Bovine brucellosis causes abortion and infertility. The authors conducted this study in order to determine pathological lesions of Korean native cows and fetuses who received experimental vaccination with Brucella abortus RB51 and were challenged with Brucella abortus 2308. Gross and histopathological lesions in endometrium and placenta were observed in cows of the vaccinated group. Twenty-five percent of pregnant cattle in the vaccinated group showed endometritis and placentitis, which was three times lower, compared with the non-vaccinated group. The pathological lesions in the uterus and placenta in both groups were consistent with previous reports. Therefore, vaccination in heifers using Brucella abortus RB51 may not provide adequate protection against infection with Brucella abortus virulent strain.
The current standard solutions for somatic cells used for calibration of electronic somatic cell counts as reference material in raw milk are preserved with bronopol, boric acid, sodium azide, or potassium dichromate, and have a shelf-life of only up to 6 days at 4 ± 2℃. In the present study, a set of somatic cell standard solutions (SCSS) with a stability of 5 months for calibration of electronic instruments was developed. Somatic cells collected from cow’s milk and stored in a bulk tank at a dairy plant were treated with 10% formaldehyde in order to improve stability, and then separated by centrifugation. The resulting somatic cell suspension was preserved with glycerin, thimerosal, and dimethyl sulfoxide, and diluted in 3% processed skim milk solution ranging from 200,000～250,000 (low level), 350,000～ 450,000 (medium level), and 550,000～650,000 (high level) cells/㎖. Each SCSS was verified by direct microscope somatic cell counting (DMSCC), C-reader, and commercial standard samples. The average somatic cell count determined by DMSCC was 248, 214, 226 × 103 cells/㎖, 436, 382, 420 × 103 cells/㎖, and 612, 595, 609 × 103 cells/㎖. The coefficient of variation representing the repeatability of DMSCC decreased as the number of cells increased, and was <10.0% in almost all SCSS samples (range 4.6～7.1%). No statistically significant difference in somatic cell concentration was observed after storage at refrigeration temperature (2～6℃) over a period of 22 weeks (5 months). The stabilized SCSS may be useful as a reference material for determination of somatic cell count and quality control in testing of bovine raw milk.
A confirmatory method based on liquid chromatography with tandem mass spectrometry was developed for determination of 12 aminoglycosides in milk. Extraction of aminoglycosides from milk was performed using by liquid extraction using a 10 mM phosphate buffer containing 2% (w/v) trichloroacetic acid, followed by performance of a solid-phase clean-up procedure on a hydrophilic-lipophilic balance solid-phase extraction (HLB SPE). Ion-pair chromatography, using a mixture of 20 mM heptafluorobutyric acid (HFBA) in water and acetonitrile as the mobile phase, was used for retention of aminoglycosides on a reversed-phase C18 column. Mass spectral acquisition was performed in the multiple reaction monitoring mode, selecting two precursor ion>product ion transitions for each target compound. Satisfied recoveries (70.1～109.6%) of all aminoglycosides were demonstrated in spiked milk at three levels from 50 ng/g to 200 ng/g. The coefficients of variation ranged from 3.2% to 14.0%. The limits of quantitation (LOQs) for aminoglycosides ranged from 2.5 ng/g to 40.3 ng/g.
A liquid chromatographic-tandem mass spectrometric (LC-MS/MS) multi-residue method for simultaneous quantification and identification of 37 anthelmintic veterinary drug residues (including benzimidazoles, macrocyclic lactones, and flukicides, levamisole, pyrantel and niclosamide) in milk has been developed and validated. For sample preparation, we used a simple modification of the QuEChERS (quick, easy, cheap, effective, rugged and safe) method, which was initially developed for analysis of pesticide residues. Anthelmintic residues were extracted into acetonitrile:methanol (9:1, v/v) using sodium chloride to induce liquid-liquid partitioning followed by dispersive solid phase extraction for cleanup. The extract was concentrated into dimethyl sulphoxide, which was used as a keeper to ensure that analytes remain in solution. Using rapid polarity switching in electrospray ionization, a single injection was capable of detecting both positively and negatively charged ions within a 15 min run time. The Limit of detection (LOD) and the Limit of quantification (LOQ) method ranged from 0.1 ng/g to 4.4 ng/g and from 0.3 ng/g to 14.6 ng/g, respectively. Validation of the developed method was based on international guidelines. Average recoveries ranged from 70% to 120%, except for 54.7% at 0.5× MRL (rafoxanide) and 69.0% at 0.5× MRL (closantel). The coefficient of variation for the described method was less than 15% over the range of concentrations studied. The result of the method was verified successfully by participation in a proficiency study for analysis of anthelmintic drugs.
In the past four years, outbreaks of acute respiratory diseases associated with canine influenza H3N2 viruses in dogs and cats have been reported in South Korea and China. For prevention of disease from spread of the disease and for administration of timely medical treatments, including countermeasures for quarantine, use of a rapid and highly sensitive detection method are important to detection of the causative viruses. This study was conducted in order to develop a real time RT-PCR for the H3N2 subtype. It was based on primers targeting the highly homologous sequences of matrix, hemagglutinin, and neuraminidase genes. The detection limit of real time RT-PCR was 10 copies/ul with matrix and hemagglutinin genes, and 1 copy with neuraminidase genes, respectively. This real time RT-PCR was as sensitive as virus isolation in 52 clinical samples. The detection system developed in this study might provide more rapid and highly sensitive results than commercial rapid kits based on immunochromatographic assay.
A tissue sample of a laryngopharyngeal mass from a 9-year-old male Dachshund dog was submitted to the Animal, Plant and Fisheries Quarantine and Inspection Agency for histopathologic evaluation. The mass measured was 3.1×3.0× 5.0 ㎝ in diameter and was first detected by computed tomography. Histopathologically, the nodules consisted of large round and polygonal cells with abundant eosinophilic cytoplasm. The mitotic index was 1～3 per view under a high power field (400×). Immunohistochemically, tumor cells were positive for vimentin and desmin, but negative for cytokeratin, S-100, and α-Smooth Muscle Actin (α-SMA). Based on these findings, the tumor was confirmed as Laryngopharyngeal Rhabdomyosarcoma. To the best of our knowledge, this is the first case report in Korea.
Over the past decade, the magnitude and variety of modelling work in the realm of veterinary services has shown a significant increase. Accordingly, the need for enhancement of communication and cooperation among modellers (those who develop models), users (those who run models), policy makers (those who use model outputs in decision making on control policy) and coordinators (those who connect modellers with policy makers) has also shown a notable increase. In this paper, terms used in epidemiological models are listed alphabetically and explained. It is expected that development of this lexicon will help to boost communication and collaboration among those concerned with modelling work and its utilization.
The Veterinary Epidemiology Division of The Animal, Plant, and Fisheries Quarantine and Inspection Agency (QIA) was established in 2002. It is the first governmental organization in the Republic of Korea to be charged with the epidemiological task of managing veterinary public health. In commemorating the previous efforts of this organization, this paper describes the brief history, concept, tools, and approaches of veterinary epidemiology. The mission of veterinary epidemiology, as a leader of 'One Health', to improve the public health status of human and animal is also discussed.