Factors associated with the occurrence of epistaxis in natural canine leishmaniasis (Leishmania infantum).

BACKGROUND: Canine leishmaniasis (CanL) is a common cause of epistaxis in dogs residing in endemic areas. The pathogenesis of CanL-associated epistaxis has not been fully explored because of the limited number of cases reported so far. HYPOTHESIS: Epistaxis in CanL could be attributed to more than 1 pathomechanism such as hemostatic dysfunction, biochemical abnormalities, chronic rhinitis, and coinfections occurring in various combinations. ANIMALS: Fifty-one dogs with natural CanL. METHODS: The allocation of 51 dogs in this cross-sectional study was based on the presence (n = 24) or absence (n = 27) of epistaxis. The potential associations among epistaxis and concurrent infections (Ehrlichia canis, Bartonella spp., and Aspergillus spp.), biochemical and hemostatic abnormalities, and nasal histopathology were investigated. RESULTS: Hypergammaglobulinemia (P= .044), increased serum viscosity (P= .038), decreased platelet aggregation response to collagen (P= .042), and nasal mucosa ulceration (P= .039) were more common in the dogs with epistaxis than in those without epistaxis. The other significant differences between the 2 groups involved total serum protein (P= .029) and gamma-globulin (P= .013) concentrations, which were higher, and the percentage platelet aggregation to collagen, which was lower (P= .012) in the epistaxis dogs. CLINICAL IMPORTANCE: CanL-associated epistaxis appears to be the result of multiple and variable pathogenetic factors such as thrombocytopathy, hyperglobulinemia-induced serum hyperviscosity, and nasal mucosa ulceration.

Acute tumour lysis syndrome in a dog with B-Cell multicentric lymphoma.

A 5-year-old, spayed female German Shepherd dog was admitted to hospital with marked generalised lymphadenomegaly and splenomegaly. A stage Va B-cell multicentric lymphoma was diagnosed on clinical, cytological (lymph node, bone marrow), histological-immunohistochemical (lymph node excision) and imaging grounds. Since no satisfactory remission was achieved using a multi-drug chemotherapy protocol that included cyclophosphamide, vincristine, cytosine arabinoside, prednisolone, and subsequently supplemented by L-asparaginase, it was replaced by another protocol combining vincristine, L-asparaginase, prednisolone, cyclophosphamide and doxorubicin. Soon after the third weekly session of the second protocol, the clinical status of the animal deteriorated suddenly and severely, with a bleeding tendency, jaundice, hyperuricaemia, hyperphosphataemia, azotaemia, hyperbilirubinaemia and, presumptive disseminated intravascular coagulation. There was also complete regression of lymphadenomegaly. This report emphasises the clinicopathological features and the diagnostic peculiarities of the acute tumour lysis syndrome, which occurs uncommonly in dogs.

Immunohistochemical investigation of amyloid beta-protein (Abeta) in the brain of aged cats.

To clarify the immunohistochemical features of amyloid deposits and cerebral amyloid angiopathy (CAA), the distribution of the amyloid beta-protein subtypes Abeta40, Abeta42, Abeta43 and Abeta precursor protein (APP) were examined in the brains of fourteen aged cats (7.5-21 year-old). Two types of plaques were detected. The first type was characterized by Ass positive antigenic material and detected in the cortical layers of the frontal and parietal lobes of all examined cats. The second type was characterized by diffuse positive immune staining representing diffuse plaques, which were detected only in the very aged cats (17-21 years old) and distributed throughout the cortical layers of the parietal lobes. Vascular amyloid and the amyloid deposits were strongly positive-stained with the antibody Abeta42. APP was exhibited in neurons and axons while the staining was stronger in the very aged cats (17-21 years old). Our findings suggest that the feline forms a spontaneous model for understanding the early changes of normal brain aging and the early stage of amyloid beta-protein deposition.

Cellular immunophenotyping of exfoliative dermatitis in canine leishmaniosis (Leishmania infantum).

Lymphocyte subsets, major histocompatibility complex (MHC)-II expressing cells and number of amastigotes in the epidermis and dermis were investigated immunohistochemically in 48 dogs with patent leishmaniosis, with or without exfoliative dermatitis (ED) to study the immunopathogenesis of this common cutaneous form of the disease. Skin biopsies were obtained and compared for ED sites (group A, n = 26), normal-appearing skin from the same animals (group B, n = 24), and leishmanial dogs not exhibiting ED (group C, n = 22), and normal controls (group D, n = 22). The CD3+, CD45RA+, CD4+, CD8+ (CD8a+), CD21+, and MHC-II+ cells and leishmania amastigotes were identified immunohistochemically and counted with the aid of an image analysis system. Pyogranulomatous to granulomatous dermatitis, expressed in various histopathological patterns, was noticed in all groups A and B and in half of group C dogs. In the epidermis, the low number of T-cells and their subsets did not differ significantly between groups A and B, but CD8+ outnumbered CD4+ lymphocytes in both groups. MHC-II+ expression on epidermal keratinocytes was intense in the skin with and without lesions from dogs with ED but not in group C dogs. CD3+, CD8+ and MHC-II+ cells were fewer in group C compared to group A and B dogs. In the dermis, CD3+ cells in group A animals were mainly represented by the CD8+. CD45RA+ and CD21+ cells were also seen in high numbers. MHC-II expression, potentially in lymphocytes, fibroblasts, dendritic cells, and macrophages was intense. The numbers of all cellular subpopulations in the dermis were significantly different between the groups, being highest in group A and lowest in group D. In sebaceous adenitis sites, CD4+ outnumbered CD8+ cells in contrast to the neighbouring dermis and the epidermis. The number of CD21+ and CD45RA+ cells was much lower in the inflamed sebaceous glands compared to the dermis. Finally, the number of amastigotes in the normal-appearing skin was significantly higher in the ED dogs (group B) than in those not exhibiting this cutaneous form of the disease (group C).

An experimental study on the pathogenicity of the caprine herpesvirus type 1 (CHV-1).

The pathogenicity of caprine herpesvirus type-1 (CHV-1) in goat kids and lambs was studied. Two experiments were carried out. In the first, two Saanen goat kids and four lambs of a local breed were infected intravenously with the Swiss strain E/CH of the virus. Clinical reaction was severe in the kids, but it was very mild in the lambs. Virus was excreted from the kids in higher titres and longer than in lambs. Virus was also isolated from tissue specimens but only from a kid that died on post inoculation day 4 (PID 4). The gross- and histopathological lesions were more severe in kids. In the second experiment only lambs were used. They were dexamethasone treated and then virus inoculated. A very mild infection developed. The lambs did not shed the virus, neither the virus was isolated from their tissues collected at necropsy. Nevertheless histopathological lesions were seen. In both experiments the animals seroconverted on PID 10.

Immunosuppression in goats by dexamethasone and cyclophosphamide.

The influence of dexamethasone and cyclophosphamide on the goat immune system was investigated. Seven goats, with a previous contact with caprine herpesvirus type 1 (CHV-1), were used. All had been vaccinated with live Mycobacterium paratuberculosis vaccine. Six goats were injected intravenously (i.v.) with dexamethasone daily for 5 days (2.5-4 mg/kg BW per day). Three also received 25 mg/kg BW of cyclophosphamide on day 0. The seventh goat was not treated. Dexamethasone alone caused depression, slight lymphopenia and fall in tuberculin reaction. Dexamethasone plus cyclophosphamide caused a severe clinical reaction, marked leukopenia (lymphopenia and polymorphopenia), fall in tuberculin reaction and significant increase in CHV-1 neutralizing antibody titres. M. paratuberculosis antibody reaction was variable and thus difficult to be assessed. CHV-1 was not isolated.

Chlamydia-induced bilateral ectropion of the inferior eyelids in pigeons.

In this study we described four cases of bilateral ectropion in pigeons that were investigated in Greece. Anemia, leukocytosis, and increased levels of enzymes lactate dehydrogenase, aspartate aminotransferase, creatine phosphokinase, and total serum proteins were found. Chlamydial elementary bodies were observed by modified Ziehl-Neelsen stain in direct smears of conjunctiva, liver, and spleen as well as in yolk sac samples after egg inoculation with eyelid material. Histologically, significant hyperplasia of the conjunctival epithelium was observed. Using immunohistochemical methods, chlamydial antigen was revealed in eyelid, liver, and spleen paraffin sections. This study suggests that Chlamydia spp. was the causative agent that induced ectropion.

The effects of immuno-modulation on the clinical and pathological expression of postweaning multisystemic wasting syndrome.

Post-weaning multisystemic wasting syndrome (PMWS), primarily caused by porcine circovirus type 2 (PCV-2), is an economically important disease of pigs in many countries. A trial was designed to investigate the hypothesis that non-specific immuno-modulation can influence the clinical and pathological expression of PMWS in pigs naturally infected with PCV-2. Eighty-four pigs on a commercial pig farm were allocated to three groups of 28 pigs each, during an outbreak of PMWS. The pigs in the first group received an intramuscular injection of a vaccine against Mycoplasma hyopneumoniae (RespiSure, Pfizer, NY, USA) at each of 7 and 28 days of age, followed by an intramuscular injection of normal saline at 42 days of age. The animals in the second group received, by intramuscular injection, normal saline at 7 days of age followed by a non-specific immuno-modulating drug (Baypamun, Bayer, Leverkusen, Germany) at each of 28 and 42 days of age. The pigs in the third (control) group received an intramuscular injection of normal saline on each of 7, 28 and 42 days of age. The trial was concluded when the pigs had reached the age of 73 days. Clinical signs characteristic of PMWS developed in 42.9% of pigs inoculated with RespiSure and in 50% of pigs treated with Baypamun; six pigs from each of these groups died. Moderate to severe gross and histopathological lesions of PMWS, associated with abundant PCV-2 antigen, were seen in a wide range of tissues of pigs from these groups at the end of the trial. In contrast, only 10.7% of pigs in the control group developed clinical signs and only one died. Mild to moderate lesions and scant PCV-2 antigen were occasionally observed in tissues of control pigs at the end of the trial. This is the first study to demonstrate that non-specific stimulation of the immune system by a vaccine or an immuno-modulator drug can potentiate viral replication and increase the severity of clinical signs during an outbreak of PMWS.

Relation of clinical signs to pathological changes in 19 cases of canine distemper encephalomyelitis.

In an attempt to associate the clinical neurological syndromes with the neuropathological features of canine distemper (CD), 19 spontaneous cases with neurological involvement were examined, before and after euthanasia. Seventeen dogs were less than one year of age and all except two (89.4%) were unvaccinated against CD. Various extraneural signs associated with CD encephalomyelitis (CDE) were seen in 15 dogs. Generalized or localized myoclonus was the most common sign observed (13/19). Seventeen of the dogs presented with signs suggestive of one neuroanatomical location of lesions. Of these animals, seven had signs of cerebral, two of cerebellar, four of cervical, one of cervicothoracic, two of thoracolumbar and two of lumbosacral syndrome. The diagnosis of CD was confirmed immunohistochemically (detection of CD viral antigen), serologically (neutralizing serum antibody titre > or = 16) and histopathologically (CDV inclusion bodies, type of central nervous system lesions). An association of the neuroanatomical lesion location and the histopathological findings was noted in 14 out of 17 dogs (82.3%). Myoclonus could be attributed to lower motor neuron damage in eight out of 13 dogs (61.5%).

Clinical evaluation of in-feed zinc bacitracin for the control of porcine intestinal adenomatosis in growing/fattening pigs.

This field trial was designed to investigate whether the incorporation of zinc bacitracin into pig feed would prevent porcine intestinal adenomatosis. Two hundred-and-eighty-eight weaned pigs on a farm with a previous history of the disease were divided into 16 pens of 18 pigs. Two dietary regimens of zinc bacitracin were tested: from weaning up to 100 days of age, either 300 or 200 ppm zinc bacitracin were incorporated; from 100 to 125 days of age, either 200 or 100 ppm zinc bacitracin were added; and from 125 to 156 days of age (slaughter), either 100 or 50 ppm zinc bacitracin were added. The results were compared with a positive control group which received 60, 60 and 30 ppm salinomycin during the same periods, and with a negative control group which received no antibacterial and/or performance enhancer. The mortality, diarrhoea scores, average daily weight gains, average daily feed intakes and feed conversion ratios of the pigs were assessed. At slaughter, samples of ileum were taken from eight randomly selected pigs per group for bacteriological and histopathological examinations. The three treated groups all performed better than the control group, and the group receiving the high dose regimen of zinc bacitracin performed significantly better than the groups receiving the low dose of zinc bacitracin or salinomycin.

[Changes in the myocardium in encephalomyocarditis of pigs]. / Veränderungen des Myokards bei Schweineenzephalomyokarditis.

The myocardial lesions of pigs (age from 2.5 to 3.5 month) with encephalomyocarditis virus infection are presented. The disease is caused by members of the genus Cardiovirus (family Picornaviridae). In Greece it was first observed 1987 in two stables of pig-breeders with a mortality of 80%. The macroscopic changes are characterized by a myocardial degeneration with greyish pale linear or round foci and by an accumulation of a clear red to yellow fluid in the pericardium and the pleural cavity. The most important histologic changes of the hearts are a diffuse or focal myocarditis with a severe infiltration of histiocytes, lymphocytes and plasma cells. Furthermore, degeneration and necrosis of cardiac muscle cells are observed. Electron microscopic investigations of the myocardial cells reveal mild mitochondrial edema, severe perinuclear and intranuclear edema, myelin figures, intra cisternal sequestrations of the rough endoplasmic reticulum, disorganization of the myofibrillar Z-line, and crystalloid viral structures between the mitochondria. Polyribosomes and accumulations of viral particles are frequently found in membrane bound cysts within myocardial cells and the capillaries. Furthermore, viral particles (single or in cysts) and crystalloid viral structures are observed in the cytoplasm of edematous endothelial cells.

Histopathology and immunohistochemistry of canine distemper virus-induced footpad hyperkeratosis (hard Pad disease) in dogs with natural canine distemper.

Hard pad disease represents an uncommon manifestation of canine distemper virus (CDV) infection with a still uncertain pathogenesis. To study the pathogenesis of this uncommon, virally induced cutaneous lesion, the footpads of 19 dogs with naturally occurring distemper were investigated for histologic changes and distribution pattern of CDV antigen. All dogs displayed clinical signs of distemper, which had lasted from 10 to 75 days. Overt digital hyperkeratosis was observed in 12 animals (group A), whereas the footpads of the remaining seven dogs appeared normal macroscopically (group B). Orthokeratotic hyperkeratosis (12/12; 100%), irregular acanthosis (11/12; 92%), thickened rete ridges (10/12; 83%), and mild mononuclear perivascular (10/ 12; 83%) and periadnexal (7/12; 58%) dermatitis were the most common findings in dogs with hard pad disease. Surprisingly, orthokeratotic hyperkeratosis (5/7; 71%), irregular acanthosis (5/7; 71%), and thickened rete ridges (4/7; 57%) were also seen in the dogs without clinical evidence of digital hyperkeratosis. CDV-specific inclusion bodies and ballooning degeneration were not observed in the footpad epidermis of the 19 dogs. Immunohis-tochemistry revealed that CDV antigen was most frequently found in the stratum spinosum and granulosum and in the epithelial cells of the eccrine sweat glands and only rarely in the basal layer. Fibroblasts, pericytes, endothelial cells, and hair follicles were also positive in some animals. Despite the obvious difference regarding the macroscopic picture, the microscopic changes were less prominent between the animal groups. The selective infection of keratinocytes in the stratum spinosum might be the key event for the development of hard pad disease in the dog.

The effect of josamycine on the control of ileitis in weaned piglets under field conditions.

The aim of this trial was to evaluate the effect of in-feed josamycine on the control of ileitis in weaned piglets. On a farm with a previous history of ileitis outbreaks, 288 piglets at weaning age (25 +/- 2 days old) were allocated into three experimental groups, each group comprising of four pens with 24 piglets in each pen. Group one (T1) served the trial as negative control group (unmedicated), group T2 was administered josamycine at 36 mg/kg of feed and group T3 was administered josamycine at 50 mg/kg of feed. Treatments lasted for 14 days followed by an observation period of 28 days. Administration of josamycine at both inclusion levels tested had a beneficial effect compared with the negative control group, by the reduction of prevalence of diarrhoea, the enhancement of growth performance and the reduction of prevalence of Lawsonia intracellularis in the intestine, as determined either by the PCR method or by specific histopathological examinations. The beneficial effect of josamycine was more pronounced at the inclusion level of 50 mg/kg of feed.

The efficacy of enrofloxacin in-feed medication, by applying different programmes for the control of post weaning diarrhoea syndrome of piglets.

Post weaning diarrhoea syndrome (PWDS) in piglets is caused mainly by enterotoxigenic Escherichia (E.) coli (ETEC) strains. Six different in-feed usage programmes of enrofloxacin (ENR/Baytril; I.E.R. 2.5%) were tested for their efficacy on the control of post weaning colibacillosis in piglets, using seven groups with totally 336 weaned piglets for a 28 day period. One group (negative control) was offered feed free of antimicrobials, three groups were offered feed medicated with 50 ppm of ENR starting on weaning day for 5, 7 and 10 days respectively, three groups were offered feed medicated with 50 ppm of ENR starting 7 days post weaning for 5, 7 and 10 days respectively, and were compared with regard to the appearance of clinical signs, mortality, weight gain and feed conversion. The results showed that all ENR treatments reduced the incidence and severity of diarrhoea. Mortality was similar in all ENR treatments, but in the groups where the ENR was added for 10 days immediately after weaning and/or 7 days post weaning for 7 and 10 days respectively was lower compared to the negative control group (P < 0.05). The evaluation of the weight gain data, as well as feed conversion ratio indicated that the six treated groups performed remarkably better than the control group (P < 0.05). No ETEC were detected on days 21 and 28 in all ENR groups contrary to the untreated control. It was concluded that a strategic medication initiated 7 days post weaning with 50 ppm of ENR and only for 7 and 10 days period of time is a useful tool in controlling PWDS due to ETEC.

The efficacy of enrofloxacin in-feed medication by applying different programmes for the control of post weaning oedema disease in weaned piglets.

Oedema disease (OD) usually occurs after weaning and is due to infection with (ETEEC) enterotoxaemic Escherichia (E.) coli. This study further examines the efficacy of three different in-feed usage programmes of enrofloxacin (ENR/Baytril I.E.R. 2.5%), on the control of post weaning OD in piglets. The recommended in-feed dosage of ENR for this clinical indication, i.e. 50 p.p.m., was used. Five groups with a total of 240 weaned piglets for 28 days period were used in this trial. One group (negative control) was offered feed free of antimicrobials, one group was offered feed as that of the negative control group except that the feed consumption was restricted for the first 12 days post weaning, and three groups were offered feed ad libitum medicated with 50 p.p.m. of ENR starting 7 days after weaning for 5, 7 and 10 days, respectively, and were compared with regard to their performance. Mortality was lower compared to the negative control group in all ENR treatments (P < 0.05). The evaluation of the growth performance data, as well as feed conversion ratio, indicated that the three treated groups performed remarkably better than the control group (P < 0.05). It was concluded that a strategic medication initiated 7 days post weaning with 50 p.p.m. of ENR and usually for a 10 day period is useful in controlling and/or preventing post weaning OD due to ETEEC.

A preliminary investigation on the latency of the goat herpesvirus BHV-6.

An experiment was designed for a preliminary investigation of the caprine herpesvirus BHV-6 latency. The experiment was carried out in two steps. In the first, the virus inoculated six kids and the control, showed a mild infection and excreted the virus for 4-12 days. The second part started about one month after the cease of all symptoms and the virus isolations of the first part. No immunosuppression and therefore no virus reactivation could be achieved after eight daily administered injections of dexamethasone (0.15-0.50 mg/kg BW), as it was judged by the hematological, virological, pathological and serological findings.

Field study on the efficacy of two different vaccination schedules with HYORESP in a Mycoplasma hyopneumoniae-infected commercial pig unit.

A trial was carried out with HYORESP a Mycoplasma hyopneumoniae (M. hyo) vaccine in order to confirm the benefit of vaccination under field conditions in a commercial industrial farrow-to-finish unit, contaminated with M. hyo. Infection with M. hyo was confirmed through positive blood and colostrum samples [enzyme-linked immunosorbent assay (ELISA) test] combined with positive gross lesions of the lung at slaughter. Two different vaccination schedules were tested. Pigs were randomly allocated to three groups: control non-vaccinated group (n = 130, given a placebo injection at 3, 25 and 70 days of age); early vaccinated group (n = 128, given vaccination at 3 and 25 days of age and a placebo at 70 days of age); late vaccinated group (n = 132, given a placebo at 3 and 25 days of age and vaccination at 70 days of age). Both growth rate and feed conversion ratio were signifcantly (P < 0.05) improved in the vaccinated groups compared with the control group. The lung lesion score was also significantly (P < 0.05) improved in both vaccinated groups. In this trial, it was clearly demonstrated that vaccination is highly effective in improving performance in pig units infected with M. hyo. The improvement in the feed conversion ratio in the vaccinated groups was especially impressive: -0.411 (13% improvement) in the group vaccinated twice at 3 and 25 days of age; -0.162 (5% improvement) in the group vaccinated once at 70 days of age. Performances were better when two shots were given early in life compared with one shot later--probably due to an infection taking place rather early in life for most of the pigs. Moreover, a significant reduction in the cost of supportive (injectable) medication was noticed in vaccinated pigs. In conclusion, HYORESP proved to be a very efficacious tool to control M. hyo in infected herds with its remarkable flexibility that allows the vaccination schedule to be adapted to the specific field conditions.

Field evaluation of the effect of in-feed doxycycline for the control of ileitis in weaned piglets.

The aim of this trial was to evaluate the effect of in-feed doxycycline (DOXY) on the control of ileitis in weaned piglets. On a farm with a previous history of ileitis outbreaks, 288 piglets at the age of weaning (25 +/- 2 days old) were divided into four experimental groups, each group comprising three pens with 24 piglets in each pen. Non-medicated animals served as negative control (NC) group, whereas groups DOXY-50, DOXY-125 and DOXY-250 received doxycycline via feed at 50, 125 and 250 ppm, respectively. Therapy lasted for 14 days followed by an observation period of 28 days. In conclusion, administration of doxycycline at a dose rate of 125 or 250 ppm had beneficial effect compared with the NC group. in terms of the reduction of diarrhoea prevalence, the enhancement of growth performance and the reduction of prevalence of Lawsonia intracellularis in the intestine, as shown either by the PCR method or by specific histopathological examinations. Treatment with 250 ppm of doxycycline for a fortnight interval post-weaning seems to be beneficial leading to better growth rates of piglets not only during treatment period, but also throughout the whole nursery phase.

Control of proliferative enteropathy in growing/fattening pigs using growth promoters.

The aim of this study was to evaluate the effect of different antibiotics used as growth promoters on the control of porcine intestinal adenomatosis when administered in weaning, growing and fattening pig diets, according to Annex I of the European Union directive (70/524/EEC and its subsequent amendments to date) for the use of feed additives. On a farm with a previous history of proliferative enteropathy outbreaks, 648 weaned piglets (23 days old) were divided into nine experimental groups according to bodyweight and sex ratio, each group comprising four pens with 18 pigs in each pen. One group served the trial as a negative (unmedicated) control: another (the positive control) received monensin via feed at 100 p.p.m. up to the end of the growing phase (107 days old) and 50 p.p.m. up to slaughter age (156 days old). The remaining seven groups were offered feed with the addition of the following antibiotics: virginia-mycin (50-20 p.p.m.), avilamycin (40-20 p.p.m.), spiramycin (50-20 p.p.m.), zinc bacitracin (50-10 p.p.m.), avoparcin (40-20 p.p.m.), tylosin (40-20 p.p.m.) and salinomycin (60-30 p.p.m.), respectively. The performance of the pigs in the positive control group was very satisfying and among the highest in the trial, verifying earlier field studies. As a general conclusion it seems that all tested growth promoters had a beneficial effect compared with the untreated control, indicated by the decrease of mortality rate, the elimination of diarrhoeal incidence and the enhancement of growth performance, although the proliferative enteropathy control achieved by each substance was not always satisfactory. More specifically, the antibiotic growth promoters tested can be scaled according to their total efficacy as follows: 1. Salinomycin, tylosin, spiramycin; 2. Virginiamycin, zinc bacitracin, avilamycin; and 3. Avoparcin. Finally, it is considered that part of the growth promotion efficacy of the tested substances is due to their potential capacity to control porcine intestinal adenomatosis; thus, in future growth performance trials, the disease background of the trial farms must be examined, especially for porcine enteropathy challenges.