bluuebunny/crossref_metadata_2025 huggingface dataset:
Pathogenesis of canine atopic dermatitis: 2004 hypothesis
Authors: Olivry T.
Published: August 2004

The exact pathogenesis of canine atopic dermatitis (AD) remains elusive at this time. However, information on selected aspects of the immunological mechanisms of canine AD can be derived from the results of static (fixed‐point) and dynamic studies. Static studies yield data from samples collected at single time points and are thus fraught with imprecision dependent on the immunological stage of the lesions. In contrast, dynamic investigations provide information from sequential samples collected after immune cell activation with or without allergens. Examples of dynamic studies include stimulation of normal and atopic canine skin with intradermal injections of anti‐IgE antibodies, epicutaneous application (e.g. patch tests) with house dust mite allergens on sensitized dogs, and environmental challenges of sensitized dogs with house dust mites. This lecture will review results from selected static studies investigating epidermal lipids, epidermotropic and dermal immune cells, and cytokines detected in the skin of dogs with AD. Cellular inflammatory infiltrates and cytokines released during dynamic experiments will be reviewed subsequently. The information collated from various studies enables the generation of a working hypothesis for the pathogenesis of canine AD. In the acute phase of AD, a putative epidermal barrier defect could facilitate the contact of environmental allergens and microbes with epidermal immune cells at skin sites of friction and trauma. Epidermal Langerhans cells capture allergens with antigen‐specific IgE and migrate to the dermis and regional lymph nodes. Keratinocytes release chemokines that include thymus and activation‐regulated chemokine (TARC/CCL17). Allergen‐specific IgE‐coated dermal mast cells release histamine, proteases including chymase and tryptase, chemokines, and cytokines including TNFα and stem cell factor. There is an early influx of granulocytes (neutrophils and eosinophils), allergen‐specific Th2 lymphocytes and dermal dendritic cells. Eosinophils degranulate upon allergen challenge and release proteins that induce dermal and epidermal damage and inflammation. Th2 lymphocytes release cytokines promoting IgE synthesis (IL‐4 and IL‐13) and eosinophil survival (IL‐5). In chronic canine AD, microbes, self‐trauma and neuromediators are suspected to contribute to chronic inflammation. Chemokines are released in a continuous allergen‐dependent and ‐independent cycle, with subsequent influx and activation of leucocytes and further release of chemokines and other mediators. There is infiltration of T lymphocytes expressing type‐2 and type‐1 cytokines (IL‐12 and IFNγ). The failure to down‐regulate proinflammatory mechanisms leads to self‐perpetuating cutaneous inflammation.
Patch test reactions to house dust mites in dogs with atopic dermatitis
Authors: Nogueira S. A. F. , Torres S. M. F. , Horne K. , Jessen C.
Published: August 2004

The purpose of this study was to determine the percentage of dogs with spontaneous atopic dermatitis that show a positive patch test reaction to a commercially available 20% house dust mites mixture containing equal parts of Dermatophagoides farinae and Dermatophagoides pteronyssinus in white petrolatum. In addition, we evaluated whether skin reactions induced after the epicutaneous application of house dust mites were clinically and histologically similar to naturally developed skin lesions of dogs with atopic dermatitis. Furthermore, we investigated if the reactions induced by house dust mites were true allergic reactions by comparing them to atopic lesional skin and to patch test reactions induced by an irritant substance (sodium lauryl sulphate). White petrolatum alone and nonlesional skin sites were used as negative controls. Macroscopic and microscopic evaluations of the patch test and control sites were performed in a blinded fashion at 48 and 72 h after patch test application. Microscopic results were evaluated in a qualitative and quantitative manner. A chi‐square test for homogenicity was used for the quantitative analysis to compare the proportion of each dermal inflammatory cell type among positive histopathological tested sites. P values ≤ 0.05 were considered significant. The study included 12 healthy nonatopic dogs and 13 dogs with nonseasonal atopic dermatitis. None of the nonatopic dogs reacted to house dust mites and white petrolatum. Ten (77%) of the 13 atopic dogs reacted macroscopically and histopathologically to house dust mites. Macroscopic reactions induced by house dust mites were characterized by erythema, oedema and papules. The macroscopic reactions induced by house dust mites were identical to lesional skin in 20% of the dogs and identical to reactions induced by sodium lauryl sulphate in 40% of the dogs. Qualitative histopathological findings showed that the reactions induced by house dust mites were similar to atopic lesional skin in 80% of the dogs and were similar to sodium lauryl sulphate in 20% of the dogs. Quantitative analyses showed that the proportion of neutrophils in reactions induced by sodium lauryl sulphate was significantly higher (P < 0.05) compared to house dust mites reactions, which could be a differentiator factor between an allergic and an irritant reaction. These results showed that the epicutaneous application of house dust mites in dogs with atopic dermatitis induced histopathological lesions similar to spontaneous atopic lesions in dogs. Therefore, this study demonstrated that house dust mites penetrated the skin of dogs with atopic dermatitis and induced an inflammatory response that resembled a true allergic reaction.

Funding: Small Companion Animal Grant, University of Minnesota.
Conventional and rush immunotherapy in canine atopic dermatitis
Authors: Mueller R. S. , Fieseler K. V. , Zabel S. , Rosychuk R. A. W.
Published: August 2004

The purposes of this double‐blinded, randomized study were to determine the success rate of rush immunotherapy in canine atopic dermatitis and compare it to conventional immunotherapy, and to assess if rush immunotherapy leads to a quicker reduction in clinical signs than conventional immunotherapy. Twenty‐two atopic dogs diagnosed by history, physical examination and appropriate exclusion of differential diagnoses were included in the study. Offending allergens were identified with an intradermal test. All dogs were premedicated for 3 days with an antihistamine, and then hospitalized for 1 day. Injections with prepared treatment sets were administered every 30 min subcutaneously for 7 h; dogs were then discharged and continued on immunotherapy for 1 year. All dogs were evaluated monthly by their owners for 12 months, and by clinicians prior to therapy and after 3, 6, 9 and 12 months of therapy using a standardized scoring system to measure pruritus, lesions present and any concurrent medications given. Eleven dogs were treated with rush immunotherapy, and 11 dogs with conventional immunotherapy. Significant differences in mean pruritus, medication, lesion and total scores between groups were determined by use of a repeated‐measures ANOVA. Mean pruritus scores decreased from 13.5 to 6.7 (P = 0.0333) and from 13.9 to 10.3, medication scores from 23.6 to 10.6 (P = 0.0001) and from 14.1 to 13.6, lesion scores from 5.9 to 1.6 (P = 0.0001) and from 3.0 to 1.9, and total scores from 42 to 18.1 (P = 0.001) and from 30.6 to 21.5 in the rush immunotherapy group and in the conventional immunotherapy group, respectively. Using a Tukey–Kramer Multiple Comparison test, differences between the total scores at the beginning of the study and at the various time points reached significance after 3 months. An improvement of >50% in pruritus was noted in six of 11 dogs in the rush immunotherapy group and in five of 11 dogs in the conventional immunotherapy group; similar improvements in lesion scores and total scores were observed in dogs treated with rush immunotherapy (seven of 11 and five of 11 dogs, respectively) and in dogs treated with conventional immunotherapy (seven of 11 and four of 11 dogs, respectively). Based on these results, rush immunotherapy seems to be associated with a higher success rate than conventional immunotherapy, and improvement is typically seen within the first 6 months of therapy.

Funding: Morris Animal Foundation.
Acceleration of healing and improvement of scarring: from laboratory discovery to clinical practice
Authors: Ferguson M. W. J.
Published: August 2004

Acceleration of wound healing and improvement of scarring at skin graft donor sites and trauma or surgical lesions are important clinical goals in human and veterinary medicine. It has been discovered that wounds made on early mouse embryos heal quickly and perfectly, with no scars. The cellular and molecular differences between scar‐free embryonic healing and scar‐forming adult healing have been investigated. As a result, molecules have been identified which can be experimentally manipulated during adult healing, both to accelerate the process and to improve scarring. Some of these molecules represent pharmaceutical targets to which novel therapeutic agents have been developed. For example, embryonic wounds have high levels of TGFβ3 from endogenous keratinocytes and fibroblasts, but relatively low levels of TGFβ1 and TGFβ2 derived from degranulating platelets and inflammatory cells, by comparison to adult wounds. Therapeutically elevating the level of TGFβ3 allows adult rodent and porcine wounds to heal significantly faster and with improved scarring. These experimental findings have progressed into further studies in humans. A number of clinical trials with novel pharmaceuticals designed to accelerate healing and prevent scarring have been successfully completed, and further large patient‐based trials are ongoing. These studies indicate that pharmaceutical treatment of healing wounds to accelerate the process (e.g. accelerated re‐epithelialization of graft sites) or improve scarring may soon supplement the current surgical and device approaches to wound management.
The role of purinoceptors in wound healing
Authors: Braun M. , Lelieur K. , Kietzmann M.
Published: August 2004

Purinoceptors are membrane‐bound receptors for adenosine, purines and pyrimidines that are expressed in nearly all cell types throughout the organism. Previous studies demonstrated that they are involved in the regulation of proliferation of most target cells. Since it is well known that several purinoceptors are expressed in skin keratinocytes, we were interested in examining their involvement in wound healing. Primary skin keratinocytes from four different mouse strains were isolated and cultured for in vitro studies. The expression patterns of metabotropic purinoceptors of the primary cells as well as a murine cell line were determined by RT‐PCR analysis. The specificity of the amplification products was verified by sequence analysis. Proliferation assays with various purinoceptor agonists and antagonists were performed using the murine cell line MSC‐P5. Cell proliferation was determined by incorporation of 5‐bromo‐2‐deoxyuridine (BrdU). Female NMRI mice were used for in vivo trials. To inhibit the wound healing process, animals were treated once daily with dexamethasone. After a week of treatment, full thickness wounds were set with biopsy punches in depilated back skin. The wound healing process was measured by determination of the wound area and the incorporation of BrdU in vivo. The purinoceptor agonists and antagonists were administered topically on the wound area. Among the examined metabotropic purinoceptors, the murine cell line MSC‐P5 expressed the receptors A2b, P2Y1, P2Y2 and P2Y6. Primary cultured murine keratinocytes possessed the same expression profile and they additionally expressed the P2Y4 receptor. Furthermore, three of the four primary cultures showed a splicing variant of the P2Y2 receptor. The purinoceptor agonists ATP, UTP and 5’‐(N‐ethyl)‐carboxamidoadenosine (NECA) enhanced the cell growth of the murine cell line MSC‐P5. The mitogenic effect of ATP and UTP was inhibited by the P2Y1, P2Y2 and P2Y6 receptor antagonist suramin, while the effect of NECA was inhibited by the selective A2b receptor antagonist enprofylline. Taking into account that other tested purinoceptor agonists, 2‐Me‐S‐ATP and UDP, exhibited no proliferative activity on MSC‐P5 cells, it can be concluded that ATP and UTP act on proliferation via the P2Y2 receptor, and NECA via the A2b receptor. In vivo trials in an animal model of impaired wound healing confirm that pharmacological actions via purinoceptors offer an intriguing possibility in the treatment of wounds. Nevertheless, further investigations are needed to fully elucidate the role of purinergic mechanisms involved in wound healing.

Funding: Self‐funded.
Histopathological and clinical characterization of dermatopathy associated with toxic shock‐like syndrome in dogs
Authors: Ramiro‐Ibanez F. , Walder E. J. , Gross T. L.
Published: August 2004

Toxic shock syndrome (TSS) in humans is a systemic disease caused by the release of bacterial toxins with superantigen activity. Most cases in humans are related to production of toxic shock syndrome toxin‐1 (TSST‐1) by strains of Staphylococcus aureus. Clinically, they manifest with high fever, hypotension, diarrhoea, myalgia, skin rash and oedema, often progressing to desquamation of the skin. External or internal infections may be the origin. In dogs, the most common bacterial organism isolated from cases of bacterial pyoderma is Staphylococcus intermedius. This bacterium has also been shown to produce exotoxins, including TSST‐1. Retrospectively, 11 dogs with clinical presentations and histopathological lesions closely resembling TSS in humans were evaluated. The animals ranged in age from 1.5 to 13 years, with a mean of 4.65 years. No sex predisposition was found. The breeds represented in the study were varied, including small breeds (pug, Boston terrier) and large breeds (golden retriever, Labrador retriever). The most common clinical presentation was multicentric to generalized cutaneous erythema (n = 10) and oedema (n = 7), in some cases with vesicles (n = 4) and pustules (n = 3) evolving to ulcers (n = 3). The extremities, ears and ventrum were frequently involved. Systemic signs were invariably present. Mild anaemia (n = 8), hypoalbuminaemia (n = 8), depression (n = 8) and neutrophilia (n = 7) were the most consistent abnormalities. Fever (n = 5) and thombocytopenia (n = 5) were also observed. Complete clinical history was not obtained in two cases that were compatible with this condition on histopathological exam. In general, there was a good response to systemic treatment with cephalexin (n = 4); in cases for which early antibiotic therapy was not instituted, the outcome was usually fatal(n = 5). In the only case cultured, pustular lesions yielded a mixed population of coagulase‐positive Staphylococcus spp. and Pseudomonas spp. Histologically, the most characteristic pattern was superficial dermatitis with epidermal neutrophilic exocytosis and necrotic (apoptotic) keratinocytes, often with neutrophilic satellitosis. The lesions evolved to panepidermal necrosis with ulceration in some dogs, a phenomenon unrelated to the final outcome. The pathogenesis of the skin lesions in human cases of TSS seems to be related to the nonspecific stimulation of lymphocytes by the bacterial superantigen and the release of high levels of cytokines, specifically TNFα. Until further characterization of the process is obtained, biopsies with features of neutrophilic exocytosis and apoptosis should warrant consideration of TSS, and immediate antibiotic treatment (cephalexin) should be instituted to prevent potential fatal progression of the disease.

Funding: Self‐funded.
P‐1  Evaluation of the influence of sex, diet and time on hair coat characteristics of cats
Authors: Bourdeau P. , Taylor K. W. , Nguyen P. , Biourge V.
Published: August 2004

Skin physiology in cats has received little attention. The aim of this study was to evaluate the long‐term influence of sex, time and the level of dietary fat and energy on the dynamics and qualities of the hair coat. Twenty‐four European short‐haired laboratory cats were followed over a 1‐year period. They were divided into eight groups of three, according to: sex (12 males and 12 females), sexual status (intact or neutered) and diets [(high energy 4300 kcal/kg as fed, 21% fat) vs. (moderate energy 3500 kcal/kg as fed, 10% fat)]. Both diets were fed for 6 months to all cats following a cross‐over design. The following parameters were evaluated throughout the study: thickness of hair coat and hair lengths (neck, rump, lateral, flank), hair regrowth (after periodic clippings of 25 cm2 areas), and telogen/anagen ratio. The thickness of the hair coat initially varied from 1.2–1.7 cm on the neck, 1–1.4 cm on the rump, 1.8–2.5 cm on the flank, and hair shaft lengths were 1.7–2.5, 3.7–3.9 and 2.5–3.2 cm, respectively. Comparison of values revealed few statistical differences: increase of the thickness of hair coat in neutered cats (male and female) during the study, and increase of the length of lateral hairs in all groups during the study. Over all periods and in all groups, the curve of growth was similar (rapid then slower). Some transient variations were attributed to temporary changes in ambient conditions. In conclusion, neither sex, nutrition or season (in housed cats) influenced the general quality of hair coat, in particular hair regrowth.

Funding: Royal Canin.
P‐10  Comparison of carpet and toothbrush methods for the detection of asymptomatic carriage of dermatophytes in cats
Authors: Bourdeau P. , Costiou F. , Peron C.
Published: August 2004

Diagnosis of Microsporum canis infection is a challenge in cats with suspected asymptomatic carriage. The aim of this study was to compare the carpet method and the toothbrush method of sample collection for dermatophyte culture. The study was conducted on apparently healthy cats in a chronically infected cattery. Sampling was performed with both a sterilized piece of carpet and a toothbrush applied to the entire body surface. Samples were inoculated on Sabouraud's media (with chloramphenicol and cycloheximide). Multiple (6) applications with the toothbrush were necessary to obtain a similar surface area of inoculation. Cultures were incubated at 27°C, then examined from day 5 to 21 for the presence and number of colonies of M. canis and other fungi. Some samples were inoculated twice (initially negative or with a low number of M.canis). A total of 112 cultures were performed (14 duplicates) from 44 cats. On day 21, infection was detected in 23 cats (54.7%): 20 (87%) with the carpet method and 21 (91%) with the toothbrush method. None of the replicated cultures allowed the detection of new cases but three were subsequently negative. In eight cases, only one to six colonies of M. canis were obtained. Both methods used are easy to perform on cats and have a similar sensitivity of approximately 90%. The carpet method is, however, much less expensive, easier to prepare, mail, store and inoculate. The lack of growth in some duplicate cultures (initial development of one or two colonies) may explain the limits of diagnosis of infection and justify the need for multiple inoculations of agar with the toothbrush method.

Funding: Self‐funded.
P‐11  Occurrence of dermatophytes in dogs and cats and their susceptibility to antifungal drugs
Authors: Zdovc I. , Mičunovi J. , Pirš T. , Ocepek M.
Published: August 2004

The purpose of this study was to evaluate the frequency of dermatophytosis in dogs and cats with skin disorders and in clinically healthy animals suspected to be a source of human dermatophyte infection. Over a 2‐year period, 776 samples from 339 dogs and 437 cats were examined. Samples were cultured on Sabouraud's dextrose agar (with chloramphenicol and actidione) for 2–3 weeks. Antifungal susceptibility tests for ketoconazole, fluconazole, itraconazole, amphotericin B and flucytosine (E test) were performed to establish the MIC values. Different dermatophyte species from the genus Microsporum and Trichophyton (M. canis, M. gypseum, T. mentagrophytes, M. persicolor) were isolated from 194 samples (25.0%). Among 57 positive dogs, M. canis was isolated from 26 (45.6%), T. mentagrophytes from 28 (49.1%), M. gypseum from two (3.5%) and M. persicolor from one (1.7%). Among 137 positive cats, M. canis was isolated from 124 (90.5%), T. mentagrophytes from 12 (8.7%) and M. gypseum from one (0.7%). These results are different to those reported in the past, where M. canis was the predominant dermatophyte species in both dogs and cats. In the last 2 years, the occurrence of T. mentagrophytes infections in carnivores has evidently increased, especially in dogs. One of the possible reasons is the increasing number of rabbits and rodents being kept as pet animals. As T. mentagrophytes is often isolated from these animals, they may serve as a source of infection. The results of susceptibility testing to antifungal agents were similar to those obtained in previous testing with most dermatophytes susceptible to ketoconazole and itraconazole, but resistant to fluconazole.

Funding: Self‐funded.
P‐12  Comparative study of griseofulvin and terbinafine therapy in the treatment of canine and feline dermatophytosis
Authors: Balda A. C. , Otsuka M. , Gambale W. , Larsson C. E.
Published: August 2004

In domestic carnivores, dermatophytosis is caused mainly by two fungal genera: Microsporum spp. and Trichophyton spp. These diseases are anthropozoonoses of significance in public health. The goal of this study was to compare the efficacy of griseofulvin and terbinafine in the therapy of the dermatophytosis. Thirty‐five animals were included in three protocols of treatment. Griseofulvin was used at a dosage of 50 mg/kg once daily. It was effective in 100% of the cases, with no side effects, and the average time until cure was 41 days. Terbinafine was used at a dosage of 5 mg/kg once daily. It was effective in 81.3% of cases, no side effects were observed, and the average time until cure was 21 days. Terbinafine used at a dosage of 20 mg/kg once daily was similarly effective. However, at this higher dosage, the average time to cure was 33 days and side effects such as vomiting, diarrhoea and an increase in transaminase and alkaline phosphatase serum activity were seen in 16.6% of the animals. This study demonstrated that terbinafine is a good therapeutic alternative, although griseofulvin is still the first‐choice drug for the treatment of dermatophytosis in dogs and cats.

Funding: Self‐funded.
P‐13  Dermatophytosis in domestic cats: treatment with lufenuron
Authors: Ramadinha R. R. , Reis R. , Campos S. G. , Ribeiro S. S. , Peixoto P. V.
Published: August 2004

Preliminary studies showed that lufenuron inhibits chitin synthesis, a dermatophyte cell wall constituent, and may be effective in the treatment of dermatophytosis. Our purpose was to evaluate the efficacy of lufenuron in the treatment of feline dermatophytosis. Forty‐six cats (Persians and mixed‐breed cats from 1‐month to 4‐years old) naturally infected with Microsporumcanis were included in this study. Fifteen cats were treated isolated in cages in the veterinary hospital and 31 were treated in their home environment (some with access to the outdoors). Dermatophyte skin lesions were seen in 29 animals while 17 other cats were asymptomatic carriers. Wood's lamp, direct microscopic examination of hairs, fungal culture and skin biopsies were used for the diagnosis. Affected cats and all in‐contact animals received lufenuron at a dose of 120 mg/kg every 21 days for four treatments. Of the 29 symptomatic cats treated with lufenuron, 70% recovered within 21 days and 28% within 42 days of initiation of therapy. One cat had only partial recovery and another was euthanized. Negative fungal culture was recorded only after the fourth dose of lufenuron in 98% of affected cats and 100% of asymptomatic carriers. There was no difference in clinical response to lufenuron between the cats treated in their home environment and those treated in the veterinary hospital. Side effects were not observed, thus the drug proved to be safe and effective for the treatment of dermatophytosis.

Funding: Novartis.
P‐14  Use of lufenuron in the therapy of canine and feline dermatophytosis in São Paulo (Brazil)
Authors: Sonoda M. , Balda A. C. , Otsuka M. , Gambale W. , Larsson C. E.
Published: August 2004

The goal of this study was to evaluate the efficacy of lufenuron in the treatment of animals with dermatophytosis [M. canis or M. gypseum (n = 48) and T. rubrum (n = 1)]. The study was performed over a 2‐year period. The 49 animals (23 dogs and 26 cats) were randomly separated into four groups, each one receiving 50–120 mg/kg of lufenuron, divided into one to four doses administered at various intervals. Liver enzyme measurement were performed on all animals. The results showed clinical and mycological cure in 22–60% of the animals treated in the study, with the highest efficacy in the group treated with 120 mg/kg given in two doses at a 3‐week interval (group IV). No systemic or cutaneous side effects or changes in liver enzyme levels were observed in any of the animals. Persian cats and Yorkshire terrier dogs had the highest rates of therapy failure. Lufenuron was more effective in dogs than cats. Morphological changes occurred in isolated Microsporum spp. colonies on culture.

Funding: Self‐funded.
P‐15  Identification of Malassezia spp. isolated from a cat and cattle, including a new species, M. nana
Authors: Hirai A. , Kano R. , Makimura K. , Yamaguchi H. , Hasegawa A.
Published: August 2004

Isolates from a cat and cattle with or without otitis externa in Japan and Brazil were thought to be Malassezia spp.,but were clearly distinct from the other nine species of Malassezia which have been reported by molecular analysis, including M. dermatis and M. japonica. These isolates resemble M. dermatis and M. sympodialis morphologically and physiologically, but can be distinguished from these two species by their ability to use cremophor EL as the sole source of lipid and to split esculin. These isolates were classified as a novel species, Malassezia nana,by mycological examination as well as molecular analysis. Methods to identify seven Malassezia species have been reported, but they do not include the three new species, M. nana, M. dermatis and M. japonica. In this study, we described a practical approach to the identification of all 10 species of Malassezia yeasts from clinical material. We improved the identification system by examining lipid requirement, catalase reaction, precipitate production on modified Dixon agar, utility of cremophor EL, ability to split esculin and the shape of cells. This approach represents an identification scheme for Malassezia spp. without elaborate equipment.

Funding: Self‐funded.
P‐16  Treatment of Malassezia otitis in dogs: a comparative field trial
Authors: Bensignor E.
Published: August 2004

Otitis externa (OE) is a very common disease of dogs. Various treatments are available for OE, but most commercial preparations contain a mixture of antifungal, anti‐inflammatory drugs and antibiotic agents. The aim of this study was to evaluate if a commercial product containing clotrimazole, marbofloxacin and dexamethasone (Aurizon®) was more effective than the use of a topical antifungal agent econazole (Daktarin®) used alone to treat Malassezia otitis. Dogs presenting with bilateral OE and numerous yeasts on cytological examination were included. Twenty dogs aged from 1 to 14 years old were treated in this trial (40 ears, 20 in each group). Each case was treated with Aurizon® (four drops) in one ear and Daktarin® in the other ear. Criteria analysed were pruritus (visual analogue scale), erythema, amount of cerumen, and the number of yeasts on cytologic smears. All animals demonstrated a good improvement in Malassezia counts after either treatment. Significant differences were noted in favour of Aurizon® for erythema, cerumen, and pruritus on various days of evaluation. This study demonstrated the superiority of a mixture of corticosteroids and antifungal agent in comparison with an antifungal agent used alone for the treatment of Malassezia OE.

Funding: Self‐funded.
P‐17  In vitro activity of posaconazole and other antifungals against Malasseziapachydermatis isolated from dogs
Authors: Bourdeau P. , Marchand A. M. , Etoré F.
Published: August 2004

The aim of this study was to determine the in vitro antifungal activity of several antifungal drugs (posaconazole, nystatin, miconazole and clotrimazole) against Malassezia pachydermatis with microdilution and agar dilution techniques. Malassezia pachydermatis isolates were obtained from the skin and ears of dogs. Tests on solid media were performed using 25‐well Petri dishes (2 mL/well containing Sabouraud's dextrose agar and diluted antifungal drug) inoculated with 5 μL suspensions of M. pachydermatis. Microtitre broth dilution used 96‐well microtitre plates containing Sabourauds dextrose broth and appropriate dilutions of antifungal drugs, inoculated with 10 μL standard suspensions of M. pachydermatis. Plates were inoculated in duplicate and incubated at 30°C for 5 days and growth assessed. The four antifungal drugs were tested in 10 dilutions (4.0‐0.007 μg/mL for posaconazole, and 32‐‐0.06 μg/mL for clotrimazole, miconazole and nystatin). Results obtained for 83 strains of M. pachydermatis and a control reference strain (CBS 1879) exhibited the same pattern. Results of the MIC between microtitre and agar methodologies showed no significant differences (≤ 2‐fold) across all drugs. For both solid and liquid methods, posaconazole was the most effective antifungal drug of the four tested with MIC90 of 1–2 μg/mL for posaconazole, 16–32 μg/mL for clotrimazole, and ≥ 32 μg/mL for miconazole and nystatin.

Funding: Schering‐Plough.
P‐18  Cryptococcosis in São Paulo (Brazil): clinical and epidemiological features (1992–2003)
Authors: Chiesa S. C. , Castro R. C. , Otsuka M. , Michalany N. S. , Larsson C. E. , Larsson C. E.
Published: August 2004

Cryptococcosis is a relatively frequent disease in the southwest region of Brazil. We have diagnosed 19 cases of cryptococcosis (1.6 cases/year) at our hospital in the last 12 years. Cats were most frequently affected (18 feline and one canine) among our cases. The disease was most frequent in purebred Siamese cats (55.5 %), and in male cats (77.8 %) with an age predisposition of 4‐ to 6‐year‐old animals (56.2%) and 7‐ to 9‐year‐old animals (18.8 %). The diagnosis was established by cytologic and histopathologic examination, fungal culture and serologic evaluation. All cases was caused by Cryptococcus neoformans serotype AD. We used fungal culture as the gold standard for the diagnosis. Histopathology was positive in 93.3% of cases and the cytologic examination in 75% of cases. Most cats were FIV and FeLV negative. Ocular involvement was found only in the canine case which is the first report of canine cryptococcosis in Brazil. Itraconazole (10 mg/kg once daily) as the sole therapy or in conjunction with 5‐fluorocytosine was effective in 95% of the patients.

Funding: Self‐funded.
P‐2  Evaluation of the influence of sex, diet and time on skin pH and surface lipids of cats
Authors: Bourdeau P. , Taylor K. W. , Nguyen P. , Biourge V.
Published: August 2004

Skin lipids and pH are two factors classically considered of importance in homeostatic characteristics of skin. Skin physiology in cats has received little attention. The aim of this study was to evaluate the long‐term influence of sex, sexual status, season, and dietary fat and energy on these parameters. Twenty‐four European short‐haired laboratory cats, 14 months of age, were followed over a 1‐year period. They were divided into 8 groups of three, according to: sex (12 males and 12 females), sexual status (intact or neutered) and diets [(high energy 4300 kcal/kg as fed, 21% fat) vs. (moderate energy 3500 kcal/kg as fed, 10% fat)]. Both diets were fed to all cats for 6 months following a cross‐over design. Parameters regularly evaluated were skin pH and hair total lipid content (extraction from samples of 0.6–1.2 g of clipped hairs). The pH of the skin varied from 6.6–6.8 initially to 7.2–7.4 at the end of the study. This increase was significant only in intact animals (male and female). The dietary changes did not affect skin pH. Hair total lipid content was not affected by sex or the diets but slightly increased in all groups over the study period from 1.5–2.4 to 2.4–3.3%. In conclusion, skin pH appeared to be potentially modified by sexual status, but not by sex or dietary lipids and energy. Hair lipids do not appear to be affected by sex or increases in dietary lipids and energy. The slight increase in pH and hair lipids during the study was attributed to the change from young adult to adult stage of all cats.

Funding: Royal Canin.
P‐20  Clinical, cytopathological and histopathological evaluation of sporotrichosis in experimentally infected cats
Authors: Farias M. R. , Franco S. R. V. S. , Fabris V. E.
Published: August 2004

The purpose of this study was to evaluate the clinicopathological aspects of experimental sporotrichosis in cats and compare the sensitivity of cytopathology, histopathology and culture as diagnostic tools in different phases of the infection. Twenty adult, mixed‐breed cats (10 males and 10 females) were inoculated subcutaneously with 106 fungal microorganisms. Clinical examination was performed weekly. Cytopathologic, histopathologic and culture examinations were performed at 15, 30 and 60 days postinoculation. Culture of multiple organs was performed after euthanasia at 30 (10 cats) and 60 (10 cats) days postinoculation. Friedman parametric and nonparametric statistical analysis were applied to the results. The nodular, tumoral and necrotic lesionsprogressed significantly until day 30 postinoculation, and partial spontaneous regression occurred at day 60, particularly in males. An intense inflammatory pyogranulatomous and lymphocytic infiltrate with rare giant cells and sparse fibrosis associated with numerous, pleomorphic, intra‐ and extracellular fungal cells were observed on day 30. These findings gradually decreased by day 60. Despite the inflammatory granuloma associated with feline sporotrichosis, a tendency for dissemination was observed, with fungal isolation in the lymph nodes, spleen and liver at the 30 and 60 days postinoculation. No significant differences were observed between cytopathology, histopathology and fungal culture during the different phases of the disease. Therefore, cytological examination was considered a simple, rapid and inexpensive diagnostic method at all stages of this disease.

Funding: Self‐funded.
P‐21  Comparison of a permethrin‐pyriproxyfen spray and fipronil spot‐on used alone in a therapeutic trial for the diagnosis of canine flea allergy dermatitis
Authors: Jasmin P. , Briggs M. , Schroeder H. , Sanquer A.
Published: August 2004

This randomized clinical trial compared two parasiticides [permethrin‐pyriproxyfen spray (Duogard® Spray/Duowin® Spray) and fipronil spot‐on (Frontline® Spot‐on)] for use in the diagnosis of canine flea allergy dermatitis (FAD). Dogs with a flea infestation, minimum FAD clinical score and a positive intradermal test were treated with either one of the parasiticides applied three times at 1‐week intervals. It was required that the dogs live partially outdoors, with at least one nontreated in‐contact pet, and an environment that had not been treated within the previous year. Both groups were compared for clinical improvement and the number of dogs showing a positive response to the therapeutic test (defined as > 75% clinical improvement). Twenty‐seven dogs were included; two were lost to follow‐up, 12 were treated with the spray and 13 with the spot‐on. Mean scores for pruritus and lesions decreased rapidly in the permethrin‐pyriproxyfen spray group, but more slowly in the fipronil spot‐on group. There was a significant difference between the two groups at all consultation time points (P < 0.05). After 3 weeks, responses were positive in all dogs treated with the permethrin‐pyriproxyfen spray, and significantly higher than with the fipronil spot‐on (P < 0.05). The sensitivity of the therapeutic trial was 100% for the spray and 31% for the spot‐on. Negative predictive values varied from 14 to 65% with the spot‐on and were 100% with the spray. No adverse effects were observed. The permethrin‐pyriproxyfen spray can be recommended as a useful product to perform a therapeutic trial in confirming a diagnosis of FAD in dogs.

Funding: Virbac SA.
P‐22  Mites of interest in canine and feline dermatology: evaluation of their survival and structural integrity in oil preparations for microscopy
Authors: Manigot G. A.
Published: August 2004

Diagnostic dilemmas often arise when veterinary practitioners suspect a parasitic skin disease but direct microscopy of collected samples are negative. It has been suggested that the delay between collection of the sample in the veterinary practice and evaluation at the referral laboratory results in parasite lysis. This study was performed to determine if delay in processing the samples may lead to negative results. A further aim was to determine if using other oil media (when mineral oil was not available) would result in parasite modification. One‐hundred samples of skin scrapings and otic smears in several oil media from dogs and cats diagnosed as positive for several mites of dermatological importance were kept under room conditions and evaluated over a 21‐day period for mite survival and retention of recognizable structural features. Mineral oil, kitchen grade olive oil, pharmaceutical grade baby oil and glycerin were used as oily media to process the samples. At the end of the study, mite survival rate was established between 2 and 5 days. Sarcoptes and Otodectes mites survived the longest. After 21 days of observation, all parasites and their eggs still remained recognizable, no matter which oil medium was used. It was concluded that a delay in the submission of samples does not result in negative findings.

Funding: Self‐funded.
P‐24  Efficacy of selamectin in canine scabies and ear mite infestation in Korea
Authors: Oh T. H. , Oh W. S. , Kim S. R. , Oh H. Y. , Hoh W. P. , Jeong A. Y. , Jeong H. H. , Park S. J.
Published: August 2004

A randomized and controlled field study was performed in canine patients to evaluate the efficacy of selamectin in the treatment of naturally occurring Sarcoptes scabiei and Otodectes cynotis infestations in dogs. A total of 227 dogs from six veterinary practices in South Korea were included. Dogs were randomly assigned to treatment with selamectin or a positive‐control product. Selamectin was administered as a unit dose providing a minimum of 6 mg/kg in a topical preparation applied to the skin in a single spot on days 0 and 30 [S. scabiei (n = 113) and O. cynotis (n = 114)]. The presence of parasites was assessed before treatment and at 14, 30 and 60 days after the initiation of treatment. The animals were evaluated clinically at each assessment period. Based on skin scrapings, the efficacy of selamectin against S. scabiei infestations on dogs was >95% by day 30, and 100% by day 60. Against O. cynotis, selamectin eliminated mites in 100% of dogs by day 60. However, clinical signs of pruritus, erythema, scale, and crusted papules did not diminish concomittantly with resolution of S. scabiei in skin scrapings. The positive‐control products achieved similar results. Therefore, selamectin was safe and effective against sarcoptic mange and ear mites in dogs.

Funding: Pfizer Animal Health.
P‐25  Sensitivity of deep skin scrapings, hair pluckings and exudate microscopy in the diagnosis of canine demodicosis
Authors: Saridomichelakis M. N. , Koutinas A. F. , Farmaki R. , Leontides L.
Published: August 2004

Diagnosis of canine demodicosis is mainly based on mite detection in deep skin scrapings (DSS). Hair pluckings (HP) are also helpful, whereas the diagnostic value of exudate microscopy (EM) has never been assessed. The objective of this study was to compare the diagnostic sensitivity of DSS, HP and EM in the various clinical forms of canine demodicosis. A total of 68 dogs with localized (45.6%) or generalized (54.4%) demodicosis, juvenile‐onset (92.6%) or adult‐onset (7.4%) demodicosis were included. Pyoderma was present on 41.2% of cases and absent in 58.8% of cases. One lesion per dog was selected for obtaining one HP, DSS and EM sample, the latter only in 14 cases demonstrating visible exudate. Mineral oil DSS and EM microscopy was focused on a 2.2 × 2.2 mm area, while a total of 100 hair shafts were evaluated by trichogram. At least one parasite was seen in 83.8% of HP, 98.5% of DSS and 100% of EM slides. The sensitivity of HP was higher in the generalized (P = 0.001) and pyoderma‐affected (P = 0.021) cases compared to the localized and noninfected cases. A higher sensitivity of DSS compared to HP was demonstrated in the localized (P = 0.004) and noninfected (P = 0.002) cases. In conclusion, HP should be viewed as a useful diagnostic tool in generalized and infected canine demodicosis, while EM is useful in all deep pyoderma‐associated cases.

Funding: Self‐funded.
P‐26  New aspects of canine demodicosis and the possibility of treatment with selamectin
Authors: Tarpataki N. , Kadocsa E. , Vörös K.
Published: August 2004

The purpose of this study was to evaluate 55 clinical cases of canine demodicosis and to compare the results of treatment using amitraz (solution), selamectin (spot‐on), ivermectin (injection) and cythioate (oral tablets). Data from the 55 cases was collected and evaluated after clinical and microbiological examination. Treatment was selected depending on the severity of demodicosis and compliance of the owner. The cases were followed for 12 months and the status of the patients was grouped on two levels: recovered (58%), or relapsed (42%). Five dogs (9%) were euthanized. The disease was commonly diagnosed in purebred dogs. Demodicosis was more common in dogs under 2 years of age (65%), in males (64%), and in the short‐haired breeds (75%). Demodicosis was generalized in 73% of cases, localised in 23% and affected the feet (pododemodicosis) in 4% of cases. Recovery was the highest in dogs between 1 and 2 years of age (73%), and in the localized cases (92%). Nonspecific treatment with glucocorticoids prior to the diagnosis lowered the rate of recovery (4%), but treatment with glucocorticoids for proven atopic dermatitis improved the rate of recovery (41%). All drugs (amitraz, selamectin, cythioate) administered for the localized form were effective (100% recovered). Recovery in generalized demodicosis was 60% using ivermectin, 55% using amitraz, 44% with the combination of amitraz and selamectin (two treatments with amitraz followed by selamectin), and 43% in cases where selamectin was used alone.

Funding: Pfizer Animal Health.
P‐27  Characteristics of Dermacentor reticulatus and Ixodes ricinus infestations in 191 dogs in France
Authors: Bourdeau P. , Ximenes T. , Beziade O.
Published: August 2004

The aim of this study was to evaluate the distribution of ticks on the body and characteristics of tick populations and their consequences. The studies were conducted in France in two clinics (A and B) over 10 months. Dogs were carefully examined for the presence of ticks (all dogs in group A, and 150 dogs per month in group B). Information on hair coat (long, medium, short), pruritus, number of ticks, distribution of ticks on the body, and identification of ticks was collected. An intradermal test (Dermatophagoides farinae, D. pteronyssinus) was performed on most of the tick‐positive dogs in group A. In group A, 87 dogs (4.5%) were infested with ticks, while in group B, 104 dogs (9%) were infested. There was no significant difference in infested dogs compared with control dogs with regard to coat length. The level of infestation was generally very low: <5 ticks in 81.5%, 5–9 ticks in 12.2%, and ≥ 10 in 6.3% of infested dogs. Of 528 ticks collected, Dermacentor reticulatus was the most abundant (67%), followed by Ixodes ricinus (32.9%) and Rhipicephalus sanguineus (0.1%). Ticks were found mainly on the head (41%) and neck (52.9%), and less frequently on the trunk, ventrum, legs, perianal and tail areas. Twenty‐eight per cent of infested dogs were pruritic compared to only 10% in ectoparasite‐free dogs. In 65 intradermal tests, 23% were positive to D. farinae and 6% to D.pteronyssinus.

Funding: Self‐funded.
P‐29  Pustular dermatosis caused by fire ant (Solenopsis invicta) stings in a dog
Authors: Conceicao L. G. , Haddad V. , Loures F. H. , Leal M. E. , Clare F.
Published: August 2004

Solenopsis invicta (lavapés ants or imported fire ants) are insects that belong to the Hymenoptera order and Formicoidea superfamily. Native to Brazil, this aggressive ant species is today disseminated throughout the Americas. In humans, the sting of the fire ant causes an urticarial papule that progresses within 24 h to a highly pruritic, sterile pustular dermatitis. Children and alcoholics are more often affected, presenting with massive injuries. Subcorneal neutrophilic pustular dermatitis is the usual histopathological finding. One study has reported that fire ant stings in dogs leads to a vertically oriented necrotizing dermatitis with collagen degeneration. This abstract reports a natural fire ant‐induced dermatosis in a dog. We report a female, intact, young‐adult, mixed‐breed dog presented for routine check‐up. Physical examination revealed several grouped, nonfollicular, circumscribed abdominal and inguinal pustules. The pustules were relatively tense, circumscribed by a slight erythematous halo, and several dead fire ants were attached to the skin and hairs. No bacteria were seen on cytological examination. Histopathological examination revealed an intraepidermal neutrophilic pustule and dense dermal interstitial, predominantly neutrophilic, infiltration, which extended to the panniculus. Collagen degeneration and edema were also observed. This case documents that fire ant stings can produce pustular intraepidermal dermatitis in dogs similar to that observed in humans.

Funding: Self‐funded.
P‐3  Involvement of the accessory gene regulatory (agr) system in quorum sensing by Staphylococcus intermedius
Authors: Sung J. M. L. , Chantler P. D. , Lloyd D. H.
Published: August 2004

Toxic exoproteins are believed to be involved in the pathogenesis of Staphylococcus intermedius pyoderma and bacterial overgrowth, although these diseases are poorly understood. This study aims to determine whether quorum sensing, a phenomenon in which cells express particular characteristics only when population densities exceed certain levels, might be involved. Production of virulence factors by S. intermedius was hypothesized to be initiated by the agr system via signalling molecules generated as cell density increased, as in S. aureus. Initial studies (agr‐specific PCR, genome walking) confirmed the presence of sequences in S. intermedius related to the agr of S. aureus. To test the hypothesis that expression of RNAIII (effector of the agr system) and two exotoxins, leukotoxin and enterotoxin C, are initiated by an environmental signal generated during bacterial growth, experiments were performed in which spent culture supernatants from different phases of growth were added to early exponential cultures of S. intermedius in which the genes are minimally expressed. Through real‐time quantitative PCR, it was shown that concentrated supernatant of midexponential and postexponential cultures from S. intermedius strains 3 and 27 up‐regulated expression of genes encoding for RNAIII, leukotoxin and enterotoxin in strain 3. This indicates that the activating substance accumulates in supernatant during growth. In contrast, S. intermedius was insensitive to spent medium from S. aureus strain J3964. This suggests that S. intermedius uses quorum sensing to monitor the proximity of other signal‐producing cells and thereby adjusts its expression of virulence genes appropriately to facilitate species‐specific and intraspecies cell‐cell communication.

Funding: Nestlé Purina Research Company.