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51.
Simbi BH Peter TF Burridge MJ Mahan SM 《The Onderstepoort journal of veterinary research》2003,70(3):231-235
Detection of heartwater is not always easy especially because all the serological assays so far available either have poor sensitivity or specificity. The indirect MAP-1B ELISA has been reported to be the most specific test for heartwater, although it does also detect antibodies to some closely related ehrlichial agents. This study was undertaken to compare two methods for the detection of heartwater infection caused by the ehrlichial agent Ehrlichia (Cowdria) ruminantium. Fifteen cattle on a heartwater-endemic farm infested with high numbers of Amblyomma hebraeum ticks, and hence exposure to E. ruminantium infection were monitored over an 8-week period by pCS20 PCR and an indirect MAP-1B ELISA. Infection was detected by pCS20 PCR in most animals with the highest number of positives (60%) in week 6 of the study. Similarly, exposure to E. ruminantium was detected by indirect MAP-1B ELISA in some animals, with the highest number of seropositives (27%) at weeks 2-6 of the study. The data demonstrated a fluctuating rickettsaemia in cattle in a heartwater-endemic area. Comparison of the two tests indicated that the pCS20 PCR assay was more reliable because it detected more infections than the indirect MAP-1B ELISA and would therefore be the method of choice for detection of E. ruminantium infection. 相似文献
52.
Dennis Rubbenstroth Volker Schmidt Monika Rinder Marko Legler Victor Max Corman Peter Staeheli 《Veterinary microbiology》2014,168(2-4):318-323
Avian bornaviruses (ABV) are known to be the causative agent of proventricular dilatation disease (PDD) in parrots and their relatives (Psittaciformes). A broad range of ABV genotypes has been detected not only in psittacine birds, but also in other avian species including canary birds (Serinus canaria forma domestica) and Bengalese finches (Lonchura striata f. dom.), which are both members of the order songbirds (Passeriformes).During this study 286 samples collected from captive and wild birds of various passerine species in different parts of Germany were screened for the presence of ABV. Interestingly, only three ABV-positive samples were identified by RT-PCR. They originated from one yellow-winged pytilia (Pytilia hypogrammica) and two black-rumped waxbills (Estrilda troglodytes) from a flock of captive estrildid finches in Saxony. The ABV isolates detected here were only distantly related to ABV isolates found in passerine species in Germany and Japan and form a new genotype tentatively called ABV-EF (for “estrildid finches”). 相似文献
53.
Amir Atabak Ronaghinia Nanett Kvist Nikolaisen Stine Green Hansen Helle Harding Poulsen Henrik Lauritz Frandsen Tina Struve Pierre‐Louis Toutain Peter Damborg 《Journal of veterinary pharmacology and therapeutics》2021,44(1):93-106
Antimicrobial agents are used extensively off‐label in mink, as almost no agents are registered for this animal species. Pharmacokinetic (PK) and pharmacodynamic (PD) data are required to determine antimicrobial dosages specifically targeting mink bacterial pathogens. The aims of this study were to assess, in a PKPD framework, the empirical dosage regimen for a combination of trimethoprim (TMP) and sulfadiazine (SDZ) in mink, and secondarily to produce data for future setting of clinical breakpoints. TMP and SDZ PK parameters were obtained experimentally in 22 minks following IV or oral administration of TMP/SDZ (30 mg/kg, i.e. 5 mg/kg TMP and 25 mg/kg SDZ). fAUC/MIC with a target value of 24 hr was selected as the PKPD index predictive of TMP/SDZ efficacy. Using a modeling approach, PKPD cutoffs for TMP and SDZ were determined as 0.062 and 16 mg/L, respectively. By incorporating an anticipated potentiation effect of SDZ on TMP against Escherichia coli and Staphylococcus delphini, the PKPD cutoff of TMP was revised to 0.312 mg/L, which is above the tentative epidemiological cutoffs (TECOFF) for these species. The current empirical TMP/SDZ dosage regimen (30 mg/kg, PO, once daily) therefore appears adequate for treatment of wild‐type E. coli and S. delphini infections in mink. 相似文献
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Peter Løvendahl Torkild Liboriussen Just Jensen Mogens Vestergaard Kristen Sejrsen 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(3):169-176
Abstract Genetic variation in plasma growth hormone (GH) concentration before and after GRF (growth hormone releasing factor) stimulation was studied in young bulls (N=284) and heifers (N=212), the progeny of 53 sires of four dairy and dual-purpose breeds (Danish Jersey, Red Dane, Danish Friesian and Danish Red and White). Male and female calves were reared, fed and tested on separate experimental stations; thus sex, station and feeding were completely confounded effects. The animals were tested at about 9 months of age, after a 24 h fast. GH concentration was measured in serial plasma samples collected for 1 h before and 1 h following intravenous administration of 2.0 ug synthetic GRF(1–29)NH2/kg live weight>0.75. Prior to statistical analysis, concentrations were loge-transformed. Response variables were BASELINE (mean GH in -15, -5 and 0 min samples) and PEAK (mean GH in 10, 15 and 20 min samples). A statistical model taking at least three generations of ancestral relationships into account was used to estimate variance and covariance components for traits in male and female calves by use of restricted maximum likelihood methods. Heritability of BASELINE was low (0.04 ± 0.12) in males but high in females (0.60 ± 0.16). The heritability of PEAK was high in both sexes (males, 0.42 ± 0.16; females, 0.60 ± 0.16). Genetic correlations between the same trait measured in males and females were low for BASELINE (r g = 0.32±0.55) but high for PEAK (r g = 0.82±0.15). Within sex, BASELINE and PEAK were both highly genetically correlated (males, r g=0.62 ± 0.40; females, r g= 1.00 ± 0.07). We conclude that growth hormone concentration is a highly heritable trait in juvenile cattle of both sexes, and that GRF stimulation is benificial to the uncovering of genetic differences among animals. 相似文献
56.
Bromination of the dichlorovinyl group of cypermethrin yielded a new compound which is a highly potent insecticide. This dibromo adduct has four asymmetric centres and therefore can exist as a mixture of 16 stereoisomers. To establish the influence of the absolute configuration at the chiral centres on the biological activities of these isomers, each of the isomers was isolated; their insecticidal activities against larvae of Heliothis virescens, and adult Calliphora erythrocephala and Blattella germanica were then determined and compared with those of (S)-α-cyano-3-phenoxybenzyl (1R)-cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylate (deltamethrin NRDC 161), of fenvalerate, and of the eight stereoisomers of cyper methrin. 相似文献
57.
Marc Lemmens Hermann Buerstmayr Rudolf Krska Rainer Schuhmacher Heinrich Grausgruber Peter Ruckenbauer 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(3):299-308
Fusarium head blight (FHB) is an important disease of wheat, which can result in the contamination of grains with mycotoxins such as deoxynivalenol (DON). Artificial inoculation of flowering ears with conidial suspensions is widely used to study FHB diseases. Our goal was to compare four inoculation treatments in which a conidial suspension was sprayed on flowering ears and to study the effect of the application of moisture during kernel setting and filling with a mist-irrigation system. Ten wheat genotypes were inoculated with a DON-producing Fusarium culmorum strain. Inoculation treatments varied in time of application of the inoculum (morning or evening) and in the method of controlling humidity during inoculation (bagging or mist irrigation). A wet season was simulated with a mist-irrigation system, keeping the crop canopy wet for at least 26 days after flowering. The severity of FHB symptoms (area under disease progress curve (AUDPC)), yield loss and DON contamination in the grains were determined. AUDPC data obtained with the different inoculation treatments were highly correlated (r=0.85–0.95). Mist irrigation after inoculation resulted in a higher mean disease severity, but in a overall lower toxin contamination as compared to the non-irrigated treatments. Genotypic differences in DON accumulation were present: for one wheat line toxin contamination significantly increased when irrigated, while two genotypes accumulated significantly less toxin. The closest relationships (r=0.73–0.89) between the visual symptoms and the DON content were obtained under moderate mean infection pressure. This relation between visual symptoms and the DON content deteriorated at higher infection levels. 相似文献
58.
Two substrains of Aedes aegypti, already resistant to DDT and pyrethroids, were further selected using either DDT or permethrin by mass exposure of the females only. DDT selection over 14 generations raised the resistance to DDT so far that no accurate LC50 values could be determined. Selection with permethrin raised the tolerance to an irregular plateau 7–10 times the original. DDT selection in the adults raised the DDT resistance of the larvae, but this could be partly overcome using a dehydrochlorinase inhibitor. The resistance to pyrethroids was increased but tolerance of dieldrin, malathion and propoxur compounds was little changed. Permethrin selection of the adults raised resistance to pyrethroids more than DDT selection but also increased DDT resistance. Similar patterns were found for the larval insects. A strain from Demerara in Guyana showed both DDT and pyrethroid resistance, including strong resistance to pyrethrins together with dieldrin and propoxur. It was concluded that two major independent resistance mechanisms existed in the selected strains, a dehydrochlorinase affecting DDT alone, and an unknown mechanism, probably nerve insensitivity (kdr) affecting both DDT and pyrethroids. 相似文献
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