The intensity of resistance by mature Merino ewes against Haemonchus contortus and Tichostrongylus colubriformis in single-species and combined-species infection

Three-year-old, non-lactating and non-pregnant Merino ewes, raised on pasture under a program of strategic treatment with anthelmintic and found to be extremely resistant to "trickle" infection with Haemonchus contortus, were given single-dose infections with either H. contortus or Trichostrongylus colubriformis or both species together. The purpose was to ascertain the intensity of protective immunity against the 2 parasites in sheep with immunity acquired from a presumably slight exposure to infection. To provide a criterion, some infected ewes were immunosuppressed with corticosteroid, dexamethasone. Untreated ewes were extremely resistant to challenge infection with either 15,000 or 150,000 H. contortus or 15,000 T. colubriformis. Surprisingly, when mixed infection was given, egg counts for H. contortus were significantly elevated compared with infection by that species alone. Antibody to antigens from infective larval and adult H. contortus was measured in serum by enzyme-linked-immunosorbent assay (ELISA) during the course of infection. Serum titres against larval antigens were significantly depressed when infections with either H. contortus or T. colubriformis were permitted by immunosuppression with dexamethasone, whereas those against adult antigen were depressed when infection with T. colubriformis was permitted.     

The distribution of barley yellow mosaic virus (BaYMV) and barley mild mosaic virus (BaMMV) in UK winter barley samples, 1987-1990

Improved diagnosis of barley yellow mosaic (BaYMV) and barley mild mosaic (BaMMV) viruses was obtained by adjusting the buffers used in immunospecific electron microscopy (ISEM) to ensure a pH ≥ 7-0 and in ELISA by replacing ovalbumin with 10 g/l full cream milk powder.
Over 70% of samples of winter barley with symptoms of mosaic received from different sites in the UK during 1987-90 had BaYMV and 37% had BaMMV, with 11% containing both viruses. BaMMV was much more common on malting cultivars than on those grown for feed and this resulted in an easterly bias to the geographical distribution of the virus. Both viruses were, however, widely distributed in areas where winter barley is grown intensively. A small number of BaYMV records were from cultivars previously regarded as resistant and these are probably a distinct strain of the virus.     

Parry's disease of pears is similar to pear decline and is associated with mycoplasma-like organisms transmitted by Cacopsylla pyricola

Mycoplasma-like organisms (MLOs) were detected by fluorescence microscopy in a number of pear cultivars and pear seedlings growing under a range of different conditions. In the cultivar Conference, MLOs were consistently associated with symptoms of Parry's disease, a decline-like disease of young trees with quince rootstocks. MLO-free pear seedlings rapidly became infected when they were planted outside. Experimental transmission of MLOs to pear seedlings and Conference trees was achieved using pear psyllids, caught outside or raised on infected plants under controlled conditions. Conference trees in an orchard trial remained free from the severe spring symptoms of Parry's disease when they were protected from feeding insects during spring of the previous year. MLOs were graft transmissible, but were not perpetuated by the standard propagation practices of budding or grafting when quince rootstocks were used. Parry's disease appears to be similar to pear decline, an MLO-induced disease well established in several other parts of the world. It is suggested that Parry's disease should be referred to as pear decline.     

Abdominal Crisis in the Horse: A Comparison of Pre-Surgical Evaluation With Surgical Findings and Results

The results of preoperative examination, surgical intervention and the outcome of 50 cases of acute abdominal crisis in the horse are presented. Pre-surgical parameters discussed in this correlative study include duration of the condition prior to sergery, pulse rate, packed cell volume (PCV), abdominal distention, intestinal motility and tympany, rectal findings, reflux of fluid after passage of a nasogastric tube, and abdominal paracentesis. A retrospective study was performed to evaluate the usefulness of each clinical parameter in deciding that a case was surgical, arriving at a specific pre-surgical diagnosis, and in giving a prognosis. Rectal examination was the single most useful diagnostic tool. Reflux of gastric fluid through the nasogastric tube usually indicated obstruction of the small intestine.     

Effects of delmadinone acetate on pituitary-adrenal function, glucose tolerance and growth hormone in male dogs

Objective To characterise the effects of delmadinone acetate on the pituitary-adrenal axis, glucose tolerance and growth hormone concentration in normal male dogs and dogs with benign prostatic hyperplasia.
Design A prospective study involving nine normal male dogs and seven with prostatic hyperplasia.
Procedure Delmadinone acetate was administered to six normal male dogs and seven dogs with benign prostatic hyperplasia at recommended dose rates (1.5 mg/kg subcuta-neously at 0, 1 and 4 weeks). Three normal controls received saline at the same intervals. Blood concentrations of ACTH, cortisol, glucose, insulin and growth hormone were measured over 50 days. Intravenous glucose tolerance and ACTH response tests were performed before and after treatment in the nine normal animals.
Results A substantial suppression of basal and 2 h post-ACTH plasma cortisol secretion was demonstrated after one dose in all dogs given delmadinone acetate. Individual responses after the second and third administration varied between recovery in adrenal responsiveness to continued suppression. Plasma ACTH concentration was also diminished after one treatment. No effects were evident on glucose tolerance or serum growth hormone concentrations.
Conclusion Delmadinone acetate causes adrenal suppression from inhibition of release of ACTH from the pituitary gland. Treated dogs may be at risk of developing signs of glucocorticoid insufficiency if subjected to stressful events during or after therapy. Neither glucose intolerance nor hyper-somatotropism seems likely in male dogs given delmadinone acetate at the recommended dose rate, but the potential for excessive growth hormone secretion in treated bitches remains undetermined.     

Plasma cortisol responses to three cortico-trophic preparations in normal dogs

Objective To compare cortisol responses to three corticotrophic preparations in normal dogs.
Animals Eight clinically normal dogs (four intact males, four intact females) of medium size.
Procedures Each dog received four treatments on four separate occasions in a duplicated Latin square pattern. Treatments were two adrenocorticotrophin (ACTH) preparations given intramuscularly at 2.2 U/kg, one of the ACTH preparations given intramuscularly at 1 U/kg and a synthetic polypeptide with ACTH-like activity (tetracosactrin, cosyntropin) given intravenously at 5 μg/kg. Plasma samples were taken for cortisol assay before and at 0.5, 1, 2 and 4 h after treatment.
Results Plasma cortisol concentrations were similar with the two ACTH preparations and at both dose rates. Tetracosactrin produced smaller mean peak cortisol concentrations, which tended to occur earlier than with ACTH, and smaller values for the area under the curve of plasma cortisol concentration from zero time to 4 h.
Conclusion The findings suggest that canine adrenal function can be tested adequately by giving ACTH intramuscularly at 1 U/kg and measuring plasma cortisol in samples taken at 0 and 2 h, or by giving tetracosactrin intravenously at 5 μg/kg and determining cortisol concentration at 0 and 1 h.     

Some biochemical properties and antibiotic sensitivities of Pasteurella piscidda isolated in Greece and comparison with strains from Japan, France and Italy

Abstract The biochemical properties and antibiotic sensitivity patterns of 13 Pasteurella piscicida isolates from Greece are described and compared with 10 Japanese and five European (Italian and French) isolates. Morphologically and biochemically, all isolates of P. piscidda tested were nearly identical and only minor differences could be detected with reference to the level of acid production from sugars (especially from glucose). Greek, Italian and French isolates showed similar antibiotic sensitivity patterns, being resistant to erythromycin, kanamycin and streptomycin, and sensitive to most of the other antibiotics tested. Resistance was also demonstrated for some isolates towards the potentiated sulphonamides. The Japanese isolates appeared to be resistant to a larger range of antibiotics including erythromycin, kanamycin, streptomycin, oxolinic acid, oxytetracycline and chloramphenicol. Multiple resistance of Japanese strains was also noted. These results are discussed in the light of future measures for the control of pasteurellosis.     

Nasopharyngeal cryptococcosis

Naturally occurring cryptococcosis in five cats, a dog and a koala is described. Involvement of the nasopharynx was documented in all patients, and nasopharyngeal mass lesions accounted for the major presenting complaints in four. Signs referable to nasopharyngeal disease included snoring, stertor, inspiratory dyspnoea and aerophagia. Diagnoses were made by caudal rhinoscopy using a retroverted flexible endoscope, vigorous orthograde flushing with saline, or at necropsy. Concurrent cryptococcal rhinitis was present in all cases, although involvement appeared limited to the caudal nasal cavity in most cases. Typical signs of nasal cavity disease, such as sneezing and nasal discharge, were often absent. Treatment of nasopharyngeal cryptococcosis should include physical dislodgement or debulking of lesion(s) to provide immediate alleviation of upper airway obstruction, followed by systemic antifungal therapy to eliminate residual infection from the nasal cavity. Infections caused by Cryptococcus neoformans var gattii accounted for a disproportionately large number of these cases.