Chiang Rai Province Research Articles

Secundilactobacillus folii sp. nov., isolated from fermented tea leaves in Thailand

A Gram-stain-positive, catalase-negative, rod-shaped, non-motile, non-spore-forming, and facultatively anaerobic strain CRM56-3T, isolated from fermented tea leaves collected from Chiang Rai province, Thailand, was characterized based on a polyphasic approach. The strain produced dl-lactic acid heterofermentatively from glucose. It grew at 15-42 °C (optimum at 30 °C), pH 3.5-8.0 (optimum pH 6.0) and in 1-4 % (w/v) NaCl. Strain CRM56-3T contained C16:0, C19:0 cyclo ω8c, and C18:1 ω7c, and/or C18:1 ω6c as major cellular fatty acids. Based on 16S rRNA gene sequence analysis, strain CRM56-3T belongs to the genus Secundilactobacillus and was closely related to Secundilactobacillus odoratitofui DSM 19909T (99.2 %), S. collinoides JCM 1123T (98.9 %), and S. paracollinoides DSM 15502T (98.7 %). The draft genome of strain CRM56-3T contained 2681617 bp with 2413 coding sequences and DNA G+C content determined from genome sequence of 44.5 mol%. The digital DNA-DNA hybridization (dDDH) between strain CRM56-3T and S. odoratitofui DSM 19909T, S. collinoides JCM 1123T, and S. paracollinoides DSM 15502T were 19.5, 20.4, and 21.6 %, respectively. The average nucleotide identity (ANIm) and the average amino acid identity (AAI) between strain CRM56-3T and closely related strains were lower than 85.0 and 80.0 %, respectively. The strain CRM56-3T was clearly distinguished from related Secundilactobacillus species by its phenotypic and chemotaxonomic characteristics, 16S rRNA gene sequence similarity, and the draft genome analysis. Therefore, the strain represents a novel species of the genus Secundilactobacillus, for which the name of Secundilactobacillus folii sp. nov. is proposed. The type strain is CRM56-3T (=JCM 34223T=LMG 31663T=TISTR 2851T).

Lasiodiplodia syzygii sp. nov. (Botryosphaeriaceae) causing post-harvest water-soaked brown lesions on Syzygium samarangense in Chiang Rai, Thailand.

BackgroundSyzygium samarangense (Wax apple) is an important tropical fruit tree with high economic and nutrient value and is widely planted in the tropics or subtropics of Asia. Post-harvest water-soaked brown lesions were observed on mature fruits of ornamental wax apples in Chiang Rai Province, Thailand. A fungus with morphological characters, similar to Lasiodiplodia, was consistently isolated from symptomatic fruits. Phylogenetic analyses, based on ITS, LSU, TEF1-a and tub2, revealed that our isolates were closely related to, but phylogenetically distinct from, Lasiodiplodia rubropurpurea.New informationMorphological comparisons indicated that pycnidia and conidiogenous cells of our strains were significantly larger than L. rubropurpurea. Comparisons of base-pair differences in the four loci confirmed that the species from wax apple was distinct from L. rubropurpurea and a new species, L. syzygii sp. nov., is introduced to accommodate it. Pathogenicity tests confirmed the newly-introduced species as the pathogen of this post-harvest water-soaked brown lesion disease on wax apples.

Sustainable community based tourism: impact, challenges and opportunities (the case of Huai Nam Guen Village, Chiang Rai Province, Thailand)

This article provides a single-case research study of Huai Nam Guen village in Chiang Rai province, Thailand. Through identifying the important facilitators and possible inhibitors to CBT, this research reveals that CBT operations can conform to the principles of sustainable tourism through participative roles of the community and the different relevant stakeholders, identity creation and maintenance, exploiting the economic, socio-cultural and ecological resources, continuous learning, and taking land ownership in the systematic design of the community landscape and agricultural best practices. Clearly, to influence CBT operations towards sustainability, it is important to influence the community at the behavioural level. In this sense, this research contributes to the fragmented knowledge and publications of CBT in the context of behavioural emphasis.

Development of ethnic tourism in poverty and drug deduction (the case study of Chiangrai Province, Thailand)

Despite significant economic growth in Thailand, in northern Thailand in particular, a growing number of indigenous communities have been turning to tourism as an alternative to expanding their commercial agriculture. However, in recent years, tourism resources have begun to deteriorate both culturally and environmentally in addition to problem of poverty. Thus, a growing gap between rich and poor, inadequate attention to the special needs of ethnic minorities, gender inequities and lack of access to basic health and education are significant problems. This paper presents the ethnic minorities’ context and their demands on tourism development as well as the key players’ roles and interests effecting on ethnic tourism promotion. The paper concluded with key issues for an achievement of creative ethnic tourism promotion in Chiang Rai Province.

Associations between sexual violence, domestic violence, neglect, and alcohol consumption among Lahu hill tribe families in northern Thailand.

Background:Domestic violence is one of the largest silent problems in the world. Women, children, and elderly individuals often fall victims to family members who use alcohol. However, there is lack of scientific evidence on alcohol consumption and domestic violence among Lahu hill tribe families.Objectives:The objective of this study was to investigate the prevalence of family violence, violence against women, and alcohol-related harm to children and elderly individuals and to determine the correlations between alcohol consumption and family violence among Lahu tribe families in northern Thailand.Method:A cross-sectional study was applied to collect data from participants living in 10 randomly selected villages from the list of Lahu villages in Chiang Rai Province, Thailand. A validated questionnaire and the Alcohol Use Disorders Identification Test were used to collect information from the participants in private and confidential rooms at a community hall between March and August 2019. Data were described and tested for correlation at the significance levels of α = 0.05 and 0.01.Findings:A total of 350 of 719 recruited Lahu families participated in the study (response rate = 48.7%). Among female participants, 22.3% reported history of sexual harassment and 4.1% had been forced to have sex. Children and elderly individuals reported several experiences with people who had used alcohol in the past year; 6.4% had been left to live alone, 5.0% experienced financial neglect, and 1.8% had been neglected while sick. In a correlation analysis, it was found that age (r = –0.02, p value < 0.009), education (r = 0.15, p value < 0.047), marital status (r = 0.25, p value < 0.001), and religion (r = 0.20, p value < 0.008) were significantly correlated with verbal arguments among family members. Experience of sexual harassment was correlated with the presence of a drinker in the family (r = 0.22, p value < 0.001).Conclusion:Government and relevant agencies should cooperate to reduce the consumption of alcohol among Lahu men. Moreover, a specific training program to personally improve one’s skill in responding to domestic violence among children, women, and elderly individuals should also be developed and implemented in Lahu communities.

Diatrypella heveae Senwanna, Phookamsak &amp;amp; K.D. Hyde (Diatrypaceae, Xylariales): a new record for the Neotropics

During an expedition to the Raso da Catarina Ecological Station, state of Bahia, Brazil, we collected litter samples from Syagrus coronata (Mart.) Becc. containing fungal stroma. The material was morphologically identified as belonging to Diatrypella heveae Senwanna, Phookamsak &amp;amp; K.D. Hyde (Diatrypaceae, Xylariales); its known geographic distribution was then limited to Thailand. Diatrypella heveae was originally described on Hevea brasiliensis L. and Brahea armata S. Watson in the Chiang Rai Province, Wiang Chiang Rung District, Thailand. We report here the first occurrence of D. heveae in the Neotropics, as well as a new host, S. coronata, a palm tree endemic to the Brazilian semiarid region.

&lt;strong&gt;&lt;em&gt;Bartalinia kevinhydei&lt;/em&gt; (Ascomycota), a new leaf-spot causing fungus on teak (&lt;em&gt;Tectona grandis&lt;/em&gt;) from Northern Thailand&lt;/strong&gt;

This paper introduces an interesting new fungus, isolated from teak (Tectona grandis) leaf-spots, collected in Chiang Rai Province, Thailand. Phylogenetic analysis of combined ITS and LSU sequence data together with morphological studies confirmed that the disease was caused by a Bartalinia species, distinct from described taxa. Detailed description, photomicrographs and a phylogenetic tree are provided to showcase the taxonomic placement of the new species, B. kevinhydei. Geographical distribution of Bartalinia species is also provided. This is the first report of a Bartalinia species growing on teak, and also the first report for Bartalinia in Thailand.

Morphology and molecular phylogeny of Macrobrachium saengphani sp. nov. (Decapoda: Palaemonidae) from Northern Thailand.

A small wild prawn of the genus Macrobrachium, found in Chiang Rai Province, Northern Thailand has some morphological features resembling four other closely related species, M. lanchesteri, M. peguense, M. kunjuramani, and M. chainatense. However, it is distinguishable from the above species in terms of distinctive golden colored antennules; number of teeth on the rostrum; number of teeth on the cutting edges of the second pereiopod; and length of carpus relative to that of chela on the second pereiopod. Moreover, DNA analysis places it far apart on the phylogenetic tree from the related species in the genus.

Effects of Maturity on Chemical Composition and Antioxidant Activity of Sacha Inchi (Plukenetia volubilis L.) Cultivated in NorthernThailand

Sacha inchi is cultivated commercially in Thailand for its edible kernels and oil. Highest quality sacha inchi is normally associated with highest oil content. Samples of 3 maturity stages: green, greenish brown, and brown and dry, were collected from 2 different harvests and comparisons were made based on composition and antioxidant analysis. In each harvest, all 3 stages were collected from the Phitsanulok and Chiang Rai provinces. There were 12 samples plus 2 controls. As maturity increased, moisture content of samples decreased, while oil content increased. Oil content ranged from 38.15 - 48.81 g/100 g. Protein content ranged from 16.23 - 18.98 g/100 g. Fibre content was 14.50 - 22.24 g/100 g, ash content was 2.70 - 3.06 g/100 g, and carbohydrate content was 7.70 - 19.47 g/100 g. The total phenolic content (TPC) was 103 - 385 mg/100 g, and antioxidant activity was 9.36 - 13.72 % for DPPH and 5,803.99 - 10,700 mg Trolox equivalent for FRAP. Average SFA, MUFA, and PUFA contents were 3.35, 4.63, and 30.91 g/100 g, respectively. Most common FA was omega-6 PUFA, followed by omega-3 and omega-9. Omega-6 to omega-3 ratio was 1.12 - 1.56. Samples with highest oil content were brown and dry samples harvested from Chiang Rai (47.26 g/100 g oil) and Phitsanulok (46.37 g/100 g oil), which were selected to test for amino acids and vitamin E. Nineteen amino acids were detected, with lysine, tyrosine, leucine, and glutamic acid predominant. Vitamin E content was 1.02 - 1.42 mg/100 g. For highest quality and greatest benefits to health, sacha inchi should be harvested when the shuck is brown and dry.

Effect of Air Quality on Cardio-Respiratory Systems in Northern Thailand (Chiang Mai, Chiang Rai and Nan Province)

Effect of Air Quality on Cardio-Respiratory Systems in Northern Thailand (Chiang Mai, Chiang Rai and Nan Province)

Gut microbiota of obese and diabetic Thai subjects and interplay with dietary habits and blood profiles.

Obesity and type 2 diabetes mellitus (T2DM) have become major public health issues globally. Recent research indicates that intestinal microbiota play roles in metabolic disorders. Though there are numerous studies focusing on gut microbiota of health and obesity states, those are primarily focused on Western countries. Comparatively, only a few investigations exist on gut microbiota of people from Asian countries. In this study, the fecal microbiota of 30 adult volunteers living in Chiang Rai Province, Thailand were examined using next-generation sequencing (NGS) in association with blood profiles and dietary habits. Subjects were categorized by body mass index (BMI) and health status as follows; lean (L) = 8, overweight (OV) = 8, obese (OB) = 7 and diagnosed T2DM = 7. Members of T2DM group showed differences in dietary consumption and fasting glucose level compared to BMI groups. A low level of high-density cholesterol (HDL) was observed in the OB group. Principal coordinate analysis (PCoA) revealed that microbial communities of T2DM subjects were clearly distinct from those of OB. An analogous pattern was additionally illustrated by multiple factor analysis (MFA) based on dietary habits, blood profiles, and fecal gut microbiota in BMI and T2DM groups. In all four groups, Bacteroidetes and Firmicutes were the predominant phyla. Abundance of Faecalibacterium prausnitzii, a butyrate-producing bacterium, was significantly higher in OB than that in other groups. This study is the first to examine the gut microbiota of adult Thais in association with dietary intake and blood profiles and will provide the platform for future investigations.

Navigating Sino-Thai ‘rocky’ bilateral ties: The geopolitics of riverine trade in the Greater Mekong Subregion

The revived plan to dynamite rapids and rocky islets in Chiang Rai province of Thailand as part of an Upper Mekong navigation improvement scheme allowing bigger tonnage Chinese cargo ships to pass more smoothly all the way to Luang Prabang in Laos has been folded into the wider visions of BRI. These rework and invert a geopolitical imaginary that has imperial origins in the Lower Mekong, when the French sought to navigate upstream from Indochina during 19th century explorations. Our paper examines the rock-blasting plans and shifting responses from and relations between Laos and Thailand in light of past and contemporary geopolitical narratives.

Seroprevalence and factors associated with hepatitis B infection among the hill tribe adult population in Thailand: a cross-sectional study

BackgroundHepatitis B virus (HBV) infection is one of the greatest public health burdens, particularly for people living with several barriers to access to health care services, such as the hill tribe adult population in Thailand. People aged 25 years and over who are out of the target population for HBV immunization under the national Expanded Program on Immunization (EPI) are at risk of HBV infection. The study aimed to estimate the prevalence and determine the factors associated with HBV infection among hill tribe adults aged 25 years and over living in Chiang Rai Province, Thailand.MethodsA cross-sectional study design was used to collect information on hill tribe adults aged 25 years and over living in 36 selected hill tribe villages in Chiang Rai Province. All people living in the selected villages who met the criteria were invited to participate in the study. A validated questionnaire and a 5-mL blood specimen were used as research instruments. Hepatitis B surface antigen (HBsAg), antibody to hepatitis B surface (anti-HBs), and antibody to hepatitis B core (anti-HBc) were detected by using the Wondfo Test Kit@, which has high sensitivity and specificity. Logistic regression was used to detect the associations between variables at the significance level of α = 0.05.ResultsA total of 1491 individuals were recruited into the analysis; 60.8% were females, 81.3% were aged between 30 and 60 years, and 86.0% were married. The majority were illiterate (54.9%), were Buddhist (55.7%), worked in agricultural sectors (87.3%), and had an annual income of less than 50,000 baht per year (72.9%). The overall prevalence of hepatitis B infection was 26.6%; 7.6% were positive for HBsAg, 19.2% were positive for anti-HBs, and 18.9% were positive for anti-HBc. In the multivariate analysis, three variables were found to be associated with hepatitis B infection: those who were in the Yao and Lisu tribes had a 1.64-fold (95% CI = 1.08–2.49) and a 1.93-fold (95% CI = 1.10–3.31) greater chance, respectively, of HBV infection than did those in the Karen tribe; those who were Christian had a 1.41-fold (95% CI = 1.06–1.87) greater chance of HBV infection than did those who were Buddhist; and those who did not use alcohol had a 1.29-fold (95% CI = 1.01–1.65) greater chance of HBV infection than did those who used alcohol.ConclusionsIt is necessary to develop and implement effective public health interventions among hill tribe adult populations who are not part of the EPI-targeted population, particularly Christians, those in the Lisu and Yao tribes, and those who do not use alcohol, to reduce the HBV infection rate, save lives and reduce medical expenses.

Nutritional composition of conserved Kadsura spp. plants in Northern Thailand

The genus Kadsura comprises woody vine plants belonging to the family Schisandraceae. Species are found mostly in Northern Thailand and widely consumed by the local population. Occurrences of these wild fruits are rare as they only grow naturally in forest areas. Nutritive values of Kadsura spp. remain unclear, leading to improper management for food applications. Nutritional composition of Kadsura spp. was evaluated to promote sustainable conservation. Nutritive values in different fruits parts (exocarp, mesocarp, seed and core) of two Kadsura species as Kadsura coccinea (Lem.) A.C. Sm. and Kadsura heteroclita (Roxb.) Craib, from Chiang Rai Province, Thailand were assessed. When comparing nutritional contents based on per 100 g dry weight, results suggested that K. coccinea exhibited higher carbohydrate (1–2 times), sugar (1–2 times) and vitamin C (3–4 times) contents than K. heteroclita, while the latter possessed higher fat (1–2 times), protein (1.6–1.9 times), and dietary fiber (1.5–1.8 times) contents. Considering each fruit part, the mesocarp (the only edible fruit part) and exocarp of both species provided high dietary fiber (11.6–20.9% recommended dietary fiber) and vitamin C (as high as 73% recommended per day) but were low in energy (30–40 kcal/100 g fresh weight), protein (0.6–1.2% recommended per day), fat (0.5–1.8% recommended per day) and sugar (2.4–5.4% recommended per day). Interestingly, seed contained higher energy (1–2 times), protein (2–3 times) and fat (4–50 times) than the other fruit parts. Results support the potential consumption of Kadsura spp. as a healthy fruit that can be used for future food applications. Seed and exocarp from Kadsura spp. also showed potential for new product development.

Feasibility study of thermal anomaly detection for earthquake: A case study from 2014 Mae Lao earthquake, Thailand

Earthquake is the natural disaster which causes damage to human lives and their properties, domestic animals and buildings in the areas near the epicentre. The ability to predict the earthquake can greatly reduce in catastrophic damages, but nowadays, earthquake prediction is still the unsolvable problem. However, the earthquake prediction is still an interesting topic for scientists all over the world. One of the important earthquakes precursors in earthquake preparatory phase is thermal anomaly. The thermal region data from remote sensing have been employed recently based on the concept of stress accumulation in the active plate tectonics region, which can be transformed as temperature variation prior event. Moderate Resolution Imaging Spectroradiometer (MODIS) Land Surface Temperature (LST) data have been commonly used to locate thermal anomalies prior to occurrence of earthquake event. In Thailand, 2014 Mae Lao Earthquake, the largest earthquake in the Thailand historical record with magnitude Mw 6.1, shook the area of Mae Lao District, Chiang Rai Province on 5th May 2014. To locate possibility of thermal anomalies, the daily data of MODIS MYD11A1 product for 30 days before and after the earthquake were processed and analysed. Average LST before and after earthquake events were used for removing background temperature in the area and comparative method was performed to detect the thermal anomalies. The result found that this simple technique detected the thermal anomaly occurrence during 12-23 days prior to the earthquake and 9-28 days after the earthquake. Nevertheless, in order to understand furthermore about earthquake mechanism, it is necessity of discovered thermal precursors.

Monitoring of the Organophosphate Pesticide Chlorpyrifos in Vegetable Samples from Local Markets in Northern Thailand by Developed Immunoassay.

Chlorpyrifos is an organophosphate pesticide that is wildly used among farmers for crop protection. However, there are concerns regarding its contamination in the environment and food chain. In the present study, an in-house indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) specific for detecting chlorpyrifos is developed and validated against gas chromatography–flame photometric detection (GC-FPD) as the conventional method. The developed ic-ELISA was used for detecting chlorpyrifos residue in vegetable samples. The developed ic-ELISA showed good sensitivity to chlorpyrifos at an IC50 of 0.80 µg/kg, with low cross-reactivity to other organophosphate pesticides. The 160 samples were collected from local markets located in the Chiang Rai, Chiang Mai, and Nan provinces in northern Thailand. The positive rate of chlorpyrifos residues in the vegetable samples was 33.8%, with the highest levels found in cucumbers, coriander, and morning glory, at 275, 145, and 35.3 µg/kg, respectively. The highest median levels of chlorpyrifos found in the detected samples were Chinese cabbage (332 μg/kg), cucumber (146.3 μg/kg) and Chinese Kale (26.95 μg/kg). The developed ic-ELISA is suitable for the rapid quantitation of chlorpyrifos residues.

Factors Associated with High-to-Severe Stress among University Students in Northern Thailand

Background: Stress is one of the most significant mental health problems among university students aged 18 to 24. University students are developing into adulthood while facing stress from several factors, including personal lifestyle and interpersonal interactions with their peers. Objective: To determine the factors associated with high-to-severe stress among university students in northern Thailand. Materials and Methods: A cross-sectional study design was applied to elicit information among randomly selected students attending three universities located in the Chiang Rai, Chiang Mai, and Pha Yao Provinces in northern Thailand in the 2018 to 2019 academic year. A validated questionnaire and the Suanprung Stress Test 20 (SPST-20) were used to collect information and assess stress levels. Participants filled out all forms voluntarily, which took 20 minutes each. Chi-square and logistic regression were used to determine the factors associated with high and severe stress at α=0.05. Results: Six hundred fifty-five students were recruited into in the present study. Most students were female (62.6%) and third year students (39.7%). Two-thirds of the students reported less regular exercise (60.2%), and almost half of the students accessed the internet 6 to 9 hours per day (47.3%), and 80.8% of these internet users used the application Facebook. One-fifth of the students had had sexual intercourse (20.9%). Almost half the of students had high stress levels (44.3%), and 16.6% of students had severe stress levels. In the multivariable model, three variables were statistically associated with high-to-severe stress among these students. Students who did not respond to the sexual intercourse experience question had a greater chance, 1.71 (95% CI 1.15 to 2.55) times greater, of high-to-severe stress than those who responded negatively to this question. Those students whose fathers graduated primary school had a greater chance of high-to-severe stress than those whose parents had no education of 3.64 times (95% CI 1.60 to 8.31). Students whose parents had high parental conflicts had greater chance of high-to-severe stress than those students whose parents had no parental conflict of 2.29 times (95% CI 1.18 to 4.47). Conclusion: Appropriate health interventions should be urgently implemented among university students to reduce stress, particularly among those who do not express their sexual intercourse experience, whose parents have little education, and whose parents have high parental conflicts. Keywords: Stress, University student, Factors associated, SPST-20

Geological model and development of the Cenozoic Wiang Pa Pao Basin, Chiang Rai Province, Northern Thailand, based on gravity data modelling and surface structural interpretation

3-D Inverse gravity modelling, constrained by surface geological data across the Neogene Wiang Pa Pao Basin (WPB), Northern Thailand, provides new subsurface models of the basin geometry and its structural development. The intermontaine WPB is seismically active and exhibits many geothermal sites; both are indicative of active fault zones. Six hundred thirty-six terrestrial gravity stations with ~500 m spacing were acquired. The residual Complete Bouguer Anomaly map (CBA) reveals an N–S elongate basin characterized by gravity lows bounded by gravity highs on the eastern margin of the basin (metasedimentary basement), and moderate gravity anomalies on the western margin (granitic basement). Structural edge detection revealed N–S trending faults along the eastern and western margins linked by NE–SW and NW–SE trending lineaments. The 3-D gravity model indicates an asymmetric graben; with a maximum depocenter depth of ~1300 m. Surface structure and seismicity confirm the gravity interpretation that the WPB is a dextral transtensional basin characterized by WSW–ENE trending R'-shears and NNE–SSW R-shears distributed in duplex-like geometries along the N–S trending principal displacement zone. The WPB displays unusually well-developed R’-shears, where Palaeozoic metasedimentary rocks in the basement and Cenozoic basin sediments are present, these faults disappear to the south, where the main N–S fault resides entirely within the granite. The WPB is associated with Cenozoic multi-phase rifting: in the Late Oligocene–Miocene, major rift basins formed under W–E extension, strongly influenced by WSW–ENE to NE–SW and NW–SE pre-existing trends. In the Latest Miocene–Recent, the younger basins, including the WPB, underwent dextral strike-slip along new and existing N–S dextral fault trends.

Assessment of genetic diversity in Thai upland rice varieties using SSR markers

Upland rice (Oryza sativa L.) is precious genetic resource containing some valuable alleles not common in modern germplasm. In this study, genetic diversity and population structure of 98 upland rice varieties from northern part of Thailand were examined using nine simple sequence repeat markers. Number of alleles detected by the above primers was 50 with a minimum and maximum frequency of 2 to 10 alleles per locus, respectively. The polymorphic information content (PIC) values ranged from 0.375 to 0.714 with an average of 0.605 for the primers RM164 and RM1, respectively. Dendrogram cluster analysis of the SSR data distinctly classified all genotypes into three major groups (I, II and III), which corresponded to their places of collection. Population structure divided these genotypes into two distinct subpopulations. Subpopulation 1 consisted of upland rice varieties that collected from Chiang Rai province while the majority of subpopulation 2 were collected from Phayao and Phitsanulok provinces. Analysis of molecular variance revealed 68% variance among two subpopulations and 32% variance within subpopulations, suggesting a high genetic differentiation between the two subpopulations. The huge genetic variability of upland rice in northern part of Thailand can be used to complement the gene pool of modern genotypes in rice breeding program.

The estimated burden of scrub typhus in Thailand from national surveillance data (2003-2018).

Scrub typhus is a major cause of acute febrile illness in the tropics and is endemic over large areas of the Asia Pacific region. The national and global burden of scrub typhus remains unclear due to limited data and difficulties surrounding diagnosis. Scrub typhus reporting data from 2003-2018 were collected from the Thai national disease surveillance system. Additional information including the district, sub-district and village of residence, population, geographical, meteorological and satellite imagery data were also collected for Chiangrai, the province with the highest number of reported cases from 2003-2018. From 2003-2018, 103,345 cases of scrub typhus were reported with the number of reported cases increasing substantially over the observed period. There were more men than women, with agricultural workers the main occupational group affected. The majority of cases occurred in the 15-64 year old age group (72,144/99,543, 72%). Disease burden was greatest in the northern region, accounting for 53% of the total reported cases per year (mean). In the northern region, five provinces-Chiangrai, Chiangmai, Tak, Nan and Mae Hong Son-accounted for 84% (46,927/55,872) of the total cases from the northern region or 45% (46,927/103,345) of cases nationally. The majority of cases occurred from June to November but seasonality was less marked in the southern region. In Chiangrai province, elevation, rainfall, temperature, population size, habitat complexity and diversity of land cover contributed to scrub typhus incidence. The burden of scrub typhus in Thailand is high with disease incidence rising significantly over the last two decades. However, disease burden is not uniform with northern provinces particularly affected. Agricultural activity along with geographical, meteorological and land cover factors are likely to contribute to disease incidence. Our report, along with existing epidemiological data, suggests that scrub typhus is the most clinically important rickettsial disease globally.