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.

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.

Feline atopy in three littermates.

This case report describes the history, clinical signs and diagnosis of a pruritic skin disease in three sibling cats living the same household. Clinical signs consistent with pruritus (i.e. hair pulling, hair loss, excessive grooming and face rubbing) were first noted when the cats were 6 months of age. The cats were treated for a possible ear mite and/or flea infestation; there was no response to treatment and clinical signs progressed. Although the presence of pruritus in a multiple cat household suggested an infectious or contagious aetiology, none could be identified. There was no improvement in clinical signs after a 60-day flea control trial, three treatments of ivermectin, an 8-week restricted diet or removal from the home for 10 days. A diagnosis of feline atopy was made on the basis of elimination of other causes of pruritus, consistent history and clinical signs, a positive intradermal skin test and response to therapy.

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.

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.

Parasitic relationship between Microsporum canis and the cat.

Cats are often cited as reservoirs of M. canis but it is questionable whether M. canis is part of the resident flora of the cat's skin and hair or only a transient organism. Studies indicate that M. canis is most often isolated from cats at risk of infection or exposure from other infected cats or from a contaminated environment. Many more cats are culture-positive for M. canis than have dermatophytosis. Culture isolation alone is not an indication of dermatophytosis; the diagnosis of dermatophytosis requires microscopic evidence of infection as well as culture evidence of the presence of the dermatophyte. The cat's hair coat adopts the culture image of its surroundings. Diverse factors may influence the frequency of isolation of M. canis. Nevertheless, isolation of M. canis implies either active disease or fomite carriage and warrants aggressive investigation of the clinical situation.

Characterization of eosinophil progenitor cells in feline bone marrow.

OBJECTIVE: To identify eosinophil progenitor cells in feline bone marrow, establishing an assay method to use in studies of eosinophilopoiesis and eosinophilopoietic factors in cats. ANIMALS: Healthy, laboratory animal source cats. PROCEDURE: Sources of colony-stimulating activity were prepared by conditioning media with bone marrow, spleen, and blood mononuclear cells from cats infected with Toxocara canis. Bone marrow cells were aspirated and cultured to develop the eosinophil progenitor cell assay and to test cells from 9 healthy cats in the assay. RESULTS: Optimal conditions for identifying colony-forming units-eosinophil and cluster-forming units-eosinophil were as follows. Bone marrow mononuclear cells (10(5)) were plated in 1 ml of supplemented medium, fetal bovine serum, and agar. The source of eosinophil growth factor(s) was bone marrow-conditioned medium made in the presence of 2.5 micrograms of concanavalin A/ml; other conditioned media also supported eosinophil colony growth. Dishes were incubated for 7 days at 37 C and 7% CO2. The colony-forming units-eosinophil formed aggregates of > 50 Luxol fast blue-positive cells and had dispersed morphology; the cluster-forming units-eosinophil formed aggregates of < 50 cells. CONCLUSION AND CLINICAL RELEVANCE: Similar to other species, cats have separate and distinct eosinophil progenitor cells. The eosinophil progenitor assay may be used to characterize altered kinetics of eosinophilopoiesis, to assess eosinophil growth factors, and to evaluate therapeutic regimens that might be useful in the management of excess eosinophil production.

Investigations of a killed dermatophyte cell-wall vaccine against infection with Microsporum canis in cats.

A laboratory-prepared killed Microsporum canis cell-wall vaccine was evaluated under conditions simulating an accidental infection of a cattery, by inoculating eight- to nine-week-old cats with the vaccine or with a placebo control. The vaccinated cats developed high titres of anti-dermatophyte IgG as measured by an ELISA, and a small cell-mediated response against M canis as measured by a lymphocyte blastogenesis assay, using a whole fungus extract. After being inoculated the cats were challenged by the introduction of an infected cat into the same room. All the vaccinated and control cats became culture-positive for M canis within four weeks of the introduction of the infected cat. Four of the six control cats and all the vaccinated cats developed lesions consistent with dermatophytosis within 16 weeks after exposure to the infected cat.

Efficacy of griseofulvin and itraconazole in the treatment of experimentally induced dermatophytosis in cats.

To evaluate the efficacy of itraconazole and griseofulvin in the treatment of Microsporum canis infection, 15 juvenile cats were infected by topical application of 10(5) live M canis macroconidia to the skin of the lateral part of the trunk, and an occlusive bandage was applied. After 3 weeks, cats were randomly assigned to 1 of 3 treatment groups (n = 5 each): cats in the first group received griseofulvin (50 mg/kg of body weight, PO, q 24 h); the second group received itraconazole (10 mg/kg, PO, q 24 h); and the third group (control) received an equivalent volume of vehicle (without drug, PO, q 24 h). Treatment continued for 100 days, or until mycologic cure (lack of dermatophyte isolation on 3 consecutive weekly fungal cultures) was achieved. Infection in all cats peaked in severity at week 6 after inoculation, then gradually resolved over the next 11 weeks. The itraconazole-treated group was the first to achieve a cure, after receiving 56 days of treatment, followed by the griseofulvin-treated group at 70 days. None of the cats in the control group reached mycologic cure after 100 days of treatment. As early as day 14 of treatment, the griseofulvin- and itraconazole-treated groups had significantly (P < 0.05) lower mean infection scores, compared with those in the control group. Significant differences in the mean infection scores between the itraconazole- and griseofulvin-treated groups were not found.(ABSTRACT TRUNCATED AT 250 WORDS)

Feline dermatophytosis. Recent advances and recommendations for therapy.

Feline dermatophytosis is one of the most common skin diseases of cats. In the past, much of the information available on this subject stemmed from clinical observations. This article summarizes current research findings on the epidemiology, immunology, pathogenesis, and treatment of feline dermatophytosis. As a result of these studies, the authors propose new recommendations for treatment.

Inability of two topical treatments to influence the course of experimentally induced dermatophytosis in cats.

An experimental model of dermatophytosis was used to compare the efficacy of 2 topical antifungal treatments against Microsporum canis infection in cats. Infection was established in 24 cats by topical application of 10(5) M canis macroconidia to the skin of the lateral part of the abdomen under an occlusive bandage. Three groups of 6 cats each then were treated twice weekly for 18 weeks with chlorhexidine shampoo and dip, detergent shampoo vehicle only, or glyceryl monolaurate shampoo. Six cats were left untreated as controls. The experimentally induced infections strongly resembled naturally developing infections of moderate to severe nature. Signs of infection peaked in severity at 5 weeks after inoculation, then gradually resolved over 7 to 16 additional weeks. Dermatophytes were consistently isolated on culture for at least 8 weeks of treatment. Mycologic cure (defined as lack of dermatophyte isolation on 3 successive weekly cultures) was attained in 8 cats at the end of 18 weeks of treatment. Infections appeared to resolve at equivalent rates in all groups of cats, including controls. Consistent or meaningful significant differences in variables such as lesion size, clinical sign score, or total infection score were not found between treated and control groups. Our study revealed that this topical treatment regimen with chlorhexidine or glyceryl monolaurate is ineffective against M canis infection in cats.

Concentrations of total serum IgE, IgA, and IgG in atopic and parasitized dogs.

Concentrations of total serum IgE, IgA, and IgG were measured in 36 atopic and 16 parasitized dogs, and compared them with 30 healthy control dogs. IgE was measured using enzyme-linked immunosorbent assay. IgA and IgG were measured using radial immunodiffusion assays. Mean total serum immunoglobulin (Ig) E concentrations in healthy, atopic and parasitized dogs were 7.1 units (U) ml-1, 5.8 U ml-1 and 14.3 U ml-1, respectively. Mean total serum IgA concentrations in the same groups were 103.3 mg dl-1, 63.2 mg dl-1 and 67.3 mg dl-1, respectively. Mean total serum IgG concentrations were 1066 mg dl-1, 1621 mg dl-1 and 1480 mg dl-1 in the three groups. There was no significant difference in IgE concentrations between these groups of dogs. IgA levels were significantly lower in atopic and parasitized dogs compared with healthy dogs (P < or = 0.05), whereas IgG levels were significantly higher in the atopic and parasitized dogs (P < or = 0.005). These results suggest that measurement of total serum IgE would be of no benefit in the preliminary clinical investigation of a suspected atopic dog. The lower IgA and higher IgG concentrations in both atopic and parasitized dogs suggest that similar regulatory mechanisms governing immunoglobulin synthesis occur in canine allergic and parasitic disease, promoting IgG synthesis but down-regulating IgA production.

Development of an experimental model of Microsporum canis infection in cats.

An experimental infection model was developed for reliable induction of Microsporum canis skin infections in cats, using a defined number of macroconidia harvested from the fungus in culture. The strain of M. canis used produced highly fluorescent hairs under ultraviolet illumination. Kittens 8 to 9 weeks of age (n = 6) received 10(5) macroconidia applied topically to a closely-shaved area of skin. Sites were dressed with an occlusive bandage for 3 days, then grooming was restricted for an additional 4 weeks. Lesions were first observed 2 weeks after inoculation, enlarged over the following 6 to 8 weeks, then decreased in size and appeared healed at 12 to 14 weeks after inoculation. Cats often developed satellite lesions on the face, ears, or other body regions. The experimental infections strongly resembled moderately severe cases of naturally-occurring feline dermatophytosis in clinical patients. This experimental infection model will be useful for evaluation of topical and systemic treatments for feline M. canis infection.

Isolation of feline eosinophils via peritoneal lavage.

Fourteen cats were inoculated orally with 1 of 2 infective doses of Toxocara canis to induce eosinophilia. Cats were subsequently challenge exposed twice via intraperitoneal injection with 1 of 2 T canis antigen preparations. Peritoneal lavage was performed 2 days after antigenic challenge exposure, and eosinophils in the peritoneal lavage fluid were quantified. None of the cats developed clinical signs of disease after infection. All cats developed peripheral eosinophilia after infection. Significant (P < 0.05) difference in mean eosinophil count from the lavage fluid was observed between lavage 1 (prechallenge exposure) and lavages 2 and 3 (postchallenge exposure) in both groups of cats. Significant difference in eosinophil count was not found between cats given different doses of eggs. After initial challenge exposure, significantly (P < 0.05) more eosinophils were obtained from cats given antigen preparation 2 (prep-2) than from those given antigen prep-1. This difference was no longer observed after the second challenge exposure with higher doses of either antigen prep-1 or prep-2. In cats given antigen prep-2, significant difference was not found between lavages 2 and 3. However, in cats given antigen prep-1, eosinophil count was significantly (P = 0.005) greater in fluid obtained from lavage 3, compared with eosinophil count from lavage 2. Mean +/- SEM percentage of eosinophils in the fluid from lavage 3 in all cats was 70.8 +/- 2.2%. Other cell types included macrophages, neutrophils, lymphocytes, and mast cells. Gross postmortem findings were mild. One- to 3-mm nodular white foci of inflammation were observed on the serosal surfaces of the liver, spleen, kidneys, and omentum.(ABSTRACT TRUNCATED AT 250 WORDS)

Humoral and cellular immune responses to Microsporum canis in naturally occurring feline dermatophytosis.

Peripheral blood lymphocytes isolated from cattery cats which were culture positive for Microsporum canis, or from cats which had recovered from M. canis infection, showed a significantly greater mean in vitro blastogenic response to M. canis antigen than lymphocytes from uninfected cats. Mean lymphocyte reactivity to concanavalin A was higher in cats which had recovered from infection than in either culture positive or uninfected cats, whereas reactivity to phytohemagglutinin was highest in the culture positive group. Antibody (both IgG and IgM) against dermatophyte glycoprotein antigen was detectable in the plasma of all cats, but was present in significantly higher titres in the culture positive group. Our results demonstrate that M. canis infected cats mount strong humoral and cellular immune responses to the organism; these responses can be detected by use of anti-dermatophyte antibody quantitation and lymphocyte blastogenesis assays, as has been reported previously for dermatophytosis in other species. Asymptomatic, culture positive cats were found in only three of seven catteries and were genetically related, raising the possibility of genetic predisposition to persisting asymptomatic infection.

Efficacy of AHR-13268, an antiallergenic compound, in the management of pruritus caused by atopic disease in dogs.

Twenty-nine pruritic, atopic dogs were entered into a double-blind, placebo-controlled, crossover study to evaluate the efficacy of an investigational antiallergenic compound, AHR-13268. Fourteen dogs were evaluated by a veterinary dermatologist (at intervals) and the owner (daily). Fifteen dogs were evaluated only by the owner. The mean (+/- SE) owner scores for pruritus, erythema, and lesions with placebo treatment (higher score = worse signs) were 3.24 (+/- 0.12), 2.73 (+/- 0.12), and 2.61 (+/- 0.09), respectively. With drug treatment, the corresponding scores were 2.89 (+/- 0.12), 2.50 (+/- 0.12), and 2.25 (+/- 0.09). Scores for pruritus and lesions (but not erythema) were significantly better with drug treatment than with placebo treatment. Investigator scores showed similar trends, but the differences were not great enough to be statistically significant. Overall, 11/29 (38%) owners reported their dogs had moderate or better improvement from drug capsules, and 4/29 dogs (14%) improved on placebo capsules. A variety of adverse effects were reported following both drug (9/29 dogs) and placebo (8/29 dogs) capsule administration, but were mild and well tolerated. Results of this study indicate that AHR-13268 has potential for empiric treatment of allergic inhalant dermatitis in some dogs.