• Parasites, Hosts and Diseases
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• v.59 no.6
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• pp.639-643
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• 2021

Enterocytozoon bieneusi is a microsporidian pathogen. Recently, the equestrian population is increasing in Korea. The horse-related zoonotic pathogens, including E. bieneusi, are concerns of public health. A total of 1,200 horse fecal samples were collected from riding centers and breeding farms in Jeju Island and inland areas. Of the fecal samples 15 (1.3%) were PCR positive for E. bieneusi. Interestingly, all positive samples came from Jeju Island. Diarrhea and infection in foals were related. Two genotypes (horse1, horse2) were identified as possible zoonotic groups requiring continuous monitoring.

• The Plant Pathology Journal
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• v.19 no.3
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• pp.133-137
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• 2003

Seedborne fungus Bipolaris spicifera, which has not been previously reported in Korea, was detected from import-ed grass seeds in the country. The most frequently detected fungi from the seeds were Fusarium species, Ulocladium atrum, B. spicifera, Alternaria, and Cuvularia lunata among 17 different seed samples of the family Gramineae. Detection frequencies of B. spicifera were 11,8,5% in Bermuda grass, tall fescue, and mixed lawn grass imported from USA, respectively, and 9％ in mixed lawn grass imported from Italy. This suggests that important seedborne pathogen could be spread between countries through seed sources. The pathogen was seed-transmitted causing damping-off of Bermuda grass seedlings and showed strong pathogenicity to vice, corn, Bermuda grass, sorghum, and tall fescue. However, it did not infect wheat and blue grass.

• Mycobiology
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• v.32 no.4
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• pp.186-189
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• 2004

The study on the cultural characteristics of Bipolaris spicifera was conducted to provide with information for the identification, and inoculation studies, etc. B. spicifera grew well at $30{\sim}35^{\circ}C$ and wide range of pH $5.0{\sim}9.0$. However, the fungal growth was retarded at pH 4.0 and 10.0, respectively. Conidia were germinated with 70% at $30^{\circ}C$ but maintained 50% germination even at $40^{\circ}C$, indicating that this pathogen could infect plants at relatively high temperature. The pathogen could not produce conidia under 24 hr fluorescent light condition for 7 days. In contrast, it produced many more conidia at 24 hr dark condition.

• Horticultural Science & Technology
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• v.18 no.1
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• pp.22-27
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• 2000

National plant quarantine inspector of exporting country should inspect agricultural products according to the quarantine requisites of counterpart country when the commodities are shipped. Export of pear fruits was held because quarantine pests including Conogethes punctiferalis were found at the point of entry in Canada. In order to examine the problems in detail, the inspected pear fruits were stored at a low temperature for 43 days, almost the same period necessary for fruit sorting, quarantine procedures, and transportation by ship. Dead larvae of fruit moths, C. punctiferalis and Grapholita molesta were found during cold storage. Quarantine pathogens were not found, but non-quarantine ones such as Penicillium sp. was infected through wounds by bruises and stabs resulted from sorting procedures. Because of the wounding problem during export procedures, pear fruits with thin exocarp, such as fruits of P. pyrifolia Nakai cv. Whangkeumbae, are required more careful handling during fruit sorting and conveyance.

• The Korean Journal of Mycology
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• v.44 no.2
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• pp.103-107
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• 2016

To establish a rapid and accurate detection of Phytophthora pinifolia, which is a quarantine pathogenic fungus in Korea, a species-specific primer was developed based on the ras-related protein (Ypt1) gene. Species-specific primer based on the DNA sequences of Ypt1 gene amplified 193 bp polymerase chain reaction (PCR) product for P. pinifolia. The primer pair yielded the predicted PCR product size exactly in testing with target pathogen DNAs, but not from the other 10 species of Phytophthora and 14 species of other phytopathogenic fungi. The primer pair also showed only the species-specific amplification curve on realtime PCR on target pathogen DNA. The detection sensitivity of real time PCR using species-specific primer pair was 10 to 100 times higher than conventional PCR, with 1 to $10pg/{\mu}L$.

• Korean Journal of Veterinary Service
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• v.41 no.3
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• pp.203-210
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• 2018

Pasteurella multocida is an opportunistic organism that plays a significant role in porcine respiratory disease complex (PRDC). In the current study, we provide nationwide information of P. multocida isolates from pneumonic lungs of slaughter pigs by determining their prevalence, subspecies, biovars, capsular types, virulence-associated genes, and minimum inhibitory concentrations. P. multocida was the second most frequently confirmed (19.2%) bacterial pathogen and most of the isolates (88.9%) showed simultaneous infection with other respiratory pathogens, especially Mycoplasma hyopneumoniae (63.3%, P<0.001) and porcine circovirus type 2 (53.3%, P=0.0205). Of 42 isolates investigated, 41 (97.6%) were identified as P. multocida subspecies multocida, and only one isolate was identified as subspecies septica (biovar 5). All the isolates were capsular type A and the most prevalent biovar was biovar 3 (40.5%), followed by biovar 2 (31.0%). Comparing virulence-associated genes and biovars, all biovar 2 isolates exhibited $hgbB^-pfhA^+$ (P<0.001); all biovar 3 (P=0.0002) and biovar 13 (P=0.0063) isolates presented $hgbB^+pfhA^-$. Additionally, all biovar 2 (P=0.0037) isolates and most of biovar 3 (P=0.0265) isolates harbored tadD. P. multocida showed the highest resistance levels to oxytetracycline (73.8%), followed by florfenicol (11.9%). Continuous monitoring is required for surveillance of the antimicrobial resistance and new emerging strains of P. multocida in slaughter lines.

• Journal of Veterinary Clinics
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• v.28 no.1
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• pp.113-121
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• 2011

Foot-and-mouth disease (FMD) is a severe vesicular disease of cloven-hoofed animals including domesticated ruminants and pigs. Acute clinical signs may be mild in sheep and goats but are associated with lameness in pigs and mouth lesions with vesicles in cattle. The required condition for a successful pathogen appears to be the ability to counteract both the host innate and adaptive immune response. FMD virus (FMDV) inhibits the induction of antiviral molecules and interferes with the secretory pathway in the infected cell. The surface expression of Major Histocompatibility Complex (MHC) class I molecules is reduced in infected cells. Thus, the ability of the host to recognize and eliminate virus infected cells is decreased. Furthermore, FMDV infection results in a rapid, but transient lymphopenia, reducing the number of T and B cells, and affecting T cell function. The virus appears to premature apoptosis-mediated cell death because it has a very short replication cycle and is able to rapidly produce large amounts of virus. FMDV engages the host protective response at multiple steps to ensure its effective replication and pathogenesis. This review describes the recent pathological and immunological studies to overcome the powerful abilities of FMDV to counteract defense mechanism of host.

• Korean Journal of Veterinary Service
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• v.42 no.4
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• pp.275-278
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• 2019

Blindness was observed in five calves born from cattle fed only a commercial feed of growing stage and dried rice straws for about two years in a farm in Gyeongsangbuk-do province. Three of them died within a month after birth, and a body and sera of his mother and other 19 cattle were submitted for diagnosis. At necropsy, the calf was very weak and filled with cerebrospinal fluid in the cerebrum. Any histopathological lesion including atrophy of death of optic nerve cells was not observed, but the irregular proliferation such as lace pattern of choroidal cells and lymphocytic infiltration just below choroid was observed. No pathogen was detected as a result of the etiological tests on the internal organs of calves and bloods. In addition, the levels of serum vitamin A in different affected and his mother cattle were all lower than normal. Finally, we determined this case as an encephalopathy caused by maternal vitamin A deficiency in a calf. This report is an extreme example of how important it is to supply adequate s diets and a good quality of hay for each stage of growth in cattle.

• Korean Journal of Veterinary Research
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• v.50 no.1
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• pp.29-35
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• 2010

Yersinia (Y.) ruckeri has been recognized as a serious bacterial pathogen to several kinds of fish, including rainbow trout. However, there are no reports about the characteristics and pathogenicity of Y. ruckeri isolated from farm-cultured eels. In this study, we isolated and characterized Y. ruckeri from the farm-cultured eel Anguilla japonica in Korea. We investigated the phenotypic and genotypic characteristics of Y. ruckeri and tested the virulence of Y. ruckeri isolates on experimentally infected eels. Examination of the flagellar morphology of Y. ruckeri by electron microscopy showed peritrichous flagella in its cell body. Biochemical reaction studies showed overall identical profiles between the isolates and the reference strain of Y. ruckeri in API 20E and API ZYM tests. We sequenced the 16S rRNA of the Y. ruckeri (1,505 bp) for the genotypic characterization (National Center for Biotechnology Information accession number EU401667). Comparison of the 16S rRNA sequences with previously reported Y. ruckeri strains revealed similar phylogenetic relationships. In the virulence assay of the Y. ruckeri on eels, the eels exhibited listlessness, but Y. ruckeri was reisolated from those of the gills and kidneys.

• The Plant Pathology Journal
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• v.17 no.1
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• pp.62-66
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• 2001

Detection of Xanthomonas axonopodis pv. citri (Xac) on citrus fruits for exporting is usually made by bacteriophage test (BPT) to demonstrate the pathogen-free status. BPT has rather time-consuming and complicate procedures for dealing with massive samples to be inspected. In this study, enzyme-linked immunosorbent assay (ELISA) was applied to detect Xac on fruits, and compared with BPT. In ELISA, positive reactions occurred in the bacterial densities of $3\times10^5$ cells/ml or more. To detect the bacterial infection on citrus fruits with a density of lower than $3\times10^5$ cells/ml, the bacterial suspensions were mixed with fruit rinse water and incubated in broth medium. Ordinary peptone sucrose broth (PSB) was not a proper medium for increasing Xac density specifically enough to be detect by ELISA. On the other hand, modified PSB (MPSP) amended with Fe-EDTA (0.25 g/$\ell$) and 2.5% potato-dextrose broth sufficed to differentiate uninfected and infected citrus fruits by ELISA after 24 h incubation of the fruit rinse water. Using various citrus samples from infected and uninfected fields, efficiencies in detecting Xac on fruits were compared between ELISA and BPT. For infected fruits samples, ELISA detected Xac by 100%, while BPT by about 44%, indicating that the detection efficiency was improved by 23.5% by ELISA, compared to BPT. In addition, ELISA has simpler procedures for testing and is less time-consuming than BPT, suggesting that ELISA may be accurate and simple method to detect Xac on citrus fruits.