Northern Gyeonggi Research Articles

Ironware supply system of Silla Fortress in 6~7th century, Northern Gyeonggi province

Ironware supply system of Silla Fortress in 6~7th century, Northern Gyeonggi province

포트 재배에 의한 화약물질 오염토양 정화용 내오염성 식물 선정

ABSTRACT Nine plant species were selected through vegetation survey at three military shooting ranges at northern Gyeonggi Province.Plants were germinated in normal soil and three seedlings were transplanted to a bottom sealed pot containing sandy loamsoils contaminated with either RDX (291 mg/kg) or TNT (207 mg/kg). Planted, blank (without plant), and control (withoutexplosive compound) pots were grown in triplicate at a green house for 134 days. During cultivation, transplanted plantsexhibited chlorosis and necrosis in flower and leaf by explosive toxicity and stress. Only three plants, Wild soybean, Amursilver grass, Reed canary grass, survived in TNT treated pot, while seven plant species except for field penny cress andjimson weed, thrived in RDX treated pot. Appreciable amount of TNT (61.6~241.2 mg/g-D.W.) was detected only in plantroots. Up to 763.3 mg/g-D.W. along with 4-amino-2,6-dinitrotoluene, an intermediate of TNT, accumulated in the root ofwild soybean. In addition, azoxy compounds, abiotic intermediates of TNT, were detected in TNT treated soils. RDXabsorbed average 1,839.95 mg/kg in shoot and 204.83 mg/kg in root. Most of TNT in plant was accumulated in undergroundpart whereas RDX was localized in aerial part. Material balance calculation showed that more than 95% of the initial TNTwas removed in the planted pots whereas only 60% was removed in the blank pot. The amount of RDX removed fromsoil was in the order of Amur Silver Grass (51%) > Chickweed (43%) > Evening primrose (38%). Based on the results ofpot cultures, Amur silver grass and Reed canary grass are selected as tolerant remedial plants for explosive toxicity.Key words : Pot culture, Phytoremediation, RDX, TNT, Toxicity

Morphodynamics and stratigraphic architecture of compound dunes on the open-coast macrotidal flat in the northern Gyeonggi Bay, west coast of Korea

Abstract Simple and compound dunes are developed on the intertidal tributary channel and channel bank of Yeochari macrotidal flat in the northern Gyeonggi Bay, west coast of Korea. Dunes are asymmetrical with the majority of their steeper lee faces and master bedding surfaces dipping toward the ebb current direction. Dunes consist of cross-bedded medium to coarse sands with a coarsening-up trend. Channel banks are comprised of sand and mud flat facies association, while the tributary channel is composed of channel facies association including fluid muds and channel lags. Three-year morphodynamic observations revealed that simple dunes on the tributary channel migrate seaward as fast as 1.5–2 m per day. In contrast compound dunes on the southern channel bank migrate either landward or seaward at much slower rates of 2–3 m per month. Despite greater current speeds on the channel bank, smaller tidal asymmetry leads to slower migration of compound dunes. In the case of intense wave activity, however, compound dunes seem to migrate at a higher rate. During the study period, compound dunes continued to shift their location toward the northern channel bank direction as the tributary channel migrates laterally back and forth perpendicular to channel thalweg. Concurrent migration of compound dunes and the tributary channel produced a complicated stratigraphic architecture consisting of a point-bar succession overlain by a coarsening-up compound-dune succession. Master bedding surfaces of compound dunes dip in a nearly opposite direction to those of point-bar succession. Tidal asymmetry, wave intensity, discharge fluctuation that controls the migration of tributary channel, and the antecedent topography of resistant substrate are seen to exert an important control on the stratigraphic architecture of compound dunes and point bars in the intertidal environment.

Permo-Triassic and Paleoproterozoic metamorphism related to continental collision in Yangpyeong, South Korea

Gneisses and migmatites exposed in the Yangpyeong area in the northern Gyeonggi Massif provide insight into the Paleoproterozoic and Triassic metamorphic events in South Korea. Garnet–biotite gneiss and sillimanite–garnet–biotite gneiss in the western part of the area reveal Paleoproterozoic metamorphism (1888–1871 Ma) at P–T conditions of 760–820 °C and 8–10 kbar and 710–750 °C and 5–7 kbar, respectively. These rocks were overprinted by low-P/T type metamorphism (590–650 °C, 3–4 kbar) during the Triassic (ca. 237 Ma). In contrast, a cordierite-rich migmatite near the post-collisional Triassic igneous complex in the eastern part of the area was strongly metamorphosed during the Triassic (ca. 235 Ma) at 750–790 °C and 7–8 kbar. The similar Triassic ages in the western and eastern areas suggest that low-P/T type metamorphism occurred as a second stage of regional metamorphism, which is characterized by the production of cordierite with an irregularly shaped garnet. The metamorphic grade of the Triassic metamorphism decreases spatially towards the west from granulite facies to amphibolite facies metamorphic conditions, and the Paleoproterozoic metamorphism is well preserved in the western part with low grade Triassic metamorphism. The new discovery of the Triassic metamorphic event in the Yangpyeong area, in addition to the previously reported Triassic post-collision igneous event, supports the idea that the continental collision belt between the North and South China blocks extends from the Hongseong area into the Odesan area through the Yangpyeong area in South Korea.

Dose - response relationship between noise exposure and the risk of occupational injury.

Many workers worldwide experience fatality and disability caused by occupational injuries. This study examined the relationship between noise exposure and occupational injuries at factories in Korea. A total of 1790 factories located in northern Gyeonggi Province, Korea was evaluated. The time-weighted average levels of dust and noise exposure were taken from Workplace Exposure Assessment data. Apart occupational injuries, sports events, traffic accidents, and other accidents occurring outside workplaces were excluded. The incidences of occupational injury in each factory were calculated by data from the Korea Workers’ Compensation and Welfare Services. Workplaces were classified according to the incidence of any occupational injuries (incident or nonincident workplaces, respectively). Workplace dust exposure was classified as <1 or ≥1 mg/m3, and noise exposure as <80, 80-89, or >90 dB. Workplaces with high noise exposure were significantly associated with being incident workplaces, whereas workplaces with high dust exposure were not. The odds ratios (95% confidence intervals) derived from a logistic regression model were 1.68 (1.27-2.24) and 3.42 (2.26-5.17) at 80-89 dB and ≥90 dB versus <80 dB. These associations remained significant when in a separate analysis according to high or low dust exposure level. Noise exposure increases the risk of occupational injury in the workplace. Furthermore, the risk of occupational injury increases with noise exposure level in a dose-response relationship. Therefore, strategies for reducing noise exposure level are required to decrease the risk of occupational injury.

Paleoproterozoic magmatic and metamorphic events in the Hongcheon area, southern margin of the Northern Gyeonggi Massif in the Korean Peninsula, and their links to the Paleoproterozoic orogeny in the North China Craton

The Hongcheon area is located at the northern part of Gyeonggi Massif (NGM) in the Korean Peninsula. The metamorphic rocks of the NGM at the Hongcheon area are composed of the Paleoproterozoic Yongduri Gneiss Complex (YGC), Euiam Group (EG) and the Euiam Gneiss Complex (EGC). The quartz-feldspathic gneisses in the northeastern part of the YGC record peak metamorphic temperature–pressure condition of 790–840°C and 7.2–8.9kbar, whereas the granitic and garnet gneisses in the western part of the YGC record peak metamorphic temperature–pressure conditions of 690–720°C and 6.1–6.9kbar, and 640–660°C and 5.0–5.4kbar, respectively. The peak metamorphic conditions represent a regional low-P/T metamorphic event (M2) in which metamorphic temperature and pressures increased towards the east. SHRIMP zircon U–Pb age dating indicates that the M2 metamorphic stage occurred at ca. 1886–1870Ma. The presence of relict kyanite in the gneisses within the YGC suggests that the intermediate-P/T metamorphic stage (M1) occurred in ca. 1925Ma. Whole-rock geochemistry of the metagranitoid in the EGC indicates that they are originally post-collision granitoid. SHRIMP zircon U–Pb age dating indicates that the metagranitoid formed at ca. 1885–1869Ma. Considering the similarity in age between the Paleoproterozoic intrusion and the M2 low-P/T metamorphism, the M2 metamorphism also occurred in a post-collision tectonic setting and the M1 intermediate-P/T metamorphism with kyanite represents collision event. Further, we suggest that the Paleoproterozoic orogeny in the Hongcheon area is closely linked to the Paleoproterozoic orogeny in North Korea and the Jiao-Liao-Ji belt in the North China Craton.

Seasonal Abundance of Culicoides (Diptera: Ceratopogonidae) Collected by Mosquito Magnet® in Northern Gyeonggi-do (Province), Korea

Biting midges (Culicoides: Ceratopogonidae) were collected by Mosquito Magnet® traps at the Neutral Nations Supervisory Commission (NNSC) camp and Daeseongdong village inside the demilitarized zone (DMZ) and near the military demarcation line (MDL) separating North and South Korea and at Warrior Base (US Army training site) and Tongilchon 3 km south of the DMZ in northern Gyeonggi Province, Republic of Korea (ROK), from May-October 2010-2012, to determine their seasonal distributions. A total of 18,647 Culicoides females (18,399; 98.7%) and males (248; 1.3%) comprising 16 species were collected. Overall, the most commonly collected species was Culicoides nipponensis (42.9%), followed by C. erairai (29.2%), C. punctatus (20.3%), C. arakawae (3.3%), C. pallidulus (1.8%), and C. circumscriptus (1.4%), while the remaining 10 species accounted for only 1.1% of all Culicoides spp. collected. The seasonal distribution of C. nipponensis was bimodal, with high numbers collected during May-June and again during September. C. erairai was more frequently collected during June-July, followed by sharply decreased populations from August-October. C. punctatus was collected in low numbers from May-September with high numbers collected during October. C. erairai was predominantly collected from the NNSC camp (85.1% of all C. erairai collected) located adjacent to the MDL at Panmunjeom in the northernmost part of Gyeonggi-do (Province), while other sites yielded low numbers of specimens.

Clinical Characteristics of Vivax Malaria Outside Northern Gyeonggi Province Korea

Kwak et al. [1] published an article entitled Clinical Characteristics of Vivax Malaria and Analysis of Recurred Patients in Infection and Chemotherapy in March 2013. This well-written report detailed the clinical characteristics of patients residing in a malaria-endemic area of Korea. However, a limited number of areas in Korea are considered malaria-endemic [2, 3, 4]. Vivax malaria also occurs outside northern Gyeonggi province, particularly as a relapse after Plasmodium protozoa infection [5]. Therefore, physicians outside this province should not dismiss malaria, particularly during the transmission season. In Korea, epidemiologic characteristics may differ between patients residing outside and inside northern Gyeonggi province. Therefore, the data presented by Kwak et al. [1] may not represent the typical clinical characteristics of vivax malaria in Korea. As a result, we performed this study to document the epidemiological characteristics of patients diagnosed with vivax malaria outside of northern Gyeonggi province. We retrospectively reviewed the medical records of patients at 2 university-affiliated hospitals located in non-endemic areas who had been diagnosed with vivax malaria using a peripheral blood smear between January 2001 and December 2012. A total of 104 patients were enrolled in our study. The mean patient age was 24.9 ± 7.5 years (range, 21-55 years), and 99 (95.2%) were male. Vivax malaria cases were most common in August (30.8%, 32/104) and July (25%, 26/104). The mean time between symptom onset and hospital visit was 9.0 ± 5.8 days (range, 0-40 days). Four patients (3.8%) were active service soldiers and 78 (75%) had been discharged from military service within 5 years of their diagnosis. These discharged soldiers developed symptoms an average of 6.4 months (range, 0-40 months) after discharge. All soldiers included in this study served in the malaria-endemic northern parts of Gyeonggi province in Korea (Fig. 1). No discharged soldiers had served in Jeolla province. Fever and chills were presented in 103 (99.0%) and 96 patients (92.3%), respectively. A total of 68 patients (65.4%) reported an accompanying headache. Of common vivax malaria complications, only hypotension was present in 2 patients (1.9%). A total of 101 patients (97.1%) had thrombocytopenia (< 150,000 cells/mm3); among them, 29 (27.9%) presented with moderate to severe cases (< 50,000 cells/mm3). Anemia (hemoglobin < 12 g/dL) was present in 39 patients (37.5%), and 56 patients (53.8%) had abnormal liver function tests (Table 1). During the study period, 4 patients (3.8%) experienced recurrent vivax malaria episodes. Most of our study patients were discharged soldiers, and the majority of these developed malaria within the 12 months after military discharge (93.6%, 73/78). In addition, most cases (97.1%, 101/104) occurred between May and October, peaking in July and August, similar to peaks reported by the majority of previous studies [1, 6]. The mean patient age was lower than in the endemic area reported by Kwak et al. [1], and almost all of our study patients were male. Figure 1 Distribution of study patient residences. Triangles indicate residences of patients in this study, and circles indicate residences of patients from the study by Kwak et al [1]. Table 1 Clinical characteristics of 104 patients diagnosed with vivax malaria outside northern Gyeonggi province Korea In conclusion, most of the malaria cases occurred outside the northern part of Gyeonggi province; patients were mostly discharged soldiers in their mid-twenties; and the clinical characteristics, laboratory findings, recurrent rates, and complications associated with malaria were similar to those reported in an endemic area.

사회복지실습생이 경험하는 스트레스와 대처

본 연구의 목적은 보다 효과적인 실습교육체계 개선방안을 모색하기 위해 사회복지실습지도 현황과 학생들의 실습스트레스 및 대처를 파악하고, 실습지도에 따른 스트레스의 차이를 살펴보는 것이다. 이를 위해 2012년에 사회복지현장실습을 경험하고 수업을 수강한 서울 및 경기북부 4개 대학교 학생들을 대상으로 설문조사를 실시하였다. 202개 설문분석 결과, 실습생은 전문지식과 기술 부족, 실습환경, 실습업무부담 영역의 순으로 높은 스트레스를 보고하였고, 스트레스 대처전략에 있어서는 문제해결중심, 사회적지지 추구, 회피중심 전략 순으로 활용하였다. 실습경험에 따른 실습스트레스의 차이에 있어서는 현장체험 유무, 봉사시간, 실습사전교육 참여 유무에 따라, 그리고 슈퍼비전의 정기성과 빈도, 전공 만족도, 실습 및 슈퍼비전 만족도에 따라 차이를 보였다. 이상의 연구결과를 토대로 실습교육체계 개선방안을 제시하였다. The purpose of this study was to examine present condition of social work field education, students' stress/stress coping strategies in their field practicum, and to find out the difference according to the factors related field education. This study carried out a survey targeting 202 students who finished their social work field practicum and took their course work in 2012, from 4 different universities in the northern Gyeonggi province & Seoul. As the result, in the area of stress, the highest rank was the lack of professional knowledge/skills, the second was the environment of field practicum, and the third was the burden of tasks that they had to perform. About the coping strategies, it was found that students utilized 'problem-solving focused' the most, pursuing 'social support' as the second, and 'avoidance' strategies as the least. Factors influencing on differences of stress level depending on field work experiences were whether they had previous field experience, how much time they participated in previous volunteer activities, whether they attended orientation for their field practicum, regularity/frequency of supervision, the satisfaction on their social work/welfare major, and the satisfaction on their field practicum or supervision. Based on the results, suggestions for development in field education system were presented.

Comparison of Dragging and Sweeping Methods for Collecting Ticks and Determining Their Seasonal Distributions for Various Habitats, Gyeonggi Province, Republic of Korea

As part of the 65th Medical Brigade tick-borne disease surveillance program to determine the abundance, geographical and seasonal distributions, and tick-borne pathogens present in the Republic of Korea, dragging and sweeping methods were compared to determine their efficiency for collecting ticks in grass and deciduous, conifer, and mixed forest habitats at military training sites and privately owned lands in northern Gyeonggi Province near the demilitarized zone from April-October, 2004-2005. Three species of Ixodid ticks, Haemaphysalis longicornis, Haemaphysalis flava, and Ixodes nipponensis, were collected. Overall, H. longicornis adults and nymphs were most frequently collected from grass and deciduous forest habitats, accounting for 98.2 and 66.2%, respectively, of all ticks collected. H. flava adults and nymphs were most frequently collected from conifer and mixed forests, accounting for 81.6, and 77.8%, respectively, of all ticks collected. I. nipponensis adults and nymphs accounted for 9.3% of all ticks collected from mixed forests, were less commonly collected from deciduous (4.1%) and conifer (4.1%) forests, and infrequently collected from grass habitats (0.9%). Overall, there were no significant differences between dragging and sweeping methods for the three species when the areas sampled were similar (sweeping = 2 x the area over the same transect). Adults and nymphs of H. longicornis were most commonly collected from April-August, while those of H. flava and I. nipponensis were most commonly collected during April-July and again during October. Larvae of all three species were most frequently observed from July-September.

Globalism of Outbreak and Prevalence of Cattle Plague(Rinderpest) around Byengjahoran (1636-1638)

This study reviewed the outbreak and prevalence of cattle plague around Byeongjahoran from the perspective of international war in East Asia. First of all, the epidemiological characteristics of cattle plague in Manchuria where the outbreak of cattle plague was first reported around Byeongjahoran were analyzed. From the study, it was found the military activities that Sarhu (Qing) had made during the growth into Empire promoted the exchanges of various germs which became naturalized in the regions in Northeast Asia, and that such extreme situation as war made various diseases taken place and dispersed. In particular, because of military activities of Sarhu (Qing), various contagious diseases including smallpox which was prevalent in Inner-Mongolia and Shanxi became prevalent in Manchuria. During the contacts with Chosun after Jeongmyohoran, pathogen occurring Rinderpest was introduced into Manchuria. Favorable conditions for the interactions with various pathogens were provided by frequent contacts with wild animals through hunting and various cultivation groups composed of Manchurians, Mongolians, Han-Chinese and Chosun people. Rinderpest breaking in Chosun around Byeongjahoran was originated in Shenyang in 1636. It was transmitted to cattle in the Korean Peninsula and expanded to Kansai Region. At that time Rinderpest occurred and rapidly expanded in a specific area due to the interactions of pathogens, hosts and environments, and suddenly disappeared because of the extinction and the separation of hosts. It is consistent with the symptoms of modern times 'Rinderpest.' In Chosun it occurred in Pyeongan-do 4 months before the outbreak of Byeongjahoran and gave great damage on the capital area and northern Gyeonggi region. Because of the large scale migration of militaries after Byeongjahoran, Rindpest was expanded to Hasamdo and was terminated in February to April leaving big damages. The damages of Byeongjahoran were very severe. From the statistical records, it was found that the mortality rate in Gyenggi-do was around 2/3, around 50% in Jeju area. The mortality rate of infected cattle was around 75%. In some records based on individual cases, 80-100% of mortality rate was addressed. It is comparable to 25% of mortality in 1627, and is near or less than the mortality rate of Rinderpest in the 19th and 20the century. When analyzing the expansion of Rinderpest from the perspective of place, the most damaged places were areas near the busy roads or the places with dense population. Therefore, the remote places far from busy roads or separated from the affected places right after the outbreak did not have much damage. Additionally, rich stock-feeders had relatively small damages and poor households with 1 or 2 stokes were badly affected. The prevention and supply of medication by government made considerably positive effects on the prevention and treatment of Finderpest.

경기도 북부지역 젖소의 Neospora caninum 항체 양성률 조사

This study was carried out to investigate the seroprevalence of Neospora caninum infection in dairy cattle of northern Gyeonggi province in Korea. A total of 716 dairy cattle from 14 dairy farms were tested for the presence of antibodies against N. caninum using a commercial ELISA test kit. Herd and individual seroprevalences of N. caninum were 92.8% (13/14) and 23.1% (166/716), respectively. The seroprevalence of dairy cattle according to age was the highest at 49~72 months (27.4%), but the difference was not statistically significant (P>0.05). No significant relationship between N. caninum seropositivity with the herd size of the dairy farms was found (P>0.05). The results indicate that N. caninum infection spreads widely in dairy farms of northern Gyeonggi province in Korea.

경기도 북부지역 젖소 사육농장의 bovine leukemia virus 감염 실태 조사

This study was carried out to investigate the prevalence of bovine leukemia virus (BLV) infection and to compare the results of enzyme-linked immunosorbent assay (ELISA) and nested polymerase chain reaction (nPCR) in dairy farms in northern Gyeonggi province from August through December 2011. A total of 625 dairy cattle from 14 dairy farms were tested for antibodies against BLV using commercially available ELISA test kit. The overall seroprevalence of BLV infection was 76.3%. The seroprevalence of diary cattle according to age was the highest at 61~72 months (88.0%, P<0.001). Two hundred fifty one dairy cattle from 7 diary farms were tested ELISA and nPCR. The kappa value of BLV between ELISA and nPCR was 0.765. The results indicate that BLV infection spread widely in dairy farms and the nPCR is rapid method for the early detection of BLV infection.

원생대 이후 트라이아스기까지의 남한과 동북아시아의 지구조 진화

최근 송림 조산운동시기인 트라이아스기에 홍성 지역의 에클로자이트와 경기육괴 내에 광범위하게 나타나는 충돌 후 화성암이 형성되었음이 확인되었다. 이러한 새로운 발견에 의해 1980년대 말에 확인된 남중국판과 북중국판의 충돌대인 트라이아스기 친링-다비-수루 충돌대가 한반도의 홍성 지역으로 연결된 후 양평 지역을 거쳐 오대산 지역으로 연결되는 모델이 제시되었다. 그 이후 충돌대는 일본 서남부의 고생대 섭입 복합체와 북한의 고생대 섭입 복합체인 연변대로 연결될 가능성이 높다. 이럴 경우 경기육괴는 홍성-양평-오대산 충돌대를 경계로 나뉘어져야하며 충돌대 북부는 북중국판에 남부는 남중국판에 대비될 것이다. 남중국판과 북중국판의 충돌은 페름기에 한반도로부터 시작하여 중국 쪽으로 진행되었으며 트라이아스기 말에 충돌이 완료되었다. 다비-수루-홍성-양평-오대산 충돌대를 따라 동측에서 서측으로 변성조건이 체계적으로 변화한다. 가장 동측에 해당하는 오대산 지역에서는 245-230 Ma 초고온 변성작용이 한반도의 서측에 해당하는 홍성지역에서는 230Ma 고압변성작용이 그리고 중국의 수루, 다비 지역에서는 220Ma의 초고압 변성작용이 일어났다. 충돌대를 따라 나타나는 체계적인 변성조건의 변화는 충돌 전 섭입된 해양지각의 양이 동측에서 서측으로 증가하여 섭입하던 대륙판과 해양판의 분리되는 깊이가 동측에서 서측으로 점차 증가하였기 때문인 것으로 생각된다. 한반도 남부 영남육괴와 남중국판 남부에 광범위하게 나타나는 페름기-트라이아스기 섭입관련 화성암은 북중국판과 남중국판의 페름기-트라이아스기 충돌이 남중국판 남쪽 경계부에서의 섭입작용을 시작시켰을 가능성이 있음을 지시한다. 즉 한반도의 송림 조산운동 시기에는 경기육괴지역에서 대륙충돌이 일어나 한반도가 형성되었으며 동시에 대륙충돌에 의해 영남육괴 남측에 섭입대를 형성되었을 것으로 예상된다. 홍성-양평-오대산 충돌대를 경계로 하여 경기육괴 북부와 남부는 모두 콜롬비아 초대륙 형성 후기인 1870-1840 Ma에 대륙충돌이나 섭입 작용에 의해 화성 및 변성작용을 강하게 받았다. 옥천 변성대는 중국 남중국판 내에 나타나는 760Ma 경에 형성된 난후아 열곡대에 대비될 수 있으며 그럴 경우 경기육괴 남부와 영남육괴는 각각 남중국판의 북부 양쯔판과 남부 커테시아판에 대비된다. 최근 경기육괴 변성퇴적암, 옥천변성대 등에서 광역적으로 발견되는 실루리아기-데본기의 쇄설성 저어콘은 경기육괴 내에 데본기 혹은 그 이후 고생대 시기의 퇴적암이 존재할 가능성을 제시하고 있으며 홍성과 광천 지역에서 확인된 데본기의 변성작용과 함께 페름기-트라이아스기의 대륙충돌 이전인 고생대 중기에도 경기육괴에 활발한 지구조 운동이 일어났음을 지시한다. Recent studies reveal that eclogite formed in the Hongseong area and post collision igneous rocks occurred throughout the Gyeonggi Massif during the Triassic Songrim Orogeny. These new findings derive the tectonic model in which the Triassic Qinling-Dabie-Sulu collision belt between the North and South China blocks extends into the Hongseong-Yangpyeong-Odesan collision belt in Korea. The belt may be further extended into the late Paleozoic subduction complex in the Yanji belt in North Korea through the Paleozoic subduction complex in the inner part of SW Japan. The collision belt divides the Gyeonggi Massif into two parts; the northern and southern parts can be correlated to the North and South China blocks, respectively. The collision had started from Korea at ca. 250 Ma and propagated to China. The collision completed during late Triassic. The metamorphic conditions systematically change along the collision belt:. ultrahigh temperature metamorphism occurred in the Odesan area at 245-230Ma, high-pressure metamorphism in the Hongseong area at 230 Ma and ultra high-pressure metamorphism in the Dabie and Sulu belts. This systematic change may be due to the increase in the depth of slab break-off towards west, which might be related to the increase of the amounts of subducted ocecnic slab towards west. The wide distribution of Permo-Triassic arc-related granitoids in the Yeongnam Massif and in the southern part of the South China block indicate the Permo-Triassic subduction along the southern boundary of the South China block which may be caused by the Permo-Triassic collision between the North and South China blocks. These studies suggest that the Songrim orogeny constructed the Korean Peninsula by continent collision and caused the subduction along the southern margin of the Yeongnam Massif. Both the northern and southern Gyeonggi Massifs had undergone 1870-1840 Ma igneous and metamorphic activities due to continent collision and subduction related to the amalgamation of Colombia Supercontinent. The Okcheon metamorphic belt can be correlated to the Nanhua rift formed at 760 Ma within the South China blocks. In that case, the southern Gyeonggi Massif and Yeongnam Massif can be correlated to the Yangtz and Cathaysia blocks in the South China block, respectively. Recently possible Devonian or late Paleozoic sediments are recognized within the Gyeonggi Massif by finding of Silurian and Devonian detrital zircons. Together with the Devonian metamorphism in the Hongseong and Kwangcheon areas, the possible middle Paleozoic sediments indicate an active tectonic activity within the Gyeonggi Massif during middle Paleozoic before the Permo-Triassic collision.

Japanese Encephalitis Virus in Culicine Mosquitoes (Diptera: Culicidae) Collected at Daeseongdong, a Village in the Demilitarized Zone of the Republic of Korea

In total, 22,846 (17,793 culicines and 5,053 Anopheles spp.) female mosquitoes were captured by a Mosquito Magnet trap at Daeseongdong, a small village adjacent to the military demarcation line (center of the demilitarized zone) in northern Gyeonggi Province, Republic of Korea (ROK). Culicine mosquitoes were identified to species, placed in pools of up to 30 mosquitoes each, and screened for flavivirus using a SYBR Green I-based real-time polymerase chain reaction. In total, 51/660 pools positive for flaviviruses and confirmed by DNA sequencing of the NS5 region, were positive for Japanese encephalitis virus (family Flaviviridae, genus Flavivirus, JEV) (50 Culex tritaeniorhynchus Giles and one Culex bitaeniorhynchus Giles). The JEV maximum likelihood estimations (MLEs) (estimated number of viral RNA-positive mosquitoes per 1,000) for Cx. tritaeniorhynchus and Cx. bitaeniorhynchus were 9.7 and 0.9, respectively. This is the first report of a Cx. bitaeniorhynchus positive for JEV in the ROK. JEV is a local civilian and military health threat and a significant concern for nonimmune (unvaccinated) U.S. soldiers, civilians, and family members deployed to the ROK.

Distribution and larval habitats of Anopheles species in northern Gyeonggi Province, Republic of Korea

A total of 180 larval collection sites (e.g., rice paddies, marshes, ground pools, ponds, stream margins, and irrigation and drainage ditches) was surveyed within a 2 km radius from Warrior Base training area, 5 km south of Panmunjeom (Joint Security Area, demilitarized zone), Gyeonggi Province, Republic of Korea (ROK), from May through October, 2007 to characterize larval habitat distributions of members of the Anopheles Hyrcanus Group (An. sinensis, An. lesteri, An. pullus, An. belenrae, An. kleini, and An. sineroides). A total of 5,859 anopheline larvae was collected from 84.4% of the sites surveyed, of which 4,071 were identified to species by polymerase chain reaction (PCR) using the ribosomal DNA internal transcribed spacer 2 (rDNA ITS2). Anopheles sinensis (52.6%) was the most frequently collected, followed by An. kleini (29.4%), An. sineroides (9.8%), An. pullus (6.7%), An. belenrae (1.1%), and An. lesteri (0.5%). Anopheles pullus and An. kleini were collected in greater proportions in May and from May - July, respectively. Few An. sinensis were collected from May - June, but it was the predominant species collected by August, and accounted for >80% of all larvae from September - October. Anopheles kleini was found in all habitats sampled; however, it was collected most frequently in young growth rice paddies, while An. sinensis was collected more frequently in mature and post-harvest paddies. Anopheles pullus was associated with pre-cultivated rice paddies, including water-filled tire ruts left from the previous fall's harvest.

Surveillance of vivax malaria vectors and civilian patients for malaria high‐risk areas in northern Gyeonggi and Gangwon Provinces near the demilitarized zone, Republic of Korea, 2003–2006

AbstractAfter re‐emergence of malaria in 1993, a continued increase in Plasmodium vivax cases was observed from 1993 to 2006 in northern Gyeonggi and Gangwon Provinces adjacent to the demilitarized zone separating North from South Korea. Annual parasite incidence per 1000 people ranged from 0.33 in 2004 to 0.89 in 2006. While malaria case rates declined (22.6%) in 2004, they increased 75.1% in 2005 and 51.7% in 2006 from the previous years. An initial incorrect diagnosis of 46.8% of malaria cases as common cold resulted in a mean delay of 1.3 days for the detection malarial parasites. Of the total cases, 10.2% from December to May were due to latent intrinsic incubation infections acquired the previous malaria season and the rest of the cases from June to November were either latent or short incubation infections. Overall, the peak anopheline population occurred from July to September, resulting in a similar peak in malaria cases. While malaria cases increased during 2005–2006, anopheline populations, based on trap indices, were not significantly different during 4 years of surveillance. To decrease the malaria patient infective period to mosquitoes, public health centers in Paju and Cheorwon in 2006 prescribed chloroquine + primaquine at days 0–3 after initial malaria diagnosis followed by an additional 11 days of primaquine (early primaquine treatment), rather than chloroquine on days 0–3 and primaquine on days 4–17 (delayed primaquine treatment). A reduction in the malaria parasite incidence during 2007 was recorded for the two locations offering the early primaquine treatment relative to other locations using the delayed primaquine treatment.

DETECTION OF RICKETTSIA TYPHI AND SEASONAL PREVALENCE OF FLEAS COLLECTED FROM SMALL MAMMALS IN THE REPUBLIC OF KOREA

Fleas were collected from live-captured small mammals to identify potential flea-borne pathogens, seasonal prevalence of flea species, and host preference as part of the US military rodent-borne diseases surveillance program conducted at one US military installation and 10 military training sites, northern Gyeonggi Province, Republic of Korea. During 2003-04, 948 fleas (563 females and 385 males) were recovered from 2,742 small mammals (seven rodent and one insectivore species). Apodemus agrarius (striped field mouse) accounted for 88.9% (2,439/2,742) of the small mammals, followed by Crocidura lasiura (4.2%), Mus musculus (2.9%), Microtus fortis (2.2%), Myodes regulus (0.6%), Micromys minutus (0.5%), Tscherskia triton (0.5%), and Rattus norvegicus (0.3%). Small mammal infestation rates (number with fleas/number captured) ranged from 7.7% (M. minutus and T. triton) to 31.3% (M. regulus). Flea indices were highest for M. regulus (0.69/captured rodent), followed by C. lasiura (0.54), M. fortis (0.41), A. agrarius (0.34), and R. norvegicus (0.33). Overall, Ctenophthalmus congeneroides (51.3%) was more frequently collected, followed by Stenoponia sidimi (42.6%), Rhadinopsylla insolita (5.5%), Neopsylla bidentatiformis (0.4%), Rhadinopsylla concava (0.1%), and Doratopsylla coreana (0.1%). Ctenophthalmus congeneroides was more frequently collected from small mammals during the spring and summer, while S. sidimi was more frequently collected during the winter season. Rickettsia typhi, the causative agent of murine typhus, was detected in 3.2% of specimens (7/220 pools from 654 fleas; minimum field infection rate [number of positive pools/total number of fleas] was 1.1%).

Records of Ixodes pomeranzevi Serdyukova, 1941 (Acari: Ixodidae) from small mammals in northern Gyeonggi and Gangwon Provinces, Republic of Korea

During 2008, small mammals were captured and examined for ticks at Chipori (Gangwon Province) and Nightmare (Gyeonggi Province) Ranges near the Demilitarized Zone, Republic of Korea (ROK). Ixodes nipponensis Kitaoka and Saito (75 nymphs, 835 larvae) was collected from Apodemus agrarius (Pallas), Micromys minutus (Pallas), and Crocidura lasiura Dobson, while Ixodes pomeranzevi Serdyukova (2 females, 4 nymphs) was collected only from A. agrarius. Separately, I. pomeranzevi (15 females, 5 nymphs, 24 larvae) was collected from Tamias sibiricus (Laxmann) near Bidulginang Falls (Gyeonggi Province). This is the first record of I. pomeranzevi from Apodemus agrarius in the ROK.

&lt;I&gt;Anopheles kleini&lt;/I&gt;, &lt;I&gt;Anopheles pullus&lt;/I&gt;, and &lt;I&gt;Anopheles sinensis&lt;/I&gt;: Potential Vectors of &lt;I&gt;Plasmodium vivax&lt;/I&gt; in the Republic of Korea

Anopheles sinensis Wiedemann (63.3%) was the most abundant Anopheles mosquito captured at cowshed resting collections in malaria high-risk areas (northern Gyeonggi Province) near the demilitarized zone (DMZ) in Korea during 2005, followed by Anopheles kleini Rueda (24.7%) and Anopheles pullus M. Yamada (8.7%). At cowshed resting collections in malaria low-risk areas (Jeonnam and Gyeongnam provinces), An. sinensis accounted for 96.8% of all Anopheles spp. collected, followed by An. kleini Rueda (2.7%), whereas no An. pullus were collected. Three species, An. kleini (50.9%), An. pullus (29.0%), and An. sinensis (13.8%), accounted for nearly all of the 224 Anopheles spp. captured by New Jersey light trap near the DMZ. In addition, An. pullus and An. kleini captured by New Jersey light trap near the DMZ and assayed by enzyme linked immunosorbent assay for Plasmodium vivax circumsporozoite antigen concentrations were higher than An. sinensis sensu stricto (s.s.), indicating higher levels of sporozoites. In laboratory studies of four concurrent artificial membrane feedings on malaria-infected blood from patients, F1 progeny of An. kleini and An. pullus had higher infection rates (8.8 and 7.5%, respectively) than An. sinensis s.s. (4.2%). These data suggest that An. kleini and An. pullus and An. sinensis are vectors of malaria in Korea. Further studies are required to determine the role of these species in the transmission of P. vivax in the Republic of Korea.