Isolation of Mycobacterium bovis from brushtail possums with non-visible lesions     

GW de Lisle  GF Yates  JD Coleman 《New Zealand veterinary journal》2013,61(4):221-224

AIM: To determine the prevalence of Mycobacterium bovis infection in brushtail possums (Trichosurus vulpecula) that did not have macroscopic lesions of bovine tuberculosis, and to evaluate culture of pooled tissues from multiple possums as a method for determining the M. bovis-infection status of wildlife populations in New Zealand.

METHODS: Pools of selected tissues were collected from possums from four different populations known to be infected with M. bovis. Tissue pools from individual animals, and combined pools from multiple animals, were cultured for M. bovis.

RESULTS: In the four populations investigated, the prevalence of possums with macroscopic lesions confirmed by culture to be infected with M. bovis ranged from 1 to 19 (mean 31/283; 10.9)%. The prevalence of possums with non-visible lesions that were culture positive for M. bovis in the same populations ranged from 4 to 10 (mean 24/283; 8.5)%. The mean of the log10 cfu of M. bovis of the macroscopic lesions and of the culture-positive samples that did not have visible lesions was 3.85 (SE 0.26) and 1.46 (SE 0.26) log₁₀ cfu, respectively (p<0.01). Mycobacterium bovis was cultured from pools of 30–50 animals in the four populations studied.

CONCLUSIONS: The finding of M. bovis infection in possums with non-visible lesions identified a potential deficiency of declaring possum populations free of M. bovis on the basis of absence of macroscopic lesions. The culturing of pools of selected tissues from multiple animals without visible lesions can be used to reduce laboratory costs of possum surveys without a major reduction in the ability to detect M. bovis infection.  相似文献   

Biotic and abiotic factors impacting development,behavior, phenology,and reproductive biology of Drosophila suzukii     

Kelly A. Hamby  David E. Bellamy  Joanna C. Chiu  Jana C. Lee  Vaughn M. Walton  Nik G. Wiman  Riki M. York  Antonio Biondi 《Journal of pest science》2016,89(3):605-619

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Development of an egg hatch assay for the diagnosis of triclabendazole resistance in Fasciola hepatica: proof of concept     

Fairweather I  McShane DD  Shaw L  Ellison SE  O'Hagan NT  York EA  Trudgett A  Brennan GP 《Veterinary parasitology》2012,183(3-4):249-259

The aim of this study was to develop an Egg Hatch Assay (EHA) test for the detection of triclabendazole (TCBZ) resistance in Fasciola hepatica. A number of fluke isolates were used, of differing sensitivity to TCBZ. Eggs were exposed to solutions of triclabendazole sulphoxide (TCBZ.SO) for 14 days, then triggered to hatch. Egg development was divided into 6 distinct and easily identifiable stages: dead, empty, unembryonated, cell division, eye spot and hatched. The number of eggs reaching those stages was recorded. Initially, the discriminating dose (1% hatch) was determined for the Cullompton isolate, used as TCBZ-susceptible (TCBZ-S) standard. Once this concentration had been resolved, the response of different isolates to this concentration was examined. The hatch rate of the Fairhurst isolate was not significantly different from that of the Cullompton isolate, confirming its TCBZ-S status. The Patagonia isolate has not been exposed to TCBZ in the field and should be TCBZ-S: the results of the EHA supported this. The egg hatch response of the Oberon and Dutch isolates differed significantly from that of the Cullompton isolate; the former isolates are regarded as TCBZ-resistant (TCBZ-R) and the results confirmed this. Another isolate, the Leon isolate, was originally described as being TCBZ-R, but has since been shown to be TCBZ-S. There was no difference in its response to TCBZ.SO in the EHA from the Cullompton (and Fairhurst and Patagonia) isolate(s), further indicating its TCBZ-S status. The impact of TCBZ.SO treatment on the component stages of egg development was determined and revealed differences between the isolates. In conclusion, the results of the study have shown that it is possible to discriminate between TCBZ-S and TCBZ-R isolates of F. hepatica on the basis of the response of their eggs to an EHA and the test could be used to evaluate the TCBZ sensitivity of unknown field isolates.  相似文献   

Studies on natural infection and egg transmission of Arizona hinshawii 7:1,7,8 in turkeys     

M C Kumar  S C Nivas  A K Bahl  M D York  B S Pomeroy 《Avian diseases》1974,18(3):416-426

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Physical, Chemical and Biological Characteristics of Two Bovine Enterovirus Plaque Variants          下载免费PDF全文

H. Rabin  J. A. Parsons  Judith Addison    C. J. York 《Canadian journal of veterinary research》1972,36(3):294-302

Large plaque (4LP) and small plaque (4SP) variants were derived from a parent bovine virus strain by serial plaque passage. Both 4LP and 4SP were resistant to chloroform and stabilized at 50°C for one hour by 1.0 M magnesium chloride. Both 4LP and 4SP had buoyant densities in cesium chloride of 1.36 gm/ml. Antigenically, 4LP and 4SP were reciprocally cross neutralizable.

The nucleic acid of 4LP was shown to be ribonucleic acid (RNA) by resistance of its infectivity to deoxynuclease (DNase) but not ribonuclease (RNase) and by increased incorporation of [³H]-uridine into cytoplasmic RNA in cells of virus infected cultures. In growth characteristics, both 4LP and 4SP had maximum adsorption times of 75 to 90 minutes but 4LP had more rapid replication and release rates and yielded nearly twice as many infectious units per cell as 4SP. The differences in growth properties correlated directly with the differential in plaque diameter which was 40-50%.

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Isolation and preliminary characterization of the jaagsiekte retrovirus (JSRV)   总被引：2，自引：0，他引：2  

D W Verwoerd  A L Payne  D F York  M S Myer 《The Onderstepoort journal of veterinary research》1983,50(4):309-316

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A Review of the Hazards and Mitigation for Airstrikes from Canada Geese in the Anchorage, Alaska Bowl     

Darryl L. York  Richard M. Engeman  John L. Cummings  Corey L. Rossi  David R. Sinnett 《Integrated Pest Management Reviews》2001,6(1):47-57

Bird strikes to aircraft are a globally pervasive safety and economic concern. In particular, the Anchorage, Alaska area holds substantial risk for destructive collisions between birds and aircraft. An international airport, a municipal airport, a seaplane base, and a U.S. Air Force base are situated throughout the area. Anchorage also has a burgeoning population of Canada geese (Branta canadensis parvipes), one of the species identified as posing the greatest airstrike hazards. A variety of methods are applied and a variety of research has been conducted to reduce the potential for airstrikes with geese around Anchorage. We review the nature of the problem, as well as the research and mitigation procedures applied to address the problem.  相似文献   

Effects and use of a modified live Anaplasma marginale vaccine in beef heifers in California     

E T Henry  B B Norman  D E Fly  R W Wichmann  S M York 《Journal of the American Veterinary Medical Association》1983,183(1):66-69

Eighty-one 11-month-old, nonpregnant, Anaplasma marginale-seronegative beef heifers were allotted to 2 groups for evaluation of a modified live A marginale vaccine (n = 50 for vaccinated group and n = 31 for nonvaccinated group). The vaccine induced a mild form of anaplasmosis, as evidenced by a significant (P less than 0.01) decrease in the packed cell volume (PCV) between days 31 and 46 after vaccination. The lowest PCV was 11%, and 3 heifers had a PCV less than 20%. Slight lethargy was evident in some of the vaccinated heifers between days 30 and 45 after vaccination. All vaccinated heifers became seropositive to A marginale, as measured by the complement fixation test and the card test on days 35 and 42 after vaccination, respectively. All nonvaccinated heifers remained seronegative.  相似文献   

The importance of agroforestry education and training     

E. T. York Jr. 《Agroforestry Systems》1990,12(1):7-12

Sustainable agriculture should involve the successful management of resources for agriculture to satisfy changing human needs, while maintaining or enhancing the quality of the environment and conserving natural resources. The rapid depletion of forest resources and agricultural sustainability — two major global concerns — could be impacted significantly through agroforestry practices. Widespread application of agroforestry concepts and techniques offers great potential for helping to alleviate critical shortages of fuelwood and contributing to sustainable farming systems. There is a vital need to broaden the knowledge base of the subject of agroforestry in order to provide a more substantive basis for effective teaching and training programs. In a typical university organization, it is fairly easy to see how interdisciplinary research teams can be brought together to work on agroforestry projects. But how do we structure the education and training programs? The purpose of this conference is to address these issues and to guide the further evolution and development of agroforestry.  相似文献   

History of atmospheric lead deposition since 12,370 (14)C yr BP from a peat bog, jura mountains, switzerland   总被引：3，自引：0，他引：3  

W Shotyk  D Weiss  PG Appleby  AK Cheburkin  RFM Gloor  JD Kramers  S Reese  Van Der Knaap WO 《Science (New York, N.Y.)》1998,281(5383):1635-1640

A continuous record of atmospheric lead since 12,370 carbon-14 years before the present (14C yr BP) is preserved in a Swiss peat bog. Enhanced fluxes caused by climate changes reached their maxima 10, 590 (14)C yr BP (Younger Dryas) and 8230 (14)C yr BP. Soil erosion caused by forest clearing and agricultural tillage increased lead deposition after 5320 (14)C yr BP. Increasing lead/scandium and decreasing lead-206/lead-207 beginning 3000 (14)C yr BP indicate the beginning of lead pollution from mining and smelting, and anthropogenic sources have dominated lead emissions ever since. The greatest lead flux (15.7 milligrams per square meter per year in A.D. 1979) was 1570 times the natural, background value (0.01 milligram per square meter per year from 8030 to 5320 (14)C yr BP).  相似文献