Vaccination against foot-and-mouth disease: the implications for Canada          下载免费PDF全文

Kahn S  Geale DW  Kitching PR  Bouffard A  Allard DG  Duncan JR 《The Canadian veterinary journal. La revue veterinaire canadienne》2002,43(5):349-354

Vaccination of susceptible animals against foot-and-mouth disease (FMD) is a well established strategy for helping to combat the disease. Traditionally, FMD vaccine has been used to control a disease incursion in countries where the disease has been endemic rather than in countries considered free of the disease. In 2001, the use of vaccine was considered but not implemented in the United Kingdom (1), whereas vaccine was used to help to control FMD in The Netherlands (2,3). Canadian contingency plans provide for the use of vaccine; Canada is a member of the North American Foot-and-Mouth Disease Vaccine Bank, which could supply vaccine if needed. This article explains why Canada might use FMD vaccine to combat an outbreak and the factors that are relevant to the disposal of vaccinated animals and their products. It concludes that vaccination is an important mechanism in Canada's preparedness for an outbreak of FMD and that products from vaccinated animals are safe for human consumption.  相似文献   

Appearance and disappearance of swainsonine in serum and milk of lactating ruminants with nursing young following a single dose exposure to swainsonine (locoweed; Oxytropis sericea)   总被引：5，自引：0，他引：5  

Taylor JB  Strickland JR 《Journal of animal science》2002,80(9):2476-2484

A series of experiments were conducted to investigate the elimination of swainsonine in the milk of lactating ruminants following a single dose oral exposure to swainsonine (locoweed; Oxytropis sericea) and to assess subsequent subclinical effects on the mothers and their nursing young. In a preliminary experiment, lactating ewes were gavaged with locoweed providing 0.8 mg swainsonine/kg BW (n = 4; BW = 75.8 +/- 3.6 kg; lactation = d 45) and lactating cows were offered up to 2.0 mg swainsonine/kg BW free choice (n = 16; BW = 389.6 +/- 20.9 kg; lactation = d 90). Serum and milk were collected at h 0 (before treatment), 3, 6, 12, and 24 for ewes, and h 0 (before treatment), 6, 12, 18, and 24 for cows. Swainsonine was highest (P < 0.05) by h 6 in the serum and milk of ewes. Consumption of at least 0.61 mg swainsonine/kg BW induced consistent (> 0.025 microg/mL) appearance of swainsonine in cow serum and milk. In response to the results obtained in the preliminary experiment, a subsequent experiment utilizing lactating ewes (n = 13; BW = 74.8 +/- 6.4 kg; lactation = d 30) and cows (n = 13; BW = 460.8 +/- 51.9 kg; lactation = d 90) was conducted. Each lactating ruminant was gavaged with a locoweed extract to provide 0 (control), 0.2, or 0.8 mg swainsonine/kg BW and individually penned with her nursing young. Serum and milk from the mothers and serum from the nursing young were collected at h 0 (before treatment), 3, 6, 9, 12, 24 and 48 (an additional sample was obtained at h 72 for ewes and lambs). Serum and milk swainsonine was higher (P < 0.05) in the 0.8 mg treated groups and maximal (P < 0.05) concentrations occurred from h 3 to 6 for ewes and h 6 to 12 h for cows (P < 0.05). Rises in alkaline phosphatase activity indicated subclinical toxicity in the treated ewes (P < 0.05). Following a single dose oral exposure to 0.2 and 0.8 mg swainsonine/kg BW provided by a locoweed extract, swainsonine was detected in the serum and milk of lactating ewes and cows, and rises in serum alkaline phosphatase activity were observed in the ewes. Neither swainsonine nor changes in alkaline phosphatase activity was detected in the serum of the lambs and calves nursing the ewes and cows dosed with swainsonine.  相似文献   

Epididymo-orchitis caused by Brucella melitensis in breeding rams in India     

Chand P  Sadana JR  Malhotra AK 《The Veterinary record》2002,150(3):84-85

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Preliminary observations on expression of transforming growth factors beta1 and beta3 in equine full-thickness skin wounds healing normally or with exuberant granulation tissue   总被引：1，自引：0，他引：1  

Theoret CL  Barber SM  Moyana TN  Gordon JR 《Veterinary surgery : VS》2002,31(3):266-273

OBJECTIVE: To determine whether transforming growth factor (TGF)-beta1 and -beta3 expression differs between equine limb wounds healing normally and those healing with experimentally induced exuberant granulation tissue (EGT). STUDY DESIGN: Six wounds were created on the lateral aspect of both metacarpi of each horse; one forelimb was untreated, and the other was bandaged to stimulate the development of EGT. Sequential wound biopsies allowed comparison of growth factor expression between the two types of wound. ANIMALS: Four horses (2 to 4 years of age; 350 to 420 kg). METHODS: Wounds were assessed grossly, histologically, and by enzyme-linked immunosorbent assay (ELISA) for TGF-beta1 and -beta3 expression at 12 and 24 hours and 2, 5, 10, and 14 days postoperatively. RESULTS: Bandaged wounds developed EGT. In all wounds, TGF-beta1 peaked early and remained elevated at 14 days. Peak TGF-beta1 concentration was higher in wounds with EGT, but not significantly so. Expression of TGF-beta3 differed from TGF-beta1, with peak TGF-beta3 concentrations being delayed. Concentrations of TGF-beta3 were higher in wounds healing normally, but this difference was not significant. CONCLUSIONS: During both normal and exuberant wound repair, the expression of TGF-beta1 occurred earlier than TGF-beta3 expression. Wounds healing with EGT tended to have higher concentrations of fibrogenic TGF-beta1 and lower concentrations of antifibrotic TGF-beta3 than wounds healing normally, although these differences were not statistically significant. CLINICAL RELEVANCE: This study suggests that the production of EGT in bandaged wounds may be related to increased expression of fibrogenic TGF-beta1 and decreased expression of antifibrotic TGF-beta3. Further investigation of the roles of TGF-beta1 and -beta3 may be important in understanding the molecular control of EGT in horses.  相似文献   

Temporal localization of immunoreactive transforming growth factor beta1 in normal equine skin and in full-thickness dermal wounds   总被引：1，自引：0，他引：1  

Theoret CL  Barber SM  Gordon JR 《Veterinary surgery : VS》2002,31(3):274-280

OBJECTIVE: To describe the localization of immunoreactive transforming growth factor (TGF)-beta1 in both normal skin and full-thickness dermal wounds of the limb and the thorax of the horse. STUDY DESIGN: Six full-thickness excisional wounds were created on the lateral aspect of one metacarpal region and on the midthoracic area of each horse. Sequentially collected tissue specimens from wound margins were assessed for TGF-beta1 expression by immunohistochemistry. ANIMALS: Four horses (2 to 4 years of age). METHODS: A neutralizing monoclonal anti-human TGF-beta1 antibody was used to detect the spatial expression of TGF-beta1 protein by immunohistochemical localization in biopsies obtained before wounding and at 12 and 24 hours, and 5, 10, and 14 days. RESULTS: No differences in localization of immunoreactive TGF-beta1 were detected between limb and thorax, for either intact skin or wounds. Unwounded epidermis stained moderately for TGF-beta1 protein throughout all layers, whereas the dermis was relatively devoid of immunoreactivity. During the acute stage of repair, migrating epithelium lost its stain, whereas cells of epidermal appendages remained strongly immunoreactive. The epithelium recovered its TGF-beta1 immunoreactivity during wound remodeling, although cells of the stratum corneum remained negative. Macrophages of the inflammatory exudate had positive cytoplasmic staining that diminished with time. Immunoreactivity of granulation tissue fibroblasts was evident early on and increased throughout the repair process. CONCLUSIONS: TGF-beta1 is constitutively expressed in normal, unwounded equine epithelium. Its expression is upregulated within the skin on injury and is associated with the cells involved in wound repair. CLINICAL RELEVANCE: A more precise understanding of the temporal and spatial expression of TGF-beta1 during wound repair in horses should provide the groundwork for possible future manipulations of both normal and aberrant tissue repair.  相似文献   

CXCL8((3-73))K11R/G31P antagonizes the neutrophil chemoattractants present in pasteurellosis and mastitis lesions and abrogates neutrophil influx into intradermal endotoxin challenge sites in vivo   总被引：1，自引：0，他引：1  

Li F  Zhang X  Mizzi C  Gordon JR 《Veterinary immunology and immunopathology》2002,88(1-2):65-77

Toxic products such as reactive oxygen intermediates released by activated polymorphonuclear neutrophil (PMN) have an important role in the pathophysiology of diseases associated with the deposition of immune complexes (IC) in tissues. IC-induced activation of PMN requires adhesion mediated by integrin adhesion receptors. Of the integrins expressed on PMN, the beta(2) family has been found to be of particular importance for activation of PMN by IC. beta(2) Integrin ligand binding must be activated to enable adhesion to IC. Both activating and inhibitory signals regulate beta(2) integrin ligand avidity and adhesion. The second messenger cyclic adenosine monophosphate (cAMP) has been demonstrated to inhibit the activation of PMN in response to a variety of stimuli. The purpose of this study is to test the hypothesis that cAMP-dependent signals inhibit beta(2) integrin-dependent adhesion of equine PMN to immobilized IC and subsequent adhesion-dependent activation of respiratory burst activity. Treatment of equine PMN with beta(2) adrenergic agonists isoproterenol or clenbuterol, which trigger an increase in intracellular cAMP concentration, inhibited adhesion of equine PMN to IC in a dose dependent manner. Similarly, inhibition of cAMP hydrolysis by the non-specific phosphodiesterase (PDE) inhibitor pentoxifylline and the PDE 4-specific inhibitor rolipram inhibited adhesion of equine PMN to IC. Elevation of intracellular cAMP levels with pentoxifylline, clenbuterol and rolipram also inhibited IC-induced activation of respiratory burst activity in equine PMN. Importantly, co-treatment of equine PMN with rolipram and either beta(2) adrenergic agonist synergistically inhibited both the adhesion of equine PMN to IC as well as the subsequent respiratory burst activity.  相似文献   

Serological responses of mares and weanlings following vaccination with an inactivated whole virus equine herpesvirus 1 and equine herpesvirus 4 vaccine     

Foote CE  Love DN  Gilkerson JR  Whalley JM 《Veterinary microbiology》2002,88(1):13-25

Equine herpesvirus 1 (EHV-1) is a major cause of respiratory disease and abortion in horses worldwide. Although some vaccines have been shown experimentally to reduce disease, there are few reports of the responses to vaccination in the field. This study measured antibody responses to vaccination of 159 mares (aged 4-17 years) and 101 foals (aged 3-6 months) on a large stud farm with a killed whole virus EHV-1/4 vaccine used as per the manufacturer's recommendations. Using an EHV glycoprotein D (gD)-specific ELISA and a type-specific glycoprotein G (gG) ELISA, respectively 13.8 and 28.9% of mares, and 42.6 and 46.6% of foals were classed as responding to vaccination. Additionally, 16.4 and 17.6% of mares were classified as persistently seropositive mares. Using both assays, responder mares and foals had lower week 0 mean ELISA absorbances than non-responder mares and foals. Responder mares were ten times more likely to have responder foals, and non-responder mares were six times more likely to have non-responder foals than other mares using the gG ELISA. Mares aged 7 years or less and foals aged 4 months or more were more likely to respond to vaccination than animals in other age groups. There was no association between response of mares and the number of previous vaccinations received and persistently seropositive mares did not respond to vaccination. This study documents the responses of mares and foals to vaccination in a large scale commercial environment in 2000, and suggests that knowledge of antibody status may allow a more selective vaccination strategy, representing considerable savings to industry.  相似文献   

Use of infrared thermography to detect injections and palmar digital neurectomy in horses     

Van hoogmoed LM  Snyder JR 《Veterinary journal (London, England : 1997)》2002,164(2):129-141

Thermography is a non-contact, non-invasive technique that detects surface heat emitted as infrared radiation. Because skin temperature reflects the status of underlying tissue metabolism and blood circulation, abnormal thermal patterns can signify areas of superficial inflammation. The objective of this study was to determine if thermography could detect the injection of analgesic and neurolytic agents and surgical palmar digital neurectomy. Procedures evaluated include injection of the lumbar region, suspensory ligaments, tibial nerve, palmar digital nerves, and palmar digital neurectomy. Thermographic images were obtained before and after the procedures until a significant difference was no longer detected. Local injection of the lumbar region and the suspensory ligament produced detectable thermal patterns for two days, and tibial nerve infiltration with a neurolytic agent was significant for two days. Analgesia of the palmar nerves was significant for 24h with bupivicaine, compared to five days for ammonium chloride. Palmar digital neurectomy produced more variable thermal patterns. While sensitive enough to detect changes in heat patterns from control regions, thermography is not specific enough to discriminate between procedures and injury inducing an inflammatory response.  相似文献   

Cytokine secretion by peripheral blood mononuclear cells from cows infected with Mycobacterium paratuberculosis     

Stabel JR 《American journal of veterinary research》2000,61(7):754-760

OBJECTIVE: To compare cytokine secretion patterns of peripheral blood mononuclear cells (PBMC) from healthy cows and cows subclinically and clinically infected with Mycobacterium paratuberculosis. ANIMALS: 5 noninfected cows, 6 cows with subclinical paratuberculosis, and 4 cows with clinical paratuberculosis. PROCEDURE: PBMC were isolated, and concentrations or activities of secreted interleukin (IL)-1, IL-2, IL-6, tumor necrosis factor (TNF), and interferon-gamma (IFN-gamma) were measured after in vitro stimulation of cells with concanavalin A (ConA), lipopolysaccharide (LPS), or a whole-cell sonicate of M paratuberculosis (MpS). Proliferative responses of PBMC were also determined after stimulation with ConA, phytohemagglutinin, pokeweed mitogen (PWM), or MpS. RESULTS: After stimulation with ConA, cells from subclinically infected cows secreted significantly more, and cells from clinically infected cows secreted significantly less, IFN-gamma, compared with cells from control cows. Cells from cows with subclinical paratuberculosis produced significantly more TNF and IFN-gamma in response to MpS than cells from the other 2 groups. Stimulation of PBMC from subclinically infected cows with ConA or MpS resulted in significantly higher proliferative responses, compared with cells from control and clinically infected cows. In contrast, clinically infected cows had significantly higher proliferative responses to PWM than cells from the other 2 groups. CONCLUSIONS AND CLINICAL RELEVANCE: A decrease in T-cell responses to mitogens or MpS was observed in cows clinically infected with M paratuberculosis, compared with subclinically infected cows, suggesting that activated T cells may delay the progression of paratuberculosis.  相似文献   

Evaluation of nitric oxide as an inhibitory neurotransmitter in the equine ventral colon     

Van Hoogmoed LM  Rakestraw PC  Snyder JR  Harmon FA 《American journal of veterinary research》2000,61(1):64-68

OBJECTIVE: To determine the role of nitric oxide and an apamin-sensitive nonadrenergic noncholingeric inhibitory transmitter on contractility of the ventral colon of horses. SAMPLE POPULATION: Strips of the circular and longitudinal muscle layers and taenia of the ventral colon from 14 horses. PROCEDURE: Muscle strips were suspended in tissue baths and attached to force transducers. Contractile activity of circular, longitudinal, and taenia muscle strips in response to electrical field stimulation was measured after addition of apamin and a nitric oxide inhibitor, N-nitro-L-arginine methyl ester (L-NAME). RESULTS: Electrical field stimulation reduced contractile activity in the circular muscle layer and taenia but not the longitudinal muscle layer. Addition of L-NAME significantly reduced inhibitory contractile activity at all frequencies for the circular muscle layer, whereas a significant effect was evident for the taenia only at the highest frequency. The combination of L-NAME and apamin resulted in a significant reduction in inhibition of the taenia at all frequencies but for circular muscle only at lower frequencies. CONCLUSIONS AND CLINICAL RELEVANCE: Nitric oxide and an apamin-sensitive neurotransmitter appear to mediate a component of inhibitory transmission in the circular muscle and taenia, but not the longitudinal muscle layer, of the equine ventral colon. Nitric oxide has a role in regulating contractile activity of the equine ventral colon, and nitric oxide synthase inhibitors may be useful in horses with ileus of the large colon.  相似文献