Vientiane Capital Research Articles

Impact of Land Use Change on the Water Environment of a Key Marsh Area in Vientiane Capital, Laos

The water environment is critical to maintaining ecosystem balance and human well-being globally. It is essential to comprehend the effects of land use change on water quantity and quality for sustainable development of the urban environment. Expansion of urban areas leads to intensified human activity and increased pollution loads in natural waterbodies. This study aimed to monitor changes in land use over a span of two decades to evaluate the condition of the water environment in That Luang Marsh (TLM). The land use and land cover (LULC) classes, including agricultural land, bare land, built-up land, vegetation, waterbody, and wetland, were categorized via Landsat images utilizing the maximum likelihood algorithm. A digital elevation model was used to estimate the water surface area and volume, and the nutrient delivery ratio model was employed to analyze nutrient distribution across the LULC classes. The results showed that from 2001 to 2020, the bare land, built-up, waterbody, and wetland areas increased by 29.92, 18.64, 0.87, and 0.16 times, respectively, while the agricultural and vegetation land decreased by 0.80 and 0.76 times, respectively. A binary logistic regression model for influential factors implies that road network expansion within the special economic zone in TLM could result in an increase in residential areas, thereby impacting the LULC classes. The increase in water volume showed a robust correlation with the expansion of built-up land, bare land, and waterbody. TLM had an average nitrate-nitrogen export of 317 tons/year with a 95% confidence interval of (56, 770) tons/year in 2020. The distribution over LULC classes affected the export, which varied dynamically. Vegetation land had the highest nitrate-nitrogen load of 0.57 tons/ha/year, probably due to poorly managed use of fertilizers. The developed land surface for an artificial lake could lead to an increase in the water volume, which could be involved in the dilution of nutrient concentration. Therefore, it is crucial to prioritize policies that aim to establish sustainable urban water environments through rational urban planning and by making LULC management a primary consideration, especially for developing countries undergoing similar processes of urbanization along the Mekong River in Southeast Asia.

Wastewater Treatment using The Photosynthetic Bacteria at Parksarp Village, Xaythany District, Vientiane Capital

Untreated waste water from the piggery farm will damage the environment and society, if, it is discharged to environment, in particular, direct impact on surrounding communities. The propose of the research is to investigate the characteristics and efficiency of the photosynthetic bacteria in employing on wastewater treatment systems. The experiment is designed and simulated the stabilization tank system that includes: an aerobic tank, sedimentation (excess sludge) tank, clear water tank and all tanks are used the same size of 50 liters, wastewater from a piggery farm was introduced into the treatment tank with a dry matter ratio 5% of the total water mass. Therefore, BOD5, COD, TSS, TKN, and pH were made prior to entering the treatment tank, photosynthetic bacteria is added 200 ml per week, detention time 7 days and after 25 days of treatment. The experiment found that, BOD5, COD, TSS, TKN concentrations reduce continuously from 366 mg/l - 192 mg/l (47.54%), 90,000 mg/l - 4,000 mg/l (95.56 %), 30 mg/l - 7 mg/l (76.67%) and 3.92 mg/l - 0.08 mg/l (97.96%), respectively.

The Concepts of Women's Empowerment in Child Malnutrition Programs in Luangprabang Province, Lao People's Democratic Republic.

In several developing countries, such as Lao People's Democratic Republic (Lao PDR), the fight against malnutrition is carried out through programs that involve collaboration between internal (national) and external (international) actors. These actors may have different perceptions on what is one of the pillars of these programs: the empowerment of women, especially mothers of young children. Little is known about these differences and the impact of these differences on the empowerment component of collaborative projects and the perception of its impact on the reduction in malnutrition in the country. A multiple case study was performed. Data collection was carried out in Vientiane Capital and Luangprabang province. The data were obtained from (1) documents, (2) semi-structured interviews with representatives of internal and external organizations, and (3) focus group discussions and individual interviews with mothers of children under five years old. Analysis consisted of characterizing the empowerment component of nutrition programs of internal and external organizations, as well as mothers, based on an OXFAM's adapted conceptual framework on women's economic empowerment. The study revealed a common understanding among government and external organizations regarding the significance of promoting women's empowerment for reducing child malnutrition in Lao PDR. However, variations were observed in the interpretation of specific determinants of women's empowerment, specifically in relation to women's autonomy and the role of social capital. The perspective of internal actors includes the political ideology and traditions that make Lao PDR a distinct country. This perspective dominates the nutrition programs conducted under the collaboration of internal and external actors. In Lao PDR, the concept of women's empowerment in nutrition programs conducted through collaboration between internal and external actors and targeting young Lao mothers gives prominence to political and socio-cultural factors.

Risk Assessment of Microplastics Dispersion and Accumulation in Urban Canals to the Water Environment in Vientiane Capital, Laos

Risk Assessment of Microplastics Dispersion and Accumulation in Urban Canals to the Water Environment in Vientiane Capital, Laos

Impact of Biomedical Waste on the Lao Community Environment: A Case Study of Vientiane Capital, Laos

Impact of Biomedical Waste on the Lao Community Environment: A Case Study of Vientiane Capital, Laos

Water Quality Assessment in Hong Xeng Channel, Vientiane Capital

In the capital Vientiane, households, communities and factories discharge wastewater into the Hong Xeng canal, which flows into the Thatluang wetland, where it ends up in the Mak Heiw stream and falls into the Mekong River. Water quality assessment is an excellent factor in indicating the existing water condition. Therefore, the aim of this study was to investigate and collect water samples at 3 locations (P1, P2, and P3) to understand the status of water quality, and analyze 12 water samples of the Hong Xeng Canal and also compare the findings with past data by standard. Methods Data was collected and analyzed in the laboratory for two months from 25 August 2008 to 6 October 2008. The results showed that the temperature was 28°C - 31.1°C, Nitrate ion (NO3-) was 3.2 mg/l - 46 mg/l, pH 5.9-6.6, electrical conductivity 87 µS/cm - 283 µS/cm, Total Suspended Solid (TSS) 22 mg/l -78 mg/l and CODMn 5.5 mg/l - 10 ,9mg/l. Therefore, these parameters are recognized and substandard. While turbidity was 42 NTU -78 NTU, BOD5 4.5 mg/l - 9.1 mg/l, Dissolved Oxygen (DO) 9.1 mg/l - 10.6 mg/l and Phosphate (PO43-) 0.05 mg/l - 0.25 mg/l. this parameter is higher concentration and above standard.

Intestinal helminth infections and associated risk factors among adults in the Lao People’s Democratic Republic

BackgroundHelminthiases are highly endemic in Southeast Asia, including the Lao People's Democratic Republic (Lao PDR). This study aimed to assess the current intestinal helminth infections and the associated risk factors among adults across the Lao PDR.MethodsA cross-sectional survey was conducted in 165 villages across 17 provinces and the Vientiane Capital, Lao PDR. A multi-stage sampling method was employed to select the adult study participants (≥ 18 years). Data collection included (1) interview of the study participants, (2) physical measurements, and (3) a five gram of stool sample from each study participant was collected and preserved in 10% formalin solution for intestinal helminth detection using formalin-ether concentration technique (FECT). Descriptive analysis was used to describe the socio-demographic characteristics of study participants and the prevalence of intestinal helminth infections. Logistic regressions were applied to test the association between intestinal helminth infection and individual risk factors. A P-value below 0.05 was considered statistically significant.ResultsA total of 2800 study participants were enrolled. Their average age was 46.0 years; 57.8% were female. Overall, 30.9%, 8.6% and 1.5% of study participants were infected with one, two, or three different intestinal helminth species, respectively. Among the study participants 21.6% were infected with hookworm, 18.8% with Opisthorchis viverrini-like (Ov-like) infection, 4.8% with Strongyloides stercoralis, 2.3% with Ascaris lumbricoides, 1.5% with Trichuris trichiura, and 3.3% with Taenia spp. Ov-like infection was of high prevalence in the southern (28.8%) and central (21.3%) provinces, while hookworm (26.3%), A. lumbricoides (7.3%), T. trichiura (3.1%), and Taenia spp. (4.2%) were prevalent in the northern provinces. Risk analysis showed that men were more likely to be infected with hookworm [adjusted odds ratio (aOR) = 1.2, P = 0.019]. The Lao-Tai ethnic group had a 5.2-times (P < 0.001) higher chance of having Ov-like infection than the minorities. Possession of toilet facility at home was associated with reduced odds for Ov-like (aOR = 0.4, P < 0.001) and hookworm (aOR = 0.6, P < 0.001) infections.ConclusionsOur study provides a nationwide update of the intestinal helminth prevalence among adults in Lao PDR. To the best of our knowledge, this is the first Lao nationwide survey on intestinal helminth infections and risk factors in adults. It provides crucial information for national control programs for intestinal helminth infections in Lao PDR.Graphical abstract

Grill workers and air pollution health effects from charcoal combustion in Vientiane capital

Introduction: Grilled street foods are popular in urban communities in Lao People's Democratic Republic (Lao PDR). Charcoal is the main fuel used for, posing a risk of elevated exposure to toxic pollutants. This study explored levels of cooking-related pollutants from grilled food business and workers’ health effects.&#x0D; Materials and methods: A quantitative approach using multiple techniques was conducted during March and April 2022 in Vientiane Capital, Lao PDR. Methods included pollutant emission estimation from charcoal-combusting grill shops/street-carts and Particulate Matter (PM2.5) measurement, and examined the exposure and health effects among grill workers. Multiple sampling techniques were applied to identify study samples. Respiratory symptoms were the health effect of interest among grill workers.&#x0D; Results: Estimated emission of pollutants was over 75 tons/year from grill shops. Average PM 2.5 level was 84.8 μg/m3 (21.6 - 254.8 μg/m3); which i above standard limits. A very high level of PM2.5 was found in grill markets. Most grill workers were female, worked 6-7 days/week, at least 8 h/day. Factors contributing to the presence of respiratory symptoms among grill workers were female gender, low income, indoor grilling, more years of grill-work, experience of intense smoke-cough, self-reliance on health and cigarette smoking.&#x0D; Conclusion: Grilling contributes to ambient air pollution, posing potential adverse environmental and public health impacts. Grill workers are likely to be exposed to high levels of all forms of air pollutants from street food grilling. Effective strategies are required to better protect grill workers from the effect of exposure to these harmful toxins and minimize the negative impacts on their health.

Flood Analysis Using Multi-Scale Remote Sensing Observations in Laos

Heavy rains usually hit Laos countrywide and cause serious floods, influencing local agriculture, households, and the economy. Therefore, it is crucial to monitor the flooding in Laos to better understand the flood patterns and characteristics. This paper aims to analyze the influence of the flooding in Laos with multi-source data, e.g., Synthetic Aperture Radar (SAR), optical multi-spectral images, and geographic information system data. First, the flood areas in Laos from 2018 to 2022 are detected using a decision fusion method. Based on the flood areas and the global Land Use/Land Cover (LULC) product, the macro scale global impact of the flood is analyzed. Second, taking the Vientiane Capital as a case study area, a flood forecasting method is applied to estimate the risk of flooding. Finally, optical images before and after the flood event are extracted for a close-up comparison at the micro scale. Based on the above multi-scale analysis, floods in Laos are found to be predominantly concentrated in the flat areas near the Mekong River, with a decreasing trend over time, which could be helpful for flood management and mitigation strategies in Laos. The validation results exhibited notable average indices across a five-year period, with mIoU (0.7782), F1 score (0.7255), and overall accuracy (0.9854), respectively.

Industrial entrepreneur’s perception of greenhouse gas emission and its impact in Vientiane Capital, Lao PDR

Laos ranked 8th in terms of total greenhouse gas emissions among ASEAN countries, with 17.9 million metric tons of carbon dioxide equivalent (MtCO2e) emissions. The energy sector was responsible for the majority of emissions, accounting for about 50% or 8.9 MtCO2e, followed by the agriculture sector at around 35% or 6.3 MtCO2e, and other sectors at approximately 15% or 2.7 MtCO2e (The Global Carbon Atlas reported, 2018). This study investigates greenhouse gas emissions and environmental issues among industrial entrepreneurs in Vientiane Capital, Lao PDR. Data was collected by using questionnaires and face-to-face interviews were conducted with participants from 80 different plants in Vientiane Capital between January 25 and March 20, 2018. It identifies various environmental problems caused by industrial plants, emphasizing the need for specific pollution source mitigation and sustainable waste management. The study reveals significant impacts on health and living conditions, highlighting the urgency for proactive measures. Climate variations, alterations in seasons, and intensified storms are identified as major contributors to violence levels. Strategies proposed by entrepreneurs include accurate measurement methods, pollution treatment systems, improved power efficiency, renewable energy adoption, an environmental protection organization, and efficiency enhancements in logistics and transportation. The study emphasizes the role of government, plant owners, and the general population in addressing CO2 emissions through collective efforts. Overall, it provides valuable insights and calls for proactive measures, stakeholder engagement, and diverse strategies for sustainability in Vientiane Capital and Laos.

The Perceived Relationship between Eco-friendly Business Practices and Firm Performance of SMEs in Vientiane Capital, Lao PDR

This study investigates the impact of environmental performance on firm profitability in Vientiane Capital, Lao PDR. Data from 419 firms were collected using an e-questionnaire distributed through a Google form. The results indicate a need to increase awareness and acknowledgment of clean activities among surveyed firms. While there is a positive trend towards energy-saving practices and the provision of designated smoking areas, more efforts are required to encourage the wider adoption of reusable practices and prioritize proper waste management. Regression analysis reveals significant impacts on firm profitability, with firms having regulations for environmentally friendly practices, acknowledging clean activities, providing free space for waste sorting or disposal, and having designated smoking areas experiencing notable increases in profitability. However, the impact of energy-saving policies on profitability is not significant, potentially due to insufficient implementation. The study recommends implementing and enforcing effective energy-saving policies, strengthening eco-friendly regulations, encouraging waste management and recycling practices, and catering to customer preferences to enhance firm financial performance. These measures can contribute to a more sustainable and environmentally responsible business landscape in Vientiane Capital, Lao PDR.

Factors influencing the practice of commercial rice production for food security in Vientiane capital, Laos

Rice is viewed as an indicator of food security and poverty reduction, but many rural areas of Laos still face rice insufficiency. Dealing with the problem requires transitioning from traditional farming to commercial production using modern techniques. This study aimed to investigate the factors influencing the adoption of commercial rice production for local food security and poverty reduction. The survey included 70 samples in the Namxouang irrigation development area of Vientiane Capital, Laos, using a questionnaire for secondary and primary data collection. Both descriptive and inferential statistics were employed to describe the collected data and analyze factors influencing commercial rice production. The findings revealed that 65.7%, 18.6%, and 15.7% of the respondents engaged in commercial, semi-commercial, and subsistence rice production, respectively. In addition, it also found that land size, labor costs, and machinery costs each had a significant positive relationship with the practice of commercial rice production at a statistical significance level of 0.01. At the same time, household size, media perception, and annual income had significant negative relationships with the practice of commercial rice production at significance levels of 0.01 and 0.05. Therefore, high-quality rice varieties, new rice production techniques, and rice production groups are needed to support farmers using the same technical practices to obtain similar yields. Moreover, regulations are required to control chemical use and manage paddy land. These changes would help achieve the government policy to promote smart farming and good agricultural practice for food security and poverty reduction.

A Six Years (2010–2016) Longitudinal Survey of the Four Serotypes of Dengue Viruses in Lao PDR

Dengue fever is the most prevalent arthropod-borne viral infection of humans in tropical and subtropical countries. Since 1979, dengue has been reported to be endemic in the Lao People's Democratic Republic (PDR), as in many countries in Southeast Asia, with a complex circulation of the four dengue viruses' serotypes (DENV-1 to DENV-4). By sequencing the complete envelope protein, we explored a panel of samples from five Lao Provinces (Vientiane capital, Luangprabang, Bolikhamxay, Saravane, Attapeu) to enrich knowledge about the co-circulation of DENVs in Lao PDR between 2010 and 2016. Phylogenetic analyses highlighted the specific circulation of DENV-1 genotype I, DENV-2 genotype Asian I, DENV-4 genotype I and the co-circulation of DENV-3 genotype II and III. The continuous co-circulation of the four serotypes was underlined, with genotype or cluster shifts among DENV-3 and DENV-1. These data suggested the emergence or re-emergence of DENV strains associated with epidemic events, potentially linked to the exchanges within the territory and with neighboring countries. Indeed, the increasing local or regional connections favored the dissemination of new isolates or new clusters around the country. Since 2012, the surveillance and alert system created in Vientiane capital by the Institut Pasteur du Laos appears to be a strategic tool for monitoring the circulation of the four serotypes, especially in this endemic country, and allows for improving dengue epidemiological knowledge to anticipate epidemic events better.

Knowledge and Practice Regarding The Administration Of the Pentavalent Vaccine Among Health Care Workers In Vientiane Capital, Lao PDR: A Mixed Method Approach

Knowledge and practice regarding the administration of the pentavalent vaccine among health care workers in Vientiane Capital, Lao PDR: A mixed method approach Abstract Background: The pentavalent vaccine is an essential, cost-effective public health measure to reduce preventable premature child mortality and childhood mobility and contributes to lowering the spread of vaccine-preventable diseases. The aim of this study is to assess the knowledge and practice of providing pentavalent vaccines and its related factors among health care workers (HCWs). Method: This was a cross-sectional analytical study, using the qualitative and quantitative methods. The study was conducted in nine district hospitals and 33 health centers in Vientiane Capital. In total, 184 health care workers were involved in the study and in-depth interviews were conducted with 12 HCWs. Descriptive and inferential statistics were applied to determine the factors associated with the knowledge and the practice of pentavalent vaccines. A thematic analysis was applied to the qualitative data. Results: The results showed that more than half (63.3%) had poor knowledge of the pentavalent vaccine, while about two thirds (65.7%) reported good practices for delivering the pentavalent vaccine. In the multiple logistic regression, significant factors associated with the knowledge of the pentavalent vaccine were the qualification of HCWs (AOR=2.6, 95% CI=1.1 – 6.3, p=0.030), receiving training on vaccines (AOR=3.4, 95% CI=1.7 – 6.8, p&lt;0.001), and incentives of working for vaccination programmes (AOR=2.7, 95% CI=1.2 – 6.1, p=0.020). The qualitative study revealed the need to improve supply-side determinants including increased training to improve the health staff’s competency, knowledge and practice of immunization. Conclusion: The data from this research indicated that more than half of the HCWs had poor knowledge about the pentavalent vaccine, despite vaccination practice being relatively good. There was a correlation between improved knowledge, with those HCWs who had higher education, and received training and incentives. These findings demonstrate there is a need for more efficient training and the continuous education of HCWs in the field of immunization. Keywords: Pentavalent vaccine, health care workers, knowledge and practice, Lao PDR.

Factors influencing the decision to purchase mackerel products from Si Vieng Thong Cold Room in Vientiane Capital, Lao PDR

The purpose of this research is to examine the elements that influence people's decisions to purchase mackerel products from Si Vieng Thong Cold Room in Vientiane Capital, Lao PDR. The sample group was 400 people. Use questionnaires as a tool to collect data. Descriptive statistics were used to describe general information and buying behavior, and inferential statistics through the Logit Model were used to study the variables influencing the purchase of mackerel products. The study's findings revealed that most of the sample groups were females, between the ages of 21 and 40, with a bachelor's degree and a monthly wage ranging from less than 20,001 to 30,000 Baht. The reason for consuming mackerel the most is its delicious taste. Most forms of consumption require cooking first. The amount of consumption per person is about 1-2 baskets, with a frequency of about 2 weeks to consume mackerel. The time of consumption was mostly in the evening. In terms of the marketing mix (4 Ps), it was at a high level. As for the variables influencing the decision to buy mackerel products, age (AGE), income (INC), and marketing mix (4 Ps) were statistically significant.

Low Transmission of Chikungunya Virus by Aedes aegypti from Vientiane Capital, Lao PDR

In 2012−2013, chikungunya virus (CHIKV) was the cause of a major outbreak in the southern part of Lao People’s Democratic Republic (Lao PDR). Since then, only a few imported cases, with isolates belonging to different lineages, were recorded between 2014 and 2020 in Vientiane capital and few autochthonous cases of ECSA-IOL lineage were detected in the south of the country in 2020. The CHIKV epidemiological profile contrasts with the continuous and intensive circulation of dengue virus in the country, especially in Vientiane capital. The study’s aim was to investigate the ability of the local field-derived Aedes aegypti population from Vientiane capital to transmit the Asian and ECSA-IOL lineages of CHIKV. Our results revealed that, for both CHIKV lineages, infection rates were low and dissemination rates were high. The transmission rates and efficiencies evidenced a low vector competence for the CHIKV tested. Although this population of Ae. aegypti showed a relatively modest vector competence for these two CHIKV lineages, several other factors could influence arbovirus emergence such as the longevity and density of female mosquitoes. Due to the active circulation of CHIKV in Southeast Asia, investigations on these factors should be done to prevent the risk of CHIKV emergence and spread in Lao PDR and neighboring countries.

Opportunities and challenges for pig production in Vientiane Capital, Laos

In Laos, pork is the second most common meat source after fish and its demand is constantly growing annually. Recently, pork has been in short supply in urban and rural areas, forcing the Lao government to import thousands of tons from neighbouring countries, particularly Thailand, Vietnam, and China. In view of the earlier-mentioned, this study aimed to look at the current situation of pork production and supply in Vientiane Capital (VC) and the prospects for pork production in VC, Laos. In 2020, Laos had a pig population of about 4.3 million, with over 91.0% being native pigs and only 366,000 heads being European pig types, with over 54.0% being reared in VC. In 2019, Laos had 578 commercial pig farms, with 188 farms (33.0%) of which were located in VC. Despite the fact that most of the commercial pig farms are located in VC, pork demand is still high, with the consequence that consumers need to pay a high price. For example, in 2020, the average price of pork was 46,000 LAK/kg ($ 4.00); it rose up by 22.0% against 2019 and by 11.0% from 2015. Several feed raw materials (maize, cassava, and rice bran) are produced in VC, and nearby provinces, which the farmers can use to combat the dramatic changes or instabilities of feed price. We concluded that there is a high potential to develop pig production in VC, especially local breeds considering the high demand for premium pork and more available raw feed materials.

Land use/land cover changes in the period of 2015–2020 in AngYai Village, Sikhottabong District, Vientiane Capital, Lao PDR

In this study, land use/land cover (LULC) changes were identified in AngYai Village, Sikhottabong District, Vientiane Capital, Laos, from 2015 to 2020 using the Geographic Information System (GIS) and remote sensing (RS). Topographic maps and Google Earth Pro satellite imagery data were used with ArcGIS 10.8 software to map land use fluctuations. The study area was classified into the six main types of LULC (agricultural, builtup, forest, main roads, waste land, and water bodies) based on field research, geographical conditions, and RS data. The results indicated sizeable increases in the built-up, main roads, and especially waste land areas over the study period. The forest and agricultural land areas decreased during the study period, possibly due to increased urbanization rates, nomadic cultivation, and indiscriminate deforestation in the study area. The river area was affected by the construction of hydroelectric dams and by the climate, leading to the drying up of water sources and causing water body areas to decrease to some extent.

Orientia tsutsugamushi in Chiggers and Small Mammals in Laos.

Background: Scrub typhus is a leading cause of febrile illness in Laos and accounts for a high burden of disease. There have been no previous studies on the causative agent, Orientia tsutsugamushi, in vector mites ("chiggers") or their small mammal hosts in Laos. Materials and Methods: Small mammals and free-living chiggers were trapped in districts of Vientiane Province and Capital. Tissues were tested for O. tsutsugamushi by PCR and serum for IgG to O. tsutsugamushi by immunofluorescence assays (IFAs). Chiggers removed from small mammals and collected in their free-living stage using black plates were identified and tested for O. tsutsugamushi by PCR. Results: Over an 18-month period, 131 small mammals of 14 species were collected in 5 districts. Seventy-eight of 131 small mammals were infested with chiggers, but all tissues were O. tsutsugamushi PCR negative. Eighteen species of chigger were identified and 1,609 were tested by PCR. A single pool of chiggers tested O. tsutsugamushi positive. Sera from 52 small mammals were tested by IFA, with 16 testing positive. Conclusions: These are the first molecular and serological data on O. tsutsugamushi in chiggers and small mammals in Laos. Further studies are needed to better understand the key vector species and ecology of scrub typhus in areas with high disease incidence in Laos.

Species status of populations of Lethocerus indicus (Lepeletier and Serville, 1825) (Heteroptera: Belostomatidae) in Southeast Asia

The giant water bug, Lethocerus indicus (Lepeletier & Serville, 1825), is an aquatic true bug that has been included in the Vietnam Red Data Book since 1992 (“ca-cuong” in Vietnamese, “maeng-da” in Laos and Thailand). This insect also has been listed as an endangered species in Japan, Laos, and South Korea. This study aimed to (1) perform a genetic analysis to determine the species status of various populations of L. indicus in Southeast Asia, and (2) initially survey their distribution in Vietnam and Laos. Four populations were collected: two from the Vientiane Capital and Savannakhet Province areas of Laos, and two from the Vinh Phuc and Long An areas of Vietnam, respectively. Cytochrome oxidase subunit I (COI) fragments longer than 600 bps were amplified by polymerase chain reaction (PCR). Twelve nucleotide polymorphisms were found among these four populations. A maximum likelihood tree based on COI showed that the genetic distances among populations were very small, ranging from 0.2% to 1.1%, and were substantially distant from other populations of Lethocerus. Therefore, they are all considered to be conspecific and to represent L. indicus.