• Korean Journal of Microbiology
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• v.36 no.2
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• pp.142-149
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• 2000

It had been evaluated the recombinant Circumsporozoite(CS) protein of Plasmodium viva in serologic diagnosis of vivax malaria. Western blot was done to analyse the sera of malaria patients according to the days after onset. The sera which have the terms within 15 days were shown 43.8%(14/32) of positive rates and the sera over the 16 days were shown 94.4%(17/18) of positive rates. So the total positive rate was 62%(31/50). It was 22.6%(7/31) which was shown negative response in Western blot, even though they were shown positive response in Immuuofluorescent antibody test(1FAT) using whole blood stage antigens. The positive rate of non-epidemic area(Yechon-gun, Kyongsangbuk-do) was 10.7%(3/28), and epidemic area(Kangwha-gun, Inchon-shi) was 27.6%(13/47) in Western blot analysis using recombinant CS protein. In order to applicate the recombinant CS protein in seroepidemiological survey, blood samples of 422 inhabitants were collected who lived in malaria epidemic areas, Chosm-ri, Majeong-ri, Hyangyang-ri and Noejo-n in Paju-shi, Kyonggi-do. All of them were negative in microscopic examination and two(0.5%) of them were positive in Polymerase Chain Reaction. 42(10.0%) of them were seropositive in FAT using whole blood antigens and 71(16.8%) of them were seropositive in Enzyme-linked immunosorbent assay using recombinant CS protein. It was figured out the positive rates were much higher according to the distances of villages which were closed to the demilitalized zone(DMZ) in all kind of diagnostic methods, respectively.

• Journal of agricultural medicine and community health
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• v.31 no.2
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• pp.157-164
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• 2006

Objectives: Early diagnosis and treatment is the most important strategy to control malaria effectively. Microscopic examination of blood films is a traditional and standard method for diagnosing malaria, which takes a long time and needs expertise, Therefore, the alternative method, rapid diagnostic kit has been used for quick diagnosis in some counties, a highly infectious region by P. vivax. The purpose of this study was to evaluate the utility of malaria rapid diagnostic kit in Ganghwa county. Methods: The utility was evaluated by mean diagnosis time and sensitivity and specificity. For monitoring mean diagnosis time, 942 cases which were diagnosed for P. vivax were collected between 1998 and 2005, And for calculating sensitivity and specificity, 434 whole bloods in EDTA which were presented for P. vivax by microscopy and rapid diagnostic kit were collected between 2004 and 2005. Results: After malaria rapid diagnostic kit was used in 2003, mean diagnosis time has decreased to 3.36-3.14 day. The sensitivity and specificity of the rapid diagnostic kit was 98.2% and 98,5% and comparable to that of microscopic examination. Conclusions: The malaria rapid diagnostic kit is useful tool in a highly infectious region like Ganghwa county.

• Parasites, Hosts and Diseases
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• v.32 no.3
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• pp.195-200
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• 1994

Malaria is estimated to have a worldwide incidence of more than 100 million clinical cases and approximately 1 miuion deaths per year. Korea, although previously tnlown as an endemic area of tertian malaria (Pzosmonin vivax), has been considered free from malaria as there had been no report on indigenous cases since 1984. Recently, however, we experienced an indigenous case of P. viuax infection in a young man who had never been abroad. The patient was a 23-year-old Korean soldier with 18-day history of recurrent fever and chill lasting 4 to 8 hours on alternative days since mid-July 1993. He had lived in Changwon, Hyongsangnam-do, before entering barracks located in Paiu-gun, Kyonggj-do on Jne 1992, and had never been out of Korea. He had no history of blood transfusion nor parenteral use of drugs. The peripheral blood smears showed typical ring forms, trophozoites, and gametocytes of p. uiuox, in addition to mild anemia and thrombocytopenia. After confirmation of the diagnosis, he was treated with hydroxychloroquine and primaquine. Follow-up blood smears no more revealed malaria parasites. It is not certain whether the present case is due to a resurgence of indigenous malaria or a secondary infection from introduced mnuia. Whichever the source of infection the domestic occurrence of mnuia cycle in Korea should be a warning sign in public health point of view.

• Parasites, Hosts and Diseases
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• v.47 no.3
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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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• v.39 no.2
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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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• v.43 no.3 s.135
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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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• v.54 no.4
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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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• v.40 no.2
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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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• v.58 no.1
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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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• v.4 no.2
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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.