• 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.

• Journal of Sericultural and Entomological Science
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• v.39 no.2
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• pp.146-153
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• 1997

The microsporidian infection with Nosema bombycis, reconfirmed its high virulence and transovarial tranmissibility, however, the characteristic symptom of the spots like pepper grains on the diseased larval skin was no more recognized by present varieties of the silkworm. Transovarial transmission rate detected from moth was above 90% in dead eggs or dead larvae in the rearing by mulberry leaves, 80% in the newly hatched larvae starved to death. Transovarially transmitted N. bombycis was easily observed from dead eggs and larvae, and were suggested an individual inspection of a few of dead eggs for detection of the pathogenic spores. The progeny population provided indicative factors on the sampling of predictive and corrective inspection. The higher concentration of N. bombycis spores included in the hindabdormal part of infected moth, applicative on the simple method of indivisual moth inspection. For the predictive inspection of growned 5th-instar larvae, N. bombycis infection was detectable without microscopic observation by the unique symptom of turbid milky-white spots on the silk gland. Inspection of the meconia artificially discharged from silkworm moth, was also succesful of microscopic observation before crossing, without killing or homogenize the moths. The results provided a basis of rational methods for the inspection of N. bombycis infection of the silkworm.

• International Journal of Industrial Entomology and Biomaterials
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• v.17 no.1
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• pp.157-163
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• 2008

Infection of pathogenic microsporidia, Nosema bombycis and Nosema mylitta (Chakrabarti and Manna, 2006) decreased egg production, fecundity, hatching % and increased sterile eggs in heavily infected mulberry silkmoth, Bombyx mori L. On an average a disease free moth laid upto 442.67 eggs with high hatching % (99.53) and less sterile eggs ($0.47{\sim}2.00%$). While an infected moth laid less number of eggs ($7.00{\sim}412.00$) with low hatching % ($32.437{\sim}98.643$) and high sterile eggs ($2.143{\sim}129.571$). Fecundity of disease free laying was highest (468.714) during season-1 then gradually decreased during season- 2 (414.000) to season- 3 (404.285). But fecundity of an infected laying was highest during season-2 and hatched eggs were lowest during season-2. Higher inoculums concentration of N. mylitta infected to 5th stage larva of mulberry silkworm drastically decreased the fecundity in season - 3 and lower inoculums concentration of N. bombycis decreased the fecundity in season-1 and 3. Season-3 was most effective season to decrease the fecundity and increase sterile eggs when both temperature and humidity were fluctuated from the optimum level.

• Parasites, Hosts and Diseases
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• v.52 no.3
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• pp.321-323
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• 2014

Encephalitozoon cuniculi is a microsporidian parasite commonly found in rabbits that can infect humans, causing encephalitozoonosis. The prevalence of encephalitozoonosis is not well documented, even when many clinics suspect pet rabbits as being highly infected. This study investigated the seropositivity of E. cuniculi using ELISA. The examination of 186 rabbits using ELISA showed that 22.6% (42/186) were seropositive against E. cuniculi. In analysis with healthy status, all 42 seropositive sera were collected from clinically normal rabbits. Moreover, the gender and age of pet rabbits did not have anysignificant effect on E. cuniculi infection. To the best of our knowledge, this is the first report to describe the seroprevalence of E. cuniculi in pet rabbits and suggests that pet rabbits could act as an important reservoir of encephalitozoonosis for both pet animals and humans in Korea.

• Journal of Apiculture
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• v.34 no.2
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• pp.137-140
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• 2019

Although honeybees (Apis mellifera) are crucial for maintenance of the ecosystem, population of honeybee has been steadily decreasing due to diseases including nosemosis. Nosemosis is a disease caused by Nosema ceranae and is now considered as a major threat to honeybees. N. ceranae is a microsporidian that stays in form of spore even before the infection, which makes it harder to control than other pathogens. People are now aware of this parasite, however, cure and preventive candidates for nosemosis are hardly found until today. In this study, in vitro experiment of Lespedeza cuneata treatment to prevent nosemosis were done using Trichoplusia ni cell line, BTI-TN5B1-4. Normal T. ni cells exhibited round shape without abnormal size. On the other hand, when N. ceranae were treated, cells deteriorated and some cells abnormally enlarged due to N. ceranae infection. Interestingly, treatment of T. ni cells with L. cuneate extract protected abnormal cell shape induced by N. ceranae infection to normal shape. Some N. ceranae spores were observed outside of the cells. Effective concentration range for N. ceranae control were experimented. Lowest concentration which can control nosemosis were 50 ㎍/mL. When the concentration of L. cuneata extract was exceeded 200 ㎍/mL, cytotoxicity started to show up.

• Journal of Veterinary Clinics
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• v.32 no.2
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• pp.212-214
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• 2015

Encephalitoozoon cuniculi is an obligate intracellular microsporidian parasite commonly found in rabbits, causing encephalitozoonosis. This organism can also infect a wide range of hosts including humans, which is known to cause opportunistic infections in immunocompromised individuals. In this case, four rabbits presented with head tilt and nystagmus were diagnosed for E. cuniculi infection using ELISA. The rabbits were treated with fenbendazole for 4 weeks and therapeutic success was evaluated by assessing the neurological symptoms. Three out of 4 rabbits showed improved health condition 3 to 5 days after treatment, but one rabbit showed persistent anorexia and head tilt after treatment and then died after 10 days. This report is the first to investigate the therapeutic response of fenbendazole for rabbit encephalitozoonosis in Korea, and suggests that pet rabbits may serve as potential E. cuniculi reservoirs for both pet animals and humans.

• International Journal of Industrial Entomology and Biomaterials
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• v.27 no.2
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• pp.219-227
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• 2013

The purpose of this study was to quickly and effectively identify the Nosema disease of bumblebees in Gangwon Province in Korea. Bumblebees are crucial pollinators of various crops, and microsporidia are the critical pathogens of these hosts. When bumblebees are infected with Nosema bombi, their abdomens can become distended. Paralyzed and infected workers often become sluggish and die early. We have identified the morphology of the microsporidium by light and electron microscopy, and found it to have fairly small oval spores, as has been described previously in many other articles. For the specific and sensitive diagnosis of the microsporidian parasite N. bombi in bumblebees, we have developed an improved method of the polymerase chain reaction (PCR) for expeditious diagnosis. Two pairs of primers were tested on N. bombi and the related microsporidia Nosema apis and Nosema sp., both of which infect Bombus ignitus and Bombus hypocrita sapporoensis. Furthermore, we have verified and analyzed the 16SrRNA sequence data of N. bombi in bumblebees by using the Basic Local Alignment Search Tool (BLAST) server at the National Center for Biotechnology Information.

• Journal of Veterinary Science
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• v.22 no.3
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• pp.40.1-40.12
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• 2021

Background: The microsporidian parasite Nosema ceranae is a global problem in honeybee populations and is known to cause winter mortality. A sensitive and rapid tool for stable quantitative detection is necessary to establish further research related to the diagnosis, prevention, and treatment of this pathogen. Objectives: The present study aimed to develop a quantitative method that incorporates ultra-rapid real-time quantitative polymerase chain reaction (UR-qPCR) for the rapid enumeration of N. ceranae in infected bees. Methods: A procedure for UR-qPCR detection of N. ceranae was developed, and the advantages of molecular detection were evaluated in comparison with microscopic enumeration. Results: UR-qPCR was more sensitive than microscopic enumeration for detecting two copies of N. ceranae DNA and 24 spores per bee. Meanwhile, the limit of detection by microscopy was 2.40 × 10⁴ spores/bee, and the stable detection level was ≥ 2.40 × 10⁵ spores/bee. The results of N. ceranae calculations from the infected honeybees and purified spores by UR-qPCR showed that the DNA copy number was approximately 8-fold higher than the spore count. Additionally, honeybees infected with N. ceranae with 2.74 × 10⁴ copies of N. ceranae DNA were incapable of detection by microscopy. The results of quantitative analysis using UR-qPCR were accomplished within 20 min. Conclusions: UR-qPCR is expected to be the most rapid molecular method for Nosema detection and has been developed for diagnosing nosemosis at low levels of infection.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.6-6
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• 2023

Nosemosis is one of the most common protozoan diseases of adult bees (Apis mellifera). Nosemosis is caused by two species of microsporidia; Nosema apis and Nosema ceranae. Nosema ceranae is potentially more dangerous because it has the ability to infect multiple cell types, and it is now the predominant microsporidian species in A. mellifera. In this study, we identified two anti-nosemosis plants, Aster scaber and Artemisia dubia, which reduced the spore development of N. ceranae in spore-infected cells. We intend to establish the anti-nosemosis activity of aqueous, ethyl acetate (EA), and butanol (BuOH) extracts of A. dubia and A. scaber. In order to determine the optimal dose, we did in vitro and in vivo toxicity for all the extracts and carried out anti-nosemosis experiments. Although all of the extracts (aqueous, EA, and BuOH) showed in vitro and in vivo anti-nosemosis activity in a dose-dependent manner, the aqueous extracts of A. dubia and A. scaber showed more potent anti-nosemosis activity than the EA and BuOH extracts. And then, we isolated five phenolic compounds [chlorogenic acid, 3,4-dicaffaeoylquinic acid (3,4-DCQA), 3,5-dicaffaeoylquinic acid (3,5-DCQA), 4,5-dicaffaeoylquinic acid (4,5-DCQA), and coumarin] from A. dubia, A. scaber, and A. dubia + A. scaber aqueous extracts and screened for their toxicities and anti-Nosema effects in both in vivo and in vitro conditions. Among these five compounds, coumarin, chlorogenic acid, and 4,5-DCQA exhibited less toxic but more potent anti-Nosema effects than the other two compounds. Especially, chlorogenic acid and coumarin showed prominent anti-Nosema activities even at the lowest concentration (10 ㎍/mL). They might have potential to be developed as alternative compounds for the control of Nosema disease.

• Current Research on Agriculture and Life Sciences
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• v.1
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• pp.67-83
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• 1983

The new microsporidia S80 isolated from, Bombyx mori L. in Korea showed ovoid in the morphology of the spores and the size were measured $2.9{\pm}0.28{\mu}$ in length and $1.7{\pm}0.29{\mu}$ width. No other microsporidian spore like this has not been so far isolated from Silkworm. The length of the polar filament extruded in hydrogen peroxide ($H_2O_2$) at $30^{\circ}C$ was $26{\mu}$ of a round cytoplasm on the top. The spores were partly stained with Giemsa, Safranin-O and Gram as the same staining properties as Nosema bombycis, Microsporidia K 79 and other microsporidian spores. The fine structures were observed under scanning eleceron microscope through ultrathin sectioning. The spore wall was composed of three layers ; the thin exospore of an electron dense rippled layer, the thick electron lucent endospore which was thinning considerably at the polar filament insertion point, and the inner limiting membrane. Polar cap present at the sporeapex, with a long polar filament of 12-13 coils, subtending angle of $60^{\circ}$ to spore axis, which is tubular made up of a multilayered and are a benes core, light ring structure enclosing the dance core, the dark ring structure enclosing the inner light ring structure and the other than and light ring structure bounded from cytoplasm. Lamellate polaroplast occupied the anterior part of the spore, and the two neclei with dense nucleoplasm bounded by a double nuclear envelope were cited in the slight downer middle portion of spore. From the characteristics of the shape, size and fine structures, it is certain to reason the Microsporidia S80 belong to the phylum Microspora, class Microspora, order Microsporida, order Microsporida. The shape of two nuclei cited seems to be genus Nosema, but in the classification for the suborder it should be defined wheather pansporoblasts be formed or not and for the genis especial attempts have been made to define the characters which distinguish the disporous genera in the life cycle. Survey through the infection of the bad cocoons during 1980 to 1982 in South Korea the areas contaminated with new microsporidia were revealed 5 provinces of Kyung-Gi, Kang-Won, Chung-Nam and Chun-Nam. Pathological effects inoculated per os at second instar larvae of silkworm, the LD 50 was $7.1{\times}10^7/ml$ as lower pathogenecity than that of Nosema bombycis Naegeli of $1.2{\times}10_7/ml$. While on the other hand the inoculation of the microsporidia at fourth instar larvae lowerd the whole cocoon weight and cocoon shell weight and significant at 1% level. The microsporidia S80 defined it can not be transmitted transovarially from the result of predictive and collective examination of 21 egg batches from the infected female moth.