Last occurrence and survival during winter of the arbovirus vector Culicoides brevitarsis at the southern limits of its distribution     

AL BISHOP  IM BARCHIA  AM HARRIS 《Australian veterinary journal》1995,72(2):53-55

SUMMARY: Linear regression analysis was used to describe the decline in numbers of Culicoides brevitarsis Kieffer into winter with monthly maximum, average and minimum temperatures at the southern limits to its distribution in New South Wales. From this, low temperature thresholds were derived when C brevitarsis would be absent from the field. The low minimum threshold ± 2 SE (95% Confidence Interval) of 8.1 ± 0.3°C was used with historical temperature data to estimate the last month that the species should occur (March to June) and the mean number of months (2 to 6.5) below the threshold at 17 selected sites. Probability for survival during winter at these sites was estimated from years when the number of consecutive months below the threshold was ≤ 2 months. This varied from zero to 51% depending on the location of the site. Last occurrence was 0.7 months later on average and absolute probabilities for survival ranged from zero to 100% when the temperatures were increased by an arbitrary 2°C.  相似文献   

Use of magnetic particles to improve the diagnosis of sheep-associated malignant catarrhal fever by polymerase chain reaction     

TM ELLIS  AM MASTERS 《Australian veterinary journal》1997,75(7):520-521

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Observations on the Histological Development of the Bovine Rumen Papillae Morphological Changes Due to Age^1,2     

J. L. Arias    R. Cabrera  A. Valencia 《Anatomia, histologia, embryologia》1978,7(2):140-151

The present study aims to characterize the main morphological changes occurring on the bovine ruminal papillae during pre- and postnatal development. Light microscopic observations of the ruminal wall from bovine fetus (3 to 9 month fetal age) and from crossbreed (Holstein-Frisian) calves (5 to 60 days-old) were analysed. The results suggest that the postnatal papillary development corresponds mainly to a fully actualization of the differentiation pattern already developed at the prenatal stage.  相似文献   

Assessment of climatic and orographic conditions on the infection by Calicophoron daubneyi and Dicrocoelium dendriticum in grazing beef cattle (NW Spain)     

Díaz P  Paz-Silva A  Sánchez-Andrade R  Suárez JL  Pedreira J  Arias M  Díez-Baños P  Morrondo P 《Veterinary parasitology》2007,149(3-4):285-289

From February 2003 to March 2004, 1148 faecal samples from autochthonous Rubia Gallega cattle breed were collected in 170 farms from Lugo (NW Spain), in order to find out the prevalence and intensity of egg-excretion by Calicophoron daubneyi and Dicrocoelium dendriticum, and the possible influence of external factors as annual mean temperature and rainfall, altitude and mean slope. Twenty-six percent (95% CI 19%, 33%) and the 18% (12, 24) of the farms were infected with rumen and lancet flukes. C. daubneyi egg-output (Me=24) was found in 13% (11, 15) of the individual samples. Six percent (5, 7) of the animals in the study had low D. dendriticum eggs (Me=8). By estimating the odds ratio values it was shown that the highest probability of infection by C. daubneyi was in pastures with a mean slope of less than 13% (OR=1.9) and situated under 600 m (OR=1.6). Annual mean rainfall and temperature were not identified as risk factors for the infection with rumen flukes. Mountainous pastures with a mean slope of higher than 25% (OR=5.8) and situated over 600 m (OR=24.6) where precipitation was high (>1000 mm; OR=7) and temperature low (<11 degrees C; 2.8) had involved the highest risk of infection by D. dendriticum. Because of the prevalences found in this study, employment of suitable management practices with strategic treatments with efficacious anthelmintics are needed to reduce the presence of both trematodes and to increase the health status of grazing beef cattle.  相似文献   

Isolation of Nocardia mexicana from focal proliferative tenosynovitis and arthritis in a steer          下载免费PDF全文

H Owen  K Buckle  J Olm  M Leitner  S Pandey  JB Gaughan  ML Sullivan  AM Lees  JS Gibson 《Australian veterinary journal》2015,93(5):170-173

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Potassium permanganate elicits a shift of the external fish microbiome and increases host susceptibility to columnaris disease     

Haitham H. Mohammed  Covadonga R. Arias 《Veterinary research》2015,46(1)

The external microbiome of fish is thought to benefit the host by hindering the invasion of opportunistic pathogens and/or stimulating the immune system. Disruption of those microbial communities could increase susceptibility to diseases. Traditional aquaculture practices include the use of potent surface-acting disinfectants such as potassium permanganate (PP, KMnO₄) to treat external infections. This study evaluated the effect of PP on the external microbiome of channel catfish and investigated if dysbiosis leads to an increase in disease susceptibility. Columnaris disease, caused by Flavobacterium columnare, was used as disease model. Four treatments were compared in the study: (I) negative control (not treated with PP nor challenged with F. columnare), (II) treated but not challenged, (III) not treated but challenged, and (IV) treated and challenged. Ribosomal intergenic spacer analysis (RISA) and pyrosequencing were used to analyze changes in the external microbiome during the experiment. Exposure to PP significantly disturbed the external microbiomes and increased catfish mortality following the experimental challenge. Analysis of similarities of RISA profiles showed statistically significant changes in the skin and gill microbiomes based on treatment and sampling time. Characterization of the microbiomes using 16S rRNA gene pyrosequencing confirmed the disruption of the skin microbiome by PP at different phylogenetic levels. Loss of diversity occurred during the study, even in the control group, but was more noticeable in fish subjected to PP than in those challenged with F. columnare. Fish treated with PP and challenged with the pathogen exhibited the least diverse microbiome at the end of the study.  相似文献   

Fermented liquid feed for pigs: an ancient technique for the future     

Joris AM Missotten  Joris Michiels  Jeroen Degroote  Stefaan De Smet 《畜牧与生物技术杂志(英文版)》2015,6(1)

Fermented liquid feed is feed that has been mixed with water at a ratio ranging from 1:1.5 to 1:4. By mixing with water, lactic acid bacteria and yeasts naturally occurring in the feed proliferate and produce lactic acid, acetic acid and ethanol which reduces the pH of the mixture. This reduction in pH inhibits pathogenic organisms from developing in the feed. In addition, when this low pH mixture is fed, it reduces the pH in the stomach of pigs and prevents the proliferation of pathogens such as coliforms and Salmonella in the gastrointestinal tract. For piglets, the use of fermented liquid feed offers the possibility of simultaneously providing feed and water, which may facilitate an easier transition from sow’s milk to solid feed. Secondly, offering properly produced fermented liquid feed may strengthen the role of the stomach as the first line of defense against possible pathogenic infections by lowering the pH in the gastrointestinal tract thereby helping to exclude enteropathogens. Finally, feeding fermented liquid feed to pigs has been shown to improve the performance of suckling pigs, weaner pigs and growing-finishing pigs. In this review, current knowledge about the use of fermented liquid feed in pig diets will be discussed. This will include a discussion of the desirable properties of fermented liquid feed and factors affecting fermentation. In addition, advantages and disadvantages of fermented liquid feed will be discussed including its effects on gastrointestinal health, intestinal pH and the types of bacteria found in the gastrointestinal tract as well as the effects of fermented liquid feeds on pig performance.  相似文献   

Planet Within a Planet: Rotation of the Inner Core of Earth     

W Su  AM Dziewonski  R Jeanloz 《Science (New York, N.Y.)》1996,274(5294):1883-1887

The time dependence of the orientation of Earth's inner core relative to the mantle was determined using a recently discovered 10-degree tilt in the axis of symmetry of the inner core's seismic-velocity anisotropy. Two methods of analyzing travel-time variations for rays traversing the inner core, on the basis of 29 years of data from the International Seismological Centre (1964-1992), reveal that the inner core appears to rotate about 3 degrees per year faster than the mantle. An anomalous variation in inner-core orientation from 1969 to 1973 coincides in time with a sudden change ("jerk") in the geomagnetic field.  相似文献   

The Nemertine Toxin Anabaseine and Its Derivative DMXBA (GTS-21): Chemical and Pharmacological Properties     

William Kem  Ferenc Soti  Kristin Wildeboer  Susan LeFrancois  Kelly MacDougall  Dong-Qing Wei  Kuo-Chen Chou  Hugo R. Arias 《Marine drugs》2006,4(3):255-273

Nemertines are a phylum of carnivorous marine worms that possess a variety of alkaloidal, peptidic or proteinaceous toxins that serve as chemical defenses against potential predators. The hoplonemertines additionally envenomate their prey with a mixture of proboscis alkaloids delivered with the help of a calcareous stylet that punctures the skin of the victim. Anabaseine, the first of these alkaloids to be identified, stimulates a wide variety of animal nicotinic acetylcholine receptors (AChRs), especially the neuromuscular [e.g., α1₂β1γδ (embryogenic) or α1₂β1γɛ (adult)] and α7 AChRs that are inhibited by the snake peptide α-bungarotoxin. A synthetic derivative, 3-(2,4-Dimethoxybenzylidene)-Anabaseine (DMXBA; also called GTS-21), improves memory in experimental animals and humans and is currently in clinical trials to determine whether it can ameliorate cognitive problems associated with schizophrenia. Here we summarize present knowledge concerning the chemistry and mechanisms of action of these two substances (anabaseine and DMXBA) on AChRs, especially those found in the mammalian brain.  相似文献   

Adsorption-desorption dynamics of cyprodinil and fludioxonil in vineyard soils     

Arias M  Torrente AC  López E  Soto B  Simal-Gándara J 《Journal of agricultural and food chemistry》2005,53(14):5675-5681

Cyprodinil and fludioxonil are new-generation fungicides that are employed to protect grapevines from botrytis and various rots. In this work, their adsorption and desorption dynamics in eight vineyard soils from Galicia (northwestern Spain) were examined in batch and column experiments. Both fungicides exhibited linear adsorption isotherms, with more ready adsorption (greater Kd) of fludioxonil. Kd values for cyprodinil were significantly correlated with soil organic matter content (r 2= 0.675, p < 0.01). Both pesticides exhibited adsorption-desorption hysteresis, but desorption was easier and more variable for cyprodinil (12-21%, RSD = 17%) than for fludioxonil (3-5%, RSD = 13%) and appeared to depend on the formation of irreversible bonds in the former case and on poor solubility in the latter. A linear adsorption model involving nonequilibrium conditions and an irreversible adsorption term was found to reproduce transport behavior accurately.  相似文献