• 미생물학회지
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• 제36권2호
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• pp.142-149
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• 2000

국내에서 유행하는 Plasmodium vivax의 유전자를 조작하여 만든 재조항 Circumsporozrozite(CS) 단백질 (22)을 이용하여 말라리아에 대한 혈청학적 검사의 유용성을 평가하였다. 최초발병일로부터 진단까지 걸린 기간을 기준으로 환자들의 면역반응을 Western blot으로 알아본 결과, 15일 이내에 진단받은 환자들은 43.8%(14/32)가 양성반응을 보였고, 16일 이상 경과한 환자들은 94.4%(17/18)가 양성반응을 보여 전체적으로는 62%(31/50)의 양성률을 보였다. Blood stage 항원에 대한 항체를 갖고 있음에도 불구하고 재조합 CS단백질 항원에 대해 음성인 환자들이 22.6%(7/31)였다. 비유행지 주민(경북 예천군)들은 10.7%(3/28),유행시 주민(인천시 강화군)들은 27.6%(13/47)의 재조합 CS 단백질에 대한 항체 양성을 보였다. 재조합 CS 단백질 항원의 역학조사시 유용성을 알아보기 위하여 말라리아 유행지인 경기도 파주시 조산리, 마정리, 항양리, 뇌조리 거주 주민 422명의 전혈을 채취하여 혈액도말법과 중합효소연쇄 반응법으로 항원검사를 실시하였으며 blood stage 항원을 이용한 간접면역형광법과 재조합 CS 단백질 항원을 이용한 효소면역측정법으로 말라리아 항체보유 여부를 조사하였다. 혈액도말법에서는 422명 모두 음성이었으나, 중합효소연쇄반응법에서는 2명(0.47%)이 양성이었다. 간접면역형광법에서는 42명(9.95%), 재조합 CS 단백질 항원을 이용한 효소변역측정법에서는 71명(16.82%)이 양성으로 나타났다. 두 검사에서 모두 항체 양성을 보인 사람은 8명(11.27%)에 불과하였다.

• 농촌의학ㆍ지역보건
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• 제31권2호
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• pp.157-164
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• 2006

본 연구는 말라리아 고위험지역인 강화군 주민을 대상으로 신속진단킷트 시행으로 인한 진단소요일의 변화와 신속진단킷트 검사의 민감도와 특이도를 평가하고자 하였다. 이를 위하여 1998년 1월부터 2005년 12월까지 인천광역시 강화군에서 발열증상으로 말라리아가 의심되어 보건소, 보건지소, 진료소, 병의원 등 보건의료기관을 내원한 검사자 중 질병관리본부의 최종 검사결과 말라리아가 확진된 검사자 942명을 대상으로 최초 발열일부터 검사일까지의 기간으로 진단 소요일을 추정하였으며, 2004년 1월부터 2005년 12월까지 보건의료기관에서 신속진단킷트 검사와 혈액도말검사를 동시에 실시한 검사자 434명을 대상으로 질병관리본부의 최종 검사결과와 비교하여 진단소요일에 따른 민감도와 특이도를 측정하였다. 연구결과, 2003년 신속진단킷트 시행으로 인하여 진단소요일은 2002년 4.68일에서 2004년 3.14일과 2005년 3.31일로 감소한 것으로 나타났다. 또한 신속진단킷트의 민감도와 특이도는 98.2%와 98.5%인 것으로 나타나 혈액도말검사의 97.5%, 100%와 비교하여 큰 차이가 없었다. 이상의 결과를 종합할 때, 말라리아 신속진단킷트 검사는 진단소요일을 단축하면서도 민감도와 특이도를 유지하는 장점이 있는 것으로 판단되었다. 말초혈액도말검사를 실시할 역량을 갖추지 못한 보건의료기관에서는 신속하고 정확한 말라리아 진단을 위하여 신속진단킷트 검사를 적극적으로 고려할 필요가 있다.

• Parasites, Hosts and Diseases
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• 제32권3호
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• pp.195-200
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• 1994

말라리아는 세계적으로 매년 1억 이상의 환자를 발생시키며 그 중 약 100만 명씩을 사망케 하고 있는 무서운 원충 질환으로 잘 알려져 있다. 우리 나라에는 과거에 삼일열 말라리아 (tefilnmuwia)의 유행이 있었으나 1970년대 말 이후부터는 토착적 환자 발생 보고가 없어 소멸된 것으로 알려져 왔다. 그러나 최근 저자 등은 해외 여행 경력이 없는 환자 1명에서 삼일열원충 (Plasmodium vivax) 감염을 확일하였기에 보고하고자 한다. 환자는 23세 남자인 국군 병사로서 1993년 7월 중순부터 18일 동안 격일로 매회 4-8시간씩 계속되는 발열과 오한을 주소로 내원하였다. 환자는 경남 창원시에 거주하였고 1992년 6월 군에 입대한 후에는 경기도 파주군의 한 야전군 부대에 근무해 왔으나 외국에 나간 일은 전혀 없다고 하였다. 과거력상 수혈을 받거나 정맥주사를 맞은 일도 없다고 하였다. 환자의 말초혈액 도말 표본에서는 삼일열원충의 ring form, trophozoite, schizont 및 gametocyte가 검출되었고, 약간의 적혈구 감소와 혈소판 감소가 관찰되었다 확진 후 hydroxychloroquine과 primaquine을 투여하여 치료하였고, 추적 혈액 도말검사에서는 말라리아 원충을 발견할 수 없었다. 이 증례가 우리 나라 토착적 말라리아의 재유행에 의한 것인지, 도입성 (introduced) 말라리아의 국내 정착에 의한 2차 감염 환자인지는 판단하기가 쉽지 않으나. 어쨌든 말라리아가 다시 유행할 가능성 에 대해서는 커다란 관심을 기울여 야 할 것으로 생각되었다.

• Parasites, Hosts and Diseases
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• 제47권3호
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• pp.227-233
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• 2009

Local malaria transmission in the United Arab Emirates (UAE) came to an end in 1997. Nevertheless, UAE has been subjected to substantial importation of malaria cases from abroad, concerning both UAE nationals and immigrants from malarious countries with a total number of 2,119 cases in 2007. To evaluate a new DNA extraction technique using nested PCR, blood samples were collected from 132 individuals who presented to Infectious Diseases Department in Rashid Hospital, Dubai, and Central Department of Malaria Control with fever and persistent headache. Giemsa-stained blood films and ELISA test for malaria antibodies were carried out for detection of Plasmodium infection. Plasmodium infections were identified with the genus-specific primer set and species differentiation using nested PCR. A rapid procedure for diagnosis of malaria infections directly from dried blood spots using for the first time DNA extract from FTA Elute cards was evaluated in contrast to extraction techniques using FTA classic cards and rapid boiling technique. Our new simple technique for DNA extraction using FTA Elute cards was very sensitive giving a sensitivity of 100% compared to 94% using FTA classic cards and 62% in the rapid boiling technique. No complex preparation of blood samples was required prior to the amplification. The production cost of DNA isolation in our PCR assay was much less incomparable to that of other DNA extraction protocols. The nested PCR detected plasmodial infection and could differentiate P. falciparum from P. vivax, and also detected the mixed infection.

• 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.

• Parasites, Hosts and Diseases
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• 제43권3호
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• pp.75-92
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• 2005

Extensive previous studies on taxonomy, behavior/bionomics and control of Anopheles sinensis are reviewed and summarized. Recent molecular identification revealed that the population of An. sinensis complex includes An. sinensis, An. pullus, An. lesteri and at least two new species, and An. yatsushiroensis is synonmy of An. pullus. An. sinensis is the main vector specie of vivax malaria in Korea. Larvae of An. sinensis breed in wide range of habitats which are naturally-made clean water, stagnant or flowing; main habitats include rice fields, ditches, streams, irrigation cannals, marshes, ponds, ground pools, etc. Their host preferences are highly zoophilic. Human blood rate is very low ($0.7-1.7\%$); nevertheless An. sinensis readily feeds on man when domestic animals are not found near by. They feed on hosts throughout the night from dusk to dawn with a peak period of 02:00-04:00 hours; they are slightly more exophagic (biting outdoors); much larger numbers come into the room when light is on. Main resting places are outdoors such as grasses, vegetable fields and rice fields. A mark-release-recapture study resulted that $37.1\%$ was recaptured within 1 km, $29.4\%$ at 1-3 km, $21.1\%$ at 3-6 km, $10.3\%$ at 6-9 km and $2.1\%$ at 9-12 km distance. An. sinensis hibernate outdoors (mostly under part of dense grasses) during October-March. At the end of the hibernation period (March-April) they feed on cows at daytime. Until today any single measure to effectively control An. sinensis population has not been found. Indoor residual spray with a long-lasting insecticide can not reduce vector population densities, but shorten their life spans in some degree, so contributes to malaria control.

• Parasites, Hosts and Diseases
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• 제54권4호
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• pp.393-397
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• 2016

Low parasitemic condition in malaria remains a diagnostic challenge; as the available diagnostic methods failed to detect. Currently, hemozoin (Hz) pigment is gaining attention in the diagnosis of malaria. The major drawback is ease of detection of Hz in routine practice. A pilot study was conducted to evaluate the role of Hz pigment and to compare the performance of quantitative buffy coat assay (QBC) and PCR in such conditions. Clinically suspected cases of malaria were examined by both Giemsa stain and immunochromatographic test (ICT). Samples positive by ICT and negative by Giemsa stain were further examined by nested PCR targeting 18S rRNA and QBC for the presence of malaria parasites and pigments. Thirty blood samples fulfilled the inclusion criteria out of which 23 were Plasmodium vivax (Pv), 4 Plasmodium falciparum (Pf), and 3 mixed (Pv and Pf) by immunochromatographic test. Twenty-one out of 30 (70%) were positive by nested PCR in comparison to 25/30 (83%) by QBC. Samples containing both malaria parasites and Hz pigment by QBC completely showed concordance with the PCR result. However, 61% of total samples containing only Hz pigment were observed positive by PCR. Hz pigment remains an important tool for malaria diagnosis. Identification of leukocytes containing pigments by QBC not only indicates recent malarial infections but also puts light on severity of the disease. QBC assay is a rapid, highly sensitive, and cost-effective method to detect malaria parasites and Hz pigment especially in low parasitemic conditions.

• Parasites, Hosts and Diseases
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• 제40권2호
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• pp.75-81
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• 2002

We investigated population densities of mosquitoes infected with sporozoites in three highly epidemic areas of Josan-ri and Jangpa-ri (Paju City) and Dongjung-ri (Yeoncheon County) in Korea. Anopheline mosquitoes were collected front both indoors and outdoors by human baiting collection method during the period of the first week of June to the second week of September 1999. Total 13,296 female mosquitoes were collected and 8,650 (65.1%) were Anophelines. Thirty seven percent (3,199) of the Anopheline mosquitoes were captured outdoors and 63.9% (5,531) indoors. Employing a sandwich enzyme-linked immunosorbent assay (ELISA), we analyzed a total of 7,820 Anopheline mosquitoes and found that 7 Anopheline mosquitoes were infected with sporozoites. The positive rate in Josan-ri was 0.14% (5/3,500) and 0.15% (2/1,370) in Jangpa-ri. The total positive rate in all three surveyed areas was 0.09% (7/7,820). The mosquitoes infected with the sporozoites were detected on June $28^{th}$ (n=2), July $5^{th}$ (n=1), July $19^{th}$ (n=1), August $9^{th}$ (n=1), September $6^{th}$ (n=1), and the last one on September $13^{th}$ (n=1). They were all classified as Anopheles sinensis, which showed positive reaction in ELISA test. Therefore it might be concluded that Anopheles sinensis plays an important role in re-emerging malaria transmission in Korea.

• Parasites, Hosts and Diseases
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• 제58권1호
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• pp.61-65
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• 2020

Majority of the imported malaria cases in Korea is attributed to Plasmodium falciparum and P. vivax infections, whereas P. malariae and P. ovale infections are very rare. Falciparum and ovale malaria are mostly imported from Africa, while most of the vivax malaria cases are imported from Southeast Asia. Here, we report 6 Korean imported ovale malaria cases (4 males and 2 females) who had visited in Africa during 2013-2016. These subjects were diagnosed with P. ovale based on microscopic findings, Plasmodium species-specific nested-PCR, and phylogenetic clade using 18S rRNA gene sequences. We identified 2 P. ovale subtypes, 1 P. ovale curtisi (classic type) and 5 P. ovale wallikeri (variant type). All patients were treated with chloroquine and primaquine, and no relapse or recrudescence was reported for 1 year after treatment. With increase of travelers to the countries where existing Plasmodium species, the risk of Plasmodium infection is also increasing. Molecular monitoring for imported malaria parasites should be rigorously and continuously performed to enable diagnosis and certification of Plasmodium spp.

• Pediatric Infection and Vaccine
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• 제4권2호
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• pp.293-297
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• 1997

Malaria, caused by any of four species of protozoan parasites of the genus Plasmodium, is charaterized by high fever, anemia and splenomegaly. Although malaria is a cause of significant morbidity and mortality worldwide, in Korea indigenous malaria has been believed to be eradicated by 1984. However, since the case report of native malaria in 1993, reported cases have been increased annually, reaching more than 300 cases in 1996. We experienced a 2 years-old male with fever, severe anemia and splenomegaly who resided in Inchon city. He had the history of travelling to the area (Yunchon) near western Demilitarized Zone for 1 month this summer. After more than 2 weeks without special attention, he was presented with pallor, anemia and splenomegaly. He was diagnosed to have malaria by Plasmodium vivax with the help of peripheral blood smears which showed various forms of malaria, i.e., ring form, trophozoites, shizonts and gametocytes. He was treated successfully with hydroxychloroquine and primaquine. We report this case with brief review of related literature.