• Parasites, Hosts and Diseases
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• v.51 no.2
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• pp.213-218
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• 2013

Malaria is a parasitic infection caused by Plasmodium species. Most of the imported malaria in Korea are due to Plasmodium vivax and Plasmodium falciparum, and Plasmodium ovale infections are very rare. Here, we report a case of a 24-year-old American woman who acquired P. ovale while staying in Ghana, West Africa for 5 months in 2010. The patient was diagnosed with P. ovale malaria based on a Wright-Giemsa stained peripheral blood smear, Plasmodium genus-specific real-time PCR, Plasmodium species-specific nested PCR, and sequencing targeting 18S rRNA gene. The strain identified had a very long incubation period of 19-24 months. Blood donors who have malaria with a very long incubation period could be a potential danger for propagating malaria. Therefore, we should identify imported P. ovale infections not only by morphological findings but also by molecular methods for preventing propagation and appropriate treatment.

• Parasites, Hosts and Diseases
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• v.37 no.3
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• pp.129-143
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• 1999

Plasmodium vivax malaria, which was highly prevalent in the Republic of Korea, disappeared rapidly since 1970s. However, malaria re-emerged with the first occurrence of a patient in 1993 near the demilitarizd zone (DMZ), the border between South Korea and North Korea. Thereafter, the number of cases increased exponentially year after year, totaling 6,142 cases (6,249 if United States Army personnels were included) by the end of 1998. Interestingly enough, the majority of cases (3,743; 61%) was soldiers aged 20-25, camping around the northern parts of Kyonggi-do or Gangwon-do (Province) just facing the DMZ. Among 2.399 civilian cases, 1,144(47.%) were those who Provinces. The re-emerging malaria characteristically revealed a combination type of short and long incubation periods with predominance of the long type. The course of illness was relatively mild, and the treatment was successful in most patients. Vector mosquitoes are Anopheles sinensis and possibly A. yatsushiroensis. Wide-scale preventive and control measures should be operated to eradicate this re-emerging disease. It has been suggested by many authors that the initial source of the re-emerging malaria was infected mosquitoes which had flown from the northern part of the DMZ.

• Pediatric Infection and Vaccine
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• v.4 no.2
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• pp.282-287
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• 1997

Malaria due to Plasmodium vivax had been known as an indigenous protozoan disease in Korea. However, massive use of insecticides and improvement of sanitation for several decades have led to rapid reduction of malaria incidence, then it was recognized to have been almost eradicated in recent years. However in 1993, one case was reported in Phajoo, Kyungki-do, and then, reported cases have been increasing annually. Recently we encountered one case of malaria in a 3 year old male child living in Dorim-dong, Seoul, who had never been abroad and had no history of transfusion, drug abuse, and travel to endemic area in Korea. He had characteristic fever, chill and splenomegaly and was confirmed as Plasmodium vivax malaria with peripheral blood smear finding. He was successfully treated with hydroxy chloroquine and primaquine. We report this case with brief review of related literature.

• Parasites, Hosts and Diseases
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• v.50 no.4
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• pp.375-377
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• 2012

Malaria is still a leading cause of morbidity and mortality. The increase in lipid peroxidation reported in malaria infection and antioxidant status may be a useful marker of oxidative stress during malaria infection. The aim of this study was to investigate the role of antioxidant enzymes against toxic reactive oxygen species in patients infected with Plasmodium vivax and healthy controls. Malondialdehyde levels, superoxide dismutase, and glutathione peroxidase activities were determined in 91 P. vivax patients and compared with 52 controls. Malondialdehyde levels, superoxide dismutase, and glutathione peroxidase activities were $8.07{\pm}2.29$ nM/ml, $2.69{\pm}0.33$ U/ml, and $49.6{\pm}3.2$ U/g Hb in the patient group and $2.72{\pm}0.50$ nM/ml, $3.71{\pm}0.47$ U/ml, and $62.3{\pm}4.3$ U/g Hb in the control group, respectively. Malondialdehyde levels were found statistically significant in patients with vivax malaria higher than in healthy controls (P<0.001). On the other hand, superoxide dismutase and glutathione peroxidase activities were found to be significantly lower in vivax malaria patients than in controls (P<0.05). There was an increase in oxidative stress in vivax malaria. The results suggested that antioxidant defense mechanisms may play an important role in the pathogenesis of P. vivax.

• Parasites, Hosts and Diseases
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• v.53 no.1
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• pp.43-49
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• 2015

The aim of the study was to explore the possible molecular markers of chloroquine resistance in Plasmodium vivax isolates in Thailand. A total of 30 P. vivax isolates were collected from a malaria endemic area along the Thai-Myanmar border in Mae Sot district of Thailand. Dried blood spot samples were collected for analysis of Pvmdr1 and Pvcrt-o polymorphisms. Blood samples ($100{\mu}l$) were collected by finger-prick for in vitro chloroquine susceptibility testing by schizont maturation inhibition assay. Based on the cut-off $IC_{50}$ of 100 nM, 19 (63.3%) isolates were classified as chloroquine resistant P. vivax isolates. Seven non-synonymous mutations and 2 synonymous were identified in Pvmdr1 gene. Y976F and F1076L mutations were detected in 7 (23.3%) and 16 isolates (53.3%), respectively. Analysis of Pvcrt-o gene revealed that all isolates were wild-type. Our results suggest that chloroquine resistance gene is now spreading in this area. Monitoring of chloroquine resistant molecular markers provide a useful tool for future control of P. vivax malaria.

• Parasites, Hosts and Diseases
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• v.38 no.3
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• pp.119-138
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• 2000

Korean vivax malaria had been prevalent for longtime throughout the country with low endemicity. As a result of the Korean war (1950-1953), malaria became epidemic. In 1959-1969 when the National Malaria Eradication Service (NMES) was implemented, malaria rates declined, with low endemicity in the south-west and south plain areas and high endemic foci in north Kyongsangbuk-do (province) and north and east Kyonggi-do. NMES activities greatly contributed in accelerating the control and later eradication of malaria. The Republic of Korea (South Korea) was designated malaria free in 1979. However, malaria re-emerged in 1993 and an outbreak occurred in north Kyonggi-do and north-west Kangwon-do (in and/or near the Demilitarized Zone, DMZ) , bordering North Korea. It has been postulated that most of the malaria cases resulted from bites of sporozoite-infected females of An. sinensis dispersed from North Korea across the DMZ. Judging from epidemiological and socio-ecological factors, vivax malaria would not be possible to be endemic in South Korea. Historical data show that vivax malaria in Korea is a typical unstable malaria. Epidemics may occur when environmental, socio-economical, and/or political factors change in favor to malaria transmission, and when such factors change to normal conditions malaria rates become low and may disappear. Passive case detection is a most feasible and recommendable control measure against the unstable vivax malaria in Korea in cost-effect point of view.

• Parasites, Hosts and Diseases
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• v.52 no.4
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• pp.377-381
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• 2014

Microscopy is considered as the gold standard for malaria diagnosis although its wide application is limited by the requirement of highly experienced microscopists. PCR and serological tests provide efficient diagnostic performance and have been applied for malaria diagnosis and research. The aim of this study was to investigate the diagnostic performance of nested PCR and a recently developed an ELISA-based new rapid diagnosis test (RDT), NovaLisa test kit, for diagnosis of malaria infection, using microscopic method as the gold standard. The performance of nested-PCR as a malaria diagnostic tool is excellent with respect to its high accuracy, sensitivity, specificity, and ability to discriminate Plasmodium species. The sensitivity and specificity of nested-PCR compared with the microscopic method for detection of Plasmodium falciparum, Plasmodium vivax, and P. falciparum/P. vivax mixed infection were 71.4 vs 100%, 100 vs 98.7%, and 100 vs 95.0%, respectively. The sensitivity and specificity of the ELISA-based NovaLisa test kit compared with the microscopic method for detection of Plasmodium genus were 89.0 vs 91.6%, respectively. NovaLisa test kit provided comparable diagnostic performance. Its relatively low cost, simplicity, and rapidity enables large scale field application.

• Parasites, Hosts and Diseases
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• v.56 no.6
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• pp.531-543
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• 2018

Historically, Plasmodium vivax malaria has been one of the most highly endemic parasitic diseases in the Korean Peninsula. Until the 1970s, vivax malaria was rarely directly lethal and was controlled through the Korean Government Program administered by the National Malaria Eradication Service in association with the World Health Organization's Global Malaria Eradication Program. Vivax malaria has re-emerged in 1993 near the Demilitarized Zone between South and North Korea and has since become an endemic infectious disease that now poses a serious public health threat through local transmission in the Republic of Korea. This review presents major lessons learned from past and current malaria research, including epidemiological and biological characteristics of the re-emergent disease, and considers some interesting patterns of diversity. Among other features, this review highlights temporal changes in the genetic makeup of the parasitic population, patient demographic features, and spatial distribution of cases, which all provide insight into the factors contributing to local transmission. The data indicate that vivax malaria in Korea is not expanding exponentially. However, continued surveillance is needed to prevent future resurgence.

• Pediatric Infection and Vaccine
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• v.10 no.2
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• pp.200-207
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• 2003

Purpose : Malaria is known to have been eradicated for a few decades through persistent national health program in South Korea. However, malaria caused by Plasmodium vivax has started to reappear incidiously among military personnel near to DMZ since 1993. After then, the number of malarial cases have been increased abruptly year by year. We analyzed the children of indigenous malaria who were diagnosed by peripheral blood smear and malarial antibody test with regards to epidemiologic and clinical manifestations. Methods : The study 13 cases below 15 years of age, who were confirmed as vivax malaria during from January 2000 to August 2003. We retrospectively analyzed epidemiologic data, clinical manifestations, laboratory findings and therapeutic responses. Results : All of 13 cases were indigenous and tested positive for Plasmodium vivax. Of 13 patients, 9 were male and 4 were female. Mean age of onset was $9.5{\pm}3.6$ years old. Ilsan(n=9) was the most prevalent area, the most patients(n=11) were presented in summer (from June to August). A characteristic feature of periodic 3 day fever in patients with P.vivax infection was reported in only 2 among 13 cases. Thrombocytopenia was most prominent findings, which was accompanied by 12 of 13 patients and pancytopenia was appeared in 3 patients on this study. The therapeutic responses of hydroxycholoquine were very good in all cases, and abnormal laboratory findings were recovered and no relapse during follow-up period. Conclusion : Vivax malaria is indigenous in Korea near to DMZ, but recently endemic area seemed to be extended southward. Plasmodium vivax is the cause of indigenous malaria of children. As for children with high fever accompanying thrombocytopenia in endemic area of Korea, malaria must be included in differential diagnosis whether the type of fewer is periodic 3 day fever or not. Malaria antibody test is helpful as a screening test for malaria.

• 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.