Geographic Regions Of Thailand Research Articles

Dengue virus transmission risk in blood donation: Evidence from Thailand.

Individuals infected with dengue virus (DENV) often show no symptoms, which raises the risk of DENV transfusion transmission (TT-DENV) in areas where the virus is prevalent. This study aimed to determine the evidence of DENV infection in blood donors from different geographic regions of Thailand. A cross-sectional study was conducted on blood donor samples collected from the Thai Red Cross National Blood Center and four regional blood centers between March and September 2020. Screening for DENV nonstructural protein 1 (NS1), anti-DENV immunoglobulin G (IgG), and IgM antibodies was performed on residual blood from 1053 donors using enzyme-linked immunosorbent assay kits. Positive NS1 and IgM samples indicating acute infection were verified using four different techniques, including quantitative real-time (q) RT-PCR, nested PCR, virus isolation in C6/36 cells, and mosquito amplification. DENV IgG seropositivity was identified in 89% (938/1053) of blood donors. Additionally, 0.4% (4/1053) and 2.1% (22/1053) of Thai blood donors tested positive for NS1 and IgM, respectively. The presence of asymptomatic dengue virus infection in healthy blood donors suggests a potential risk of transmission through blood transfusion, posing a concern for blood safety.

Distribution of Wolbachia infection in butterflies (Lepidoptera): First systematic report from Thailand

ABSTRACT Wolbachia is a genus of Rickettsia-like bacteria that infects a broad range of insect species throughout the world. It often influences host reproduction to facilitate its transmission to their offspring and spread through populations. The occurrence and ecology of Wolbachia has not been surveyed in detail in Thai butterflies. In this study, we conduct the first systematic survey of Wolbachia infection by sampling 623 specimens from 46 butterfly species from 5 families obtained from tropical forests in 3 geographic regions of Thailand. Wolbachia infections were detected using three PCR primer sets: 16S rRNA, ftsZ and wsp. The results showed evidence for widespread Wolbachia infection in Thai butterflies. The Wolbachia presence was confirmed in 291 individuals from 17 butterfly species of 2 families, comprising 86 individuals from the Central Region (32 males and 54 females), 72 individuals from the Northeast Region (25 males and 47 females), and 133 individuals from the West Region (46 males and 87 females). This report will be useful for understanding the distribution of Wolbachia in butterflies from Thailand.

Metabolite Fingerprinting of Piper nigrum L. from Different Regions of Thailand by UHPLC-QTOF-MS Approach and In Vitro Bioactivities

This study aimed to profile the metabolites, piperine content, and biological activities (antioxidant, anti-inflammatory, anticancer, antibacterial, and apoptotic cell) of 15 samples of Piper nigrum L. from various geographic regions of Thailand. UHPLC-QTOF-MS was applied to establish alkaloid profiles of the P. nigrum L. samples. PCA and HCA analysis showed that the samples from the PN-1, PN-2, and PN-11 sources differed significantly from those of other sources in terms of compound type and alkaloid concentration profile. Comparative analysis based on a validated HPLC-DAD method was used for the standardization of 15 varieties of P. nigrum L. with piperine as a standard phytomarker which revealed that PN-4 source possessed a high content of piperine. PN-2 showed the highest antioxidant capacity (DPPH activity) while PN-10, PN-12, and PN-15 showed the highest FRAP activity. PN-11 source showed high inhibition of anti-inflammatory and anticancer properties. Furthermore, PN-3, and PN-4 also showed the highest both anti-inflammatory and antibacterial activity. Almost samples have been shown to induce late apoptosis and necrosis in SW480 cell line. This study will also be useful for the development of quality control parameters through the standardization of varieties of P. nigrum L. as raw materials in traditional medicine formulations. HIGHLIGHTS Metabolite profiling of the nigrum L. varieties from 15 different geographical locations in Thailand Quality control parameter for standardization based on marker analysis by HPLC-DAD using piperine as the marker compound Comparisons of metabolites among 15 different cultivations by Principal Component Analysis (PCA) and hierarchical cluster analysis (HCA) Biological activity of the nigrum L. varieties from 15 different geographical locations in Thailand GRAPHICAL ABSTRACT

The impact of insect growth regulators on adult emergence inhibition and the fitness of Aedes aegypti field populations in Thailand

BackgroundThe frequent use of insecticides in vector control causes the development of insecticide resistance. Insect growth regulators (IGRs), which effect insect development, are used as a promising alternative to control resistant insect vectors. This study aimed to develop novel effective tools for Aedes aegypti control by evaluating the efficacy of different IGRs on larval development, blood feeding capacity, fecundity, and fertility in females and sperm productivity in males across geographical regions of Thailand. MethodsThe efficacy of 16 technical grade IGRs were evaluated against laboratory strain Ae. aegypti larvae in order to determine their emergence inhibition (EI) at 50% and 95% under laboratory conditions. Six IGRs were selected for fecundity, fertility, and sperm productivity studies using feed-through treatments at EI95 concentration levels against adult Ae. aegypti field strains. ResultsThe results from larval bioassay tests indicate that juvenile hormone mimics (EI50 = 0.010–0.229 ppb; EI95 = 0.066–1.118 ppb) and chitin synthesis inhibitors affecting CHS1 (EI50 = 0.240–2.412 ppb; EI95 = 0.444–4.040 ppb) groups effectively inhibited adult Ae. aegypti emergence. Methoprene and fenoxycarb significantly reduced blood feeding capacity. Egg production was comparable among strains while methoprene, pyriproxyfen and diflubenzuron induced egg production. Egg retention was detected in females fed on diflubenzuron. Methoprene, fenoxycarb, diflubenzuron, and teflubenzuron reduced egg hatching rates in mosquito field strains compared to laboratory strain. Male mosquitoes fed on fenoxycarb showed significantly lower sperm production compared to other treatments. ConclusionJuvenile hormone analogues and chitin synthesis inhibitors affecting CHS1 groups showed excellent results in adult emergence inhibition in this study. They also disrupted reproductive systems in both adult males and females. This study suggested that they can be used as an alternative larvicide in mosquito control programs.

Landmark Data to Distinguish and Identify Morphologically Close Tabanus spp. (Diptera: Tabanidae).

Simple SummaryTabanus spp. (Diptera: Tabanidae) are blood-sucking parasites of animals and humans. The accurate identification of these flies is very important for determining the vector species involved in disease transmission and for planning effective vector control and management strategies. We explored the effectiveness of landmark-based geometrics at distinguishing and identifying morphologically similar species of Tabanus (T. megalops, T. rubidus, and T. striatus) in Thailand. Our study reveals that geometric morphometrics is effective at distinguishing between the three species of Tabanus. Furthermore, our study material can be used as reference material for species identification.Tabanus spp., also known as horse flies (Diptera: Tabanidae), are important vectors of several animal pathogens. Adult females of Tabanus megalops and Tabanus striatus, which are members of the T. striatus complex, are morphologically similar and hence difficult to distinguish using morphological characteristics. In addition, molecular identification by DNA barcoding is also unable to distinguish these species. These two species can occur sympatrically with Tabanus rubidus, which is morphologically similar to T. megalops and T. striatus. Wing geometric morphometrics has been widely used in various insects to distinguish morphologically similar species. This study explored the effectiveness of landmark-based geometrics at distinguishing and identifying T. megalops, T. rubidus, and T. striatus in Thailand. Specimens were collected from different geographical regions of Thailand, and only unambiguously identified specimens were used for geometric morphometric analyses. Left wings of females of T. megalops (n = 160), T. rubidus (n = 165), and T. striatus (n = 85) were photographed, and 22 wing landmarks were used for the analysis. Wing shape was able to distinguish among species with high accuracy scores, ranging from 94.38% to 99.39%. We showed that morphologically very close species of Tabanus can be reliably distinguished by the geometry of their wing venation, and we showed how our experimental material could be used as a reference to tentatively identify new field collected specimens.

Infection density, diversity, and distribution of Wolbachia bacteria in moths (Order Lepidoptera): First systematic report from Thailand

• First systematic report on Wolbachia infections in moths from Thailand. • Surveys in various habitats from 5 provinces in 3 geographic regions of Thailand. • Wolbachia were detected in 28 of 58 moth species and 625 of 1235 individuals. • Some moth species had not been described previously as infected. • Most specimens were collected from the West region of Thailand. Members of the genus Wolbachia are a group of Rickettsia -like, intracellular, maternally inherited bacterial endosymbionts that infect a diverse range of insects and cause reproductive changes in their hosts. Although Wolbachia ’s role in many insects has been extensively studied, only a little of their effects on host’s reproduction and their infection frequencies were reported in Lepidopteran which is one of the most diverse insects. Here, we present the first systematic survey of the Wolbachia infection status in different species of moths from three different geographic regions of Thailand, which was carried out during January to December in 2019 with the screening of 1,235 specimens in total of 58 moth species from 13 families. Specimens were collected from Khao Yai National Park (the Central and the Northeast regions), and Kaeng Krachan National Park (the West region). Infections of Wolbachia were screened by using polymerase chain reaction with 16S rRNA, ftsZ and wsp gene primers which the results indicated high rates of Wolbachia infection in moth populations from Thailand. Wolbachia was found in all different geographically populations in total of 625 individuals in total of 28 moth species from 9 families, including 144 individuals (46 males and 98 females) from the Central, 156 individuals (49 males and 107 females) from the Northeast, and 325 individuals (114 males and 211 females) from the West. The highest infection rate was 90.47% in the West populations and the average infection rate was 61.90%. The detection of Wolbachia in different moth populations from all regions was identical when all primers were used to screen for Wolbachia . The relative densities of Wolbachia within each individual were determined using quantitative real-time PCR and the result showed that there was a low Wolbachia infection density in these moth populations. These findings indicated that Wolbachia are distributed throughout the moth populations from Thailand.

Estimation of the Genetic Diversity and Population Structure of Thailand’s Rice Landraces Using SNP Markers

Rice is a staple food for more than half of the world’s population. Modern rice varieties have been developed for high yield and quality; however, there has been a substantial loss of diversity. A greater number of genetically dynamic landraces could offer valuable and useful genetic resources for rice improvement. In this study, the genetic diversity and population structure of 365 accessions of lowland and upland landraces from four populations from different geographical regions of Thailand were investigated using 75 SNP markers. Clustering analyses using maximum likelihood, Principal Coordinate Analysis (PCoA), and Discriminant Analysis of Principal Components (DAPC) clustered these landraces into two main groups, corresponding to indica and japonica groups. The indica group was further clustered into two subgroups according to the DAPC and STRUCTURE analyses (K = 3). The analysis of molecular variance (AMOVA) analysis results revealed that 91% of the variation was distributed among individuals, suggesting a high degree of genetic differentiation among rice accessions within the populations. Pairwise FST showed the greatest genetic differentiation between the northeastern and southern populations and the smallest genetic differentiation between the northern and northeastern populations. Isolation-by-distance analysis based on a Mantel test indicated a significant relationship between the genetic distance and geographic distance among the Thai rice landraces. The results from this study provide insight into the genetic diversity of Thai rice germplasm, which will enhance the germplasm characterization, conservation, and utilization in rice genetics and breeding.

Influence of healthy lifestyle behaviors on life satisfaction in the aging population of Thailand: a national population-based survey

BackgroundUnderstanding the influence of healthy lifestyle behaviors on population-level life satisfaction is few known in the aging population, especially in low- and middle-income countries in Asia. The objective of our study was to analyse the association of lifestyle behaviors with life satisfaction in a nationally-representative sample of older persons in Thailand.MethodsThe sample was obtained from a baseline phase of a nationally-representative, longitudinal survey of the Thai population. The study employed a multistage sampling technique to recruit study participants age 60 years or older from the five geographic regions of Thailand. In this study, 1460 adults age 60 years or older from 3670 households successfully completed face-to-face interviews by trained staff with a structured questionnaire. Information on self-reported life satisfaction, lifestyle behaviors, and sociodemographic characteristics were collected via survey questionnaire. Life satisfaction was assessed using the Scale with Life Satisfaction (SWLS) [1 to 7] response. Binary logistic regression analysis was used in investigating the association between lifestyle behaviors and life satisfaction.ResultsThe median age of the participants was 68.1 (60–93 years). The overall mean life satisfaction score was 24.2 ± 5.6. Regular physical activity (at least 30 min per day) and sufficient fruit and vegetable (FV) intake (at least 400 g per day) were significantly associated with older people’s life satisfaction (p ≤ 0.001 and p ≤ 0.10, respectively) after controlling all sociodemographic variables. Participants who had regular physical activity were 1.7 times as likely to be satisfied as those with less physical activity (95% CI 1.284–2.151). Participants with sufficient daily FV intake were 1.3 times as likely to be satisfied with life as those with insufficient daily FV (95% CI 0.994–1.723). Life satisfaction score also differed significantly by sociodemographic characteristics (sex, age, marital status, educational attainment) and presence of chronic disease.ConclusionsTo improve the life satisfaction of older persons, taking into account sociodemographic characteristics of the population and absence of chronic disease, the need for promotion of healthy lifestyle behaviors, especially regular physical activity and sufficient FV intake, must be recommended.

Inadequate Calcium Consumption Among Thai Pregnant Women: A Cross Sectional Descriptive Study

Background: Low calcium intake during pregnancy can cause not only rapid bone turnover, increased risk of preeclampsia but also increase the risk of osteoporosis and high blood pressure in the next generation. This study aimed to assess the dietary calcium intake and evaluate the inadequacy of calcium consumption in Thai pregnant women across the country. Methods: A multicenter hospital-based cross-sectional study was performed nationwide in five study sites from four geographical regions of Thailand during 1st November 2017 and 31st January 2019. Thai healthy singleton pregnant women aged > 19 years were recruited. Pregnant women with any conditions that either hampered the dietary intake or contraindicated to take calcium were excluded. Dietary intake records immediately after eating for two working days and one holiday were obtained and compared to Thai food composition data-base analyzed via INMUCAL-NV3.0 program of Mahidol University by experienced nutritionists. Findings: A total amount of 1,549 records were obtained across the country. The mean calcium intake was 602·4 +/- 264·5 mg/dL. The overall prevalence of inadequate calcium intake (less than 800 mg/day) based on the Thai dietary reference intake (DRI)) was 82·0%. If the international recommendation (US Institute of Medicine) (less than 1,000 mg/day) is considered, the prevalence of inadequate calcium intake was 93·4%. Interpretation: The prevalence of inadequate calcium consumption of the Thai pregnant women across country was 82·0% and 93·4% according to Thai dietary reference intake in pregnancy and the international recommendation respectively. Routine calcium supplementation for Thai pregnant women should be recommended. Funding Statement: Thailand Research Fund (Distinguished Research Professor Award). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: This study was approved by the central research ethic committee (ref. no.CREC008/60BRm). Written informed consents were obtained from all recruited subjects.

Molecular Epidemiology and Genetic Diversity of Zika Virus from Field-Caught Mosquitoes in Various Regions of Thailand.

Zika virus (ZIKV) infection is an emerging and re-emerging arbovirus disease that is transmitted to humans through the bite of infected mosquitoes. ZIKV infections were first described in Thailand in 1954 from the sera of indigenous residents and several travelers returning from Thailand in 2014. However, reported cases in Thailand have been increasing since 2015 and 2016, and epidemiological information about the vectors of ZIKV is unclear. We investigated the molecular epidemiology and genetic diversity of ZIKV from mosquitoes collected from different geographic regions experiencing ZIKV outbreaks in Thailand. Polymerase chain reaction was used to amplify the non-structural protein (NS5) gene of ZIKV, which was then sequenced. A total of 1026 mosquito samples (626 females, 367 males, and 33 larvae) were collected from active ZIKV patients’ houses. ZIKV was detected in 79 samples (7.7%), including Aedes aegypti (2.24% female, 1.27% male, and 0.19% larvae), Culex quinquefasciatus (1.85% female, 1.66% male, and 0.29% larvae), and Armigeres subalbatus (0.1% female and 0.1% male), whereas no ZIKV was detected in Aedes albopictus. Phylogenetic analysis of the 79 positive samples were classified into two clades: Those closely related to a previous report in Thailand, and those related to ZIKV found in the Americas. This is the first report of the detection of ZIKV in Ae. aegypti, Cx. quinquefasciatus, and Ar. subalbatus mosquitoes, and genetic variations of ZIKV in the mosquitoes collected from several geographic regions of Thailand were examined. Detection of ZIKV in male and larval mosquitoes suggests that vertical transmission of ZIKV occurred in these mosquito species. This study provides a more in-depth understanding of the patterns and epidemiologic data of ZIKV in Thailand; the data could be used for future development of more effective prevention and control strategies of ZIKV in Thailand.

Molecular characterization of lepidopteran-specific toxin genes in Bacillus thuringiensis strains from Thailand.

A total of 511 local isolates of Bacillus thuringiensis from different geographical regions of Thailand were analyzed for the presence of the cry1A, cry1B, cry2A, cry9, and vip3A genes encoding for lepidopteran-specific toxins. PCR results revealed that 94.32% (482/511) of B. thuringiensis isolates harbored at least one of the detected genes, of which the cry1A, cry1B, cry2A, cry9, and vip3A genes were detected at frequencies of 90.61%, 89.63%, 76.32%, 40.70%, and 48.18%, respectively. Nineteen gene-combination profiles were discovered among 482 B. thuringiensis isolates, of which the most frequently detected profile contained the cry1A, cry1B, cry2A, and vip3A genes. Sixty-one isolates (12.66%), which harbored all of the detected insecticidal toxin genes, were further detected for the exochitinase (chi36) gene and chitinase activity. The results revealed that all 61 isolates contained the chi36 gene and exhibited chitinase activity. Insect bioassays showed that five isolates were highly toxic (more than 80% mortality) against second instar larvae of Spodoptera litura, of which the highest insect mortality (93%) was obtained from the B. thuringiensis isolates 225-15 and 417-1. Scanning electron microscopy revealed that the crystal morphologies of the five effective isolates were bipyramidal and cuboidal shapes. SDS-PAGE analysis of the spore-crystal mixture showed major bands of approximately 65 and 130kDa. These five effective strains are alternative candidates for use as a microbial insecticide for the control of the S. litura pest.

Distribution of Scedosporium species in soil from areas with high human population density and tourist popularity in six geographic regions in Thailand.

Scedosporium is a genus comprising at least 10 species of airborne fungi (saprobes) that survive and grow on decaying organic matter. These fungi are found in high density in human-affected areas such as sewage-contaminated water, and five species, namely Scedosporium apiospermum, S. boydii, S. aurantiacum, S. dehoogii, and S. minutisporum, cause human infections. Thailand is a popular travel destination in the world, with many attractions present in densely populated areas; thus, large numbers of people may be exposed to pathogens present in these areas. We conducted a comprehensive survey of Scedosporium species in 350 soil samples obtained from 35 sites of high human population density and tourist popularity distributed over 23 provinces and six geographic regions of Thailand. Soil suspensions of each sample were inoculated on three plates of Scedo-Select III medium to isolate Scedosporium species. In total, 191 Scedosporium colonies were isolated from four provinces. The species were then identified using PCR and sequencing of the beta-tubulin (BT2) gene. Of the 191 isolates, 188 were S. apiospermum, one was S. dehoogii, and species of two could not be exactly identified. Genetic diversity analysis revealed high haplotype diversity of S. apiospermum. Soil is a major ecological niche for Scedosporium and may contain S. apiospermum populations with high genetic diversity. This study of Scedosporium distribution might encourage health care providers to consider Scedosporium infection in their patients.

Genetic diversity and antigenicity variation of Babesia bovis merozoite surface antigen-1 (MSA-1) in Thailand

Babesia bovis, an intraerythrocytic protozoan parasite, causes severe clinical disease in cattle worldwide. The genetic diversity of parasite antigens often results in different immune profiles in infected animals, hindering efforts to develop immune control methodologies against the B. bovis infection. In this study, we analyzed the genetic diversity of the merozoite surface antigen-1 (msa-1) gene using 162 B. bovis-positive blood DNA samples sourced from cattle populations reared in different geographical regions of Thailand. The identity scores shared among 93 msa-1 gene sequences isolated by PCR amplification were 43.5–100%, and the similarity values among the translated amino acid sequences were 42.8–100%. Of 23 total clades detected in our phylogenetic analysis, Thai msa-1 gene sequences occurred in 18 clades; seven among them were composed of sequences exclusively from Thailand. To investigate differential antigenicity of isolated MSA-1 proteins, we expressed and purified eight recombinant MSA-1 (rMSA-1) proteins, including an rMSA-1 from B. bovis Texas (T2Bo) strain and seven rMSA-1 proteins based on the Thai msa-1 sequences. When these antigens were analyzed in a western blot assay, anti-T2Bo cattle serum strongly reacted with the rMSA-1 from T2Bo, as well as with three other rMSA-1 proteins that shared 54.9–68.4% sequence similarity with T2Bo MSA-1. In contrast, no or weak reactivity was observed for the remaining rMSA-1 proteins, which shared low sequence similarity (35.0–39.7%) with T2Bo MSA-1. While demonstrating the high genetic diversity of the B. bovis msa-1 gene in Thailand, the present findings suggest that the genetic diversity results in antigenicity variations among the MSA-1 antigens of B. bovis in Thailand.

Decreasing Hepatitis C Virus Infection in Thailand in the Past Decade: Evidence from the 2014 National Survey.

Hepatitis C virus (HCV) infection affects ≥ 180 million individuals worldwide especially those living in developing countries. Recent advances in direct-acting therapeutics promise effective treatments for chronic HCV carriers, but only if the affected individuals are identified. Good treatment coverage therefore requires accurate epidemiological data on HCV infection. In 2014, we determined the current prevalence of HCV in Thailand to assess whether over the past decade the significant number of chronic carriers had changed. In total, 5964 serum samples from Thai residents between 6 months and 71 years of age were obtained from 7 provinces representing all 4 geographical regions of Thailand and screened for the anti-HCV antibody. Positive samples were further analyzed using RT-PCR, sequencing, and phylogenetic analysis to identify the prevailing HCV genotypes. We found that 56 (0.94%) samples tested positive for anti-HCV antibody (mean age = 36.6±17.6 years), while HCV RNA of the core and NS5B subgenomic regions was detected in 23 (41%) and 19 (34%) of the samples, respectively. The seropositive rates appeared to increase with age and peaked in individuals 41–50 years old. These results suggested that approximately 759,000 individuals are currently anti-HCV-positive and that 357,000 individuals have viremic HCV infection. These numbers represent a significant decline in the prevalence of HCV infection. Interestingly, the frequency of genotype 6 variants increased from 8.9% to 34.8%, while the prevalence of genotype 1b declined from 27% to 13%. These most recent comprehensive estimates of HCV burden in Thailand are valuable towards evidence-based treatment coverage for specific population groups, appropriate allocation of resources, and improvement in the national public health policy.

A Revised Checklist of Chigger Mites (Acari: Trombiculidae) From Thailand, with the Description of Three New Species

Chigger mites of Thailand were studied on the basis of larvae collected from 19 small mammal species (17 species of Rodentia, 1 species of Erinaceomorpha, and 1 species of Scandentia) and revision of published data. Samples of 38 trombiculid species were collected from 11 provinces. Three new species were described: Trombiculindus kosapani sp. nov., Helenicula naresuani sp. nov., and Walchia chavali sp. nov. Ten species were recorded in Thailand for the first time: Leptotrombidium sialkotense Vercammen-Grandjean and Langston, 1976; Leptotrombidium subangulare Wen and Xiang, 1984; Leptotrombidium tenompaki Stekolnikov, 2013; Leptotrombidium turdicola Vercammen-Grandjean and Langston, 1976; Leptotrombidium yunlingense Yu, Yang, Zhang and Hu, 1981; Lorillatum hekouensis Yu, Chen and Lin, 1996; Helenicula pilosa (Abonnenc and Taufflieb, 1957); Gahrliepia xiaowoi Wen and Xiang, 1984; Walchia minuscuta Chen, 1978; and Walchia ventralis (Womersley, 1952). In all, 99 chigger mite species were considered; the presence of 93 species was established in Thailand by original data or properly documented records in the scientific literature. Evidence for 64 species records of 147 from a previous checklist of Thai chiggers (Tanskul 1993) remains unknown. Distribution of chigger species by geographical regions of Thailand is discussed.

Genetic and linguistic correlation of the Kra-Dai-speaking groups in Thailand.

The Kra-Dai linguistic family includes Thai and Lao as well as a great number of languages spoken by ethnic minorities in Southeast Asia. In Thailand, a dozen of other Kra-Dai languages are spoken in addition to Thai, the national language. The genetic structure of the Kra-Dai-speaking populations in Thailand has been studied extensively using uniparentally inherited markers. To extend this line of genetic investigation, this study used 15 autosomal microsatellites of 500 individuals from 11 populations, belonging to nine Kra-Dai ethnicities, namely, the Kaleung, Phu Thai, Saek, Nyo, Lao Isan, Yuan, Black Tai, Phuan and Lue. These ethnolinguistic groups are dispersed in three different geographic regions of Thailand, that is, Northern, Northeastern and Central. The results show a very low average of pairwised F(st) (0.0099), as well as no population substructure based on STRUCTURE analysis, indicating genetic homogeneity within the Kra-Dai-speaking group, possibly owing to shared linguistic ancestry. The Mantel test, an analysis of molecular variance, and the approximate Bayesian computation procedure employed to evaluate potential factors for driving genetic diversity revealed that language is the predominant factor affecting genetic variations, whereas geography is not. The result of distance-based clustering analyses and spatial analysis of molecular variance revealed genetic distinctions of some populations, reflecting the effects of genetic drift and gene flow on allele frequency within populations, in concordance with the result of R-matrix regression. The genetic and linguistic affiliations of the contemporary Kra-Dai-speaking groups are consistent with each other despite certain deviation due to various evolutionary factors that may have occurred during their migrations and resettlements.

Wolbachia infection in leafhoppers and planthoppers: Diversity, density and geographic distribution in tropical rice agroecosystems

Members of the genus Wolbachia are a group of endosymbiotic bacteria that infect a wide range of arthropods and cause reproductive alterations in their hosts. A survey of these endosymbionts in leafhoppers and planthoppers in rice agroecosystems from 20 provinces in 4 different geographic regions of Thailand was carried out during January 2012 to December 2013. Most species were collected from growing rice fields among 5 habitat types surveyed from the Central and the Northeast regions. Infections of Wolbachia were screened by using polymerase chain reaction with wsp, ftsZ, 16S rRNA and groE gene primers and distinguished between A and B supergroup using wsp primers. Species of 15 leafhoppers and 18 planthoppers were collected and identified with 1, 14, 2, 14, 1 and 1 sp. representing the family Aphrophoridae, Cicadellidae, Cixiidae, Delphacidae, Lophopidae and Meenoplidae, respectively. Wolbachia were detected in 1377 of 1849 individuals (74.5%) representing 17 of 33 species (51.5%) of leafhoppers and planthoppers. Wolbachia had not been previously reported from Oliarus sp., Pyrilla perpusilla, Sogatella kolophon and S. vibix. The relative densities of Wolbachia within each individual were determined using quantitative real-time PCR and the result showed that the small brown planthopper Laodelphax striatellus had the highest Wolbachia density. These findings indicated that Wolbachia are distributed throughout leafhoppers and planthoppers from Thailand, suggesting that Wolbachia dynamics in nature may be affected by ecological factors.

Molecular survey of the head louse Pediculus humanus capitis in Thailand and its potential role for transmitting Acinetobacter spp.

BackgroundHead louse infestation, which is caused by Pediculus humanus capitis, occurs throughout the world. With the advent of molecular techniques, head lice have been classified into three clades. Recent reports have demonstrated that pathogenic organisms could be found in head lice. Head lice and their pathogenic bacteria in Thailand have never been investigated. In this study, we determined the genetic diversity of head lice collected from various areas of Thailand and demonstrated the presence of Acinetobacter spp. in head lice.MethodsTotal DNA was extracted from 275 head louse samples that were collected from several geographic regions of Thailand. PCR was used to amplify the head louse COI gene and for detection of Bartonella spp. and Acinetobacter spp. The amplified PCR amplicons were cloned and sequenced. The DNA sequences were analyzed via the neighbor-joining method using Kimura’s 2-parameter model.ResultsThe phylogenetic tree based on the COI gene revealed that head lice in Thailand are clearly classified into two clades (A and C). Bartonella spp. was not detected in all the samples, whereas Acinetobacter spp. was detected in 10 samples (3.62%), which consisted of A. baumannii (1.45%), A. radioresistens (1.45%), and A. schindleri (0.72%). The relationship of Acinetobacter spp. and the head lice clades showed that Acinetobacter spp. was found in clade A and C.ConclusionsHead lice in Thailand are classified into clade A and B based on the COI gene sequences. Pathogenic Acinetobacter spp. was detected in both clades. The data obtained from the study might assist in the development of effective strategies for head lice control in the future. Detection of pathogenic bacteria in head lice could raise awareness of head lice as a source of nosocomial bacterial infections.

Distinct gut microbiota of healthy children from two different geographic regions of Thailand

In Thailand, food consumption by people from each region is different. This can be an important environmental factor which shapes the gut microbiota further affecting their health. This study aimed to use quantitative PCR (qPCR) to investigate the intestinal microbial community in 60 healthy children (aged 8-11 years) living in specific areas, namely central (CT) and northeastern (NE) Thailand where each region has its own typical food consumption. The children from NE had significantly higher consumption frequency of meat (chicken and beef), a wide variety of carbohydrate sources (noodle, fermented rice and sweet potato) including vegetables and fruit, while in CT, there was a significant preference for rice, breakfast cereal and cow milk. The qPCR analysis resulted in significantly higher abundance of lactobacilli, Clostridium coccoides-Eubacterium rectale, Clostridium leptum, Prevotella and Bacteroides fragilis in children from the NE region. However, no significant difference in the count of Bifidobacterium spp., Enterobacteriaceae and methanogens was observed. Considering the correlation of food sources and microbial groups, the consumption frequency of vegetables showed a moderately positive correlation coefficient of 0.42 and 0.34 to the Lactobacillus group (P = 0.001) and the Prevotella group (P = 0.008), respectively, while a diet of fish and beef showed a moderately negative correlation coefficient of -0.41 (P = 0.001) and -0.33 (P = 0.09) to Bifidobacterium spp., respectively. Our results suggested that high frequency consumption of varieties of carbohydrates, protein sources, fruits and vegetables by the NE children promoted a high abundance of bacterial species in the phyla Firmicutes and Bacteroidetes.

Distribution, diversity and density of wolbachial infections in cladocerans and copepods from Thailand

Species of the genus Wolbachia comprise a group of Rickettsia-like, maternally-inherited bacteria that cause several reproductive alterations in arthropod hosts. The best known are cytoplasmic incompatibility and feminization. Here, the first systematic surveys of wolbachial infections in cladocerans and copepods from six geographic regions of Thailand, including Northern, Northeastern, Western, Central, Eastern and Southern are reported. Using gene amplification assays with wsp and groE primers, wolbachiae were detected in 239 (4 spp.) of 1885 (57 spp.) copepods and cladocerans from all regions of Thailand surveyed. Screening results obtained with wsp primers or groE primers were similar in all cases. The presence of wolbachiae was only detected in copepods, not in cladocerans. Sex ratio analyses of the progeny of two species of copepods, Mesocyclops aspericornis and Mesocyclops thermocyclopoides, naturally or artificially infected with wolbachiae showed infection causes feminization (female-bias). The relative density if infection in naturally infected populations of three copepod species, M. thermocyclopoides, Heliodiaptomus elegans and Neodiaptomus blachei, were determined using real-time quantitative PCR assay based on the wsp gene. The density of wolbachiae in M. thermocyclopoides was significantly higher than in the other two species. These results suggest that wolbachial infections are distributed throughout Thailand, and that possibly the natural occurrence of these in copepods may be due to their predation on mosquito larvae. This apparent novel biology may have importance as a genetic drive system for control of vector borne diseases in the future.