Crop booms as regime shifts.

A crop boom is a sudden, nonlinear and intense expansion of a new crop. Despite their large impacts, boom-bust dynamics are not well understood; booms are largely unpredictable and difficult to steer once they unfold. Based on the striking resemblances between land regime shifts and crop booms, we apply complex systems theory, highlighting the potential for regime shifts, to provide new insights about crop boom dynamics. We analyse qualitative and quantitative data of rubber and banana plantation expansion in two forest frontier regions of northern Laos. We show that preconditions, including previous booms, explain the occurrence (why) of booms, and triggers like policy and market changes explain their timing (when). Yet, the most important features of booms, their intensity and nonlinearity (how), strongly depended on internal self-reinforcing feedbacks. We identify built-in feedbacks (neighbourhood effects and imitation) and emergent feedbacks (land rush) and show that they were social in nature, multi-scale from plot to region and subject to thresholds. We suggest that these are regular features of booms and propose a definition and causal-mechanistic explanation of crop booms, examining the overlap between booms and regime shifts and the role of frontiers. We then identify opportunities for management interventions before, during and after booms.

Viscoelastic Reversibility of Carrageenan Hydrogels under Large Amplitude Oscillatory Shear: Hybrid Carrageenans versus Blends.

The viscoelastic response of carrageenan hydrogels to large amplitude oscillatory shear (LAOS) has not received much attention in the literature in spite of its relevance in industrial application. A set of hybrid carrageenans with differing chemical compositions are gelled in the presence of KCl or NaCl, and their nonlinear viscoelastic responses are systematically compared with mixtures of kappa- and iota-carrageenans of equivalent kappa-carrageenan contents. Two categories of LAOS response are identified: strain softening and strain hardening gels. Strain softening gels show LAOS non-reversibility: when entering the nonlinear viscoelastic regime, the shear storage modulus G' decreases with increasing strain, and never recovers its linear value G0 after successive LAOS sweeps. In contrast to this, strain hardening carrageenan gels show a certain amount of LAOS reversibility: when entering the nonlinear regime, G' increases with strain and shows a maximum at strain γH. For strains applied below γH, G0 shows good reversibility and the strain hardening behavior is maintained. For strains larger than γH, G0 decreases significantly indicating an irreversible structural change in the elastic network. Strain hardening and elastic recovery after LAOS prevail for hybrid carrageenan and iota-carrageenan gels, but are only achieved when blends are gelled in NaCl, suggesting a phase separated structure with a certain degree of co-aggregated interface for mixed gels.

A new species of Nesolotis Miyatake, 1966 (Coccinellidae, Coccinellinae, Sticholotidini) from Laos.

Background: Nesolotis Miyatake, 1966 shows a high diversity in the Oriental Realm. New information: Here, we recorded this genus in Laos for the first time and provided a detailed description of a new species, namely Nesolotislaotica Lv & Wang, sp. nov.

Assessment of Erythrocyte Transketolase, Whole Blood Thiamine Diphosphate, and Human Milk Thiamine Concentrations to Identify Infants and Young Children Responding Favorably to Therapeutic Thiamine Administration: Findings from the Lao Thiamine Study, a Prospective Cohort Study.

Background: There is limited information on relationships among biomarkers of thiamine status (whole blood thiamine diphosphate [ThDP], erythrocyte transketolase activity coefficient [ETKac], and human milk thiamine [MTh]) and clinical manifestations of thiamine deficiency. Objectives: This study aimed to explore correlations among these biomarkers and thiamine responsive disorders (TRDs), a diagnosis based on favorable clinical response to thiamine. Methods: Hospitalized infants and young children (aged 21 d to <18 mo) with respiratory, cardiac, and/or neurological symptoms suggestive of thiamine deficiency were treated with parenteral thiamine (100 mg daily) for ≥3 d alongside other treatments and re-examined systematically. Clinical case reports were reviewed by 3 pediatricians, who determined TRD or non-TRD status. Children in a community comparison group were matched by age, sex, and residence. Venous whole blood ThDP and MTh were determined by high-performance liquid chromatography fluorescence detection and ETKac in washed erythrocytes by ultraviolet spectrophotometry. Associations between biomarkers were assessed using Spearman correlations, and biomarker cutoffs predictive of TRD and ETKac >1.25 were explored using area under the receiver operating characteristic curve framework. Results: Thiamine biomarkers were available for 287 hospitalized children and 228 community children (mean age 4.7 mo; 59.4% male). Median (interquartile range [IQR]) ThDP and ETKac were 66.9 nmol/L (IQR: 41.4, 96.9 nmol/L) and 1.25 nmol/L (IQR: 1.11, 1.48 nmol/L), respectively, among hospitalized children, and 64.1 nmol/L (IQR: 50.0, 85.3 nmol/L) and 1.22 nmol/L (IQR: 1.12, 1.37 nmol/L) among 228 community children (P > 0.05 for both). Forty-five percent of breastfeeding mothers of infants <6 mo had MTh <90 µg/L. ThDP and ETKac, but not MTh, were significantly different between 152 children with TRD and 122 without TRD, but overlapping distributions undermined prediction of individual responses to thiamine. Conclusions: Although ETKac, ThDP, and MTh are useful biomarkers of population thiamine status, none of the biomarkers reliably identified individual children with TRD. ThDP is more practical for population assessment because preparing washed erythrocytes is not required.This trial was registered at clinicaltrials.gov as NCT03626337.

Effect of particle stiffness and surface properties on the non-linear viscoelasticity of dense microgel suspensions.

HYPOTHESIS: Particle surface chemistry and internal softness are two fundamental parameters in governing the mechanical properties of dense colloidal suspensions, dictating structure and flow, therefore of interest from materials fabrication to processing. EXPERIMENTS: Here, we modulate softness by tuning the crosslinker content of poly(N-isopropylacrylamide) microgels, and we adjust their surface properties by co-polymerization with polyethylene glycol chains, controlling adhesion, friction and fuzziness. We investigate the distinct effects of these parameters on the entire mechanical response from restructuring to complete fluidization of jammed samples at varying packing fractions under large-amplitude oscillatory shear experiments, and we complement rheological data with colloidal-probe atomic force microscopy to unravel variations in the particles' surface properties. FINDINGS: Our results indicate that surface properties play a fundamental role at smaller packings; decreasing adhesion and friction at contact causes the samples to yield and fluidify in a lower deformation range. Instead, increasing softness or fuzziness has a similar effect at ultra-high densities, making suspensions able to better adapt to the applied shear and reach complete fluidization over a larger deformation range. These findings shed new light on the single-particle parameters governing the mechanical response of dense suspensions subjected to deformation, offering synthetic approaches to design materials with tailored mechanical properties.

Investigation of Escherichia coli isolates from pigs and humans for colistin resistance in Lao PDR- a cross-sectional study.

Background: In Laos, colistin is not currently registered for use in humans. This One Health study aimed to estimate the prevalence of meat-producing pigs carrying colistin-resistant Escherichia coli, and investigate if E. coli causing invasive human infections were colistin-resistant. Methods: Between September 2022 and March 2023, rectal swabs were collected from 895 pigs from abattoirs in 9/17 Lao provinces. Pig rectal swabs and stored E. coli isolates from human blood cultures, submitted to Mahosot Hospital Microbiology laboratory between 2005 and 2022, were screened for colistin resistance on selective chromogenic agar with organism identification confirmed using MALDI-TOF MS. Suspected colistin-resistant isolates underwent colistin susceptibility testing by broth microdilution following European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. Isolates with MIC values of ≥2 µg/ml were tested for plasmid-mediated colistin resistance genes (mcr-1, mcr-2, and mcr-3) by multiplex SYBR Green PCR. Results: A total of 15/620 (2.41%) invasive human E. coli isolates were phenotypically colistin-resistant by broth microdilution (MIC values 4 to 8 µg/ml). The earliest isolate was from 2015 in a patient from Phongsaly province in Northern Laos. A total of 582/895 (65.02%) pig rectal swab samples contained colistin-resistant E. coli. The detected colistin resistance genes were predominantly mcr-1 (57.8%, 346/598), followed by mcr-3 (20.23%,121/598), and 22.24% (133/598) were found to co-harbour mcr-1 and mcr-3. Among the 15 human isolates with colistin MIC values of ≥4 µg/ml, 12/15 were mcr-1. Conclusions: We found that colistin resistant E. coli is causing invasive infection in humans in Laos despite the fact it is not available for human use. Use in animals seems to be widespread, confirmed by high carriage rates of colistin-resistant E. coli in pigs. It is probable that food-producing animals are the source of colistin-resistant E. coli bloodstream infection in Laos, although these have been infrequent to date. This is a serious public health concern in the region that needs to be addressed by appropriate enforceable legislation.

Enhancing the nonlinear rheological property and digestibility of mung bean flour gels using controlled microwave treatments: Effect of starch debranching and protein denaturation.

In this study, we examined the possibility of using industrial microwave processing to enhance the gelling properties and reduce the starch digestibility of mung bean flour (MBF). MBF (12.6 % moisture) was microwaved at a power of 6 W/g to different final temperatures (100-130 °C), and then its structural and functional properties were characterized. The microwave treatment had little impact on the crystalline structure or amylose content of the starch, but it roughened the starch granule surfaces and decreased the short-range ordered structure and degree of branching. In addition, the extent of mung bean protein denaturation caused by the microwave treatment depended on the final temperature. Slightly denaturing the proteins (100 °C) did not affect the nature of the gels (protein phase dispersed in a starch phase) but the gel network became more compact. Moderately denaturing the proteins (110-120 °C) led to more compact and homogeneous starch-protein double network gels. Excessive protein denaturation (130 °C) caused the gel structure to become more heterogeneous. As a result, the facilitated tangles between starch chains by more linear starch molecules after debranching, and the protein network produced by moderate protein denaturation led to the formation of stronger gel and the improvement of plasticity during large deformation (large amplitude oscillatory shear-LAOS). Starch recrystallization, lipid complexion, and protein network retard starch digestion in the MBF gels. In conclusion, an industrial microwave treatment improved the gelling and digestive properties of MBF, and Lissajous curve has good adaptability in characterizing the viscoelasticity of gels under large deformations.

Epidemiological characteristics of human infections with avian influenza A(H5N6) virus, China and Laos: A multiple case descriptive analysis, February 2014-June 2023.

Background: The first human infection with highly pathogenic avian influenza A(H5N6) virus was reported in 2014. From then until June 30, 2023, 85 human cases with confirmed A(H5N6) infection have been reported worldwide. Objective: To address the present gap in knowledge of the overall epidemiology of human A(H5N6) infections, the epidemiological characteristics of human infection with A(H5N6) in China from February 2014 to June 2023 are described. Methods: Considering the severity of human infections with A(H5N6) virus (case fatality rate: 39%), the increased frequency of case reports from 2021 to present day, and lack of comprehensive epidemiologic analysis of all cases, we conducted a multiple-case descriptive analysis and a literature review to create an epidemiologic profile of reported human cases. Case data was obtained via a literature search and using official intelligence sources captured by the Public Health Agency of Canada's International Monitoring and Assessment Tool (IMAT), including Event Information Site posts from the World Health Organization. Results: Most human A(H5N6) cases have been reported from China (China: 84; Laos: 1), with severe health outcomes, including hospitalization and death, reported among at-risk populations. The majority (84%) of cases reported contact with birds prior to illness onset. Cases were detected throughout the course of the year, with a slight decrease in illness incidence in the warmer months. Conclusion: As A(H5N6) continues to circulate and cause severe illness, surveillance and prompt information sharing is important for creating and implementing effective public health measures to reduce the likelihood of additional human infections.

Factors associated with hepatitis B vaccination in Laos: findings from the multiple indicator cluster surveys in 2011/12 and 2017.

Background: Within Laos, the vaccination coverage rates with the monovalent hepatitis B birth dose vaccine and hepatitis B antigen-containing combination vaccines remain stagnant with 75% and 64%, respectively, in 2021. In this study, we used data from the Multiple Indicator Cluster Surveys to identify possible factors that represent barriers for receiving these childhood vaccinations. Methods: Data from the Multiple Indicator Cluster Surveys in 2011/12 and 2017 were analysed to examine factors associated with receiving the hepatitis B-containing vaccines using regression modelling. Data analyses were conducted in R. Findings: In 2011/12, the weight-adjusted coverage rate for receiving the hepatitis B birth dose was 48%, while the coverage with the hepatitis B antigen-containing combination vaccine was 55.1% based on both vaccination documents and recall; compared to 69.3% and 59.4% respectively in 2017. Ethno-linguistic group, maternal education, healthcare utilization and wealth were associated with receiving the vaccinations against hepatitis B. Interpretation: National estimates of vaccination coverage rates can conceal country-specific regional or socio-economic variations. Children from Hmong-Mien households, from less wealthier households and whose mothers were less educated and were not able to or did not utilize healthcare were identified as being less likely to receive the vaccinations. These findings indicate the need for improving access to healthcare, in particular for minority groups. Funding: This work was supported by the Ministry of Foreign and European Affairs, Luxembourg and the Luxembourg Institute of Health (project "Luxembourg-Laos Partnership for Research and Capacity Building in Infectious Disease Surveillance").

Measuring Occupational Well-Being Indicators: Scale Construction and Validation.

The purpose of this study is to carry out the scale development of occupational well-being (OWB) (affective, professional, social, cognitive, psychological and psychosomatic well-being) in Laos. Using multiple sampling data, we developed a valid OWB scale with a large Laotian sample (n = 1745). The validity of the OWB-47 scale was analyzed using exploratory factor analysis (EFA). Cross-validity, the initial model, and confirmatory factor analysis (CFA) were performed using Stata 19 to assess the validity of the scale development. Consistent with the valid model, the CFA revealed a unidimensional structure in the OWB scale. The initial measurement of the OWB scale was significantly correlated with the measure of the six-dimensional model. Regarding the full model testing, the CFA model was developed to test the validity of the OWB-47 scale, suggesting the acceptability of the fit model.

Burkholderia pseudomallei Bacteria in Ornamental Fish Tanks, Vientiane, Laos, 2023.

In 2019, a melioidosis case in Maryland, USA, was shown to have been acquired from an ornamental fish tank contaminated with Burkholderia pseudomallei bacteria, likely derived from Southeast Asia. We investigated the presence of B. pseudomallei in ornamental fish tanks in the endemic area of Vientiane, Laos.

Prospects for the development of community-based care in remote rural areas: a stakeholder analysis in Laos.

BACKGROUND: Community-based health programmes have been a cornerstone of primary care in Laos for decades. The study presented here aimed to document prospects for the development of current programmes, considering perceptions about health and health care priorities in the communities, implementation challenges, the policy landscape and opportunities associated with the availability of new technologies. METHODS: The research design primarily involved qualitative in-depth interviews with stakeholders (n = 35) responsible for the planning, management, or implementation of community-based care in Laos at different levels of the health system. These included health managers at central departments or institutes of the Ministry of Health, provincial health departments, district health offices, heads of health centres, village health volunteers, community representatives, and international stakeholders. RESULTS: There was consensus that service delivery is still a challenge in many areas, due to geographic inaccessibility of health facilities, communication barriers, health-seeking behaviour, trust, and gender discrimination, particularly among ethnic minorities. In these settings, community health workers have the potential to extend the reach of the formal health system, acting as cultural brokers across sectors of society, ethnicities, and worldviews. To maximise impact, planners need to carefully consider the implementation model, financing arrangements, health system integration, and changing health priorities in the communities. CONCLUSIONS: This study examined challenges to, and opportunities for, the expansion and health system integration of community-based care in Laos. Further development and horizontal integration of community-based care remains a complex financing and governance challenge, although the renewed emphasis on primary care and the ongoing process of decentralisation provide a favourable policy environment in the country to sustain and potentially expand existing programmes.

Risk factors for anaemia among women and their young children hospitalised with suspected thiamine deficiency in northern Lao PDR.

Anaemia among women and young children remains a major public health concern. This secondary study describes the anaemia prevalence among young hospitalised children and their mothers in northern Lao People's Democratic Republic and explores possible nutritional causes and risk factors for anaemia. Hospitalised children (ages 21 days to <18 months) with clinical symptoms suggestive of thiamine deficiency disorders were eligible along with their mothers. Venous blood was collected for determination of haemoglobin, ferritin, soluble transferrin receptor (sTfR), retinol-binding protein (RBP), erythrocyte glutathione reductase activation coefficient (EGRac), thiamine diphosphate (ThDP) and acute phase proteins. Risk factors for anaemia were modelled using minimally adjusted logistic regression controlling for age. Haemoglobin results were available for 436 women (mean ± SD age 24.7 ± 6.4 years; 1.6% pregnant) and 427 children (4.3 ± 3.5 months; 60.3% male). Anaemia prevalence (Hb < 120 g/L for nonpregnant women and <110 g/L for pregnant women and children) was 30.7% among women and 55.2% among children. In bivariate analyses, biomarkers significantly associated with anaemia in women were ferritin, sTfR, RBP, EGRac and ThDP. Other risk factors for women were lower BMI, mid-upper arm circumference < 23.5 cm, lower education, lower socioeconomic index, food insecurity, Hmong ethnicity, not/rarely having attended antenatal care, not having taken antenatal iron-containing supplements and not meeting minimum dietary diversity. Risk factors for anaemia among children were older age, male sex, stunting, sTfR, ThDP and alpha-1-acid-glycoprotein. Anaemia was common among women and their hospitalised children and was associated with micronutrient deficiencies and socioeconomic, dietary and health care-seeking risk factors, suggesting that multiple strategies are required to prevent anaemia among women and children.

Women's Attitudes Toward Intimate Partner Violence in Low- and Middle-Income Countries of Southern Asia.

PURPOSE: The present study identified the vulnerable IPV cohorts of South Asian women, and the prevalence of and predictors of the women's IPV acceptance. DESIGN: Cross-sectional survey - the United Nations Children's Fund multiple index cluster survey. SETTING: Many South Asian women are accepting of IPV. Studies mostly focus on individual countries. SUBJECT: 103 139 ever-married women from Bangladesh, Laos and Nepal. MEASURES: Women's attitudes toward IPV were measured using a set of five, fixed, binary responses. ANALYSIS: Following bivariate analysis, complex survey weight adjusted logistic regression models were fitted for individual country data, and the pooled sample. RESULTS: Of the sampled South Asian women 27.8% accepted IPV, and no major variation among countries in IPV acceptance. Education was the most reliable protector against IPV acceptance whereby, higher educational attainment systematically reduced IPV acceptance (OR = .61 [.56-.83]). Other significant protective factors were being un-married (Married OR = 1.34 [1.28-1.42]), having increased wealth (OR = .71 [.56-.83]), and being over 24 years old (OR = .88 [.83-.97]). CONCLUSION: Only education produced absolute consistency at the country and region level; there seems to be no blanket solution for regionally reducing women's IPV acceptance rates in Southern Asia. Focus on the least educated women and making education more accessible should be prioritised. Future IPV studies can consider measurement methods for women's direct exposure to patriarchal standards and within community interaction.

Proximal ejecta of the Bolaven extraterrestrial impact, southern Laos.

Sediments in southern Laos and eastern Thailand confirm that the Australasian tektite strewn field came from an extraterrestrial impact crater on the Bolaven Plateau of southern Laos. The principal evidence is the Bolaven diamicton, a pebbly to bouldery breccia that is thickest and coarsest on the plateau. Tektites, the melted target material strewn widely by the forces of the impact 789.0 ± 1.8 ka ago, lie either within the uppermost part of the diamicton or atop it. On the flanks of the plateau, the basal diamicton often contains clasts from preimpact lavas and gravels and sometimes mantles broken Mesozoic bedrock. Locally, its upper portions contain unweathered boulders of basalt or sandstone. Its sharp upper contact with a thick sandy silt implies that the two beds formed in rapid succession. These characteristics of the Bolaven diamicton show that it resulted primarily from the excavation, comminution, and launch of sandstone and weathered basaltic lavas from a crater on the Bolaven Plateau, and entrained other materials while in transit.

A critical study of the nonlinear rheological properties in major classes of foods using the Sequence of Physical Processes (SPP) method and the Fourier Transform Coupled with Chebyshev Decomposition (FTC) method.

The nonlinear rheological behaviors of three different classes of foods (emulsion, suspension, and elastic network) were studied and analyzed using the Rogers Sequence of Physical Processes (SPP) method and the Ewoldt-McKinley method of coupling Fourier Transform with Chebyshev Decomposition (FTC). SPP analysis led to instantaneous rheological parameters G't and G″t at any point in time, providing a more accurate picture of the linear viscoelastic region and crossover points by the 3D amplitude sweep. When G't is plotted against G″t, the resulting graph is a deltoid which offers a detailed and distinctive intracycle behavior of each class of food. Analyzing the revolution of deltoids with increasing strain allows for the determination of a critical strain, beyond which irreversible network breakdown occurs. The strain range between the linear viscoelastic limit and the critical strain found in SPP is comparable to the MAOS region as determined with FTC. Under increasing amplitude, predominantly elastic networks showed a gradual structural rearrangement, while more erratic and abrupt changes were observed in the suspension and emulsion we studied. Under increasing frequency, elastic responses dominate viscous responses in all samples due to the shorter experimental time, allowing less relaxation.

Bionomics of malaria vectors in Lao PDR, 2018-2020: entomological surveillance as a key tool for malaria elimination.

BACKGROUND: The Lao PDR National Strategic Plan for malaria control and elimination for year 2021-2025 emphasizes the importance of routine entomological surveillance being conducted in areas with high transmission and in active malaria foci in elimination targeted areas. The collection of entomological surveillance data that is closely linked to recent epidemiological data is crucial for improving impact, as it contributes to the evidence package that supports operational and strategic decision-making of national malaria programmes, as they accelerate their last mile of elimination. METHODS: The Center for Malariology Parasitology and Epidemiology (CMPE) entomology team conducted entomological surveillance activities at 13 sentinel sites in 8 provinces and at active transmission foci sites from 2018 to 2020. The techniques used for the mosquito collection were indoor and outdoor human landing collections (from houses and from cultivation areas) and cattle baited net trap collections. RESULTS: There were 5601 Anopheles mosquito females captured and identified throughout the study, on both human and cow bait. They represented 15 different species or species complexes. The primary malaria vectors as well as the secondary vectors were present in all collection sites in the south, indicating that people living in these rural areas with high malaria incidence are exposed to the vectors. The vectors were highly zoophilic, but they still bite humans throughout the night with a high peak of activity before midnight, both indoors and outdoors. Overall, 17% of the malaria vectors were collected indoors when the people are sleeping. This confirms the importance of bed net use during the night. Thirty-two percent of primary and secondary vectors were collected outdoors at times when people are usually awake and outdoors, which shows that people are exposed to potentially infectious mosquitoes and the importance of personal protection at these times. The findings showed that residual transmission may occur outdoors in the villages, and outside the villages in cultivation fields and forested areas. Epidemiological data showed that transmission was higher in surveillance sites which were targeted as part of a malaria response rather than sentinel sites. CONCLUSIONS: Understanding where and how transmission is persisting, monitoring and mapping vector species distribution in areas with active transmission, monitoring biting trends, and designing evidence based and effective vector control interventions are critical to accelerating progress toward malaria elimination. In this context, the role of entomological surveillance combined with epidemiological data should be considered as a cornerstone in achieving malaria elimination.

3D Printing of Bioactive Gel-like Double Emulsion into a Biocompatible Hierarchical Macroporous Self-Lubricating Scaffold for 3D Cell Culture.

The interconnected hierarchically porous structures are of key importance for potential applications as substrates for drug delivery, cell culture, and bioscaffolds, ensuring cell adhesion and sufficient diffusion of metabolites and nutrients. Here, encapsulation of a vitamin C-loaded gel-like double emulsion using a hydrophobic emulsifier and soy particles was performed to develop a bioactive bioink for 3D printing of highly porous scaffolds with enhanced cell biocompatibility. The produced double emulsions suggested a mechanical strength with the range of elastic moduli of soft tissues possessing a thixotropic feature and recoverable matrix. The outstanding flow behavior and viscoelasticity broaden the potential of gel-like double emulsion to engineer 3D scaffolds, in which 3D constructs showed a high level of porosity and excellent shape fidelity with antiwearing and self-lubricating properties. Investigation of cell viability and proliferation using fibroblasts (NIH-3T3) within vitamin C-loaded gel-like bioinks revealed that printed 3D scaffolds offered brilliant biocompatibility and cell adhesion. Compared to scaffolds without encapsulated vitamin C, 3D scaffolds containing vitamin C showed higher cell viability after 1 week of cell proliferation. This work represented a systematic investigation of hierarchical self-assembly in double emulsions and offered insights into mechanisms that control microstructure within supramolecular structures, which could be instructive for the design of advanced functional tissues.

Effect of Drinking Water and Sanitation on Child Undernutrition and Diarrhea in Lao PDR.

Childhood undernutrition and diarrhea remain a global health burden in the 21st century. We assessed the effect of access to basic drinking water and sanitation at home on reducing children's likelihood of being undernourished and experiencing diarrhea in Laos. We pooled two rounds of nationally representative cross-sectional household surveys: the Lao Social Indicator Surveys 2011/2012 and 2017, encompassing 23 070 children aged <5 years. We employed multivariate multilevel logistic regression for the analysis. The results showed that access to basic drinking water was associated with a reduced likelihood of undernutrition and was effective in improving child undernutrition. Moreover, access to basic sanitation reduced diarrhea in addition to undernutrition. Notably, sanitation facilities only mitigated childhood stunting and diarrhea when basic drinking water facilities were present in the household. We also confirmed that socio-economic disparities existed among children accessing basic drinking water and sanitation. Consequently, further efforts are needed toward equitable access to these facilities in Laos.

Longitudinal comparison of bacterial pathogen seropositivity among wet market vendors in the Lao People's Democratic Republic.

Wild animal trade for human consumption is a global issue, involving complex interactions between economics, culture, food security and conservation. Whilst being a biodiversity issue, it is also a major public health concern, with recent epidemics and pandemics of zoonotic pathogens linked to interactions with wildlife. At three time points, between March 2017 and June 2018, a longitudinal sero-survey of 150 market vendors from three wet markets in Laos (selling vegetables, domestic animal meat and/or wildlife meat) was conducted to determine if vendors had been differentially exposed to three endemic bacterial pathogens - Orientia tsutsugamushi, Rickettsia typhi, and Leptospira spp. A total of 367 serum samples were tested by IgG enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assay (IFA, for scrub typhus group (STG) and typhus group (TG) only). Among vendors, 32.7% were IgG-positive for at least one pathogen, 13.3% sero-converted during the study. Multi-season occupancy modelling for STG indicated a significantly higher prevalence of STG IgG in vegetable vendors (27.3%) and wildlife vendors (28.4%) than in domestic animal meat vendors (6.9 %, p=0.05), and higher in Phonsavanh market (OR=9.6, p=0.03) compared to Lak Sao and Salavan markets. Estimated mean incidence was 57 cases per 10,000 per 7.5-month period. For TG, vendor age had a significant effect on prevalence (OR=1.04, p=0.006), estimated mean incidence was 64 cases per 10,000 per season (7.5-month period). Despite individuals selling domestic meat having a higher prevalence of Leptospira infections than those that did not (11.6% versus 4.5%), the difference was not significant. Whilst this study has a number of limitations, including vendors changing what food types they sold and no investigation of exposure outside of markets, the finding that the risk of exposure of vendors to zoonotic pathogens may be associated with types of food sold for human consumption warrants further investigation.