Western Canada. Rabies Diagnosis July 1–December 31, 1987          下载免费PDF全文

Ken Loewen  Bert Prins 《The Canadian veterinary journal. La revue veterinaire canadienne》1988,29(4):393

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Editorial     

Urlings BA 《The Veterinary quarterly》1993,15(4):121-122

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Assessment of the genetic risk and impact of lateral transmission in a valine-associated scrapie outbreak in sheep     

Evoniuk JM  Stoltenow CL  O'Rourke KI  Moore BL  Redmer DA 《American journal of veterinary research》2005,66(8):1302-1307

OBJECTIVE: To characterize an outbreak of valine-associated scrapie, assess the relative risk of scrapie infection in relation to allele frequency at codon 136, and investigate lateral transmission of infection in a sheep flock within the United States. ANIMALS: 1,006 sheep. PROCEDURE: To determine genotypes, blood or semen samples were assessed via commercial testing; in 190 slaughtered sheep, scrapie status was determined via immunohistochemical evaluation of tissues. Scrapie-positive sheep born to scrapie-negative dams and sheep infected after 1 year of age were identified to assess lateral transmission. RESULTS: Genotypes were determined for codon 171 (164 sheep) or codons 136 and 171 (842 sheep). Forty-four of 160 slaughtered sheep of known genotype were scrapie positive. In these sheep, the presence of at least 1 valine allele at codon 136 (V136) was highly correlated with scrapie-positive status. Lateral transmission was the probable source of infection for 4 scrapie-positive sheep born to scrapie-negative dams and for 11 sheep in which scrapie was diagnosed at > 50 months of age. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the outbreak of scrapie was associated with a relatively high frequency of V136 in the flock, introduction of a valine-dependent scrapie strain, and the occurrence of lateral transmission. Genotyping of sheep may assist management decisions following diagnosis of scrapie in a sheep with at least 1 V136. It may be prudent to remove sheep of the diploid genotype AVQR (at codons 136 and 171) from infected flocks.  相似文献   

Epidemiologic features of Campylobacter infection among cats in the upper midwestern United States     

Bender JB  Shulman SA  Averbeck GA  Pantlin GC  Stromberg BE 《Journal of the American Veterinary Medical Association》2005,226(4):544-547

OBJECTIVE: To describe the epidemiologic features of Campylobacter infection among cats in the Minneapolis-Saint Paul metropolitan area. DESIGN: Prevalence survey. ANIMALS: 152 cats examined at 3 private veterinary clinics and an animal humane society. PROCEDURES: Fecal samples were submitted for bacterial culture for Campylobacter spp. To determine the duration of Campylobacter carriage, follow-up fecal samples were collected from cats with positive Campylobacter culture results. RESULTS: Campylobacter organisms were cultured from 37 of the 152 (24%) fecal samples. Campylobacter isolates were identified as Campylobacter upsaliensis (29 cats), Campylobacter jejuni (2), and Campylobacter coli (1); species of the remaining 5 isolates could not be determined. Campylobacter organisms were isolated from 36 of the 122 (30%) cats that were < or = 1 year old but from only 1 of the 30 (3%) cats that were > 1 year old, and shedding was more common during the summer and fall months. No association between Campylobacter shedding and clinical signs of disease was identified. For 4 of 13 cats from which follow-up fecal samples were obtained, duration of Campylobacter carriage could not be determined because Campylobacter organisms were isolated from all follow-up samples. For the remaining 9 cats, median duration of Campylobacter carriage was 44 days. CONCLUSIONS AND CLINICAL RELEVANCE: C. upsaliensis can commonly be isolated from the feces of overtly healthy kittens in the Midwest United States. Because carriage may be prolonged, veterinarians should encourage good hand hygiene among owners of cats, especially among owners with new kittens in their household.  相似文献   

Plasma acylcarnitine and fatty acid profiles during exercise and training in Standardbreds     

Westermann CM  Dorland B  de Sain-van der Velden MG  Wijnberg ID  Van Breda E  De Graaf-Roelfsema E  Keizer HA  Van der Kolk JH 《American journal of veterinary research》2008,69(11):1469-1475

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Agricultural performance in Tanzania under structural adjustment programs: Is it really so positive?     

Bert Meertens 《Agriculture and Human Values》2000,17(4):333-346

The performances in the food and cashcrop sectors and the availability and consumption ofagricultural inputs in Tanzania during structuraladjustment programs (1986–1996) are compared withperiods prior to this IMF/World Bank backed reform.The positive developments in the first five years ofreform appear to be not sustainable. Presentlyproductivity levels per rural capita for importantfood and cash crops are declining. There are nofurther improvements in the availability andconsumption of agricultural inputs. The removal ofsubsidies on agricultural inputs from 1991 onwards iscrucial in explaining the decline in maize production,the main food crop in Tanzania. Some assumptionsbehind the reform measures are proving to be wrong.Modifications are thus needed to improve theagricultural sector of Tanzania in a sustainable way.Structural adjustment programs usually go too far inreducing the role of the government. However,government involvement might be necessary to ensure ahigher consumption of agricultural inputs and thus abetter performance of the agricultural sector inTanzania. A higher productivity in the agriculturalsector is needed in Tanzania to avoid food securityproblems in the future.  相似文献   

Nematode succession during composting and the potential of the nematode community as an indicator of compost maturity     

Hanne Steel  Eduardo de la Peña  Koen Willekens  Wim Bert 《Pedobiologia》2010,53(3):181-363

One of the key issues in compost research is to assess when the compost has reached a mature stage. The maturity status of the compost determines the quality of the final soil amendment product. The nematode community occurring in a Controlled Microbial Composting (CMC) process was analyzed with the objective of assessing whether the species composition could be used as a bio-indicator of the compost maturity status. The results obtained here describe the major shifts in species composition that occur during the composting process. Compared to terrestrial ecosystems, nematode succession in compost differs mainly in the absence of K-strategists and numerical importance of diplogastrids. At the beginning of the composting process (thermophilic phase), immediately after the heat peak, the nematode population is primarily built by bacterial feeding enrichment opportunists (cp-1) (Rhabditidae, Panagrolaimidae, Diplogastridae) followed by the bacterial-feeding general opportunists (cp-2) (Cephalobidae) and the fungal-feeding general opportunists (Aphelenchoididae). Thereafter, during the cooling and maturation stage, the bacterial-feeding-predator opportunistic nematodes (Mononchoides sp.) became dominant. Finally, at the most mature stage, the fungal-feeding Anguinidae (mainly Ditylenchus filimus) were most present. Both, the Maturity Index (MI) and the fungivorous/bacterivorous ratio (f/b ratio), increase as the compost becomes more mature (ranging, respectively, from 1 to 1.86 and from 0 to 11.90). Based on these results, both indices are suggested as potential suitable tools to assess compost maturity.  相似文献   

Remediation of Metal Contaminated Soil by Organic Metabolites from Fungi I—Production of Organic Acids     

Zandra Arwidsson  Emma Johansson  Thomas von Kronhelm  Bert Allard  Patrick van Hees 《Water, air, and soil pollution》2010,205(1-4):215-226

Investigations were made on living strains of fungi in a bioremediation process of three metal (lead) contaminated soils. Three saprotrophic fungi (Aspergillus niger, Penicillium bilaiae, and a Penicillium sp.) were exposed to poor and rich nutrient conditions (no carbon availability or 0.11 M d-glucose, respectively) and metal stress (25 µM lead or contaminated soils) for 5 days. Exudation of low molecular weight organic acids was investigated as a response to the metal and nutrient conditions. Main organic acids identified were oxalic acid (A. niger) and citric acid (P. bilaiae). Exudation rates of oxalate decreased in response to lead exposure, while exudation rates of citrate were less affected. Total production under poor nutrient conditions was low, except for A. niger, for which no significant difference was found between the poor and rich control. Maximum exudation rates were 20 µmol oxalic acid g^?1 biomass h^?1 (A. niger) and 20 µmol citric acid g^?1 biomass h^?1 (P. bilaiae), in the presence of the contaminated soil, but only 5 µmol organic acids g^?1 biomass h^?1, in total, for the Penicillium sp. There was a significant mobilization of metals from the soils in the carbon rich treatments and maximum release of Pb was 12% from the soils after 5 days. This was not sufficient to bring down the remaining concentration to the target level 300 mg kg^?1 from initial levels of 3,800, 1,600, and 370 mg kg^?1in the three soils. Target levels for Ni, Zn, and Cu, were 120, 500, and 200 mg kg^?1, respectively, and were prior to the bioremediation already below these concentrations (except for Cu Soil 1). However, maximum release of Ni, Zn, and Cu was 28%, 35%, and 90%, respectively. The release of metals was related to the production of chelating acids, but also to the pH-decrease. This illustrates the potential to use fungi exudates in bioremediation of contaminated soil. Nonetheless, the extent of the generation of organic acids is depending on several processes and mechanisms that need to be further investigated.  相似文献   

Metabolic profiling of ‘Conference’ pears under low oxygen stress     

Romina Pedreschi  Christine Franck  Jeroen Lammertyn  Alexander Erban  Joachim Kopka  Maarten Hertog  Bert Verlinden  Bart Nicolaï 《Postharvest Biology and Technology》2009,51(2):123-130

Pears (Pyrus communis L. cv. Conference) may develop core breakdown when stored under low oxygen or elevated carbon dioxide conditions. This physiological disorder is characterized by the development of brown spots due to oxidation of phenolic compounds, and eventually, cavities in the center of the fruit. Based on metabolic profiling of brown and sound tissue using GC-EI-TOF-MS, the hypothesis that this disorder is due to an imbalance between oxidative and reductive processes at the cellular level was investigated. Brown tissue was clearly characterized by a distinctive pattern in changes which included a decrease of malic acid and an increase in fumaric acid and gamma aminobutyric acid (GABA), which indicated a reduced metabolic activity at the level of the Krebs cycle and a putative block of the GABA shunt pathway. Increased gluconic acid concentration might be related to ascorbic acid degradation due to insufficient reducing equivalents or to an impaired pentose phosphate pathway. For the first time, GABA and gluconic acid have been shown to be metabolic markers for core breakdown. The concentrations of other compounds which are believed to be related to hypoxic stress response such as trehalose and putrescine were also considerably higher in brown tissue than in sound tissue. The concentration of some sugars which are typically found in xyloglucans also increased during brown development, possibly indicating cell wall breakdown due to enzymatic processes or chemical reactions of hydroxyl radicals.  相似文献   

Multi-event capture–recapture modeling of host–pathogen dynamics among European rabbit populations exposed to myxoma and Rabbit Hemorrhagic Disease Viruses: common and heterogeneous patterns     

Simone Santoro  Isa Pacios  Sacramento Moreno  Alejandro Bertó-Moran  Carlos Rouco 《Veterinary research》2014,45(1):39

Host–pathogen epidemiological processes are often unclear due both to their complexity and over-simplistic approaches used to quantify them. We applied a multi-event capture–recapture procedure on two years of data from three rabbit populations to test hypotheses about the effects on survival of, and the dynamics of host immunity to, both myxoma virus and Rabbit Hemorrhagic Disease Virus (MV and RHDV). Although the populations shared the same climatic and management conditions, MV and RHDV dynamics varied greatly among them; MV and RHDV seroprevalences were positively related to density in one population, but RHDV seroprevalence was negatively related to density in another. In addition, (i) juvenile survival was most often negatively related to seropositivity, (ii) RHDV seropositives never had considerably higher survival, and (iii) seroconversion to seropositivity was more likely than the reverse. We suggest seropositivity affects survival depending on trade-offs among antibody protection, immunosuppression and virus lethality. Negative effects of seropositivity might be greater on juveniles due to their immature immune system. Also, while RHDV directly affects survival through the hemorrhagic syndrome, MV lack of direct lethal effects means that interactions influencing survival are likely to be more complex. Multi-event modeling allowed us to quantify patterns of host–pathogen dynamics otherwise difficult to discern. Such an approach offers a promising tool to shed light on causative mechanisms.  相似文献