• Parasites, Hosts and Diseases
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• v.51 no.1
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• pp.107-114
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• 2013

Fishborne trematode (FBT) metacercariae were investigated in fish from 3 Provinces of Lao PDR. Total 242 freshwater fish of 40 species were collected in local markets of Luang Prabang (59 fish of 16 species), Khammouane (81 fish of 19 species), and Saravane (97 fish of 14 species), and each of them was examined by artificial digestion method. Four species of metacercariae (Opisthorchis viverrini, Haplorchis taichui, Haplorchis yokogawai, and Centrocestus formosanus) were detected. O. viverrini was detected in 35 fish (14.5%), and their density was 252 per infected fish (Luang Prabang, 88 metacercariae in 5 fish; Khammouane, 187 in 6 fish; Saravane, 303 in 24 fish). H. taichui was found in 102 fish (42.1%), and their density was 485 per infected fish (Luang Prabang, 260 metacercariae in 38 fish; Khammouane, 1,084 in 23 fish; Saravane, 359 in 41 fish). H. yokogawai was detected in 92 fish (38.0%), and their density was 222 per infected fish (Luang Prabang, 362 metacercariae in 17 fish; Khammouane, 126 in 20 fish; Saravane, 214 in 55 fish). Metacercariae of C. formosanus were found in 8 fish (3.3%), and their density was 3 per infected fish. In the present study, it has been confirmed that FBT metacercariae, in particular, H. taichui, H. yokogawai, and O. viverrini, are highly prevalent in fish from Luang Prabang, Khammouane, and Saravane Province, Lao PDR.

• Parasites, Hosts and Diseases
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• v.47 no.1
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• pp.25-29
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• 2009

Paragonimus harinasutai metacercariae were found in a species of freshwater crab, Indochinamon ou, collected in a small stream of Namback District, Luang Prabang Province, Lao PDR. Adult flukes were recovered after experimental infection of the metacercariae to dogs. Metacercariae were round or slightly elliptical, $0.666{\times}0.626\;mm$ in average size, and had a thin cyst wall of about $20{\mu}m$ in thickness, a black excretory bladder, convoluted ceca, and some pinkish materials in the body. Adults were somewhat elongated, $95.2{\times}36.5\;mm$ in average size, covered with single-tipped tegumental spines, had a smaller oral sucker than the ventral sucker, a moderately branched ovary, and 5-6 lobulated testes. Eggs were ovoid and bilaterally symmetrical in shape, $79{\times}45{\mu}m$ in average size, and had a uniformly thickened shell. By the present study, it has been confirmed that I. ou is a new second intermediate host for P. harinasutai.

• Korean Journal of Plant Resources
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• v.25 no.3
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• pp.357-362
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• 2012

The potential cultivation of buckwheat species in Luang Prabang region, Lao PDR where the species has not been naturally grown and not traditionally utilized was studied to introduce buckwheat as a new agricultural material, especially for food and medicine. The growth of Tartary buckwheat species was higher than common buckwheat showing 2.3 fold of plant height compared to common buckwheat. Number of flower per plant in Tartary buckwheat (731) was three fold higher than common buckwheat (244). Dry weight per plant was respectively 1.7 g in Suwon No. 1, 2.6 g in Suwon No. 2, and 1.4 g in KW45. The rate average of seed setting was similar between common buckwheat (41 to 46 %) and Tartary buckwheat (44%). Total seed yield of Tartary buckwheat (184 kg/10 a) in 10a could be estimated to be higher than that of common buckwheat (108 kg/10 a).

• Parasites, Hosts and Diseases
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• v.51 no.2
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• pp.259-263
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• 2013

Human taeniasis was investigated in Lao People's Democratic Republic (Lao PDR) between 2000 and 2011 as part of the nation's helminthiasis survey. A total of 55,038 inhabitants, including 29,846 school children, were examined using the Kato-Katz and scotch-tape anal swab method, and morphological observation of adult worms. Molecular identification of Taenia tapeworms was performed by multiplex PCR or DNA sequence analysis of the mitochondrial cox1 gene. Taenia eggs were present at a rate of 1.5% (845/55,038) in the subject population. Adult tapeworms were identified as T. solium or T. saginata by analyzing the collectable stool specimens (n=126). Three specimens identified as T. solium were found in Luang Prabang, while the remaining 123 specimens, which were T. saginata, were found in Bokeo, Bolikhamxay, Champasak, Houaphan, Khammouane, Luang Namta, Luang Prabang, Oudomxay, Phongsaly, Saysomboune, Saravane, Savannakhet, Xayaboury, Xekong, Xieng Khouang Province, and Vientiane Municipality.

• Korean Journal of Remote Sensing
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• v.10 no.1
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• pp.43-53
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• 1994

By Using MOS-1 satellite image(taken on 24 April 1990, after slash and burn), Shifting cultivation areas were estimated for the sub-basin area. In tropical region to analyse the correlation between shifting cultivation rate and bifurcation rate network which was calculated from topographic map, PC Arc - Info and IDRISI GIS software were used. As the distribution rate of shifting cultivation increases, the bifurcation rate is high. From the correlation analysis between the shifting cultivation and drainage network, it was found that shifting cultivation leads to land degradation and head erosion at the stream valley. To prevent such problems, it is mecessary that shifting cultivation areas should be converted to permanent paddy fields.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.1
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• pp.19-23
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• 2014

Here, we studied the genetic diversity of native fowls in Laos by analyzing a mitochondrial DNA (mtDNA) sequence polymorphism. A 546-bp fragment of the mtDNA D-loop region was sequenced in 129 chickens from the areas of Vientiane, Luang Prabang and Pakse. In total, 29 haplotypes were identified and formed five clades. Haplotype diversity and nucleotide diversity of the native fowls in Laos were $0.85536{\pm}0.0172$ and $0.010158{\pm}0.005555$, respectively. Although the Laotian native fowls were distributed across five clades, most of them were clustered in two main clades (A and B), which were originated in China. The other haplotypes were contained in clades D, F, and I, which originated from continental southeast Asia. These results suggest that multiple maternal lineages were involved in the origin of domestic chicken in Laos. Moreover, there appear to be at least two maternal lineages, one from China and the other from the southeast Asian continent.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.194-194
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• 2022

정확한 강우-유출 해석은 하천 홍수예경보, 댐 유입량 산정 및 방류량 결정 등 수자원 관리 및 계획수립에 있어 중요하며 밀도높은 관측망(raingauge network)으로 부터 수집된 강우 자료는 강우-유출 해석의 가장 중요한 기초 자료로 활용된다. 본 연구 대상 지역인 메콩강 유역은 국가공유하천(6개국: 중국, 라오스, 태국, 미얀마, 베트남, 캄보디아)은 기초 자료 수집이 어렵고, 구축된 자료의 양적, 질적 품질이 국가별로 상이하여 수문해석 결과의 불확실성을 높일 우려가 있다. 최근 원격탐사 기술의 발달로 격자형 글로벌 강수자료의 획득이 용이해졌으며, 이를 활용한 다양한 연구들이 수행된 바 있다. 이에 본 연구에서는 준 분포모형인 SWAT (Soil & Water Assessment Tool) 모형을 활용하여 격자형 위성 강수 자료(TRMM, GSMaP, PERSIANN-CDR)와 격자형 지점 강수 자료(APHRODITE, GPCC)의 메콩강 유역 강우-유출 모의에 대한 성능을 평가하였다. 유출량 산정을 위한 관측소로는 Luang Prabang, Pakse, Stung Treng, Prek Kdam 관측소를 선정하였으며 지점강수량 정보가 비교적 충분한 2000-2007년을 대상으로 매개변수 보정(2000-2003) 및 유출모의 검증(2004-2007)을 수행하였다. 격자형 강우를 이용한 유출분석 결과, APHRODITE, GPCC 및 TRMM이 다른 격자형 강수 자료(GSMaP, PERSIANN-CDR)보다 우수한 성능을 보였다.

• Parasites, Hosts and Diseases
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• v.52 no.1
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• pp.51-56
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• 2014

The prevalence of helminthic infections was surveyed on a total of 6,178 residents (males 2,549 and females 3,629) in 102 villages of 9 provinces in Lao PDR between 2007 and 2011 under the project of Korea-Laos Collaborative Project for Control of Foodborne Trematode Infections in Lao PDR. Fecal specimens were collected and examined by the Kato-Katz thick smear and Stoll's egg counting techniques. The overall liver/intestinal helminth egg positive rate was 71.9% with a single or mixed infections with Opisthorchis viverrini and minute intestinal flukes (Ov/MIF), Ascaris lumbricoides, hookworms, Trichuris trichiura, Trichostrongylus sp., echinostomes, Taenia spp., and others. Ov/MIF revealed the highest prevalence (55.6%) followed by hookworms (27.8%) and T. trichiura (6.5%). The endemic regions with the highest prevalence of Ov/MIF were Savannakhet, Khammouane, Vientiane (Nam Ngum), Champasak (Khong Island), and Saravane Province. High prevalences of A. lumbricoides (33.8%), hookworms (47.8%), and T. trichiura (32.6%) were observed in Phongsaly, Luang Prabang, and Vientiane (Nam Ngum) areas, respectively. The results of this study highlight helminth parasites of current public health significance in different areas of Lao PDR.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.65-65
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• 2023

최근 기후변화로 인해 홍수, 가뭄 등 수재해가 세계 곳곳에서 빈번하게 발생하고 있다. 이로 인해 정확한 강우-유출 해석의 중요도는 높아지고 있으며 강우-유출 해석에 따라 수자원 관리 및 계획수립의 정도가 달라질 수 있다. 본 연구 대상 지역인 메콩강 유역은 중국과 동남아시아 5개국(라오스, 태국, 미얀마, 베트남, 캄보디아)을 관통하는 국가공유하천으로 기초자료의 획득이 어렵고 국가별로 구축된 자료가 질적, 양적 품질이 상이하여 수문해석에서의 기초자료로 사용하기에 불확실성이 있다. 최근 기술의 발달로 글로벌 격자형 강수자료 획득이 용이함에 있어 미계측 대유역에서의 다양한 연구들이 수행되고 있지만, 지점강수자료와 시·공간적 오차로 인한 불확실성을 내포하고 있다. 이에 본 연구에서는 글로벌 격자형 강수자료의 적용성을 평가하기 위하여 지점 격자형 강수자료(APHRODITE)와 4개의 위성강수자료(CHIRPS, CMORPH, PERSIANN-CDR, TRMM)를 수집하고 합성곱 신경망 모형인 ConvAE 기법을 이용하여 위성강수자료의 시·공간 편의 보정을 수행하였다. 또한, 하천 수위에 대한 장기간 정보 수집이 가능한 메콩강 본류 4개 관측소(Luang Prabang, Pakse, Stung Treng, Kratie)를 선정하였으며 SWAT 모형을 이용하여 매개변수 보정(2004~2013)과 격자형 강수자료의 보정 전·후의 유출모의(2014~2015) 결과를 비교·분석하였다. 격자형 강우를 이용한 보정 및 유출 분석 결과 4개의 위성강수자료 모두 성능이 향상되었으며 그 중 보정된 TRMM이 가장 우수한 성능을 보여 해당 유역에서의 APHRODITE를 대체할 수 있다고 판단하였다. 따라서 본 연구에서 제시하는 ConvAE를 이용한 보정기법과 이를 이용한 강우-유출 해석은 향후 다양한 격자형 강수자료를 활용한 미계측 대유역에서의 수문해석에서 활용이 가능할 것으로 판단된다.

• Journal of Korea Water Resources Association
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• v.56 no.2
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• pp.75-89
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• 2023

As the Mekong River basin is a nationally shared river, it is difficult to collect precipitation data, and the quantitative and qualitative quality of the data sets differs from country to country, which may increase the uncertainty of hydrological analysis results. Recently, with the development of remote sensing technology, it has become easier to obtain grid-based precipitation products(GPPs), and various hydrological analysis studies have been conducted in unmeasured or large watersheds using GPPs. In this study, rainfall-runoff simulation in the Mekong River basin was conducted using the SWAT model, which is a quasi-distribution model with three satellite GPPs (TRMM, GSMaP, PERSIANN-CDR) and two GPPs (APHRODITE, GPCC). Four water level stations, Luang Prabang, Pakse, Stung Treng, and Kratie, which are major outlets of the main Mekong River, were selected, and the parameters of the SWAT model were calibrated using APHRODITE as an observation value for the period from 2001 to 2011 and runoff simulations were verified for the period form 2012 to 2013. In addition, using the ConvAE, a convolutional neural network model, spatio-temporal correction of original satellite precipitation products was performed, and rainfall-runoff performances were compared before and after correction of satellite precipitation products. The original satellite precipitation products and GPCC showed a quantitatively under- or over-estimated or spatially very different pattern compared to APHPRODITE, whereas, in the case of satellite precipitation prodcuts corrected using ConvAE, spatial correlation was dramatically improved. In the case of runoff simulation, the runoff simulation results using the satellite precipitation products corrected by ConvAE for all the outlets have significantly improved accuracy than the runoff results using original satellite precipitation products. Therefore, the bias correction technique using the ConvAE technique presented in this study can be applied in various hydrological analysis for large watersheds where rain guage network is not dense.