Investigations of an enteric infection of cockatoos caused by an enterovirus-like agent

An enteric infection in cockatoos associated with a 30 nm diameter enterovirus-like agent seen in faeces and intestinal epithelial cells is described. The disease is characterised by intractable, profuse, mucoid diarrhoea, weight loss, dehydration and death. Lesions in the intestine consist of villous atrophy, villous fusion, enterocyte hyperplasia and, in some cases, chronic inflammation. Affected birds so far examined have concurrent psittacine beak and feather disease.     

Evaluation of von Willebrand Factor During Pregnancy,Lactation and Oestrous Cycle in Bitches Affected and Unaffected by von Willebrand Disease

Plasmatic concentrations of von Willebrand Factor (vWF) increase during pregnancy in humans and dogs; however the mechanism of such increase is still not well defined. The aims of this study were: (i) to evaluate changes in vWF concentration during pregnancy and during the subsequent oestrous cycle in bitches affected and unaffected by von Willebrand Disease (vWD); (ii) to correlate the vWF levels and cortisol levels in both groups. Seven vWD affected (GI) and nine unaffected (GII) bitches were used. The animals were assessed during pregnancy, parturition, lactation and non‐gestational oestrous cycle in 11 moments (Pregnancy 1, Pregnancy 2, Parturition, Lactation 1, Lactation 2, Lactation 3, Anestrus, Proestrus, Oestrus, Diestrus 1, and Diestrus 2). The following tests were performed; measurement of von Willebrand factor antigen (vWF:Ag), albumin and cortisol. In both groups, vWF concentration remained stable during the non‐gestational oestrous cycle, but increased during pregnancy, with the highest value observed at parturition. Increases of 70% and 124% in vWF were seen in GI and GII, respectively, compared to anestrus. No correlation was found between vWF and cortisol. Values of vWF:Ag changed during pregnancy, with a peak at parturition, both in vWD affected and unaffected animals. Values of vWF were not altered in the different phases of the oestrous cycle following pregnancy in both groups. Evaluation of vWF during pregnancy can cause false negative results for vWD, but assessment can be performed at any point in the oestrous cycle of non‐pregnant bitches.     

Susceptibility of cats to equine morbillivirus

Objective To assess the susceptibility of cats to equine morbillivirus (EMV) by direct administration of the virus by subcutaneous, intra-nasal or oral routes, and following exposure to infected cats.
Design A disease transmission study, with controls, using ten cats.
Procedure Groups of cats were given the virus by the designated methods and assessed for evidence of infection by clinical examination, plus pathological and virological tests.
Results All cats administered the virus by subcutaneous, intra-nasal or oral routes became infected and developed the disease within 4 to 8 days. One of two cats in contact with affected cats also developed the disease, but two cats kept near to affected cats did not become infected. The virus was isolated from a range of tissues collected from the infected cats, and the lesions observed in affected cats were similar to those previously observed in horses naturally and experimentally infected with the virus.
Conclusion This is the first demonstration that animals can be infected with EMV by non-parenteral means, that the virus can transmit naturally between animals and confirms other reports of the similarity of EMV disease in horses and cats.     

A retrospective evaluation of the surgical management of equine carpal injury

SUMMARY: Records of 220 thoroughbred horses presented to the Randwick Equine Centre or the University of Queensland Veterinary Teaching Hospital for surgical management of carpal injury were reviewed. Details of racing performance were obtained, enabling evaluation of racing success following surgery. Age and sex matched control horses not known to have suffered carpal injury were selected from the Australian Stud Book and the Australian Racehorse Register. Control and treated populations were compared in terms of overall career racing success.
Radiographs or xeroradiographs from 198 horses were available for evaluation. The dorsomedial aspects of the distal articular surface of the radial carpal bone and the proximal articular surface of the third carpal bone were the most commonly observed locations of osteochondral fracture. Bilateral carpal injury was found to be sufficiently common to warrant routine radiographic examination of both limbs. The dorsolateral-palmaromedial oblique, flexed lateral and dorsoproximal-dorsodistal oblique (skyline) projections were the most useful views for evaluation of carpal degenerative joint disease. Surgical removal of osteochondral fractures by arthrotomy or arthroscopy was found to be a suitable method of treatment.
Arthroscopy was associated with a significantly shorter convalescent period than arthrotomy. Seventy-six percent of the treated population returned to racing following surgery. Average earnings following surgery were 20 000. However, the median value was only 1400 and 48% of the treated population failed to earn more than 1000. Male horses in both the treated and control groups performed significantly better than females. Treated horses performed significantly better than the randomly selected control population.     

Effect of chronic administration of recombinant bovine tumor necrosis factor to cattle

Cachectin/tumor necrosis factor-alpha (TNF), a protein produced by macrophages upon stimulation, has been implicated as an important mediator of inflammatory processes and of clinical manifestations in chronic infectious diseases. In order to study further the potential role of TNF in infectious diseases, a homologous system was employed in which recombinant Escherichia coli (E. coli) derived bovine TNF (rBoTNF) was injected in cattle, either as a single bolus or in a repetitive treatment-regime. No clinical signs were observed, although changes occurred in hematologic and immunologic parameters when less than 0.5 mg of TNF/100 kg body weight was administered twice daily for 18 days. Prolonged treatment with 0.05-0.5 mg/100 kg induced histologic but no gross changes in the kidneys and liver. When doses were increased above 0.5 mg/100 kg, depression, anorexia, cachexia, and diarrhea appeared rapidly. Pathologic changes were apparent in various tissues including liver, kidneys, and lymphoid organs; body fat depots were depleted. Most of these changes appeared to be reversible; return to normal tissue-morphology occurred within 3 weeks of withdrawal of rBoTNF. The clinical and pathologic changes induced by prolonged rBoTNF administration resembled those observed in some chronic parasitic and viral infections of cattle in which macrophage-activation characteristically occur. Our finding may be relevant to the elucidation of the pathogenesis of these and other chronic infections.     

Clinical and immunological effects of single bolus administration of recombinant interleukin-2 in cattle.

Recombinant bovine interleukin-2 (rBoIL-2) was administered as a single intramuscular bolus to healthy calves to determine the minimal dose capable of exerting a biological response. Doses ranging from 2.5 to 0.05 micrograms rBoIL-2/kg did not induce pyrexia, diarrhea, or depression, nor did they alter any blood chemistry or hematological parameters commonly associated with IL-2 toxicity. Moreover, the only significant immunological change observed was a reduction in the number of peripheral blood lymphocytes identified with the monoclonal antibodies B7A, BAQ4A (WC1+ cells), CACTB6A (WC2+ cells) and DH59B (monocytes). The decrease in cells associated with these markers did not influence non-MHC restricted cytotoxicity or in vitro lymphocyte proliferative responses to mitogens and IL-2. The treatments had no effect on delayed type hypersensitivity responses to phytohemagglutinin. These results indicate that IL-2 may be involved in the regulation of trafficking patterns of a unique subpopulation of lymphocytes in cattle.     

Peanut agglutinin (PNA): binding and stimulation of bovine intestinal and peripheral blood leukocytes

The use of peanut agglutinin (PNA) as a reliable marker for bovine T lymphocytes as well as its in vitro lymphoblastogenic capacity were investigated and compared to those of concanavalin-A (ConA). The binding ability of fluorescein isothiocyanate conjugated PNA (FITC-PNA) and FITC-ConA to bovine leukocytes isolated from peripheral blood (PBL) as well as from the intraepithelium (IEL), lamina propria (LPL) and Peyer's patches (PPL) of the small intestinal mucosa of five normal adult cows (n = 5) was analyzed using laser flow cytometry (LFC) and fluorescence microscopy. Monoclonal antibodies (mAb) specific for bovine T cells (B26A), B cells (PIg45A), "null" cells (B7A1) and monocytes/granulocytes (DH59B) were employed to determine the phenotype of the cell lineage(s) expressing PNA surface receptor(s). There were no significant variations (P greater than 0.1) in the proportion of PNA-binding cells in PBL (76%), PPL (77%), IEL (79%) and LPL (81%) even though there were significant differences between the percentages of B26A+ T cells in IEL (26%) and LPL (38%) (P less than 0.001) and in PPL (44%) and PBL (57%) (P less than 0.01). These studies clearly indicate that cells other than T cells bind PNA. Although the proportions of PNA-binding cells in enriched PP-B cells (30%) and enriched PP-plastic adherent cells (44%) were significantly lower (P less than 0.001) than those in enriched PP-T cells (95%), the results indicated that a reasonable number of non-T cells can specifically bind FITC-PNA. Additional support was obtained by similar results observed with the equivalent cell subsets from PBL. Using in vitro lymphoblastogenesis, the PNA stimulating capacity significantly varied between the various cell populations (P less than 0.001 between IEL and PBL; and P less than 0.02 between PPL and PBL). In addition, marked differences were observed between the binding ability and stimulating capacity of PNA on each leukocyte population (P less than 0.01 in PBL to P less than 0.001 in IEL). Concanavalin A which bound to approximately 100% of each cell population, revealed significant variation in its mitogenic activity between IEL and PBL (P less than 0.001) but not between LPL and PPL (P greater than 0.1). The finding that PNA can bind to bovine T cells as well as to some B cells, monocytes/macrophages and possibly some granulocytes and "null" cells disputes its reliability as a specific bovine T cell marker. Furthermore, the binding abilities of PNA and ConA to bovine leukocytes are not necessarily correlated to their in vitro mitogenic capacities.     

Prevalence and risk factors for medical events following exercise at Australian Greyhound race meetings

Aim

A prospective, observational study to determine the prevalence of post‐exercise conditions at Australian Greyhound race meetings and to assess association with race performance and other environmental, race‐ and dog‐related factors was undertaken.

Methods

A total of 4020 starters were observed (2813 Greyhounds, 1009 trainers, 536 races, 52 race meets, 48 race dates and 11 race tracks) following a race. The presence of diaphragmatic flutter (DF), ataxia, seizure, collapse or sudden death was recorded. Risk factors were screened by univariable logistic regression prior to multivariable backward stepwise model building.

Results

In this study, 962 starters (n = 768 dogs) had DF (23.9%), 16 starters were ataxic (0.4%) and there were no observed cases of collapse, seizure or sudden death. Race track location, increasing race distance, race grade based on increasing 1st place prize value, lower (earlier) race number at the meeting, age, a previous observation of DF at the last start, females, colour (white) and better finishing position were all associated with an increased risk of a Greyhound being observed with DF. However, when logistic regression assessing the random effect of dog was performed, the presence of previous DF was not significant. In this cohort, DF was common following strenuous exercise in Greyhounds and on its own does not appear to result in reduced performance or distress to the animal.

Conclusion

The incidence of ataxia was low and collapse, seizure and sudden death were not observed. However, even though uncommon, ataxia has welfare concerns for racing Greyhounds that warrants further investigation.     

Seroprevalence of porcine circovirus type 2 in swine populations in Canada and Costa Rica

Porcine circovirus (PCV) was recently divided into 2 antigenically distinct types that differ (65% amino acid identity) in the protein encoded by open reading frame 2 (ORF2). Porcine circovirus 1 is apparently non-pathogenic and, in contrast, PCV2 is associated with porcine multisystemic wasting syndrome (PMWS). Our objective was to determine the extent of exposure of normal pigs in Canada and Costa Rica to PCV2. Recombinant DNA techniques were used to produce an antigen from ORF2 of PCV2 that was suitable for the detection of antibody in swine sera. The presence of PCV2 nucleotide sequences was detected using polymerase chain reaction (PCR) techniques. Using these tests, specific antibody and nucleotide sequences were demonstrated in sera from a cohort of pigs during a PMWS outbreak. Antibody was detected in normal, healthy hogs slaughtered in Canada (82.4% of 386) and in Costa Rica (14.6% of 322). This is the first report indicating the presence of PCV2 in Latin America. More than 50% of these sera also contained PCV2 nucleotide sequence. Although these hogs were healthy when slaughtered, they were infected with PCV2 and may have previously been ill. The widespread occurrence of PCV2 in swine suggests that this virus is adapted to replication in porcine tissue.