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1.  Lawsonia intracellularis-associated ulcerative and necro-hemorrhagic enteritis in 5 weanling foals 
The Canadian Veterinary Journal  2013;54(9):853-858.
This report describes 5 cases of fatal Lawsonia intracellularis-associated ulcerative and necro-hemorrhagic enteritis in weanling Thoroughbred and Standardbred foals. The lesions are similar to those of the L. intracellularis-associated ulcerative and necro-hemorrhagic enteritis syndrome in pigs. Two foals had concurrent severe typhlo-colitis as a result of a large burden of encysted cyathostomes. The clinical, diagnostic, and therapeutic challenges, and the potential complications encountered during the management of such cases are discussed.
PMCID: PMC3743569  PMID: 24155489
2.  Clostridium perfringens type A fatal acute hemorrhagic gastroenteritis in a dog 
The Canadian Veterinary Journal  2012;53(5):555-557.
The morning after participating in a dog show, a 2-year-old Pomeranian dog was found dead in a pool of bloody feces. Necropsy revealed hemorrhagic gastroenteritis of the entire gastrointestinal tract, with many Gram-positive bacilli on the surface and in the lumen and crypts of the intestine. Enterotoxin-positive type A Clostridium perfringens were isolated in large numbers. This dramatic case of fatal C. perfringens gastroenteritis highlights the need to better understand the role of this bacterium in enteric disease of dogs.
PMCID: PMC3327598  PMID: 23115371
3.  Unsuccessful treatment of a horse with mandibular granulomatous osteomyelitis due to Halicephalobus gingivalis 
The Canadian Veterinary Journal  2008;49(11):1099-1103.
An 8-year-old horse was presented with a submandibular swelling. Biopsy of the lesion indicated granulomatous osteomyelitis due to Halicephalobus gingivalis. In the absence of evidence of involvement of the central nervous system at the time of diagnosis, the horse was treated with ivermectin. Unfortunately, the horse did not survive.
PMCID: PMC2572094  PMID: 19183732
4.  The emergence of a new strain of porcine circovirus-2 in Ontario and Quebec swine and its association with severe porcine circovirus associated disease — 2004–2006 
In the late fall of 2004 more severe lesions of porcine circovirus-2 associated disease (PCVAD) than usual occurred during an outbreak of porcine circovirus-2 (PCV-2) infection in Ontario nursery and grower/finisher pigs. The lesions were of unprecedented severity and included diffuse bronchointerstitial pneumonia, granulomatous enteritis, vasculitis, interstitial nephritis, and new lesions of splenic infarction. Some affected herds had up to 50% mortality. The outbreak correlated with the sudden emergence of a variant PCV-2, with PCR restriction fragment length polymorphism (RFLP) type 321. Phylogenetic comparison of ORF2 sequences and full genome sequences showed the new variant to be different from the previously dominant RFLP type 422 viruses, and similar to viruses that had occurred in France and other European and Asian countries. A subsequent retrospective study showed a statistically significant increase in the frequency of histological lesions in lymph node, spleen, lung, small intestine, colon and kidney, for pigs spontaneously infected with RFLP type 321, compared with the older RFLP type 422 strain. Viral burden, based on IHC staining in lymph node, also showed a statistically significant increase in pigs infected with the newer variant RFLP type 321, compared with the older RFLP type 422 strain. This enhanced virulence in pigs infected with PCV-2 RFLP type 321 strain may be related to the genetic differences in this new strain of PCV-2. This virus is now the dominant strain of PCV-2 virus found in Ontario and Quebec swine.
PMCID: PMC2327251  PMID: 18505190
11.  An evaluation of selected screening tests for bovine paratuberculosis. 
The objective of this study was to evaluate the performance of the lipoarabinomannan antigen enzyme-linked immunosorbent assay (LAM-ELISA), carbohydrate antigen complement fixation (CH-CFT), and protein D antigen agar gel immunodiffusion (D-AGID) tests for bovine paratuberculosis, relative to histopathology, and to culture and isolation of Mycobacterium paratuberculosis from tissues and feces. Samples for test evaluation were collected from four sources including blood and tissues from 400 cull cows at three abattoirs in Ontario, blood and feces from a paratuberculosis survey of cattle from 120 dairy farms in Ontario, a serum bank containing samples from cattle from Ontario and Québec, and a bank of sera from cattle from Pennsylvania and the northeastern United States. The data were analyzed using receiver operator characteristic curves, estimates of relative sensitivity and specificity, and kappa statistics of agreement between tests. The LAM-ELISA performed significantly better than both the CH-CFT and the D-AGID tests. The LAM-ELISA was better at predicting fecal shedding status than tissue infection. However, the LAM-ELISA also had limitations. When interpreted as positive or negative (+/-), at a critical optical density of 0.675, its sensitivity and specificity relative to bacteriology were 49% and 87% respectively. Although the serological tests examined in this study provided some information, they did not predict well the infection status of individual animals.
PMCID: PMC1263460  PMID: 1909601
12.  An epidemiological study of paratuberculosis in dairy cattle in Ontario: study design and prevalence estimates. 
An observational study involving 304 dairy herds and three abattoirs was conducted between 1986 and 1989 to investigate the epidemiology of paratuberculosis in dairy cattle in Ontario. The objectives of this paper were to describe the method of data collection for the study, to present descriptive production statistics and to present estimates of the prevalence of paratuberculosis among dairy cattle in Ontario. Mycobacterium paratuberculosis was isolated from the distal ileum and/or the ileocecal lymph node of 5.5% of 400 cull cows. Based on a lipoarabinomannan antigen enzyme-linked immunosorbent assay (LAM-ELISA) on sera, the predicted true prevalence of paratuberculosis among 14,923 dairy cattle from 304 herds, was 6.1%. Nineteen percent of 2,943 fecal cultures were uninterpretable because of overgrowth with contaminating bacteria or fungi. It was concluded that the true prevalence of paratuberculosis among dairy cattle in Ontario was no greater, and may be less than the true prevalence among dairy cattle from various regions of the United States. However, at a practical level, for the purposes of trade policy, the present study suggests that the functional prevalence is very similar in the two countries.
PMCID: PMC1263459  PMID: 1889036
15.  Colitis in calves: natural and experimental infection with a verotoxin-producing strain of Escherichia coli O111:NM. 
Verotoxin-producing Escherichia coli O111:NM were isolated from two five week old Holstein calves with dysentery. On necropsy both calves had pseudomembranous ileitis, mucohemorrhagic colitis and proctitis. Large numbers of E. coli O111:NM were isolated from the colon and lesions typical of attaching-and-effacing E. coli were evident. The isolates from both calves had identical biochemical reactions and antimicrobial resistance patterns. Oral inoculation of a four day old colostrum deprived calf with 1 x 10(10) organisms of E. coli O111:NM produced a mild, focal colitis with typical attachment and effacement lesions. We conclude that the strain of E. coli O111:NM isolated from the clinical cases has the ability to produce colitis characterized by attachment and effacement of the colonic mucosa.
PMCID: PMC1255496  PMID: 3058279
16.  Extensive large colon resection in the pony. II. Digestibility studies and postmortem findings. 
The nutritional implications and adaptive processes resulting from resection of 75% of the length of the large colon in ponies were investigated. Ten ponies in good physical condition were divided into two groups: six in the experimental group and four in the control group. During the sixth postoperative month, two digestibility studies were conducted, and phosphate fractional renal excretion and serum biochemical profiles were determined in both groups. The ponies (N = 10) were euthanized six months postoperatively, and gross and histopathological examinations were performed. Results of the serum biochemical profiles, phosphate fractional renal extraction and digestibility studies showed no statistically significant difference between groups except for the serum phosphate concentration. However, large colon resection was associated with hypophosphatemia in three of the six ponies and produced an overall significantly lower phosphate concentration in the experimental ponies. This hypophosphatemia suggests that some dietary modifications may be needed postoperatively in ponies or horses undergoing this surgical procedure. Postmortem examination and histopathological examination failed to demonstrate differences between groups. Adaptive mechanisms, specifically mucosal hypertrophy or hyperplasia, were not observed.
PMCID: PMC1255277  PMID: 3567754
17.  Caprine β-Mannosidosis in Kids from an Ontario Herd 
The Canadian Veterinary Journal  1985;26(5):155-158.
Caprine β-mannosidosis, a fatal inherited deficiency of the lysosomal enzyme β-mannosidase, was diagnosed in neonatal female Nubian crossbred twin kids from a small herd near Guelph, Ontario. The kids had been tetraplegic since birth, with whole body tremors, abnormal nystagmus and an intention tremor of the head.
At necropsy, the histological lesions found consisted of widespread neuronal and visceral clear cytoplasmic vacuolation. Ultrastructurally, vacuoles were limited by a single membrane, and were empty or contained a small amount of amorphous dense material.
Biochemical assay of sera and tissues confirmed negligible levels of β-mannosidase activity, consistent with those of previously reported cases of caprine β-mannosidosis.
Vacuoles seen with light and electron microscopy are presumed to be lysosomes containing stored disaccharide and trisaccharide, the end products of incomplete catabolism of the oligosaccharide component of certain glycoproteins.
PMCID: PMC1679981  PMID: 17422528
Caprine β-mannosidosis; neurological diseases; genetic diseases; lysosomal-storage disease
22.  Vitamin E, Selenium and Methionine Supplementation of Dystrophogenic Diets for Pigs 
Forty-eight weanling S.P.F. Yorshire pigs were used to study the influence of supplemental vitamin E (25 IU per kg of diet) selenium (0.5 ppm in diet) and methionine (0.1% in diet) on the incidence of hepatosis dietetica and mulberry heart disease when fed a torula yeast-corn diet. Vitamin E and/or selenium increased pig survival. Supplemental selenium resulted in increased liver selenium concentrations. No hepatosis dietetica was observed in any of the pigs. The addition of vitamin E and/or selenium at the levels used did not reduce the frequency of myocardial lesions; however, they prevented skeletal muscular dystrophy and exudative diathesis. The myocardial lesions were less severe in supplemented pigs compared with unsupplemented controls.
PMCID: PMC1319707  PMID: 4263922

Results 1-25 (31)