time. Good efficacy was achieved with a shorter contact time (3 mins) only if combined with an AHP rinse.

Conclusions and relevance

Lime sulfur and enilconazole continued to show good efficacy. In countries or situations where these products cannot be used, shampoos containing ketoconazole, miconazole or climbazole are alternative haircoat disinfectants, with a 10 min contact time or 3 mins if combined with an AHP rinse.

Decontamination of laundry exposed to Microsporum canis hairs and spores

Objectives

The objective of this study was to determine the efficacy of decontamination of fabric exposed to Microsporum canis hairs and spores by mechanical washing using hot or cold water with or without a sodium hypochlorite additive, and to field test a washing protocol for terry cloth and denim exposed to M canis via direct contact with infected cats.

Methods

Cotton, terry cloth and denim fabric swatches were contaminated with isolated infective spores and hairs and then washed in water at temperatures of 30°C and 60°C, with and without a sodium hypochlorite additive, and with and without mechanical drying. Terry cloth and denim were contaminated by direct contact with infected kittens and washed at 30°C until culture-negative.

Results

All prelaundering samples had >300 colony forming units (cfu)/plate. Experimentally contaminated fabrics were culture-negative, regardless of fabric type, water temperature, the presence or absence of sodium hypochlorite, or tumble drying after one wash. After one wash, 22/34 (65%) of terry cloth towels and 12/20 (60%) denim fabric squares were culture-positive, but the infective load was minimal (1–5 cfu/plate). After two washes in cold water there was no detectable contamination of fabric. The rinse water was not contaminated with spores. The laundry tub was easily decontaminated via mechanical cleaning followed by use of a disinfectant.

Conclusions and relevance

Washable textiles exposed to M canis can be decontaminated via mechanical washes in cold water without the addition of bleach. Two washes are recommended to ensure removal of spores. Laundry can be effectively decontaminated by washing twice in cold water on a long wash cycle (for ⩾14 mins). It is important to ensure maximal agitation (ie, the machine should not be overloaded).

Dinotefuran/pyriproxyfen/permethrin pemphigus-like drug reaction in three dogs

BACKGROUND

Pemphigus foliaceus (PF) can occur spontaneously or as a reaction pattern associated with cutaneous adverse drug reactions.

HYPOTHESIS/OBJECTIVES

To provide clinical, histological and immunological assessments of three dogs that developed cutaneous adverse drug reactions following application of a topical flea and tick control product, which contained dinotefuran, pyriproxyfen and permethrin.

ANIMALS

Three client-owned dogs.

RESULTS

The dogs exhibited rapid onset of papules, pustules and crusts at the site of application of the flea control product. In two dogs, the lesions became generalized, while the third exhibited a localized phenotype. Both dogs with generalized lesions required immunosuppressive treatment; one achieved remission after 1 year of treatment and one was euthanized due to adverse effects of glucocorticoids. The dog with a localized phenotype was treated with topical glucocorticoids exclusively and achieved remission after 10 months. Histology revealed subcorneal pustular dermatitis, with acantholysis of keratinocytes and focal to multifocal full-thickness epidermal necrosis. These features are similar to those previously reported for pesticide-triggered and spontaneous PF. Tissue-bound IgG was detected in two of three dogs, and autoantibodies targeting canine desmocollin-1 were identified in the serum of the one dog from which a sample was available.

CONCLUSIONS AND CLINICAL IMPORTANCE

Cutaneous adverse drug reaction caused by a flea control product containing dinotefuran, pyriproxyfen and permethrin closely resembled those reported for other pesticide-associated PF-like cutaneous adverse drug reactions. Although it appears to be a rare entity, clinicians and pathologists should be aware of the potential for flea and tick control products to trigger PF-like reactions.

Feline dermatophytosis: steps for investigation of a suspected shelter outbreak

PRACTICAL RELEVANCE

Dermatophytosis (ringworm) is the most important infectious and contagious skin disease of cats in shelters. Its importance relates to the fact that it can affect all cats, but tends to affect those which would otherwise have good chances for adoption. Although many diseases in shelters fit this description, dermatophytosis is of particular significance because of associated public health concerns.

CLINICAL CHALLENGES

Disease management in animal shelters is challenging because new animals are frequently entering the population, numerous animals are often housed together, and resources are almost always limited. GLOBAL RELEVANCE: Outbreaks of dermatophytosis occur worldwide and no animal shelter is completely shielded from possible introduction of the disease into the population.

AUDIENCE

This article offers a flexible stepwise approach to dealing with a known or suspected outbreak of dermatophytosis in an animal shelter. It is based on the authors' experiences spanning more than a decade of responses and/or consultations. While primarily aimed at veterinarians involved in shelter medicine, the principles largely apply to other group-housing situations, such as catteries and breeding establishments.

AIMS

The goals in dealing with a potential dermatophytosis outbreak are to ascertain if the 'outbreak' is actually an outbreak, to develop a shelter-specific outbreak management plan and to implement a long-term plan to prevent recurrences.

Infectious diseases in large-scale cat hoarding investigations

Animal hoarders accumulate animals in over-crowded conditions without adequate nutrition, sanitation, and veterinary care. As a result, animals rescued from hoarding frequently have a variety of medical conditions including respiratory infections, gastrointestinal disease, parasitism, malnutrition, and other evidence of neglect. The purpose of this study was to characterize the infectious diseases carried by clinically affected cats and to determine the prevalence of retroviral infections among cats in large-scale cat hoarding investigations. Records were reviewed retrospectively from four large-scale seizures of cats from failed sanctuaries from November 2009 through March 2012. The number of cats seized in each case ranged from 387 to 697. Cats were screened for feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) in all four cases and for dermatophytosis in one case. A subset of cats exhibiting signs of upper respiratory disease or diarrhea had been tested for infections by PCR and fecal flotation for treatment planning.

Mycoplasma felis (78%), calicivirus (78%), and Streptococcus equi subspecies zooepidemicus (55%) were the most common respiratory infections. Feline enteric coronavirus (88%), Giardia (56%), Clostridium perfringens (49%), and Tritrichomonas foetus (39%) were most common in cats with diarrhea. The seroprevalence of FeLV and FIV were 8% and 8%, respectively. In the one case in which cats with lesions suspicious for dermatophytosis were cultured for Microsporum canis, 69/76 lesional cats were culture-positive; of these, half were believed to be truly infected and half were believed to be fomite carriers. Cats from large-scale hoarding cases had high risk for enteric and respiratory infections, retroviruses, and dermatophytosis. Case responders should be prepared for mass treatment of infectious diseases and should implement protocols to prevent transmission of feline or zoonotic infections during the emergency response and when transferring the rescued cats to other shelters or to adopters.

Efficacy of disinfectants containing accelerated hydrogen peroxide against conidial arthrospores and isolated infective spores of Microsporum canis and Trichophyton sp

BACKGROUND

Accelerated hydrogen peroxide is a proprietary disinfectant formulation that is available for both commercial and home use and is labelled as antifungal.

HYPOTHESIS/OBJECTIVES

To determine the antifungal efficacy of accelerated hydrogen peroxide disinfectants against Microsporum and Trichophyton spp.

METHODS

Three products formulated as ready to use and three concentrates were used. Concentrates were tested at dilutions of 1:8, 1:16 (recommended dilution) and 1:32. One product was a surgical instrument disinfectant. Sterile water, sodium hypochlorite (1:32 dilution) and over-the-counter 3% hydrogen peroxide were used as controls. Conidial suspensions contained ~9.6 × 10(5) /mL Microsporum canis, ~1.0 × 10(7) /mL M. gypseum or ~2.0 × 10(7) /mL Trichophyton sp. and were tested at 1:10 dilution. Isolated infective spore suspensions of M. canis from an untreated cat and T. erinacei from an untreated hedgehog were tested at 1:10, 1:5 and 1:1 spore-to-disinfectant dilutions.

RESULTS

Too many colonies to count were present on untreated control plates. Accelerated hydrogen peroxide and household hydrogen peroxide inhibited growth of both pathogens in conidial (1:10 dilution) and spore suspensions (1:10, 1:5 and 1:10 dilution). There was no lack of efficacy of products that were >12 months old.

CONCLUSIONS AND CLINICAL IMPORTANCE

Accelerated hydrogen peroxide products are an option for environmental disinfection of surfaces exposed to M. canis and Trichophyton sp. after appropriate gross decontamination and mechanical cleaning with a detergent. The results from conidial testing were identical to those of isolated infected spore testing, which suggests that accelerated hydrogen peroxide products with label claim as antifungal against Trichophyton mentagrophytes may be suitable as an alternative disinfectant to sodium hypochlorite.

A case of apparent canine erysipeloid associated with Erysipelothrix rhusiopathiae bacteraemia

BACKGROUND

Erysipelothrix rhusiopathiae is a Gram-positive facultative anaerobe found worldwide and is most commonly associated with skin disease in swine, while anecdotal reports of cases in dogs have been associated with endocarditis.

HYPOTHESIS/OBJECTIVES

Clinicians should consider systemic infectious diseases as a potential cause of erythematous skin lesions.

ANIMALS

A 5-year-old female spayed Labrador retriever presented with lethargy, anorexia and erythematous skin lesions while receiving immunosuppressive therapy for immune-mediated haemolytic anaemia. Four days prior to presentation, the dog had chewed on a raw turkey carcase.

METHODS

Complete blood count, serum chemistry profile, urinalysis and blood cultures.

RESULTS

Blood cultures yielded a pure growth of E. rhusiopathiae serotype 1b. Amoxicillin 22 mg/kg orally twice daily for 2 weeks and discontinuation of azathioprine resulted in remission of fever and skin lesions.

CONCLUSIONS AND CLINICAL IMPORTANCE

This report is the first documentation, to the best of the authors' knowledge, of Erysipelothrix infection, a known zoonosis, in an immunosuppressed dog, highlighting the need for infectious disease monitoring in patients receiving such therapy. This information may also help educate veterinarians to include Erysipelothrix infection as a differential diagnosis in dogs with fever and skin lesions, as well as the role of blood cultures in diagnosing this disease.

Use of itraconazole and either lime sulphur or Malaseb Concentrate Rinse ® to treat shelter cats naturally infected with Microsporum canis: an open field trial

In an open non-randomized study, 90 cats with severe dermatophytosis were treated with 21 days of oral itraconazole at 10 mg/kg and one of three topical antifungal rinses applied twice weekly: lime sulphur (LSO); reformulated lime sulphur with an odour-masking agent (LSR); or a 0.2% miconazole nitrate and 0.2% chlorhexidine gluconate rinse (MC). Weekly examinations and fungal cultures were used to monitor the cats' response to therapy. If at day 42 of treatment cats were still strongly fungal culture positive and/or developing new lesions, they were retreated with oral itraconazole and LSO. Cats were not prevented from licking the solutions and none developed oral ulcerations. Thirty-one cats were treated with LSO, 27 with LSR and 32 with MC. The median number of days to cure was 30 (range 10-69 days) and 34 (range 23-80 days) for LSO and LSR, respectively. Thirty-two cats were treated with MC, and 13 of 32 cats required repeat treatment because of persistent culture-positive status and development of new lesions. Median number of days of treatment for the 19 cats that cured with MC was 48 (range 14-93 days). When the number of days to cure was compared between the groups, there was a significant difference between cats treated with LSO and LSR (P=0.029) and cats treated with LSO and MC (P=0.031), but no significant difference between the number of days to cure for cats treated with LSR and MC (P=0.91).

Pilot study: prevalence of positive aeroallergen reactions in 10 cats with small-airway disease without concurrent skin disease

The purpose of this study was to determine the prevalence of positive allergen reactions in cats with small-airway disease (i.e. 'feline asthma', 'feline allergic bronchitis', 'feline bronchial disease'). Intradermal skin tests (IDT) and serum immunoglobulin E (IgE) tests were performed in 10 cats with idiopathic small-airway disease and in 10 normal cats without a history of respiratory disease. None of the cats had a history of skin disease or clinical signs of skin disease at the time of testing. Significantly more individual positive allergen reactions were found on serum IgE tests than on IDT in both groups of cats. Affected cats had significantly more individual positive allergen reactions on both tests than unaffected cats. Both IDT and serum IgE tests resulted in more individual positive allergen reactions to weeds, trees, grasses, and/or moulds in affected cats than in normal cats. Significantly more positive allergen reactions to house dust mites were found in affected compared to non-affected cats by IDT but not by serum IgE testing. One unexpected obstacle to inclusion of more affected cats in the study was the concurrent presence or history of suspect or known allergic skin disease. Concurrent allergic skin disease has not been reported in association with small-airway disease in cats. The increased prevalence of individual positive allergen reactions in affected cats may be due to increased immunological reactivity in these cats. Further studies are needed to answer this question and to determine what role, if any, aeroallergens have in the pathogenesis of this complex feline disease.

Use of isolated infected spores to determine the sporocidal efficacy of two commercial antifungal rinses against Microsporum canis

In this study, isolated infective Microsporum canis spores were used in an in vitro test model to compare the sporocidal activity of two commercial topical antifungal rinses. The two commercial test solutions used in the study were a lime sulphur solution 97.8% (LymDyp) and miconazole base 5.2%/chlorhexidine gluconate 5.9% mixture (Malaseb Concentrate Rinse). Water and household bleach were used as controls. Isolated infective spores were harvested from infected hairs and 500 microL of the spore suspension was incubated with an equal volume of dilutions of lime sulphur or the miconazole/chlorhexidine gluconate combination for 5 min and 4 h followed by fungal culture. There were too many to count colonies on the water control plates. Lime sulphur was 100% sporocidal at all test dilutions at both times. Miconazole/chlorhexidine gluconate was 100% sporocidal at all but the 1 : 128 dilution after 5 min of incubation and 100% sporocidal when incubated with spores for 4 h. It is not known if the two products have similar antifungal activity against infective spores on or within hairs; however, based on the findings of this study there is good evidence to recommend either rinse as an adjuvant topical therapy in a dermatophyte treatment and control program.

Efficacy of pre-treatment with lufenuron for the prevention of Microsporum canis infection in a feline direct topical challenge model

Oral lufenuron is reportedly an effective treatment for some cats with dermatophytosis. The purpose of this study was to determine if lufenuron, when used as a pre-treatment prior to challenge exposure, would be protective against the development of infection after the direct topical application of fungal macrocondia (Microsporum canis spores). Three groups (n = 6/group) of juvenile cats were treated with either monthly oral lufenuron (30 or 133 mg/kg) or placebo. After 2 months of treatment, kittens were challenged using 10(5)Microsporum canis spores applied to the skin under occlusion. Cats were examined weekly and the following data collected: Wood's lamp examination; scoring for scale/crust, erythema and induration; lesion size; and the development of satellite lesions. Fungal cultures were performed bi-weekly. All cats became infected; the infections progressed, and then regressed, in a similar fashion in all groups. There were no consistent statistically significant differences in weekly infection scores between treated and untreated cats throughout the study. Treated cats did not recover faster than untreated cats. We conclude that oral lufenuron at the dosing schedule and conditions used in this study did not prevent dermatophytosis or alter the course of infection by direct topical challenge.

Zoonotic skin diseases of dogs and cats

Although there are over 250 zoonotic diseases, only 30-40 of them involve dogs and cats. Transmission of zoonotic infections occurs via bites, scratches or touch; exposure to saliva, urine or feces; inhalation of particles or infectious aerosols; contact with a transport or intermediate host (e.g. ticks, fleas); or exposure to contaminated water, soil or vegetation. This paper summarizes the most important common zoonotic dermatological diseases of dogs and cats. The most common dermatological zoonoses are flea and tick infestations and the diseases they transmit; dermatophytosis; and mite infestations (Sarcoptes and Cheyletiella). Prevention of zoonotic infestations or infections can be accomplished easily by the use of routine flea and tick control, screening of new pets for dermatophytosis, and routine hand-washing.

Development of an in vitro, isolated, infected spore testing model for disinfectant testing of Microsporum canis isolates

The isolated infected hair model is a commonly used technique to test the fungicidal efficacy of topical therapies against Microsporum canis. The most commonly used model uses mats of infective hairs, and results from various laboratories have differed. The objectives of this study were to develop a method to produce spores for testing when only mycelial forms were available and to develop a semiquantitative testing method that used only infective spores from hairs, and not pooled hair samples for testing. Ten isolates of M. canis were used in this study. Juvenile guinea pigs were easily infected using mycelial forms of M. canis and large numbers of spores were easily harvested for testing. Eight dilutions of disinfectants were tested. Fungal culture data were evaluated using an endpoint dilution at which there was 100% fungicidal activity, i.e. no growth on the plates. The 10 samples showed identical results. Chlorhexidine and Virkon(R) S were ineffective even when used at x4 the manufacturer's recommended dilution. Lime sulphur (1 : 33), enilconazole (20 microL mL(-1)), and bleach (1 : 10) were consistently effective when used at the recommended dilution. In addition, lime sulphur and enilconazole were 100% fungicidal even when the recommended concentration was diluted 1 : 4 or x4 as dilute as recommended.

Treatment of dermatophytosis in dogs and cats: review of published studies

The recent literature on the treatment of dermatophytosis in dogs and cats was reviewed. Based upon in vitro studies using isolated infected hairs and controlled or field in vivo studies, the following topical treatments were consistently found to be antifungal (i.e. antidermatophyte): lime sulfur (1:16), 0.2% enilconazole rinses, and a combined 2% miconazole/chlorhexidine shampoo. Animals or hairs were either bathed or rinsed once or twice weekly. Itraconazole, griseofulvin and terbinafine were evaluated in controlled or field studies, most commonly involving cats. Griseofulvin (50 mg kg(-1)) was reported to cure infected animals in 41-70 days. Itraconazole (10 mg kg(-1) once daily or in a combined daily/pulse therapy 10 mg kg(-1) once daily for 28 days and then week on/week off) was reported to cure infected animals in 56-70 days. Low-dose itraconazole (1.5-3.0 mg kg(-1)) in 15-day cycles required 1-3 cycles (15-45 days). Various doses of terbinafine (5-40 mg kg(-1)) were reportedly used to treat dogs or cats. The higher doses of terbinafine (> 20 mg kg(-1)) were required to achieve a mycological cure; the number of treatment days to cure varied from 21 to > 126 days. Lufenuron was reported anecdotally to be an effective cure, however, this was not substantiated in controlled studies. Finally, fungal vaccines were not found to be effective against challenge exposure, however, there is evidence that they may be useful in treatment protocols.

The prevalence of immediate and delayed type hypersensitivity reactions to Microsporum canis antigens in cats

Spontaneous recovery from Microsporum canis infections in cats is thought to be dependent on the development of a competent immune response. The purpose of this study was to determine the prevalence of positive delayed type hypersensitivity reactions in cats with and without dermatophytosis. Four groups of cats were intradermally skin tested with M canis extract and test sites were evaluated both subjectively and objectively at 0, 24 and 48 h after injection. Delayed intradermal testing (IDT) reactions were absent in cats not exposed to dermatophytosis (n=20); infected-recovered cats (n=38 culture negative lesion negative and n=43 lesion negative but culture positive) had significantly larger IDT reactions than unexposed cats and cats that were still actively infected (n=18). Based on the results of this study, IDT with M canis extract can be used to assess the cellular immune response of cats with dermatophytosis.

Effects of lufenuron treatment in cats on the establishment and course of Microsporum canis infection following exposure to infected cats

OBJECTIVE

To determine effects of lufenuron treatment in cats on the establishment and course of Microsporum canis infection following exposure to infected cats.

DESIGN

Experimental trial.

ANIMALS

24 healthy juvenile domestic shorthair cats.

PROCEDURE

8 cats were given lufenuron PO (133 mg/cat/mo, equivalent to a dose of 100 to 130 mg/kg [45 to 59 mg/lb] at the beginning of the study and 25 to 35 mg/kg [11 to 16 mg/lb] at the end of the study), and 8 were given lufenuron SC (40 mg every 6 months). The remaining 8 were used as untreated control cats. After 4 months, cats were challenged by the introduction of cats with mild, experimentally induced M canis infection into the rooms where cats were housed. Extent of resulting infections in the naïve cats was monitored for 22 weeks by physical examination and fungal culture.

RESULTS

All lufenuron-treated and control cats became infected with M canis. Cats treated with lufenuron had significantly lower infection scores, compared with control cats, during the early weeks following exposure, and there was a more prolonged initial progression phase of the infection. Once infections reached peak intensity, they resolved over similar periods in lufenuron-treated and control cats.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that oral or SC administration of lufenuron to cats, at the dosages used and under the conditions of this study, did not prevent establishment of dermatophytosis following exposure to infected cats. Infection was established more slowly among cats treated with lufenuron, but once established, infection resolved in approximately the same amount of time in lufenuron-treated as in control cats.

Safety and immunologic effects after inoculation of inactivated and combined live-inactivated dermatophytosis vaccines in cats

OBJECTIVE

To determine antidermatophyte immunologic effects of an experimental combined live-inactivated dermatophytosis vaccine (CLIDV) and a commercial inactivated dermatophytosis vaccine (IDV) in cats and to evaluate adverse effects associated with administration of these vaccines.

ANIMALS

20 healthy juvenile domestic shorthair cats.

PROCEDURE

Cats were injected with 2 doses of CLIDV at the standard dosage or 1 dose of CLIDV at 10 times the standard dosage; IDV was administered at the manufacturer-recommended dosage. Cats were observed for illness and reactions at inoculation sites. Periodically, samples were obtained for fungal culture, lymphocyte blastogenesis test (LBT) as an indicator of cell-mediated immunity against dermatophyte antigens, and antidermatophyte IgG titers. Following vaccination, cats were challenge-exposed by topical application of Microsporum canis macroconidia and examined weekly for clinical signs of dermatophytosis.

RESULTS

of 10 cats given CLIDV developed focal crusts at the injection site that resolved without treatment; these were areas of dermatophyte infection with the vaccine strain. Antidermatophyte IgG titers increased significantly with all vaccination protocols. Cellular immunity against M canis increased slightly and variably during the vaccination period and did not differ significantly between vaccinated and control cats. All cats developed dermatophyte infection after challenge exposure. Vaccination with CLIDV or IDV was associated with slightly reduced severity of initial infection.

CONCLUSIONS AND CLINICAL RELEVANCE

Noculation with IDV or CLIDV did not provide prophylactic immunity against topical challenge exposure with M canis. Inoculation with either vaccine did not provide a more rapid cure of an established infection.

Multiple-center study of reduced-concentration triamcinolone topical solution for the treatment of dogs with known or suspected allergic pruritus

OBJECTIVE

To determine the efficacy of triamcinolone acetonide topical solution (TTS) in dogs for use in reduction of clinical signs of pruritic inflammatory skin diseases of a known or suspected allergic basis and to evaluate adverse effects associated with TTS administration.

ANIMALS

103 pruritic adult dogs with known or suspected allergic skin disease.

PROCEDURE

Dogs were treated for 4 weeks with TTS or with vehicle solution (control dogs) in a multiple-center study. Clinical signs were scored by owners and by examining veterinarians before and after treatment. Blood samples obtained before and after treatment were subjected to routine hematologic and serum biochemical analyses.

RESULTS

Treatment success, as defined by an improvement of at least 2 of 6 grades in overall clinical score, was evident in 35 of 52 (67%) TTS-treated dogs (mean improvement, 1.98) and 12 of 51 (24%) control dogs (mean improvement, 0.29). For several criteria, TTS was significantly more effective than vehicle in reducing clinical signs. Minor alterations in hematologic determinations in TTS-treated dogs were limited to slightly lower total leukocyte, lymphocyte, and eosinophil counts after treatment. Minor adverse effects were reported by owners in 6 of 52 (12%) TTS-treated and 9 of 51 (18%) control dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Triamcinolone used as a spray solution at a concentration approximately one-sixth the concentration of triamcinolone topical preparations currently available for veterinary use is effective for short-term alleviation of allergic pruritus in dogs. Adverse effects are few and mild and, thus, do not preclude prolonged treatment with the solution.

Diagnostic techniques for dermatophytosis

This article reviews the use of common diagnostic tools for the identification and isolation of dermatophyte infections in small animals. The use of the Wood's lamp as a screening tool is discussed, along with its usefulness as an aid in the microscopic examination of hairs for fungal elements. Tests for the definitive diagnosis of dermatophytosis are highlighted and include: direct examination of hair for ectothrix spores, fungal cultures, and skin biopsy. Sampling techniques, procedures, and interpretation of test results are also detailed.

The effects of thyroid hormones on the skin of beagle dogs

The effects of hypothyroidism on canine skin were determined by comparing morphologic, morphometric, and hair cycle differences in skin biopsy samples from 3 groups of age- and gender-matched Beagle dogs: (1) euthyroid dogs; (2) dogs made hypothyroid by administration of 131I; and (3) dogs made hypothyroid and maintained in a euthyroid state by treatment with synthetic thyroxine. After 10 months of observation, there was slower regrowth of hair 2 months after clipping in the untreated-hypothyroid dogs. Untreated-hypothyroid dogs had a greater number of follicles in telogen and fewer hair shafts (ie, a greater number of hairless telogen follicles) than did the control group. The control dogs had a greater number of telogen follicles but the same number of hair shafts as the treated-hypothyroid group. Treated-hypothyroid dogs had the greatest number of follicles in the growing stage of the hair cycle (anagen). This study suggests that, at least in Beagles, induced hypothyroidism does not affect the pelage as dramatically as has been described in naturally occurring disease. This is because normal Beagles retain hair shafts in follicles for long periods, and the alopecia of hypothyroidism appears to evolve slowly because of the prolongation of this haired telogen stage. The evaluation of thyroxine-treated hypothyroid dogs demonstrates that thyroid hormone supplementation of Beagle dogs with induced hypothyroidism stimulates hair growth.