The occurrence of equine arteritis virus in Australia

This paper reports the first isolation of equine arteritis virus (EAV) in Australia and serological evidence of exposure to EAV in Australian horses. Twelve Standardbred stallions imported from North America were found to shed EAV in semen. One hundred and seven stallions were tested for serum antibodies to EAV and 73% of Standardbred stallions tested were seropositive as compared to 8% of Thoroughbred stallions. Serum antibody was detected in 71% of Standardbred mares, 6% of Standardbred racehorses and 1% of Thoroughbred mares and racehorses. Examination of stored serums demonstrated that EAV had been present in Australia since at least 1975.     

Effects of increasing days of exposure to prepartum diets on the concentration of certain blood metabolites in dairy cows

Objective To evaluate the effect of the number of days exposure to a prepartum transition diet on mineral, energy and protein metabolism in dairy cows. Design A prospective cohort study. Procedures The prepartum transition diet consisted of ryegrass pasture, cereal hay, grain, grain by-product, protein meals, BioChlor®, rumen modifiers, minerals and vitamins and contained 13.9% crude protein, 10.0 MJ metabolisable energy/kg and a dietary cation anion difference of −35 meq/kg dry matter. Forty cows were bled bi-weekly from their introduction to the prepartum transition diet until day 35 of lactation. Blood samples were submitted for estimation of a range of metabolites. Cubic smoothed splines were fitted to scatterplots of metabolite concentration as a function of day relative to calving and the area under the curve (AUC) was calculated. Linear regression modelling determined the effect of days exposed, age, body condition score (BSC) and calving day on AUC. Results The prepartum AUC of blood phosphorus and beta-hydroxybutyrate increased and the AUC of blood calcium and cholesterol decreased with increasing days exposed to the diet. The postpartum AUC of beta-hydroxybutyrate and non-esterified fatty acids decreased with increasing days exposed but increased with days exposed × age and days exposed × BCS, respectively. The AUC of other metabolites did not vary significantly with number of days exposed. Conclusions Increasing exposure to the prepartum diet significantly altered the AUC of blood metabolites associated with mineral, energy and protein metabolism in ways consistent with improvements in production and reproduction previously reported and the result suggests links between energy, protein and skeletal metabolism.     

Serovar profiling of Haemophilus parasuis on Australian farms by sampling live pigs

Objective Investigate the diversity of serovars of Haemophilus parasuis (Hps) present in Australian pig herds. Design Nasal swabs were used to obtain multiple isolates of Hps, which were grouped first by genotyping and then by serotyping representative isolates. Procedure Swabs were taken from the nasal cavity of just-weaned healthy pigs from multiparous sows on 12 farms and from post-weaned pigs of multiparous sows on 1 farm. On 5 of the 13 farms, nasal swabs were also obtained from pigs showing clinical signs suggestive of Glässer's disease. On a further 7 farms, nasal swabs were obtained only from pigs with clinical signs suggestive of Glässer's disease. Results A total of 556 Hps isolates were genotyped, and 150 isolates were serotyped. Hps was detected on 19 of the 20 farms, including 2 farms with a long history of freedom from Glässer's disease. Isolates of Hps belonging to serovars regarded as potentially pathogenic were obtained from healthy pigs at weaning on 8 of the 10 farms with a history of Glässer's disease outbreaks. Sampling 213 sick pigs yielded 115 isolates of Hps, 99 of which belonged to serovars that were either potentially pathogenic or of unknown pathogenicity. Only 16 isolates from these 213 sick pigs were of a serovar known to be non-pathogenic. Conclusion Healthy pigs contain a range of Hps serovars, even on farms free of Glässer's disease. Nasal swabbing of both healthy and sick pigs seems a useful method of serovar profiling of farms.     

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.     

Presence of Ureaplasma diversum in the Australian cattle population

In cattle, Ureaplasma diversum has been associated with decreased fertility, granular vulvovaginitis, endometritis, salpingitis and spontaneous abortion in cows and seminal vesiculitis, balanoposthitis and changes in bull sperm. The presence of U. diversum within the Australian cattle population has not been established. One of the aims of this study was to determine if U. diversum was present in Australian cattle, using culture and polymerase chain reaction (PCR), both of which are considered to be gold standards for bacterial identification. Of 100 samples collected from 66 male and 34 female cattle, 15 were positive for U. diversum. Therefore, Australia can no longer be considered free of U. diversum. Further studies should be conducted to ascertain the effects of U. diversum within Australian cattle herds and, if warranted, to investigate prevention, treatment and eradication protocols.     

Diabetes mellitus in a koala (Phascolarctos cinereus)

Objective To describe a case of diabetes mellitus in a koala (Phascolarctos cinereus).
Design A case report with controls.
Procedures We describe clinical and laboratory findings in a 6-year-old, free-living, female koala presented with traumatic injury and subsequently found to have polydipsia, hyperglycaemia and glucosuria. Over a 5 week period, serum biochemical analyses, haematological examinations, urinal-yses, measurement of serum insulin and fructosamine concentrations, necropsy, histopathological examination of a range of tissues and immunohistochemical examination of the pancreas for insulin-containing cells were done. For reference purposes, serum insulin and fructosamine concentrations were determined in four and two healthy koalas, respectively, and three healthy koalas pancreases were examined histo-logically and immunohistochemically.
Results The koala had persistent hyperglycaemia, hyperlipidaemia, hyponatraemia, hypochloraemia and glucosuria. Serum insulin concentration of the diabetic koala was only marginally smaller than that of healthy koalas, but all concentrations were smaller than reference concentrations in dogs and people. Fructosamine concentration did not allow the diabetic koala to be distinguished from healthy koalas and concentrations of all koala analytes were greater than expected for healthy dogs and people. Histopathological examination revealed extensive degeneration of pancreatic islet cells and fatty infiltration of hepatocytes. Immunoperoxidase staining revealed decreased or absent insulin in the b cells of the affected koala.
Conclusion Clinical signs, clinicopathological results and histopathological changes were consistent with diabetes mellitus. The pathogenesis of the condition could not be determined but may have been related to the administration of a parenteral corticosteroid preparation, the stress of capture or tissue damage and inflammation.