[Show abstract][Hide abstract] ABSTRACT: Egg drop syndrome virus (EDSV) is an important pathogen of poultry that decreases egg production in chickens and causes respiratory
disease in goslings. In 2011, we obtained serum samples from 139 domestic Pekin ducks, 416 one-day-old Pekin ducklings, and
75 wild ducks (67 mallards and 8 pintails) to survey their exposure to EDSV. A total of 123 of 139 sera (88.5%) from Pekin
ducks, 396 of the ducklings (95.2%), and 16 of 67 mallards (23.9%) were positive. Field cases of EDSV in wild and domestic
ducks were investigated. Six cases from domestic Pekin ducks were identified by PCR detection and were used for virus isolation
and molecular analysis. Phylogenetic analyses of the partial hexon and full fiber genes showed that the D11-JW-012 and D11-JW-017
strains among 6 isolates belonged to different clusters compared with other known strains including the 127 strain. We assessed
cell growth efficiency by hemagglutination (HA) titers and cytopathic effects in duck embryo liver cells and chicken embryo
liver (CEL) cells to investigate host adaptation. The D11-JW-017 strain propagated more in chicken embryo liver than the D11-JW-012
strain and the field isolate from chickens. Our results demonstrate the high prevalence of EDSV in wild and domestic ducks
in South Korea and provide information on EDSV from ducks that showed variable adaptability in chickens.
[Show abstract][Hide abstract] ABSTRACT: Infections with Pasteurella multocida, Salmonella enterica, Riemerella anatipestifer, and Escherichia coli result in high morbidity and mortality, which cause significant economic loss in the poultry industry. It can be difficult
to distinguish these pathogens based on clinical signs because these pathogens can cause similar clinical signs and coinfections
can occur. Thus, rapid and sensitive detection of these 4 major bacterial pathogens are important in ducks. The aim of this
study was to develop a multiplex PCR (mPCR) assay for simultaneously detecting and identifying these 4 pathogenic bacteria
in a single tube reaction. The target genes used were KMT1 of P. multocida, the invasion protein gene of S. enterica, 16S rDNA of R. anatipestifer, and the alkaline phosphatase gene of E. coli. The detection limit of the assay for all bacterial DNA was 10 pg. The mPCR did not produce any nonspecific amplification
products when tested against other related pathogens, including Staphylococcus aureus, Streptococcus pyogenes, Clostridium perfringens, Mycoplasma gallinarum, Mycoplasma synoviae, and Mycoplasma gallisepticum, which can also infect ducks. We applied mPCR to field samples, and the results were the same as the single PCR results.
These results suggest that mPCR for the 4 bacteria is a useful and rapid technique to apply to field samples.
[Show abstract][Hide abstract] ABSTRACT: The Republic of Korea experienced a foot-and-mouth disease (FMD) outbreak during May-June 2002. The present study describes epidemiological characteristics of the 2002 FMD outbreak in Korea, including the pattern of the outbreak in both time and space, transmission routes among infected farms, and control measures. One of the notable features of the 2002 FMD epidemic in Korea was that the virus infected mostly pigs [15 of 16 infected premises (IPs)], despite the presence of other susceptible animals on infected and neighbouring farms. The epidemic showed temporal clustering at 8-9 day intervals, suggesting five generations of infection during the outbreak, and 13 of 16 (81.3%) IPs were located within a 10 km-radius of the index case. The clinical signs that prompted notification of infection included vesicles around hooves and snouts. The age of lesions was significantly less among cases reported by farmers compared with veterinarians. The high awareness of farmers from an earlier FMD outbreak greatly helped the animal hygiene authority in efforts associated with disease control and eradication. The outbreak was eradicated within <2 months as a result of the intensive control efforts of the animal hygiene authorities and the cooperation of the Korean people. Although the outbreak was a costly lesson for the Korean people, the experience gained will contribute to future efforts in the prevention and control of animal infectious diseases.
No preview · Article · Nov 2008 · Transboundary and Emerging Diseases
[Show abstract][Hide abstract] ABSTRACT: In November 2004, antibodies to classical swine fever virus (csfv) were detected in finishing pigs during the annual serological surveillance in Jeju Province, Korea. In addition, csf vaccine viruses (lom strain) had recently been isolated from pigs raised on farms known to have csfv antibody-positive pigs. In contrast with mainland Korea, Jeju Province had been csf free and its pigs had not been vaccinated against csf for more than five years. An epidemiological investigation team from the National Veterinary Research and Quarantine Service investigated the current status of csf prevention on the Korean mainland and in Jeju Province to determine possible routes of introduction of the virus into the province. It was concluded that improperly processed blood meals, manufactured on mainland Korea, had been contaminated with the csf vaccine lom strain, and that the lom strain had been transmitted to pigs fed feed or feedstuffs containing the contaminated meal.
No preview · Article · Feb 2008 · The Veterinary record
[Show abstract][Hide abstract] ABSTRACT: Activation of P2X receptors on macrophages is an important stimulus for cytokine release. This study seeks evidence for functional expression of P2X receptors in macrophages that had been only minimally activated.
Whole-cell recordings were made from macrophages isolated 2-6 h before by lavage from mouse peritoneum, without further experimental activation. ATP (1-1000 muM) elicited inward currents in all cells (holding potential -60 mV). The properties of this current were compared among cells from wild type, P2X1 (-/-) and P2X4 (-/-) mice.
Immunoreactivity for P2X1 and P2X4 receptors was observed in wild type macrophages but was absent from the respective knock-out mice. In cells from wild type mice, ATP and alpha beta methyleneATP (alpha beta meATP) evoked inward currents rising in 10-30 ms and declining in 100-300 ms: these were blocked by pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid (PPADS, 10 microM). ATP also elicited a second, smaller ( approximately 10% peak amplitude), more slowly decaying (1-3 s) at concentrations > or =10 microM: this was resistant to PPADS and prolonged by ivermectin. Macrophages from P2X1 (-/-) mice responded to ATP (>100 microM) but not alpha beta meATP: these small currents were prolonged by ivermectin. Macrophages from P2X4 (-/-) mice responded to ATP and alpha beta meATP as cells from wild type mice, except that ATP did not evoke the small, slowly decaying component: these currents were blocked by PPADS.
Mouse peritoneal macrophages that are minimally activated demonstrate membrane currents in response to ATP and alpha beta meATP that have the predominate features of P2X1 receptors.
Full-text · Article · Dec 2007 · British Journal of Pharmacology
[Show abstract][Hide abstract] ABSTRACT: Eugenol, a natural capsaicin congener, is widely used in dentistry. Eugenol inhibits voltage-activated Na(+) and Ca(2+) channels in a transient receptor potential vanilloid 1 (TRPV1)-independent manner. We hypothesized that eugenol also inhibits voltage-gated K(+) currents, and investigated this in rat trigeminal ganglion neurons and in a heterologous system using whole-cell patch clamping. Eugenol inhibited voltage-gated K(+) currents, and the inhibitory effects of eugenol were observed in both capsaicin-sensitive and capsaicin-insensitive neurons. Pre-treatment with capsazepine, a well-known antagonist of TRPV1, failed to block the inhibitory effects of eugenol on K(+) currents, suggesting no involvement of TRPV1. Eugenol inhibited human Kv1.5 currents stably expressed in Ltk(-) cells, where TRPV1 is not endogenously expressed. We conclude that eugenol inhibits voltage-gated K(+) currents in a TRPV1-independent manner. The inhibition of voltage-gated K(+) currents is likely to contribute to the irritable action of eugenol. Abbreviations: human Kv1.5 channel, hKv1.5; transient receptor potential vanilloid 1, TRPV1.
No preview · Article · Oct 2007 · Journal of Dental Research
[Show abstract][Hide abstract] ABSTRACT: Although eugenol is widely used in dentistry, little is known about the molecular mechanisms responsible for its anesthetic properties. In addition to calcium channels, recently demonstrated by our group, there could be another molecular target for eugenol. Using a whole-cell patch-clamp technique, we investigated the effect of eugenol on voltage-gated sodium channel currents (I(Na)) in rat dental primary afferent neurons identified by retrograde labeling with a fluorescent dye in maxillary molars. Eugenol inhibited action potentials and I(Na) in both capsaicin-sensitive and capsaicin-insensitive neurons. The pre-treatment with capsazepine, a competitive antagonist of transient receptor potential vanilloid 1 (TRPV1), failed to block the inhibitory effect of eugenol on I(Na), suggesting no involvement of TRPV1. Two types of I(Na), tetrodotoxin (TTX)-resistant and TTX-sensitive I(Na), were inhibited by eugenol. Our results demonstrated that eugenol inhibits I(Na) in a TRPV1-independent manner. We suggest that I(Na) inhibition by eugenol contributes to its analgesic effect.
No preview · Article · Nov 2006 · Journal of Dental Research
[Show abstract][Hide abstract] ABSTRACT: Using the stochastic and spatial simulation model of between-farm spread of disease, InterSpread Plus, we evaluated the effect of alternative strategies for controlling the 2002 epidemic of foot-and-mouth disease (FMD) in the Republic of Korea. InterSpread Plus was parameterised to simulate epidemics of FMD in the population of farms containing susceptible animal species in the Korean counties of Yongin, Icheon, Pyongtaek, Anseong, Eumseong, Asan, Cheonan, and Jincheon. The starting point of our analyses was the simulation of a reference strategy, which approximated the real epidemic. The results of simulations of alternative epidemic-control strategies were compared with this reference strategy. Ring vaccination (when used with either limited or extended pre-emptive depopulation) reduced both the size and variability of the predicted number of infected farms. Reducing the time between disease incursion and commencement of controls had the greatest effect on reducing the predicted number of infected farms.
No preview · Article · Jun 2006 · Preventive Veterinary Medicine
[Show abstract][Hide abstract] ABSTRACT: Since the first rabies case was reported in a dog in 1907, the disease was enzootic up to 1975 in Korea. After a steady decrease in the number of rabies cases from 1976 to 1984, no case was reported for 8 years from 1985 to 1992. Then, a resurgence of the disease was noted in 1993, and a continuous increase of rabies cases was observed during the following years. This report provides information on rabies in South Korea during the reemerging period 1993-2003. A total of 364 rabies cases in five different animal species and five deaths in human beings as a result of rabies were reported. Cattle and dogs accounted for 46.4% and 40.4% of total animal cases, respectively, and raccoon dogs commanded an overwhelming majority (44/48) of rabies cases in wildlife animal species. All animal and human rabies cases occurred only in two provinces, Gyeonggi and Gangwon; majority of them in two counties of Gyeonggi and one county of Gangwon province that border the demilitarized zone. From the three counties, the disease continued to expand to the other areas of the two provinces. The average monthly frequency of animal rabies cases during the 11-year period peaked in January, and the incidence was highest during winter. There were three major rabies outbreaks in animals and the number of animal rabies cases increased with time. Data indicate that the temporal patterns were attributable to the ethology of raccoon dogs in the areas of outbreak.
No preview · Article · May 2006 · Journal of Veterinary Medicine Series B
[Show abstract][Hide abstract] ABSTRACT: During the 2003-2004 epidemic in Korea, the infection time and within-farm spread pattern of virus were analysed for the highly pathogenic avian influenza (HPAI) outbreak on chicken farms using regression models based on epidemiological data. Mortality observed on a given day had a positive linear association with time after initial infection. HPAI spread more rapidly on farms managed by employees and on farms with larger numbers of chicken houses in use. The disease spread more rapidly among layer chickens than among broilers. Using statistical model, we found that farmers recognize the abnormally high mortality resulting from HPAI approximately 5 days after infection. Without any intervention, entire flocks would die within 12 days of introduction of the HPAI virus to the infected farm.
Preview · Article · Jan 2006 · Journal of Veterinary Medicine Series B
[Show abstract][Hide abstract] ABSTRACT: Eugenol is a topical analgesic agent widely used in the dental clinic. To elucidate the molecular mechanism underlying its analgesic action, we investigated the effect of eugenol on high-voltage-activated calcium channel (HVACC) currents in dental primary afferent neurons, and with a heterologous expression system. Dental primary afferent neurons were identified by retrograde labeling with a fluorescent dye, DiI. Eugenol inhibited HVACC currents in both capsaicin-sensitive and capsaicin-insensitive dental primary afferent neurons. The HVACC inhibition by eugenol was not blocked by capsazepine, a competitive transient receptor potential vanilloid 1 (TRPV1) antagonist. Eugenol inhibited N-type calcium currents in the cell line C2D7, stably expressing the human N-type calcium channels, where TRPV1 was not endogenously expressed. Our results suggest that the HVACC inhibition by eugenol in dental primary afferent neurons, which is not mediated by TRPV1 activation, might contribute to eugenol's analgesic effect. Abbreviations: high-voltage-activated calcium channel, HVACC; transient receptor potential vanilloid 1, TRPV1; trigeminal ganglion, TG; dorsal root ganglion, DRG; capsazepine, CZP.
No preview · Article · Oct 2005 · Journal of Dental Research