Staggering disease in cats: isolation and characterization of the feline Borna disease virus

A Borna disease virus (BDV)-like agent was isolated from the central nervous system (CNS) of cats with a spontaneous non-suppurative encephalomyelitis ('staggering disease'). In contrast to the rabbit-adapted BDV strain V, which can be propagated in several primary and permanent cell cultures, the cat virus grew only in embryonic mink brain cells. Infection of adult Wistar rats with feline brain tissue material did not result in clinical disease during a period of 5 months, nor in growth of infectious virus in the brain. However, using the brain suspension of a newborn rat inoculated with feline brain tissue material, it was possible to induce typical Borna disease (BD) in four adult rats. This indicates a possible adaptation of the cat virus during passages in rats. By the use of an RT-PCR technique, BDV-specific RNA could be detected in a majority of brain samples from diseased cats. BDV-specific antigen was demonstrated in feline CNS samples both by immunohistochemistry and ELISA. However, the amount of BDV RNA and BDV antigen was less in the cats as compared to horses with BD, providing further support for the notion that a distinct feline BDV strain exists.

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.

Duration of immunity to shedding of Toxoplasma gondii oocysts by cats

Cats that have shed Toxoplasma gondii oocysts are considered to be immune to reshedding of oocysts. To investigate if this immunity persists in cats for 6 yr, 12 4-6-mo-old cats without T. gondii antibodies were inoculated orally with tissue cysts of the ME-49 strain (6 cats) and the TS-2 strain (6 cats) of T. gondii. All of them shed > or = 20 million oocysts between 4 and 13 days after feeding tissue cysts. Two cats became ill between 11 and 13 days after primary infection; 1 died on the 13th day, and the other had to be killed on the 11th day because of generalized acute toxoplasmosis. Toxoplasma gondii oocysts were not found on the hair of 10 cats examined 7 days after cats had shed millions of oocysts. On day 39 after primary infection, 5 cats (2 infected with the ME-49 strain and 3 infected with the TS-2 strain) were challenged orally with tissue cysts of the ME-49 strain. None of the challenged cats shed oocysts. One cat died due to causes unrelated to toxoplasmosis. Seventy-seven months after primary infection, the remaining 9 cats were challenged orally with tissue cysts of the P89 strain of T. gondii. Four of these 9 cats re-shed T. gondii oocysts; 3 of them had been challenged also at 39 days after primary infection. Two control cats housed together with chronically infected cats for 6 yr remained seronegative for T. gondii; both of these shed oocysts after challenge with the P89 strain.

Cytophilic antibodies in cats with miliary dermatitis and eosinophilic plaques: passive transfer of immediate-type hypersensitivity

Passive cutaneous anaphylaxis test and Praunitz-Küstner tests were performed in healthy recipient cats with heated and unheated sera of 17 cats suspected of having allergic dermatitis and of 12 healthy control cats. Positive reactions occurred with heated and unheated sera. It was therefore hypothesized that a heat-stabile cytophilic antibody is involved in the pathogenesis of eosinophilic plaques and miliary dermatitis in some cats.

Uterine carcinomas in mother cats after intrafetal inoculation of allogeneic tumor cells (K248 C and P)

Three out of 13 queens that had undergone injection of tumor cells from an allogeneic feline mammary carcinoma cell line through the wall of the pregnant uterus developed a carcinoma of the uterus. The possible role of immune tolerance associated with pregnancy and/or major histocompatibility complex (MHC) compatibility is discussed.

Experimental Microsporum canis infection in cats: correlation between immunological and clinical observations

Microsporum canis infection was induced in five of six adult cats by the application of mycelium to shaved and mildly abraided skin. The clinical course of the disease was monitored over 16 weeks by physical examination and Wood's lamp illumination. The incubation period (time from inoculation to first appearance of infected hairs) varied between 8 and 13 days and was followed by a progressive phase of slow peripheral expansion of lesions accompanied by scaling, alopecia and skin thickening that lasted for approximately 2 weeks. In four of the five cats the lesions then remained stable for between 1 and 6 weeks before regression occurred, with clinical resolution evident in these cats by 11-14 weeks post-infection. In one cat disease was more prolonged, with regression only beginning at the end of the study, and this cat also developed a satellite lesion. Immunological responses during infection were monitored every 2 weeks and consisted of ELISA to measure serum M. canis-specific IgG, IgM and IgA antibody concentrations, M. canis antigen-specific lymphocyte proliferation assay, and mitogen-induced (ConA) lymphocyte proliferation assay. In all three immunoglobulin classes evaluated, a significant (P < or = 0.020) rise in antibody concentration was seen in response to infection, and occurred earliest with the IgM class (2 weeks post-infection). Overall, a heterogeneous antibody response was found, and changes in antibody concentration showed no clear temporal relationship to recovery from disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Therapeutic effects of diethylcarbamazine and 3'-azido-3'-deoxythymidine on feline leukemia virus lymphoma formation

Twenty-four specific pathogen-free kittens were infected with the Rickard strain of feline leukemia virus (FeLVR). The kittens were divided into four equal groups and were orally administered either a high dose of diethylcarbamazine (DECH, 12 mg kg-1), a low dose of diethylcarbamazine (DECL, 3 mg kg-1), 3'-azido-3'-deoxythymidine (AZT, 15 mg kg-1, b.i.d.), or a placebo (250 mg granular dextrose) daily for 10 weeks. Blood was collected at 2-week intervals for complete blood counts (CBC) and flow cytometric analysis (FACS) of peripheral blood lymphocytes (PBL). Plasma was assayed for antibodies to FeLV gp70 and for FeLV p27 antigen using ELISA assays. For FACS analysis, lymphocytes were incubated with monoclonal antibodies to feline Pan T, CD8+, CD4+, and B cell (Anti-Ig) antigens. In the placebo treated cats, FeLVR infection caused an early (2 weeks p.i.) and persistent decrease in leukocyte numbers attributable primarily to a decrease in neutrophil numbers and a secondary lesser decrease in B and CD4+ lymphocyte numbers. The DEC-treated groups showed a delayed but similar leukopenia by 4 weeks p.i. The lymphopenia in the DEC groups (primarily B cells and CD4+ cells) was reversed by 10 weeks p.i., but the neutropenia persisted. AZT treatment inhibited FeLVR-induced lymphopenia but did not prevent a reduction in neutrophil numbers. A marked p27 antigenemia that peaked at 4 weeks p.i. was noted in the placebo treated cats and in most cats (11/12) treated with either dose of DEC. However, AZT significantly inhibited the p27 antigenemia and all cats were negative for p27 antigen between 6 and 10 weeks of treatment. In general, placebo treated cats as well as DECH and DECL cats had low levels of antibody to gp70 throughout the study, suggesting FeLVR-induced immunosuppression. In contrast, significantly higher titers of anti-gp70 antibodies were seen in AZT-treated cats at 6 weeks p.i., and were maintained throughout treatment. Eighteen month survival rates provide efficacy data for AZT as well as both DEC treatment groups. While all placebo treated cats were euthanized by 52 weeks p.i. due to FeLV associated lymphomas with a mean survival time of 35.5 weeks p.i., median survival time of the AZT treated group was > or = 102 weeks p.i., while that of the DECH and DECL groups was 69.7 and 72 weeks p.i., respectively. Thus, DEC as well as AZT therapy delays the development of lymphomas associated with FeLV infection and significantly improves survival.

The Carl Prausnitz Memorial Lecture. What can we learn from the allergic zoo?

Several animal species, in particular dogs, cats and horses spontaneously develop IgE-mediated allergic diseases. They can also be experimentally sensitized. Comparative veterinary allergology is increasingly providing valuable information in allergy research.

[Comparison of the detection of Giardia intestinalis cysts with the presence of specific antibodies in dogs and cats]

We investigated giardiosis of dogs and cats with a view to cysts in fecal samples and antibodies in the blood serum. Cysts were found in 25 fecal samples (5.5%) out of 458. Cysts were excreted frequently in puppies and adolescent dogs. In 15 cases giardiosis was diagnosed together with canine distemper or parvovirosis as an opportunic infection. Indirect immunofluorescence was used for detection of specific antibodies. We tested sera of 588 dogs and specific antibodies were detected in 156 cases (36.5%) in titres 10-160. In basic dilution 1:10 antibodies were detected in 61% positive samples. Titres 20-160 were found in 39% of the positive sera. In cats cysts were found only in 1 fecal sample out of 135 due to the difficulties in obtaining fecal samples for repeated examinations. Specific antibodies were detected in 107 cats (56.9%) out of 188 at titres 10-320. In basic dilution 1-10 antibodies were detected only in 30% of the positive sera but on the other hand in 70% we detected higher titres, i.e. 20-320. We did not consider titre 10 as significantly positive in both dogs and cats because cross-parasitic infections frequently occur. The number of serological positive dogs and cats grew with their age because they acquired giardiosis in the course of their life mostly as asymptomatic infection. The detection of specific antibodies cannot be used for the diagnosis because their level in blood serum persists for months. We must tread every dog and cat excreting cysts in fecal samples to stop transmission to other animals and humans-zoonosis.

Analysis of leucocytes and lymphocyte subsets in cats with naturally-occurring cryptococcosis but differing feline immunodeficiency virus status

Although cryptococcosis is a well-characterised disease of cats, the factors predisposing individuals to infection are unknown. As an indication of the immune status of an individual, lymphocyte subsets can be analysed. Reference ranges for feline lymphocyte subsets (Pan T+, CD4+, CD8+ and B cells) were established using a rapid whole blood technique and flow cytometry. There were no effects of age or sex on lymphocyte subset values. The numbers of circulating leucocytes and lymphocyte subsets were determined in FIV-positive and FIV-negative cats with cryptococcosis and compared with a group of healthy control cats. There were only minor differences in the numbers of lymphocyte subsets among the subgroups of cats examined in the study and the predisposition to cryptococcosis in cats could not be explained by deficiencies in lymphocyte subsets. There was a tendency for FIV-negative cats with cryptococcosis to have reduced numbers of circulating CD4+ cells and lower CD4:CD8 ratios compared with normal cats, although the interpretation of this finding was complicated by the wide reference range for normal cats. The extent to which this is the cause of the fungal infection was not determined. The only difference in leucocyte or lymphocytes subset values between FIV-negative cats with cryptococcosis and FIV-positive cats with cryptococcosis was that the CD4+ percentage was lower in the FIV-positive cats. The absolute CD4+ count was similar however, in FIV-positive and FIV-negative cryptococcosis cases. On the basis of this and other available information, the categorisation of cryptococcosis as a disease defining the AIDS phase of FIV infection may be incorrect.

Immunologic, histologic, and virologic features of herpesvirus-induced stromal keratitis in cats

Sequential histologic, immunologic, and virologic features of herpesvirus-induced keratitis were studied in 18 experimentally infected cats. Histologic changes were assessed by use of light microscopy, and the presence of viral antigen, B lymphocytes, and T lymphocytes was verified immunohistochemically. Flow cytometry was used to monitor changes in blood T lymphocytes (CD4 and CD8 homologues) and B lymphocytes. Cellular immunity was assessed by use of the lymphocyte proliferation assay. Development of stromal keratitis was preceded by prolonged absence of corneal epithelium, decreased numbers of circulating lymphocyte subsets, decreased mitogen responses, and acquisition of viral antigen by the corneal stroma. Return to normal of circulating lymphocyte numbers and function was temporally associated with the arrival of neutrophils and B and T lymphocytes in the corneal stroma. Sequelae to stromal inflammation were fibrosis and scarring. Findings suggest that suppression of local immune responses allows virus access to the corneal stroma, and that subsequent keratitis is mediated by an immune response to viral antigen.

Cyproheptadine-induced attenuation of type-I immediate-hypersensitivity reactions of airway smooth muscle from immune-sensitized cats

We assessed the effect of serotonergic inhibition by cyproheptadine on the responsiveness of tracheal smooth muscle (TSM) strips and epithelium-intact third-generation bronchial rings from immune-sensitized (Ascaris suum) cats after exposure to antigen. Cats were sensitized by IM administration of antigen and adjuvant twice over a 4-week period. Sensitization was confirmed in vivo by skin testing with antigen and by physiologic airway responses after exposure to nebulized antigen. Tissues were tethered isometrically to force transducers and were actively equilibrated by exposures to KCl-substituted perfusate. Maximal response after exposure to antigen (expressed as percentage of maximal contraction of each tissue to 63 mM KCl (%KCl) was 169 +/- 18% KCl for sensitized TSM and 43 +/- 18% KCl for sensitized TSM pretreated with cyproheptadine (P < 0.001). Similarly, maximal response to antigen was 81 +/- 27% KCl for sensitized bronchial rings, compared with 16 +/- 14% KCl for sensitized bronchial rings pretreated with cyproheptadine (P = 0.05 vs control). Blockade of leukotriene synthesis by 10(-6) to 10(-4) M A-64077, a selective 5-lipoxygenase inhibitor, had no significant effect on peak response for either TSM (193 +/- 13% KCl vs 169 +/- 18% KCl for sensitized untreated TSM) or bronchial rings (79 +/- 20% KCl vs 81 +/- 27% KCl for sensitized untreated bronchial rings). Release of serotonin from airway tissues was confirmed by the presence of serotonin in the perfusate of 8 sensitized TSM preparations after, but not before, antigen challenge.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunophenotypic characterization of cutaneous lymphoid neoplasia in the dog and cat

Clinical, histopathological and immunohistochemical findings are presented from a series of cutaneous lymphoid neoplasms including canine epitheliotrophic lymphoma (n = 7), canine non-epitheliotrophic cutaneous lymphoma (n = 10), canine cutaneous plasmacytoma (n = 10) and feline non-epitheliotrophic cutaneous lymphoma (n = 6). Three cases of canine epitheliotrophic lymphoma expressed the CD3 T-lymphocyte marker, but the remainder were negative for this molecule and for a panel of B-cell markers. Non-epitheliotrophic cutaneous lymphoma was shown to be predominantly of T-cell phenotype (CD3+) in the dog (eight of 10 cases) and cat (five of six cases), the remaining cases in both species being of B-cell origin, expressing the gamma heavy chain of immunoglobulin (with or without lambda light chain). One canine non-epitheliotrophic B-cell lymphoma expressed IgG of the IgG2 subclass. Two of the biopsies from dogs with cutaneous plasmacotyoma were shown to express immunoglobulin alpha chain (one with lambda chain) and two neoplasms were positive for immunoglobulin gamma chain (both with lambda chain). One of the latter immunoglobulins was of the IgG4 subclass. In the majority of all cases of cutaneous lymphoid neoplasia examined, there was a local polyclonal immune response, manifested as infiltration by a mixed population of plasma cells expressing IgG (IgG2, IgG4), IgA or IgM. In the feline tumours CD3+ small T lymphocytes were included in these infiltrates.

Hemostatic disorders in feline immunodeficiency virus-seropositive cats

The hemostatic function of 40 feline immunodeficiency virus (FIV) seropositive and 8 FIV and feline leukemia virus (FeLV) seropositive cats was evaluated and compared with reference values from 30 clinically healthy cats. The FIV-positive cats were divided into 3 groups: group I included asymptomatic carriers; group II comprised sick FIV-infected cats with illnesses not likely to influence the hemostatic system; and group III included FIV-positive cats with diseases potentially associated with coagulopathies. Platelet counts in FIV/FeLV-infected cats were significantly lower than in healthy cats (P < .003), whereas the differences in the 3 groups of FIV-positive cats were variable (group I, P = .009; II, P = .05; III, P = .09). Thrombocytopenia (< 145,000 platelets/microL) was present in 4 FIV-positive and 3 FIV/FeLV-positive cats. Platelet aggregation induced by collagen (0.5 and 0.25 micrograms/mL), adenosine diphosphate (ADP) (1 and 0.6 mumol/L), and thrombin (0.4 and 0.25 IU/mL) was not significantly different from that of healthy cats. The plasma coagulation system was evaluated by measuring one-stage prothrombin time (OSPT), activated partial thromboplastin time (APTT), thrombin time, fibrinogen concentration, coagulation factor assays, fibrinogen and fibrin degradation products (FDP), and plasma exchange test. The OSPT was similar in FIV-seropositive cats and in the healthy control group. Cats with FIV infection, however, had markedly shorter clotting times than healthy cats when using a modified test system (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Gastrointestinal allergy

Many problems have been attributed to allergic reactions arising by way of the gastrointestinal tract. The term "food allergy" must be used with greater care. Allergy is but one of many adverse reactions to foods, several of which respond to dietary manipulation. Although gastrointestinal allergy is known to occur in animals, there is a need for greater precision in the use of terminology, further clarification of the problems, and challenge to confirm the diagnosis.

Allergic- and immunologic-mediated diseases of the eye and adnexae

Significant allergic- and immunologic-mediated diseases of the eye are reviewed. Included are diseases of the lacrimal gland namely keratoconjunctivitis sicca, immune-mediated diseases of the conjunctiva, atopic blepharoconjunctivitis, and marginal blepharitis, uveitis including lens-induced uveitis, episcleritis, orbital cellulitis, and optic neuritis. Significant diagnostic features, an approach to diagnostic workup, and treatment are presented.

Overview of the immune system and immunodeficiency diseases

The principal role of the immune system is the protection of the host against invasion by infectious disease agents and other substances considered foreign to the host. The term "immunity" refers to all the mechanisms that the body uses to protect itself against environmental antigens. This article gives an overview of the immune system and its defense immunodeficient diseases.

Allergic- and immune-associated diseases of the urinary tract

Glomerular injury has a decided immunologic basis. Any infectious, inflammatory, neoplastic, or degenerative processes capable of sustained antigenic stimulation can induce immune-mediated glomerular injury. A variety of conditions and antigens, both endogenous and exogenous, are known to initiate immunologic glomerular damage. In many clinical situations, however, the precise antigenic source is occult and unrecognizable, and the glomerular disease is referred to as idiopathic.

Rheumatoid arthritis

Much has been learned about the interactions of immunologic events and the development of musculoskeletal disease. Much more needs to be learned. The partnership of astute clinicians and investigators will enhance this learning process and eventually benefit the health and well being of our patients, and perhaps, humankind.

Expression of an Onchocerca volvulus Ov33 homolog in Dirofilaria immitis: potential in immunodiagnosis of heartworm infection

In this study, the expression of an Onchocerca volvulus Ov33 homolog was demonstrated in Dirofilaria immitis. Rabbit antiserum raised against a recombinant fusion protein of O. volvulus, MBP/OvD 5B (Ov33), was found to react with a 31-33 kDa glycoprotein (DiT33) of adult worms of D. immitis. An antibody response to MBP/OvD 5B was observed in dogs, as early as 11 weeks post infection with infective larvae of D. immitis, and in dogs with occult infection. Cats both experimentally and naturally infected with D. immitis also reacted strongly with the recombinant antigen. In contrast, sera from dogs receiving chemically-abbreviated infection or from animals harbouring a variety of other helminths failed to react. These data suggest that antibody responses generated by DiT33 may have potential in immunodiagnosis of heartworm infection in cats and dogs.

Ocular and disseminated candidiasis in an immunosuppressed cat

Ocular and systemic candidiasis was diagnosed in an immunosuppressed and diabetic 12-year-old cat that initially was examined because of polyuria, polydipsia, and urinary tract disease. Bilateral recurrent corneal erosions and chorioretinitis, urinary tract infections attributable to bacteria or Candida sp, and renal dysfunction developed during the next 2 months. Examination of corneal scrapings revealed spherical to oval, budding, yeast-like cells. The cat's condition progressively deteriorated, and it was euthanatized. Toxoplasmosis was diagnosed by fecal flotation and from serum titers, and pituitary-dependent hyperadrenocorticism was detected at postmortem histologic evaluation. Candida budding yeasts and pseudohyphae with blastospores were detected in the corneas, vitreous bodies, retinas, CNS, pharynx, trachea, esophagus, kidneys, and urinary bladder at postmortem examination.