Veterinary Science - Theses
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ItemIsolation, characterisation and molecular typing of feline mycoplasma species( 2009)The exact role of mycoplasma in feline ocular and respiratory disease is not yet understood. The results of previous studies are contradictory in this regard. There is some evidence to suggest that M. felis has a pathogenic role in such diseases, but it is inconclusive. The aim of this study was to investigate the prevalence and anatomical distribution of mycoplasmas in a population of shelter cats, to determine which species were present, and establish the association of their presence with ocular or respiratory disease. The prevalence of mycoplasma in the 110 cats examined was 71.8%, as determined by in vitro culture. Mycoplasma was most commonly isolated from the pharynx, followed by the bronchus and conjunctiva. In infected cats, mycoplasmas were likely to be isolated from multiple anatomical sites. The polymerase chain reaction (PCR) was used to amplify part of the 16S rRNA gene, and the mutation scanning technique non-isotopic single-strand conformation polymorphism (SSCP) was utilised to delineate mycoplasma isolates based on nucleotide sequence variation. PCR-SSCP proved to be a useful method to screen large numbers of samples for variation and to group them according to species. The species of mycoplasma identified by nucleotide sequencing were M. felis and M. gateae. It was not determined whether it was possible to differentiate between M. gateae and M. arginini based on SSCP profile results with the target DNA region used due to their almost identical nucleotide sequence. This group of M. gateae/M. arginini served as a useful non-pathogenic comparison group to M. felis. There was no statistically significant difference between M. felis and the M. gateae/M. arginini group with respect to prevalence or anatomic distribution. There was no evidence of any association of mycoplasma with disease linked to any of the anatomic locations studied. Mycoplasmas were isolated from the lower respiratory tract in 42.7% of cats. The isolation of mycoplasmas from the lower respiratory tract of healthy cats has been reported once, but this is the first report of M. felis being isolated from this location in healthy cats. This finding indicates that the isolation of mycoplasmas from the lower respiratory tract is not sufficient evidence to implicate a role in respiratory disease. Mycoplasmas were not significantly involved in ocular or respiratory disease in the population of cats studied. More likely, they are commensal organisms in the conjunctiva, pharynx and bronchus. Whether they are capable of playing an opportunistic role in disease, or what conditions may facilitate such a role remains to be determined.
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ItemMorphometrical study of bony elements of the forelimb fetlock joints in some equine breeds( 2009)Many pathologic lesions and several types of fractures in the equine forelimbs involved the bony elements of the metacarpophalangeal joints (fetlock joints) especially the third metacarpal bones and the proximal sesamoid bones. Although the bones of the fetlock joint have been described in a general manner, the variations between equine breeds are still insufficient and differences within the breeds are not completely covered. Therefore, the aim of the current study was to identify the morphometrical variations of these bones between and within some different equine breeds. Right and left metacarpal, proximal phalangeal and proximal sesamoid bones were collected from 23 horses (10 Thoroughbreds, 5 Standardbreds and 8 Ponies) euthanized for non-orthopaedic reasons. The bones were boiled between 95°C and 99°C for 30 hours, then cleaned and left for 24 hours at room temperature for air drying. Finally, the bones were dried in the drying cabinet at 49.5°C for 8 hours. A number of dimensional parameters were measured using a custom-built apparatus, calliper and plastic tape. These measurements included proximodistal height, lateromedial width, and dorsopalmar depth. All the statistical data were analysed using the ANOVA test and SPSS statistic software except the repeatability data which were analysed by calculating the repeatability coefficient. This study showed that there were significant variations between the medial and lateral sides of all bones in all breeds. The length to the lateral condyle of Mc3 was greater than the length to the medial condyle of Mc3 in all breeds. The width and depth of the medial condyle was greater than the lateral condyle in all breeds. The lengths of the lateral sides of the P1 bones were greater than the lengths of the medial sides in the right forelimbs of Thoroughbreds and Standardbreds. The width of the medial articular cavity of P1 was greater than the width of the lateral articular cavity except in the left limb of Ponies. The depth of the medial articular cavity of P1 was greater than the depth of the lateral articular cavity except in the left limb of Standardbreds. The lateral sesamoid bones in both limbs of Thoroughbreds and Ponies were significantly longer or tended to be longer than the medial sesamoid bones. The lateral sesamoid bones were wider than the medial sesamoid bones in both limbs of Ponies. The depths of the lateral sesamoid bones were the significantly greater or tended to be greater than those of the medial sesamoid bones in both limbs of Thoroughbreds and Standardbreds. There were many morphometrical variations in the bony elements of the equine fetlock joints of Thoroughbreds, Standardbreds and Ponies. Further studies are needed to identify the reasons and mechanical effects of these differences.