Experimental transmission of intestinal coccidiosis to piglets: clinical, parasitological and pathological findings.   总被引：2，自引：0，他引：2       下载免费PDF全文

Y Robinson  M Morin  C Girard    R Higgins 《Canadian journal of veterinary research》1983,47(4):401-407

Twenty-eight piglets coming from a "specific pathogen free" herd were inoculated at three days of age with 50 000 or 100 000 sporulated oocysts of Isospora suis. Fecal samples were examined for oocyst shedding daily and several clinical parameters were recorded. Ten piglets were used as normal controls. Groups of piglets were euthanized from three days to 12 days postinoculation and routine necropsies were performed. Bacteriological, virological, parasitological and histopathological examinations were made on the intestinal tracts. The incubation period was four to five days. Clinical signs and microscopic intestinal lesions observed in the experimentally infected animals were similar to those reported in spontaneous cases of porcine neonatal coccidiosis. Lesions of villous atrophy in the small intestine seemed to result from the destruction of villous epithelial cells mainly during the peak of asexual reproduction which occurred around four to five days postinoculation. Intracellular coccidial organisms were difficult to find during the late atrophic and villous regrowth stages of the intestinal lesions. The prepatent period varied from four to seven days and the most common was five days. Eighty percent of the piglets kept alive more than four days postinoculation have shed oocysts. Piglets dosed with old sporulated oocysts (ten months old) shed many more oocysts than those infected with a fresh inoculum (less than two months old). The patent period was not determined precisely with the design of the experiment but some of the infected piglets shed oocysts for at least five days.  相似文献   

Further characterization of dandelion yellow mosaic virus from lettuce and dandelion     

L. Bos  N. Huijberts  H. Huttinga  D. Z. Maat 《European journal of plant pathology / European Foundation for Plant Pathology》1983,89(5):207-222

A damaging virus isolated in the Netherlands from lettuce was studied and compared with a virus isolated from dandelion orginating from Czechoslovakia. It was found to biologically resemble dandelion yellow mosaic virus incompletely described from dandelion and lettuce in Great Britain (Kassanis, 1944, 1947) and from dandelion in Germany (Hein, 1963). Mechanical transmission was greatly improved by buffer solution and transmission byMyzus persicae seemed to be in the non-persistent manner. Longevity in vitro of the virus hardly exceeded one day. Thermal inactivation was between 60 and 65 °C and the dilution end-point was between 10 000 and 100 000. It was still infectious in leaf material dried and stored over CaCl₂ at 4 °C for 6 1/2 years. The virus was isolated and purified with difficulty and was found to consist of one type of spherical particle of ca 30 nm diameter, with a sedimentation coefficient of 159 S, a buoyant density of 1.42 g.cm^?3 and an A₂₆₀/A₂₈₀ ratio of 1.67. An antiserum was prepared with a titre of 256 in the agar double-diffusion test. The virus could be identified in crude extracts from lettuce andChenopodium amaranticolor by enzyme-linked immunosorbent assay (ELISA), but not by agar double diffusion. It could only be visualized in crude sap in the electron microscope after trapping of virus particles on antiserum-coated grids. The virus cannot yet be assigned to any known virus group. It is of potential economic importance to lettuce because of its occurrence in widely differing regions in Europe, its aggressiveness and virulence on 22 out of 23 lettuce cultivars tested (and on endive) and its pathogenicity toLactuca genotypes which are resistant to lettuce mosaic virus and other important pathogens of lettuce. ‘Laibacher Eis’ was the only cultivar showing some tolerance.  相似文献   

Behavior of the menstrual cycle and fertility in milking cows after administration of chlormadinoneacetate (CAP) at the time of second insemination     

E Grunert  C Hellge 《Berliner und Münchener tier?rztliche Wochenschrift》1971,84(6):101-103

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Pathogenesis of canine herpesvirus in specific-pathogen-free dogs: 5- to 12-week-old pups     

M J Appel  M Menegus  I M Parsonson  L E Carmichael 《American journal of veterinary research》1969,30(12):2067-2073

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Mixed hemadsorption technique for study of avian leukosis-sarcoma viruses: studies with avian leukosis viruses     

C R Rossi  D Segre 《American journal of veterinary research》1969,30(5):831-836

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Methyl 2-benzimidazolecarbamate, a fungitoxic compound isolated from cotton plants treated with methyl 1-(butylearbamoyl)-2-benzimidazolecarbamate (benomyl)     

J J Sims  H Mee  D C Erwin 《Phytopathology》1969,59(11):1775-1776

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EFFECT OF PARAQUAT ON MICROBIAL ACTIVITIES IN SOILS*     

C. M. TU  W. B. BOLLEN 《Weed Research》1968,8(1):28-37

Summary. When paraquat was added to four different soils, nitrification was not appreciably affected but ammonification of soil organic-matter nitrogen was slightly retarded. Carbon dioxide evolution as well as oxygen consumption was used as an index of metabolic activity of soil micro-organisms and paraquat had a stimulatory effect at higher concentrations. Oxidation of added sulphur was slightly depressed. Paraquat decreased both the total mould and bacterial populations in Chehalis silt loam. After 30 days incubation the percentages of Streptomyces and Penicillia were markedly increased by most treatments but were little affected in Chehalis silt clay and Woodburn soils. Except for the temporary suppression of nitrification, paraquat had no significant influence on general microbial activities of importance to soil fertility. Some bimodal effects or toxicity inversions were observed with intermediate concentrations. Effet du paraquat sur les activités microbiennes dans les sols  相似文献   

THE YIELD AND QUAEITY OF RED BEET SEED AS AFFECTED BY DESICCANT SPRAYS AND HARVEST DATE     

R. B. AUSTIN  P. C. LONGDEN 《Weed Research》1968,8(4):336-345

Summary. Diquat and sodium monochloroacetate (SMA) were used to desiccate seed crops of red beet in experiments from 1963 to 1965. The seed plants became brown and dry about 7 days after spraying and were then judged suitable for combine harvesting, although this was not done in these experiments. Yields of seed 7 days after spraying were as good as those from the control plants, but were lower than the control yields when harvested 14 days after spraying. In laboratory tests in moist sand at 20° C the percentage of the embryos which germinated was not markedly affected by diquat or SMA treatment. The emergence of seedlings in the field, however, was affected adversely by treatment of the seed crop with 11 and 22 oz/ac of diquat ion in 1963 and by SMA at 20 lb/ac in 1964 and 1965. Diquat at 6·6 oz/ac in 120 gal/ac water in 1964 and 1965 had no serious adverse effects on embryo emergence. Residues of diquat ion in seed varied from 2 to 4 ppm, but the impairment of embryo emergence by diquat was believed to be due to the premature arrest of growth of the seed on the desiccated plants.
It is concluded that when harvesting conditions are poor, desiccants could be valuable.
Influence des traitements dessicants et de la date de récolte sur le rendement et la qualité de la sentence de betterave rouge  相似文献   

Comparative resistance of foot-and-mouth disease virus to formalin and hydroxylamine     

E E Nikitin  V L Uziumov  A A Kravchenko  M A Muliar  M A Romanenko 《Veterinariia》1968,45(5):21-22

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Effect of ruminal heating on thyroid function and heat production of cattle     

M K Yousef  W D Robertson  H D Johnson  L Hahn 《Journal of animal science》1968,27(3):677-683

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