• Parasites, Hosts and Diseases
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• 제56권1호
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• pp.53-59
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• 2018

Tick saliva is critically important for continuous attachment to the host, blood feeding for days, and transmission of tick-borne pathogens. To characterize the patterns of inflammatory cytokine gene expression during its attachment and blood sucking time, peripheral blood samples of rabbits infested with Haemaphysalis longicornis ticks were collected at different intervals. Blood histamine concentration was evaluated as well as gene encoding IFN-${\gamma}$, TNF-${\alpha}$, IL-2, IL-6, IL-4, and IL-10 were compared with non-infested rabbits. Blood histamine concentration of tick-infested rabbits during fast feeding time was significantly higher than that of non-infested rabbits. In both nymph and adult tick infested rabbits, expression of TNF-${\alpha}$ and IFN-${\gamma}$ genes were decreased significantly (P<0.05), while expression of IL-4, IL-6, and IL-10 were increased 1.3 to 7 folds in adult infested rabbits with the exception of IL-6 that was significantly (P<0.05) decreased in nymph infested rabbits. IL-2 was not expressed in either nymph or adult infestation. H. longicornis saliva is capable of modulate host responses through a complex correlation with histamine and Th1, Th2 mediated cytokines that suppress the inflammatory responses directed toward inflammatory mediators introduced into the host during tick feeding.

• Parasites, Hosts and Diseases
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• 제52권2호
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• pp.169-175
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• 2014

There are 60 species of blood-feeding land leeches, 50 species belonging to the family Haemadipsidae and 10 species belonging to the family Xerobdellidae. Despite recent papers on the land leeches, their taxonomic identification is not fully understood, especially at a species level. In Korea, there have been no historical records of the terrestrial leeches, but recently an unrecorded blood-feeding land leech was discovered at Gageo-do (Island), Korea. Molecular analysis was used to identify the species of 29 leeches collected from Mt. Dock-Sil in Gageo-do. Conventional PCR was conducted using nuclear 18S rRNA and mitochondrial cytochrome c oxidase subunit 1 (CO1) genetic marker. The 18S rRNA sequences revealed that the leeches share 99.9% identity with Haemadipsa rjukjuana (inhabiting Taiwan), and the CO1 sequences revealed that the leeches are very close to H. rjukjuana (inhabiting Taiwan). The CO1 sequences were separated into 2 categories, 1 with 94.6% and the other with 94.3% similarity to the H. rjukjuana L00115A (inhabiting Taiwan). This new finding of the land leech is the first record in Korea. In addition, the north range of the distribution of the blood-feeding leech (Hirudiniformes: Haemadipisidae) should be reconsidered including Korea.

• KSBB Journal
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• 제21권6호
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• pp.433-438
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• 2006

Bacillus subtilis BB-1 (KFCC l1344P)으로부터 분리된 혈전용해효소 유전자 (BCF-1)를 대량발현 벡터인 pEB 벡터에 크로닝하여 순수분리 된 혈전용해효소를 rat 경구 투여하여 출혈시간, 혈액의 응고, serum의 혈전용해능 등에 대한 in vivo 실험을 실시하였으며, 혈전용해효소의 단회경구투여에 따른 독성을 검사하였다. 효소의 경구투여에 따른 rat의 출혈시간에서는 대조군에 비하여 모든 경구 투여군에서 출혈시간이 유의적으로 약 1.75배 이상 길게 나타남을 확인하였고(P<0.05), 혈액의 출혈시간 또한 활발히 진행됨을 관찰하였다. 혈액으로부터 분리된 serum의 혈전용해작용 있어서는 경구투여 후 1시간부터 채혈한 혈액 내에서 혈전용해효소의 활성이 검출되기 시작하여 3시간째까지 높은 활성을 보였으며 4시간째부터 서서히 활성이 감소하는 것을 확인하였고 혈액의 응고 역시 대조군에 비하여 경구 투여군에서 상당히 지연되는 것을 알 수 있었다. Western blot에 의한 효소 검출에서는 경구 투여군에서 30,000 Da 크기의 단일밴드를 확인하였으며, 혈전용해효소의 rat에 대한 단회경구투여 독성실험에서 중량의 변화, 장기의 이상여부, 사망률 등에서 어떠한 이상이나 병변이 발견되지 않았다. 이상의 결과로 동물실험을 통한 혈전용해 효소의 경구투여에 의한 작용을 혈액 내에서 확인 할 수 있었으며, 본 효소의 단회 경구투여 시의 독성은 전혀 없음을 확인할 수 있었다.

• 한국임상수의학회지
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• 제29권1호
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• pp.63-67
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• 2012

Mosquitoes are the vectors of a number of viral diseases in cattle, such as Akabane disease, bovine ephemeral fever, Ainovirus infection, Chuzan virus infection, and Ibaraki disease. These diseases are transmitted from an infected animal to a non-infected host via the blood feeding of the vector. In Korea, the National Veterinary Research and Quarantine Services, Ministry for Food, Agriculture, Forestry and Fisheries is responsible for planning, implementation, laboratory investigations and reporting the results of the national surveillance program for mosquito-borne bovine diseases (MBD). The surveillance program, which was started in 1993, focused to determine the seroprevalence of each disease in cattle herds in space and time. From the epidemiological point of view, more important component of the surveillance program is to monitor infection rates in vectors for specific pathogens because this information is essential for a more precise understanding the dynamics of these diseases in a given environment and for determining risk of transmission. The aim of this study was to describe and compare methods for estimation of vector infection rates using maximum likelihood (MLE) and minimum infection rate in pooled samples. Factors affecting MLE such as number of pools, pooling size and diagnostic test performance are also discussed, assuming some hypothetical sampling scenarios for MBD.

• 한국동물학회지
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• 제13권2호
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• pp.51-56
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• 1970

Studies on the feeding and resting behavior of Culex pipiens pallens, a possible vector of Japanese encephalitis in Korea, was carried out at Kobu-Ri, Kobu-Myon, Chongup Kun. Cholla Pukdo in 1967. 1. Indoor and outdoor human biting collections showed that 47.3 per cent Culex pipiens pallens were collected indoors and 52.7 per cent outdoors. 2.Feeding occurred throughout the night from dusk to dawn, with the peak period from 23:00-24:00 hours outside the house and from 24:00-01:00 hours inside. 3. Culex pipiens pallens females preferred man for their blood feeding to domestic animals. The results of human and cow biting collections showed that the feeding ratio between man and cow was 2.1 to 1. As to the feeding preference to the domestic animals, the ratio among cow, pig and horse was 7.3 to 5.1 to 5.4 4. Daytime resting collections showed that large numbers of Culex pipiens pallens females rest inside the house, especially in the bed room and the chicken pen. As temperatures increased, fewer mosquitoes resting indoors and more mosquitoes rest ing outdoors were caught. By means of sweep-net collections at outdoors resting places, a small number of Culex pipiens pallens mosquitoes were caught in such places as grass fields, vegetable fields, barley fields, bean fields, culverts, bomb shelters, and so on. A comparison between number of mosquitoes collected resting during the day in bedrooms and verandahs with resting collections in the same places at night showed that more mosquitoes were present at night. It was observed that the majority of the unfed females rested before feeding at night.

• Parasites, Hosts and Diseases
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• 제39권2호
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• pp.185-192
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• 2001

To evaluate the factors that determine the transmission level of vivax malaria using vectorial capacity, entomological surveys were conducted from .lune to August, 2000. From 6 nights of human-bait collection in Paju, the human biting rate (ma) was counted as 87.5 bites/man/night. The parity of Anopheles sinensis from human baiting collections fluctuated from 41% to 71% (average 48.8%) of which the rate gradually increased as time passed on: 35.2% in Jun. ; 55.0% in July; 66.2% in Aug. From this proportion of parous, we could estimate the probability of daily survival rate of An. sinensis to be 0.79 assumed with 3 days gonotrophic cycle and the expectancy of infective life through 11 days could be defined as 0.073. Blood meal analysis was performed using ELISA to determine the blood meal source. Only 0.8% of blood meals were from human hosts. We could conclude that An. sinensis is highly zoophilic (cow 61.8%) Malaria is highly unstable (stability index < 0.5) in this area. From these data, vectorial capacity VC) was determined to be 0.081. In spite of a high human biting rate (ma), malaria transmission potential is very low due to a low human blood index. Therefore, we could conclude that malaria transmission by An. sinensis is resulted by high population density, not by high transmission potential. For this reason, we need more effort to decrease vector population and vector-human contact to eradicate malaria in Korea.

• 대한수의학회지
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• 제33권3호
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• pp.471-478
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• 1993

Culicoides arakawae is a kind of the main blood sucking insects of domestic fowls and serves as a vector of Leukocytozoom caulleryi, the causative protozoon of chicken leukocytozoonosis. In this study, the complete life history of C arakawae was cycled by laboratory colonization. Adult midges were collected from various poultry farm by light trap. The laboratory colonization was performed under the conditions of constant temperature of $25{\pm}1^{\circ}C$ and relative humidity of 80% or above. The hatched larvae were cultured in larval medium consisted of rice field mud and activated charcoal powder. The surface of medium was continuously flowed with biologically conditioned water. The fine powder meal composed of pellet feed for mice and equal mount of yeast was supplied for feeding larvae at every 72 hours. The life cycle completed at $25^{\circ}C$ in 35~35 days ; the period of preoviposition, egg. larval and pupal stage was 2~3, 3~4, 28~30 and 3 days, respectively. The measurements of the eggs, the lst instar larvae, the 4th instar larvae and pupae was $36.28{\mu}m{\pm}1.95$, $13.58{\mu}m{\pm}0.72$, $4000{\mu}m{\pm}1.47$ and $219.95{\mu}m{\pm}6.25$ in $mean{\pm}S.D.$, respectively. In order to confirm experimental colonization of C arakawae in laboratory, the colonized adult midges were allowed to suck blood from chicken infected with L caulleryi. The oocysts and sporozoites could be identified in midguts and salivary grands of engorged midges at 72 hours after blood sucking.

• 한국응용곤충학회지
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• 제61권1호
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• pp.91-100
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• 2022

진드기는 박테리아, 바이러스, 원생동물 및 균류를 포함한 다양한 병원체를 전달할 수 있는 감염병매개체이다. 진드기는 불리한 환경조건에서도 생존할 수 있는 능력이 있으며, 흡혈이 필수적인 절지동물의 진화적 산물로써 비흡혈 기간이 장기간 지속되는 경우에도 생존이 가능하다. 특히, 높은 온도와 낮은 습도 환경에서도 견딜 수 있는 수분 조절 메커니즘과 내열성의 생리적 특징은 진드기가 전 세계적으로 분포하도록 한 중요한 요인이다. 진드기의 침샘, 말피기관, 후장 그리고 뇌를 포함하는 여러 기관이 관여하는 물과 이온의 획득 및 배출은 복합적인 메커니즘에 의해 조절된다. 진드기가 수분을 확보하는 주요 경로는 흡혈과정 또는 공기 중 수증기를 직접 포집하는 방식이며, 이와 더불어 진드기가 자연조건에서 맺힌 물방울을 직접 마시며 수분을 보충한다는 것이 최근 본 연구진의 연구를 통해 밝혀졌다. 물방울에서 획득된 수분은 진드기 침샘의 포도상 부위(유형 I) 또는 중장을 통해 체내로 흡수된다는 것이 형광물질 추적을 통해 확인되었다. 이 연구 결과는 진드기 방제 및 병원체 전파 억제를 위한 전략 개발에 새로운 방향을 제시하였다. 본 종설에서는 진드기 방제를 위한 잠재적 표적인 진드기의 수분조절 및 표피 배설의 생리적 메커니즘을 종합적으로 다룬다.

• Parasites, Hosts and Diseases
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• 제62권2호
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• pp.226-237
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• 2024

Ticks, blood-sucking ectoparasites, spread diseases to humans and animals. Haemaphysalis longicornis is a significant vector for tick-borne diseases in medical and veterinary contexts. Identifying protective antigens in H. longicornis for an anti-tick vaccine is a key tick control strategy. Enolase, a multifunctional protein, significantly converts D-2-phosphoglycerate and phosphoenolpyruvate in glycolysis and gluconeogenesis in cell cytoplasm. This study cloned a complete open reading frame (ORF) of enolase from the H. longicornis tick and characterized its transcriptional and silencing effect. We amplified the full-length cDNA of the enolase gene using rapid amplification of cDNA ends. The complete cDNA, with an ORF of 1,297 nucleotides, encoded a 432-amino acid polypeptide. Enolase of the Jeju strain H. longicornis exhibited the highest sequence similarity with H. flava (98%), followed by Dermacentor silvarum (82%). The enolase motifs identified included N-terminal and C-terminal regions, magnesium binding sites, and several phosphorylation sites. Reverse transcription-polymerase chain reaction (RT-PCR) analysis indicated that enolase mRNA transcripts were expressed across all developmental stages of ticks and organs such as salivary gland and midgut. RT-PCR showed higher transcript levels in syn-ganglia, suggesting that synganglion nerves influence enolase's role in tick salivary glands. We injected enolase double-stranded RNA into adult unfed female ticks, after which they were subsequently fed with normal unfed males until they spontaneously dropped off. RNA interference significantly (P<0.05) reduced feeding and reproduction, along with abnormalities in eggs (no embryos) and hatching. These findings suggest enolase is a promising target for future tick control strategies.