Risk factors associated with Neospora caninum seropositivity in randomly sampled Canadian dairy cows and herds

Our objective was to determine cow- and herd-level risk factors associated with seropositivity for Neospora caninum in a large number of randomly selected Canadian dairy herds, controlling for important confounding variables and co-infections with bovine leukemia virus (BLV), bovine viral diarrhea virus (BVDV) and Mycobacterium avium subspecies paratuberculosis (MAP). Serum samples were obtained from 30 randomly selected cows, where available, in 240 herds using monthly milk testing, within 6 of 10 provinces, and these samples were tested for antibodies against BLV, MAP and N. caninum using commercially available ELISA test kits. Five unvaccinated cattle >6 months old from each herd were tested for antibodies to BVDV using virus neutralization. Most herd-level predictors were obtained through personal interviews with questionnaires administrated to each farm manager. A mixed logistic-regression model was built using N. caninum serostatus at the cow-level as the outcome variable, with herd as a random effect and province as a fixed effect. A BLV seropositive cow was 1.50 times more likely to be seropositive for N. caninum than a BLV-seronegative cow, and this was the only cow-level variable to remain in the final model. Regarding herd-level variables, with “no on-farm dogs” as the baseline, “presence of dogs but not known to eat placentas and/or fetuses” increased the odds of seropositivity for N. caninum by a factor of 1.66. For “presence of dogs known to eat placentas and/or fetuses”, the odds ratio (OR) was 2.75, demonstrating a dose–response relationship. “Using embryo transfer” (OR = 0.69), “asking for a BVDV-negative test before introducing an animal” (OR = 0.30), “using monensin in dry cows” (OR = 0.71), and “heifers having nose-to-nose contact with calves” (OR = 0.73) were all dichotomous variables negatively associated with seropositivity for N. caninum. “Number of milk cows on the farm” (OR = 0.99), and “area (acres) used for forage production” (OR = 0.99) were continuous variables negatively associated with N. caninum seropositivity.     

Outcome of and complications associated with prophylactic percutaneous laser disk ablation in dogs with thoracolumbar disk disease: 277 cases (1992-2001)

OBJECTIVE: To determine outcome of and complications associated with prophylactic percutaneous laser disk ablation in dogs with thoracolumbar disk disease. DESIGN: Retrospective study. ANIMALS: 277 dogs. PROCEDURE: Medical records of dogs with a history of thoracolumbar disk disease in which the 7 intervertebral disks from T10-11 through L3-4 were ablated with a holmium-yttrium-aluminum-garnet laser inserted through percutaneously placed needles were reviewed. Complications and episodes of a recurrence of neurologic signs (eg, paresis or paralysis) were recorded. Owners were contacted by telephone for follow-up information. RESULTS: Nine of 262 (3.4%) dogs for which follow-up information was available had a recurrence of paresis or paralysis. Follow-up time ranged from 1 to 85 months (mean, 15 months); signs recurred between 3 and 52 months (mean, 15.1 months) after laser disk ablation. Acute complications occurred in 5 dogs and included mild pneumothorax in 1 dog, an abscess at a needle insertion site in 1 dog, and proprioceptive deficits in 3 dogs, 1 of which required hemilaminectomy within 1 week because of progression and severity of neurologic signs. One dog developed diskospondylitis. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that prophylactic percutaneous laser disk ablation is associated with few complications and may reduce the risk of recurrence of signs of intervertebral disk disease in dogs.     

Feline papillomas and papillomaviruses

Papillomaviruses (PVs) are highly species- and site-specific pathogens of stratified squamous epithelium. Although PV infections in the various Felidae are rarely reported, we identified productive infections in six cat species. PV-induced proliferative skin or mucous membrane lesions were confirmed by immunohistochemical screening for papillomavirus-specific capsid antigens. Seven monoclonal antibodies, each of which reacts with an immunodominant antigenic determinant of the bovine papillomavirus L1 gene product, revealed that feline PV capsid epitopes were conserved to various degrees. This battery of monoclonal antibodies established differential expression patterns among cutaneous and oral PVs of snow leopards and domestic cats, suggesting that they represent distinct viruses. Clinically, the lesions in all species and anatomic sites were locally extensive and frequently multiple. Histologically, the areas of epidermal hyperplasia were flat with a similarity to benign tumors induced by cutaneotropic, carcinogenic PVs in immunosuppressed human patients. Limited restriction endonuclease analyses of viral genomic DNA confirmed the variability among three viral genomes recovered from available frozen tissue. Because most previous PV isolates have been species specific, these studies suggest that at least eight different cat papillomaviruses infect the oral cavity (tentative designations: Asian lion, Panthera leo, P1PV; snow leopard, Panthera uncia, PuPV-1; bobcat, Felis rufus, FrPV; Florida panther, Felis concolor, FcPV; clouded leopard, Neofelis nebulosa, NnPV; and domestic cat, Felis domesticus, FdPV-2) or skin (domestic cat, F. domesticus, FdPV-1; and snow leopard, P. uncia, PuPV-2).     

Occurrence of 14 cases of bovine spongiform encephalopathy in a closed dairy herd

Fourteen cases of bovine spongiform encephalopathy (BSE) were diagnosed on the basis of clinical examination in a closed herd of British Friesian cows during a 9-month period from October 1987 until June 1988. The diagnosis was confirmed on histopathological examination of brain tissue from five of the six samples submitted. The main presenting clinical signs were of altered behaviour: apprehension, anxiety and hyperaesthesia. One cow was euthanized after a short period of recumbency; the remaining 13 cows were slaughtered on humane or economic grounds. No protein of animal origin had been fed to either heifers or cows in this herd during the past 5 years and there had been no direct contact with sheep. The epidemiology of BSE in this report suggests that, if the postulate of Morgan (1988) is correct, infection is ingested within the first 6 months of life and there then follows a 4-5-year period before clinical signs appear.     

Euryhaline zooplankton of the Sundays estuary and notes on trophic relationships

The euryhaline component of the Zooplankton in the Sundays River estuary was sampled monthly at 10 stations from August 1979 to April 1981. In deeper regions surface and near-bottom samples were taken (Stations 1-7) using WP2 nets. Shallow (< 2,0 m) stations were sampled in surface waters only. Water temperature ranged between 14-27 °C. A full salinity gradient was present and salinity stratification was well developed. Acartia longipatella was most abundant during winter and spring (maximum 73 300 m^-3) in the lower estuary. The interaction of temperature and salinity as factors regulating temporal and spatial distribution was evident, these factors also interacting in the water column owing to stratification. The pioneer copepod species, seudodiaptomus hessei, attained high abundance following floods or increased river inflow. Three species of mysid shrimps were common in the plankton in summer, each species showing clear zones of maximum distribution. Zooplankton standing stock (dry mass) ranged from < 10 mg m^-3 to 1 450 mg m^-3 In surface samples and < 10 mg m ^-3 to 8 275 mg m ^-3 in bottom samples. Contribution of mysids to standing stock was rarely less than 70% and often exceeded 90%. Differences in standing stock between surface and bottom samples were owing to behavioural differences between the Zooplankton species, particularly the mysids. Behavioural adaptations play an important role in the retention of the indigenous Zooplankton in the estuary. Aspects of trophic relationships are discussed and demonstrate the significance of the Zooplankton in the transfer of energy to higher trophic levels In this estuary.     

The characterisation of E. coli O157:H7 isolates from cattle faeces and feedlot environment using PFGE

The objectives of this study were to investigate the diversity of Escherichia coli O157:H7 isolates obtained over a 3-month period from a cattle feedlot in order to assess the relationship between environmental and faecal isolates and to determine the pattern of transmission of E. coli O157:H7 between groups of cattle. Faecal samples were obtained from cattle housed in four adjacent feedlot pens at monthly intervals, with environmental pen samples collected simultaneously. All E. coli O157:H7 isolates obtained were examined by pulsed field gel electrophoresis (PFGE), polymerase chain reaction (PCR) to detect eaeA, ehxA, stx1 and stx2 genes and antibiotic sensitivity profiling. Ten isolates were subjected to acid shock to imitate conditions in the acidic cattle abomasum and assess the effect on PFGE profiles. E. coli O157:H7 was isolated from 69 faecal samples and 26 environmental samples. All isolates (n=95) carried the genes for eaeA, ehxA and stx2 and were sensitive to all antibiotics tested. The PFGE profiles of all isolates differed by no more than two bands and clustered within 80% similarity following dendrogram analysis. Acid shock had no effect on the subsequent PFGE patterns. A total of 8.7% (6/69) of cattle were shedding E. coli O157:H7 in the first month with faecal shedding increasing to 52% (36/69) by the third month of the study. A single isolate of E. coli O157:H7 may be passed rapidly through cattle pens, with the environment acting as a significant reservoir for transmission. PFGE is a useful tool for tracking the direct and indirect transmission of E. coli O157:H7 isolates on the farm.     

Panniculitis in a horse with peripancreatitis and pancreatic fibrosis.

A 22-year-old pinto mixed breed mare was admitted for evaluation of severe colic signs and gastric reflux. Multiple nonpainful, variably sized hard masses were palpated in the subcutis over the thorax, abdomen, and hindquarters of the horse. The mare was diagnosed with sterile peritonitis and had systemically high gamma-glutamyltransferase, amylase, and lipase. Three days into treatment she became febrile with signs of persistent and mild abdominal discomfort; euthanasia was elected. Necropsy revealed peripancreatitis, pancreatic fibrosis, abdominal steatitis and panniculitis. Panniculitis associated with peripancreatitis has been described in humans and dogs but not in horses. Pathogenic models for this entity are discussed.     

Efficacy of famotidine for the prevention of exercise-induced gastritis in racing Alaskan sled dogs

BACKGROUND: Omeprazole reduces the severity of exercise-induced gastritis but not the prevalence of gastric lesions in sled dogs. The frequent feeding of sled dogs during competition likely results in decreased absorption of omeprazole and, thereby, decreased efficacy. HYPOTHESIS: Famotidine, a histamine-2 blocker with good bioavailability in the presence of food, would reduce the incidence and severity of exercise-induced gastric disease in sled dogs. ANIMALS: Sixteen fit Alaskan sled dogs (4 female, 12 male, all intact, age 2-6 years). METHODS: Dogs were randomly assigned to treatment (22 mg famotidine PO q24h) or control groups (n = 8 per group). Famotidine was administered with a meal to the treatment group once daily for 7 days before a challenge and once during exercise. Control dogs were fed an identical diet as the principal group. The 16 dog team completed a 100-mile exercise challenge in 18 hours. A gastroscopy was performed 24 hours after the challenge. The appearance of the mucosa was scored by an individual by using a scoring system. RESULTS: Treatment with famotidine significantly reduced the severity score compared with control (P = .0004). No adverse effects of treatment were reported. CONCLUSIONS AND CLINICAL RELEVANCE: Famotidine is effective in reducing the severity of exercise-induced gastric disease in racing Alaskan sled dogs, with minimal to no adverse effects, and may be recommended for prophylactic use in short distance races.     

Serum chemistry alterations in Alaskan sled dogs during five successive days of prolonged endurance exercise

OBJECTIVE: To determine the impact of successive days of endurance exercise on select serum chemistry values in conditioned Alaskan sled dogs. DESIGN: Prospective cohort study. ANIMALS: 10 conditioned Alaskan sled dogs. PROCEDURES: All dogs ran 160 km/d for 5 consecutive days. Serum was obtained prior to exercise and immediately after each exercise run; all samples were obtained before dogs were fed. Serum electrolyte, mineral, protein, total bilirubin, urea nitrogen, creatinine, and cardiac troponin-I concentrations and serum alkaline phosphatase, alanine aminotransferase, creatine kinase, and aspartate aminotransferase activities were measured. Data were analyzed by means of analysis of covariance for a randomized complete block design with dog as a blocking variable, time as a covariate, and distance run as the treatment of interest. Least square mean values were compared with values obtained prior to exercise, and linear and quadratic contrasts were examined. RESULTS: Serum globulin concentration was low prior to exercise (mean +/- SD, 2.2 +/- 0.3g/dL) and progressively decreased as exercise continued. Exercise was associated with increases in serum chloride, urea nitrogen, and cardiac troponin-I concentrations and serum alanine aminotransferase, creatine kinase, and aspartate aminotransferase activities and with progressive decreases in serum potassium, total protein, and albumin concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that multiple successive days of endurance exercise resulted in mild aberrations in serum chemistry variables in conditioned sled dogs. Changes likely reflected the metabolic stresses of prolonged endurance exercise as well as dietary composition. Hypoglobulinemia in resting, conditioned sled dogs may reflect the immunosuppressive or catabolic effects of intense endurance training.