Dogkeeping practices as reported by readers of an Australian dog enthusiast magazine.

OBJECTIVE: To characterise Australian domestic dogkeeping practices relevant to canine health and welfare. PROCEDURE: A quantitative questionnaire was distributed nationally through Dog's Life magazine. Data on management practices, household and dog demographics from 690 Australian dogs in 485 self-selected respondent households were analysed using ordinal and binary regression. RESULTS: Several variables, relating to dog, owner and environment were associated with management practices. The size of the dog correlated positively with being fed outdoors (P < 0.001), gameplaying (P = 0.016) and being trained (P = 0.001) and negatively with time spent indoors (P < 0.001). Neutered dogs were more likely to be walked every day (P = 0.027) and have had prior treatment for unwelcome behaviours (P < 0.001) but less likely to be fed outdoors (P < 0.013). The number of children in the household correlated with the dog being fed outdoors (P < 0.001). The number of adult female humans in the household correlated with dog being neutered (P < 0.001) whereas the reverse was linked to number of adult male humans in the household (P < 0.013). Larger numbers of adult female humans in the household were associated with a higher incidence of prior treatment for unwelcome behaviours (P = 0.020). The number of dogs in the household correlated negatively with dogs being walked every day (P < 0.004) and gameplaying (P = 0.001). Pure bred dogs were more likely to have attended puppy preschool than cross breeds (P = 0.002). CONCLUSION: Reference to previous studies of Australian dog owners suggests that the current data are representative in terms of location of households, sex and age of dogs, however, the proportion of pure bred dogs in the current survey was surprisingly high. This was perhaps because respondents were from a particular sector of the Australian dog-owning population. It must be acknowledged that Dog's Life magazine readers may be atypical of Australian dog owners, nevertheless, the study demonstrates that variables relating to the dog, owner or environment can be used to characterise management styles.

Sequence variation at a Bmy I/Rsa I restriction site in ovine herpes virus 2.

DNA samples extracted from a bovine brain, one blood and one buffy coat sample from three cattle with malignant catarrhal fever, and from 47 samples of pooled sheep sera, were amplified by nested polymerase chain reaction (PCR) using primers specific for ovine herpes virus 2 (OHV-2). Confirmation of the specificity of the amplified DNA segment by restriction enzyme analysis with Rsa I and Bmy I as described by Baxter et al. was obtained in most samples. Nine amplified DNA samples could not be digested, or were only partially cut, with these enzymes. Sequencing of six samples revealed a two-nucleotide substitution in the middle of the restriction site (AA vs. CG) in four of these samples (the bovine brain and three sera), and two peaks at each of these positions (C or A, G or A) in two samples from pooled ovine serum. These results indicate the existence of a variant of OHV-2, and that both the previously sequenced OHV-2 and the variant were present in some samples of pooled ovine serum.

Dermatophilus congolensis: strain differences in expression of phospholipase activities.

Interactions between Dermatophilus congolensis strains and with other bacteria of known haemolytic activities were used to elucidate the complex nature of haemolytic activities present in various D. congolensis strains. This was further analysed by measuring their specific phospholipase activities against defined substrates by thin layer chromatography. D. congolensis strains demonstrated haemolytic interactions (synergistic or antagonistic) with other D. congolensis strains and also other species of bacteria. Most isolates expressed lyso-phospholipase-D activity, while various strains also expressed sphingomyelinase-D activity, phospholipase-A versus phosphatidylcholines and/or cephalins, phospholipase-D versus phosphatidylcholines or all these activities, under the culture conditions used.

Difference between lambs with chronic and mild dermatophilosis in frequency of alleles of CD3 gamma.

Southern blots prepared with DNA from 20 Merino lambs that previously had chronic dermatophilosis (chronic) and 20 lambs that previously had mild dermatophilosis lesions (resistant) were hybridised with DNA sequences of the genes for the T-cell receptor-beta (TCR beta), a TCR-associated peptide 'cluster designation 3 gamma chain' (CD3 gamma) and ovine Major Histocompatibility Complex class 1 (ov. MHC class 1). There was a significant difference in the incidence of an allele of CD3 gamma between the chronic and resistant lambs. No significant difference in the incidence of alleles of TCR beta or ov. MHC class 1 was detected.

Dermatophilus chelonae sp. nov., isolated from chelonids in Australia.

Three isolates of a previously undescribed Dermatophilus sp. obtained from chelonids (two strains obtained from turtles and one strain obtained from a tortoise) were compared with 30 Dermatophilus congolensis isolates obtained from Australian mammals. The microscopic appearance, the colony morphology, and most biochemical test results for the chelonid isolates were characteristic of the genus Dermatophilus. Our isolates differed from the mammalian D. congolensis isolates in a number of cultural characteristics, including faster growth at 27 degrees C than at 37 degrees C, formation of two hemolysis zones around colonies on blood agar at 37 degrees C in the presence of 10% CO2, poor motility, and production of a distinctive odor. The DNA restriction enzyme digestion and protein electrophoresis patterns of our strains were distinct. The electrophoretic mobilities of 11 enzymes differed from the mobilities observed with D. congolensis strains. A monoclonal antibody to a surface antigen of an ovine isolate did not react with zoospores or filaments of the chelonid isolates. Biochemical differences between our isolates and D. congolensis included the ability of the chelonid isolates to reduce nitrate to nitrate and the fact that the chelonid isolates exhibit collagenase activity in vitro. We propose that the chelonid isolates should be placed in a new species, Dermatophilus chelonae. Strain W16, which was isolated from a nose scab on a snapping turtle, is the type strain; a culture of this strain has been deposited in the American Type Culture Collection as strain ATCC 51576.

Genetic analysis of dermatophilus spp. using multilocus enzyme electrophoresis.

Multilocus enzyme electrophoresis was used to examine a collection of 41 mainly Australian isolates of Dermatophilus congolensis that had been cultured from sheep, cattle, horses, a goat, a marsupial and Chelonids. Allelic variation was examined at 16 enzyme loci. The isolates were divided into eight distinct electrophoretic types (ETs) with a mean genetic diversity per locus of 0.41. The three isolates from Chelonids represented a distinct clone in ET 1 which was separated from the remaining cluster of isolates of D. congolensis by a genetic distance of 0.852. These findings supported a previous proposal that the isolates from Chelonids represent a new species of Dermatophilus. The other 38 D. congolensis isolates were separated into two divisions (I and II) by a genetic distance of 0.560. The divisions were both subdivided into groups that either only contained alpha-hemolytic or beta-hemolytic isolates, but all isolates in each ET had only one hemolytic pattern. Isolates originating from the same animal species, or from the same geographic location, were not all closely related genetically. The allocation of isolates into ETs correlated well with their distribution into DNA restriction endonuclease analysis patterns previously established for the collection. Although relatively few distinct strains of D. congolensis were identified amongst the collection, significant genetic diversity existed within this population.

Variation in cultural, morphological, biochemical properties and infectivity of Australian isolates of Dermatophilus congolensis.

Recent vaccination studies with Dermatophilus congolensis showed that variation of challenge strains had a considerable influence on protection afforded by the vaccines. In this study cultural, morphological and biochemical properties of 30 D. congolensis isolates from throughout Australian were investigated. The infective dose required to produce lesions of equivalent severity by these isolates for sheep, rabbits and guinea pigs was also examined and the isolates were grouped into four clusters of similar infectivity ranking. Analysis of the relationship between cultural, morphological and biochemical characteristics and infectivity rankings of clusters was undertaken to determine if certain properties were linked to infectivity. Considerable variability was found in haemolytic activity on blood agar, mucoid nature of colonies, motility, flagella density and polarity, capsule width, restriction enzyme profiles of bacterial DNA, protein electropherotype, carbohydrate content, and enzymic activity against proteins, maltose, chondroitin-4-sulphate, phospholipids and lipids. Of these properties haemolytic activity and enzyme activity against casein, chondroitin-4-sulphate and lipids showed some link with infectivity ranking for these isolates.

Blood T6-lymphocyte antigen levels as a poor resistance marker in ovine dermatophilosis.

Merino ewes lambs from a flock expected to have a high prevalence of dermatophilosis were examined for lesions at marking, weaning and prior to first shearing. Blood was collected at marking and prior to shearing to enable quantification of T6-lymphocyte antigen levels in peripheral blood mononuclear cells (PBM) using monoclonal antibody SBU-T6 20-27. A group of the lambs that had persistent and/or severe dermatophilosis had significantly lower (P < 0.05) mean levels of T6-lymphocyte staining in PBM than those with minimal or no dermatophilosis in blood samples collected prior to shearing. However, the wide variability of this parameter in resistant and susceptible lambs indicated that this would not be a satisfactory procedure to rank sheep for resistance to dermatophilosis.

Investigation of sex-hormone binding globulin interference in direct radioimmunoassays for testosterone and estradiol.

The aim of this study was to find reasons for the interference of sex-hormone binding globulin (SHBG) in direct radioimmunoassays (RIAs) for testosterone and estradiol. 125I-labeled testosterone and estradiol were compared with 3H-labeled testosterone and estradiol for their affinity to SHBG. The 3H-labeled steroids bound far more avidly to SHBG than did the corresponding 125I-labeled steroids. The SHBG concentration in the standard matrix of two kits was significant. Finally, 3H-labeled steroids were compared with 125I-labeled steroids for their affinity to the antibody supplied with the kits. The 125I-labeled steroids bound more avidly than did the 3H-labeled steroids to the corresponding antibodies. Direct testosterone and estradiol results would be influenced according to the SHBG in the sample, as observed.

Emergency serum and urine HCG analyses with the 'Tandem ICON' procedure.

A comparison between new urine and serum enzyme immunoassay techniques and existing serum radioimmunoassay techniques for the detection of HCG in the diagnosis of ectopic and early intrauterine pregnancy was undertaken. Urine HCG estimations by enzyme immunoassay were not found to be adequate for the exclusion of ectopic pregnancy due to a false negative rate of 12.5% (2 of 16 patients). Serum HCG estimations by enzyme immunoassay were found to compare favourably with radioimmunoassay techniques in the detection of HCG in both ectopic and early intrauterine pregnancy.