Publications by authors named "Somchai Sangkitporn"

37 Publications

Intravitreal autologous mesenchymal stem cell transplantation: a non-randomized phase I clinical trial in patients with retinitis pigmentosa.

Stem Cell Res Ther 2021 Jan 9;12(1):52. Epub 2021 Jan 9.

Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkok Noi, Bangkok, 10700, Thailand.

Background: Retinitis pigmentosa (RP) is a progressive inherited retinal disease with great interest for finding effective treatment modalities. Stem cell-based therapy is one of the promising candidates. We aimed to investigate the safety, feasibility, and short-term efficacy of intravitreal injection of bone marrow-derived mesenchymal stem cells (BM-MSCs) in participants with advanced stage RP.

Methods: This non-randomized phase I clinical trial enrolled 14 participants, categorized into three groups based on a single dose intravitreal BM-MSC injection of 1 × 10, 5 × 10, or 1 × 10 cells. We evaluated signs of inflammation and other adverse events (AEs). We also assessed the best corrected visual acuity (BCVA), visual field (VF), central subfield thickness (CST), and subjective experiences.

Results: During the 12-month period, we noticed several mild and transient AEs. Interestingly, we found statistically significant improvements in the BCVA compared to baseline, although they returned to the baseline at 12 months. The VF and CST were stable, indicating no remarkable disease progression. We followed 12 participants beyond the study period, ranging from 1.5 to 7 years, and observed one severe but manageable AE at year 3.

Conclusion: Intravitreal injection of BM-MSCs appears to be safe and potentially effective. All adverse events during the 12-month period required observation without any intervention. For the long-term follow-up, only one participant needed surgical treatment for a serious adverse event and the vision was restored. An enrollment of larger number of participants with less advanced RP and long-term follow-up is required to evaluate the safety and efficacy of this intervention.

Trial Registration: ClinicalTrials.gov, NCT01531348 . Registered on February 10, 2012.
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http://dx.doi.org/10.1186/s13287-020-02122-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7796606PMC
January 2021

Identification of GII.14[P7] norovirus and its genomic mutations from a case of long-term infection in a post-symptomatic individual.

Infect Genet Evol 2020 12 1;86:104612. Epub 2020 Nov 1.

Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections, Nonthaburi, Thailand. Electronic address:

Norovirus is a leading cause of acute gastroenteritis worldwide. Norovirus shedding typically lasts one week to one month after the onset of diarrhea in immunocompetent hosts. The occurrence of mutations in the genome during infection has contributed to the evolution of norovirus. It has been suggested that genomic mutations in the P2-domain of capsid protein VP1, the major antigenic site for virus clearance, are involved in the evasion of host immunity and prolonged shedding of norovirus. In our previous study, we found a case of long-term shedding of GII.14 norovirus in a post-symptomatic immunocompetent individual that lasted about three months. In this study, we characterized the genomic sequence of the GII.14 strain to gain insight into the context of long-term shedding. By sequencing a 4.8 kb region of the genome corresponding to half of ORF1 and the entire ORF2 and ORF3, which encode several non-structural proteins and the structural proteins VP1 and VP2, the GII.14 strain was found to be classified as recombinant GII.14[P7]. Six point-mutations occurred during the three-month period of infection in a time-dependent manner in the genomic regions encoding RNA-dependent RNA polymerase, VP1, and VP2. Three of the six mutations were sense mutations, but no amino acid substitution was identified in the P2-domain of VP1. These results suggest that there is a mechanism by which long-term shedding of norovirus occurs in immunocompetent individuals independent of P2-domain mutations.
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http://dx.doi.org/10.1016/j.meegid.2020.104612DOI Listing
December 2020

Norovirus transmission mediated by asymptomatic family members in households.

PLoS One 2020 23;15(7):e0236502. Epub 2020 Jul 23.

Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections, Nonthaburi, Thailand.

The transmission of human norovirus excreted from infected persons occasionally causes sporadic infections and outbreaks. Both symptomatic patients and asymptomatic carriers have been reported to contribute to norovirus transmission, but little is known about the magnitude of the contribution of asymptomatic carriers. We carried out a 1-year survey of residents of a district of Bangkok, Thailand to determine the percentage of norovirus transmissions originating from asymptomatic individuals. We screened 38 individuals recruited from 16 families from May 2018 to April 2019 for GI and GII genotypes. Norovirus was detected every month, and 101 of 716 stool samples (14.1%) from individuals with no symptoms of acute gastroenteritis were norovirus-positive. The average infection frequency was 2.4 times per person per year. Fourteen genotypes were identified from the positive samples, with GII.4 being detected most frequently. Notably, 89.1% of the norovirus-positive samples were provided by individuals with no diarrhea episode. Similar to cases of symptomatic infections in Thailand, asymptomatic infections were observed most frequently in December. We detected 4 cases of NV infection caused by household transmission, and 3 of the 4 transmissions originated from asymptomatic individuals. We also identified a case in which norovirus derived from an asymptomatic individual caused diarrhea in a family member. These results suggest that asymptomatic individuals play a substantial role in both the maintenance and spreading of norovirus in a community through household transmission.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0236502PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7377487PMC
September 2020

High prevalence of equine-like G3P[8] rotavirus in children and adults with acute gastroenteritis in Thailand.

J Med Virol 2020 02 19;92(2):174-186. Epub 2019 Sep 19.

Department of Pediatrics, Fujita Health University School of Medicine, Toyoake, Aichi, Japan.

Group A rotavirus (RVA) is a major cause of acute gastroenteritis in infants and young children worldwide. This study aims to clarify the distribution of G/P types and genetic characteristics of RVAs circulating in Thailand. Between January 2014 and September 2016, 1867 stool specimens were collected from children and adults with acute gastroenteritis in six provinces in Thailand. RVAs were detected in 514/1867 (27.5%) stool specimens. G1P[8] (44.7%) was the most predominant genotype, followed by G3P[8] (33.7%), G2P[4] (11.5%), G8P[8] (7.0%), and G9P[8] (1.3%). Unusual G3P[9] (0.8%), G3P[10] (0.4%), G4P[6] (0.4%), and G10P[14] (0.2%) were also detected at low frequencies. The predominant genotype, G1P[8] (64.4%), in 2014 decreased to 6.1% in 2016. In contrast, the frequency of G3P[8] markedly increased from 5.5% in 2014 to 65.3% in 2015 and 89.8% in 2016. On polyacrylamide gel electrophoresis, most (135/140; 96.4%) of the G3P[8] strains exhibited a short RNA profile. Successful determination of the nucleotide sequences of the VP7 genes of 98 G3P[8] strains with a short RNA profile showed that they are all equine-like G3P[8] strains. On phylogenetic analysis of genome segments of two representative Thai equine-like G3P[8] strains, it was noteworthy that they possessed distinct NSP4 genes, one bovine-like and the other human-like. Thus, we found that characteristic equine-like G3P[8] strains with a short RNA electropherotype are becoming highly prevalent in children and adults in Thailand.
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http://dx.doi.org/10.1002/jmv.25591DOI Listing
February 2020

Molecular epidemiology and antimicrobial susceptibility of outbreak-associated Corynebacterium diphtheriae in Thailand, 2012.

Infect Genet Evol 2019 11 28;75:104007. Epub 2019 Aug 28.

Faculty of Public Health, Kasetsart University Chalermphrakiat Sakon Nakhon Province Campus, Sakon Nakhon, Thailand. Electronic address:

Infections caused by Corynebacterium diphtheriae remain endemic in many countries. Since the implementation of the DTP (Diphtheria-Tetanus-Pertussis) vaccination program in 1977, only sporadic diphtheria cases have been reported in Thailand. In 2012, a diphtheria outbreak occurred in rural Thailand and 38 cases were reported, with the majority being adults (mean 22.1 years, range 5-72 years). The current study determined the genetic diversity of C. diphtheriae isolated from 83 individuals associated with either sporadic (n = 34) from 1994, 1996, 1997, 1998, 1999, 2000, 2012, and 2018, or 2012 outbreak (n = 49) diphtheria occurrences in Thailand. Antimicrobial susceptibility testing was performed on 41/83 isolates using broth microdilution. All sporadic (n = 27) and epidemic (n = 14) C. diphtheriae isolates (41/41; 100%) were susceptible to erythromycin (≤0.5 μg/ml), clindamycin (≤0.5 μg/ml), gentamicin (≤ 4 μg/ml), ciprofloxacin (≤1 μg/ml), and vancomycin (2 μg/ml), except tetracycline with a resistance rate of 34.1% (14/41 isolates). All isolates were intermediately resistant to penicillin (MIC range, 0.25-2 μg/ml). Multilocus sequence typing (MLST) revealed 17 sequence types (STs) among 83C. diphtheriae isolates. For the 2012 outbreak isolates, the predominant ST was ST243 (n = 34/49; 69.4%), followed by ST245 (n = 5/49; 10.2%) and ST244 (n = 4/49; 8.1%), whereas the main STs among the sporadic isolates were ST248 (n = 15/34; 44.1%), followed by ST209 (n = 7/34; 20.6%) and ST258 (n = 3/34; 8.8%). The ST243 outbreak strain was a single-locus variant of sporadic ST258. Phylogenetic analysis using concatenated sequences of 7 MLST genes from 17 STs revealed that ST243, ST248, and ST258 were located in the same cluster and ST243 appeared to have evolved from ST258, an endemic strain. This study highlights the importance of epidemiological surveillance together with characterization of C. diphtheriae strains to help inform the future control and prevention of diphtheria.
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http://dx.doi.org/10.1016/j.meegid.2019.104007DOI Listing
November 2019

T-SPOT®.TB test and clinical risk scoring for diagnosis of latent tuberculosis infection among Thai healthcare workers.

J Microbiol Immunol Infect 2021 Apr 5;54(2):305-311. Epub 2019 Jun 5.

Division of Infectious Diseases, Faculty of Medicine, Thammasat University, Pathumthani, Thailand. Electronic address:

Background: Screening for latent tuberculosis infection (LTBI) is important to identify healthcare workers (HCWs) benefiting from preventive therapy. Interferon-gamma release assays (IGRAs) are sensitive and specific tests for LTBI diagnosis. However, in settings where IGRAs are not available, clinical risk assessment may be used as an alternative to diagnose LTBI.

Methods: A cross-sectional study was conducted among HCWs of a tertiary-care university hospital in Thailand. All HCWs underwent T-SPOT®.TB test (T-SPOT) and assessment of LTBI clinical risks. Clinical risks associated with T-SPOT positivity were determined by multivariable logistic regression analysis and were given scores accordingly. The performance of the clinical risk scoring was evaluated in comparison to T-SPOT.

Results: Among 140 enrolled HCWs, 125 (89%) were females, the median age was 27 years and 23 (16%) had T-SPOT positivity. Independent factors associated with T-SPOT positivity were age ≥30 years (adjusted odds ratio [aOR] 3.95; P = 0.002), working duration ≥60 months (aOR 3.75, P = 0.004) and frequency of TB contact ≥6 times (aOR 8.83, P = 0.005). The study's clinical risk scoring had the area under the curve by receiver operating curve analysis of 0.76 (P < 0.001) using T-SPOT positivity as a reference standard. The score of ≥3 had the best performance in diagnosing LTBI with sensitivity, specificity, positive predictive value and negative predictive value of 70%, 71%, 32% and 92%, respectively.

Conclusions: In this setting where LTBI was prevalent among HCWs but IGRAs are not widely available, the clinical risk scoring may be used as an alternative to diagnose LTBI in HCWs.
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http://dx.doi.org/10.1016/j.jmii.2019.04.013DOI Listing
April 2021

Long-term circulation of Zika virus in Thailand: an observational study.

Lancet Infect Dis 2019 04 27;19(4):439-446. Epub 2019 Feb 27.

Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR2000, CNRS, Paris, France; Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA. Electronic address:

Background: Little is known about the historical and current risk of Zika virus infection in southeast Asia, where the mosquito vector is widespread and other arboviruses circulate endemically. Centralised Zika virus surveillance began in Thailand in January, 2016. We assessed the long-term circulation of Zika virus in Thailand.

Methods: In this observational study, we analysed data from individuals with suspected Zika virus infection who presented at hospitals throughout the country and had biological samples (serum, plasma, or urine) tested for confirmation with PCR at the National Institute of Health laboratories in Bangkok. We analysed the spatial and age distribution of cases, and constructed time-resolved phylogenetic trees using genomes from Thailand and elsewhere to estimate when Zika virus was first introduced.

Findings: Of the 3089 samples from 1717 symptomatic individuals tested between January, 2016, and December, 2017, 368 were confirmed to have Zika virus infection. Cases of Zika virus infection were reported throughout the year, and from 29 of the 76 Thai provinces. Individuals had 2·8 times (95% CI 2·3-3·6) the odds of testing positive for Zika virus infection if they came from the same district and were sick within the same year of a person with a confirmed infection relative to the odds of testing positive anywhere, consistent with focal transmission. The probability of cases being younger than 10 years was 0·99 times (0·72-1·30) the probability of being that age in the underlying population. This probability rose to 1·62 (1·33-1·92) among those aged 21-30 years and fell to 0·53 (0·40-0·66) for those older than 50 years. This age distribution is consistent with that observed in the Zika virus epidemic in Colombia. Phylogenetic reconstructions suggest persistent circulation within Thailand since at least 2002.

Interpretation: Our evidence shows that Zika virus has circulated at a low but sustained level for at least 16 years, suggesting that Zika virus can adapt to persistent endemic transmission. Health systems need to adapt to cope with regular occurrences of the severe complications associated with infection.

Funding: European Research Council, National Science Foundation, and National Institutes of Health.
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http://dx.doi.org/10.1016/S1473-3099(18)30718-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6511259PMC
April 2019

Loop-Mediated Isothermal Amplification for Rapid Identification of Mycobacterium tuberculosis in Comparison with Immunochromatographic SD Bioline MPT64 Rapid in a High Burden Setting.

Jpn J Infect Dis 2019 Mar 31;72(2):112-114. Epub 2018 Oct 31.

Division of Global Epidemiology, Hokkaido University Research Center for Zoonosis Control.

Loop-mediated isothermal amplification (LAMP) was assessed for rapid identification of Mycobacterium tuberculosis complex (MTC) in comparison with an immunochromatographic test (ICT) using SD Bioline Ag MPT64 Rapid. One hundred and fifty-one MGIT cultures positive for acid-fast bacilli were tested for MTC. DNA was extracted from a small portion of culture samples by heat lysis and subjected to LAMP analysis. Of these, 144 were positive and 5 were negative by both tests. One culture that was ICT negative but was LAMP positive was confirmed to have a mutation in the mpt64 gene. The agreement was 98.68% (95% confidence interval [CI]: 94.80-99.77), and the kappa value was 0.83% (95% CI: 0.59-1.00). Good correlation results suggested that LAMP assay is a reliable molecular test for rapid identification of MTC and is practical for use in resource-limited, high burden settings.
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http://dx.doi.org/10.7883/yoken.JJID.2018.128DOI Listing
March 2019

QuantiFERON-TB Gold In-Tube test in active tuberculosis patients and healthy adults.

Rev Inst Med Trop Sao Paulo 2018 Oct 22;60:e56. Epub 2018 Oct 22.

Ministry of Public Health, Department of Disease Control, Bureau of Tuberculosis, Bangkok, Thailand.

Interferon-gamma (IFN-γ) release assays have improved latent tuberculosis (TB) detection and have been considered promising for the diagnosis of TB disease. However, diagnosis efficacy data is limited in high burden countries. The aim of this study was to determine the diagnostic potential of the QuantiFERON-TB Gold In-Tube (QFT-GIT) test for the diagnosis of active TB in an endemic setting for TB. A cross-sectional study was conducted in a group of 102 Thai patients with clinical symptoms and chest x-ray findings suggesting of active pulmonary TB and a group of 112 healthy adults. Testing was carried out using sputum microscopy, mycobacterial culture and QFT-GIT test. Of these patients, QFT-GIT was positive in 73 (71.57%), negative in 27 (26.47%), and undetermined in 2 (1.96%) cases. Among healthy controls, QFT-GIT was positive in 18 (16.07%), negative in 93 (83.04%), and undetermined in 1 (0.89%) person. Based on TB culture results, the sensitivity of QFTGIT for diagnosing active TB was 84.21% (95% confidence interval (CI); 72.13-92.52). The positive and negative predictive values were 65.75% (95% CI; 59.26-71.70) and 66.67% (95% CI; 49.94-80.04), respectively. The median IFN-γ level in culture-confirmed TB patients was 3.91 compared to 0.03 IU/mL of the healthy group. QFT-GIT appears to be a useful indirect test for TB diagnosis in Thailand and its use is recommended in association with clinical and radiological assessments for identifying active or latent TB.
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http://dx.doi.org/10.1590/S1678-9946201860056DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6199127PMC
October 2018

External Quality Assessment Scheme for HIV-1 Drug-Resistance Genotyping in Thailand.

AIDS Res Hum Retroviruses 2018 12 10;34(12):1028-1035. Epub 2018 Nov 10.

3 Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections (RCC-ERI), Nonthaburi, Thailand.

The efficacy of antiretroviral (ARV) therapy can be compromised by the emergence and transmission of HIV-1 drug-resistant strains. HIV-1 drug-resistance (DR) genotypic testing thus plays an important role in the selection of optimal treatment regimens for HIV-infected individuals. Given the complexities of the testing procedures and the variety of approaches used, there is considerable potential for results to vary between laboratories. In Thailand, the national External Quality Assessment (EQA) scheme assesses the DR genotype testing performance of laboratories. Here, we evaluated the performance of laboratories in nucleotide sequencing and compared drug-resistance-associated mutations (DRMs) in the HIV-1 protease (PR) and reverse transcriptase (RT) genes during 2010-2015. The EQA samples in the 12 panels showed predominance for the CRF01_AE (85%) and subtype B (15%). Fourteen laboratory datasets were generated: eight using TruGene (TG), two using ViroSeq (VS), and four using in-house (IH) assays. All IH and VS laboratories had penalty scores <7, whereas five of the eight TG laboratories had fluctuating penalty scores. Moreover, seven and six TG laboratories could not amplify the two identical samples, 10B and 10E samples, or the CRF01_AE. Our findings demonstrate the requirement for laboratory participation in the ongoing EQA program and the optimization of kit assays using CRF01_AE samples. Our results also indicate that one advantage of participation is that the laboratories can monitor and investigate the source of laboratory errors.
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http://dx.doi.org/10.1089/AID.2017.0299DOI Listing
December 2018

Characterization of a G10P[14] rotavirus strain from a diarrheic child in Thailand: Evidence for bovine-to-human zoonotic transmission.

Infect Genet Evol 2018 09 15;63:43-57. Epub 2018 May 15.

Department of Virology and Parasitology, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan.

An unusual rotavirus strain, DB2015-066 with the G10P[14] genotype (RVA/Human-wt/THA/DB2015-066/2015/G10P[14]), was detected in a stool sample from a child hospitalized with acute gastroenteritis in Thailand. Here, we sequenced and characterized the full-genome of the strain DB2015-066. On whole genomic analysis, strain DB2015-066 was shown to have a unique genotype constellation: G10-P[14]-I2-R2-C2-M2-A3-N2-T6-E2-H3. The backbone genes of this strain (I2-R2-C2-M2-A3-N2-T6-E2-H3) are commonly found in rotavirus strains from artiodactyls such as cattle. Furthermore, phylogenetic analysis indicated that each of the 11 genes of strain DB2015-066 could be of artiodactyl (likely bovine) origin. Thus, strain DB2015-066 appeared to be derived from through zoonotic transmission of a bovine rotavirus strain. Of note, the VP7 gene of strain DB2015-066 was located in G10 lineage-6 together with ones of bovine and bovine-like rotavirus strains, away from the clusters comprising other G10P[14] strains in G10 lineage-2/4/5/9, suggesting the occurrence of independent bovine-to-human interspecies transmission events. Our observations provide important insights into the origins of rare G10P[14] strains, and into dynamic interactions between artiodactyl and human rotavirus strains.
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http://dx.doi.org/10.1016/j.meegid.2018.05.009DOI Listing
September 2018

Viral etiologies of influenza-like illness and severe acute respiratory infections in Thailand.

Influenza Other Respir Viruses 2018 07 8;12(4):482-489. Epub 2018 May 8.

Influenza Program, Thailand Ministry of Public Health - U.S. Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand.

Background: Information on the burden, characteristics and seasonality of non-influenza respiratory viruses is limited in tropical countries.

Objectives: Describe the epidemiology of selected non-influenza respiratory viruses in Thailand between June 2010 and May 2014 using a sentinel surveillance platform established for influenza.

Methods: Patients with influenza-like illness (ILI; history of fever or documented temperature ≥38°C, cough, not requiring hospitalization) or severe acute respiratory infection (SARI; history of fever or documented temperature ≥38°C, cough, onset <10 days, requiring hospitalization) were enrolled from 10 sites. Throat swabs were tested for influenza viruses, respiratory syncytial virus (RSV), metapneumovirus (MPV), parainfluenza viruses (PIV) 1-3, and adenoviruses by polymerase chain reaction (PCR) or real-time reverse transcriptase-PCR.

Results: We screened 15 369 persons with acute respiratory infections and enrolled 8106 cases of ILI (5069 cases <15 years old) and 1754 cases of SARI (1404 cases <15 years old). Among ILI cases <15 years old, influenza viruses (1173, 23%), RSV (447, 9%), and adenoviruses (430, 8%) were the most frequently identified respiratory viruses tested, while for SARI cases <15 years old, RSV (196, 14%) influenza (157, 11%) and adenoviruses (90, 6%) were the most common. The RSV season significantly overlapped the larger influenza season from July to November in Thailand.

Conclusions: The global expansion of influenza sentinel surveillance provides an opportunity to gather information on the characteristics of cases positive for non-influenza respiratory viruses, particularly seasonality, although adjustments to case definitions may be required.
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http://dx.doi.org/10.1111/irv.12554DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6005612PMC
July 2018

The dynamics of norovirus genotypes and genetic analysis of a novel recombinant GII.P12-GII.3 among infants and children in Bangkok, Thailand between 2014 and 2016.

Infect Genet Evol 2018 06 20;60:133-139. Epub 2018 Feb 20.

Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections (RCC-ERI), Nonthaburi 11000, Thailand; Research Institute of Microbial Diseases, Osaka University, Suita, Osaka 565-0781, Japan; Osaka Institute of Public Health, Osaka 537-0025, Japan. Electronic address:

Norovirus (NoV) is the leading cause of viral acute gastroenteritis among all age groups in the world. We performed a molecular epidemiological study of the NoVs prevalent in Bangkok between November 2014 and July 2016 to investigate the emergence of new NoV variants in Thailand. A total of 332 stool specimens were collected from hospitalized pediatric patients with acute gastroenteritis in Bangkok, Thailand. NoVs were detected by real-time PCR. The genome of the N-terminal/shell domain was amplified, the nucleotide sequence was determined, and phylogenetic analyses were performed. GII NoV was detected in 58 (17.5%) of the 332 specimens. GII.17, a genotype strain prevalent from 2014 to mid-2015, was hardly detected and replaced by the GII.3 genotype strain. Entire genome sequencing followed by phylogenetic analysis of the GII.3 genotype strains indicated that they are new recombinant viruses, because the genome encoding ORF1 is derived from a GII.12 genotype strain, whereas that encoding ORF2-3 is from a GII.3 genotype strain. The putative recombination breakpoints with the highest statistical significance were located around the border of 3D and ORF2. The change in the prevalent strain of NoV seems to be linked to the emergence of new forms of recombinant viruses. These findings suggested that the swapping of the structural and non-structural proteins of NoV is a common mechanism by which new epidemic variants are generated in nature.
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http://dx.doi.org/10.1016/j.meegid.2018.02.028DOI Listing
June 2018

Naturally Occurring Mutations in HIV-1 CRF01_AE Capsid Affect Viral Sensitivity to Restriction Factors.

AIDS Res Hum Retroviruses 2018 04 13;34(4):382-392. Epub 2018 Feb 13.

3 National Institute of Health , Department of Medical Science, Ministry of Public Health, Nonthaburi, Thailand .

TRIM5α and MxB are known as restriction factors that inhibit the early step of intracellular HIV-1 replication cycle. Both factors are believed to interact with the incoming virus core to suppress HIV-1 infection. The extreme diversity of HIV-1 is thought to be a consequence of its propensity to mutate to escape immune responses and host restriction factors. We recently determined the capsid sequences for 144 HIV-1 CRF01_AE viruses obtained in Thailand from 2005 to 2011. In this study, we further analyzed the amino acid variations among the capsid sequences of 204 HIV-1 CRF01_AE obtained in Thailand and China, including 84 of the aforementioned 144 viruses, to detect mutations permitting escape from restriction by host factors. We found a characteristic combination of E79D, V83T, and H87Q in sequences from Chinese viruses and subsequently showed that this combination conferred partial resistance to MxB. Interestingly, this combination conferred resistance to human TRIM5α as well. The H87Q mutation alone conferred resistance to MxB in the CRF01_AE background, but not in subtype B virus. In contrast, the H87Q mutation alone conferred resistance to human TRIM5α in both the CFR01_AE and subtype B backgrounds. BLAST analysis revealed the presence of the E79D, V83T, and H87Q combination in CRF01_AE viruses isolated not only in China but also in many other countries. Although the mechanistic details as well as precise role of MxB antiviral activity in infected individuals remain to be clarified, our data suggest an interaction between MxB and the HIV-1 capsid in vivo.
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http://dx.doi.org/10.1089/AID.2017.0212DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5899301PMC
April 2018

Identification and characterization of a human G9P[23] rotavirus strain from a child with diarrhoea in Thailand: evidence for porcine-to-human interspecies transmission.

J Gen Virol 2017 Apr 6;98(4):532-538. Epub 2017 Apr 6.

Department of Virology and Parasitology, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan.

An unusual rotavirus strain with the G9P[23] genotype (RVA/Human-wt/THA/KKL-117/2014/G9P[23]) was identified in a stool specimen from a 10-month-old child hospitalized with severe diarrhoea. In this study, we sequenced and characterized the complete genome of strain KKL-117. On full-genomic analysis, strain KKL-117 was found to have the following genotype constellation: G9-P[23]-I5-R1-C1-M1-A8-N1-T1-E1-H1. The non-G/P genotype constellation of this strain (I5-R1-C1-M1-A8-N1-T1-E1-H1) is commonly shared with rotavirus strains from pigs. Furthermore, phylogenetic analysis indicated that each of the 11 genes of strain KKL-117 appeared to be of porcine origin. Our observations provide important insights into the dynamic interactions between human and porcine rotavirus strains.
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http://dx.doi.org/10.1099/jgv.0.000722DOI Listing
April 2017

An Outbreak of Acute Hepatitis Caused by Genotype IB Hepatitis A Viruses Contaminating the Water Supply in Thailand.

Intervirology 2016 17;59(4):197-203. Epub 2017 Feb 17.

National Institute of Health, Ministry of Public Health, Nonthaburi, Thailand.

Background: In 2000, an outbreak of acute hepatitis A was reported in a province adjacent to Bangkok, Thailand.

Aims: To investigate the cause of the 2000 hepatitis A outbreaks in Thailand using molecular epidemiological analysis.

Methods: Serum and stool specimens were collected from patients who were clinically diagnosed with acute viral hepatitis. Water samples from drinking water and deep-drilled wells were also collected. These specimens were subjected to polymerase chain reaction (PCR) amplification and sequencing of the VP1/2A region of the hepatitis A virus (HAV) genome. The entire genome sequence of one of the fecal specimens was determined and phylogenetically analyzed with those of known HAV sequences.

Results And Conclusions: Eleven of 24 fecal specimens collected from acute viral hepatitis patients were positive as determined by semi- nested reverse transcription PCR targeting the VP1/2A region of HAV. The nucleotide sequence of these samples had an identical genotype IB sequence, suggesting that the same causative agent was present. The complete nucleotide sequence derived from one of the samples indicated that the Thai genotype IB strain should be classified in a unique phylogenetic cluster. The analysis using an adjusted odds ratio showed that the consumption of groundwater was the most likely risk factor associated with the disease.
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http://dx.doi.org/10.1159/000455856DOI Listing
April 2017

Emergence of plasmid-mediated colistin resistance and New Delhi metallo-β-lactamase genes in extensively drug-resistant Escherichia coli isolated from a patient in Thailand.

Diagn Microbiol Infect Dis 2017 Feb 14;87(2):157-159. Epub 2016 Nov 14.

Division of Global Health Protection, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.

We reported a case of Escherichia coli with colistin resistance and an extensively drug-resistant phenotype. Molecular analysis revealed that the isolate carried mcr-1 and multiple β-lactamase genes includingbla, bla, bla, and bla. This is the first report of a clinical mcr-1 isolate in Thailand highlighting the urgent need for a comprehensive antimicrobial resistance containment strategy to prevent further spread.
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http://dx.doi.org/10.1016/j.diagmicrobio.2016.11.005DOI Listing
February 2017

Full Genome Characterization of Novel DS-1-Like G8P[8] Rotavirus Strains that Have Emerged in Thailand: Reassortment of Bovine and Human Rotavirus Gene Segments in Emerging DS-1-Like Intergenogroup Reassortant Strains.

PLoS One 2016 1;11(11):e0165826. Epub 2016 Nov 1.

Department of Virology and Parasitology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan.

The emergence and rapid spread of unusual DS-1-like intergenogroup reassortant rotavirus strains have been recently reported in Asia, Australia, and Europe. During rotavirus surveillance in Thailand in 2013-2014, novel DS-1-like intergenogroup reassortant strains having G8P[8] genotypes (i.e., strains KKL-17, PCB-79, PCB-84, PCB-85, PCB-103, SKT-107, SWL-12, NP-130, PCB-656, SKT-457, SSKT-269, and SSL-55) were identified in stool samples from hospitalized children with severe diarrhea. In this study, we determined and characterized the complete genomes of these 12 strains (seven strains, KKL-17, PCB-79, PCB-84, PCB-85, PCB-103, SKT-107, and SWL-12, found in 2013 (2013 strains), and five, NP-130, PCB-656, SKT-457, SSKT-269, and SSL-55, in 2014 (2014 strains)). On full genomic analysis, all 12 strains showed a unique genotype constellation comprising a mixture of genogroup 1 and 2 genes: G8-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2. With the exception of the G genotype, the unique genotype constellation of the 12 strains (P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2) was found to be shared with DS-1-like intergenogroup reassortant strains. On phylogenetic analysis, six of the 11 genes of the 2013 strains (VP4, VP2, VP3, NSP1, NSP3, and NSP5) appeared to have originated from DS-1-like intergenogroup reassortant strains, while the remaining four (VP7, VP6, VP1, and NSP2) and one (NSP4) gene appeared to be of bovine and human origin, respectively. Thus, the 2013 strains appeared to be reassortant strains as to DS-1-like intergenogroup reassortant, bovine, bovine-like human, and/or human rotaviruses. On the other hand, five of the 11 genes of the 2014 strains (VP4, VP2, VP3, NSP1, and NSP3) appeared to have originated from DS-1-like intergenogroup reassortant strains, while three (VP7, VP1, and NSP2) and one (NSP4) were assumed to be of bovine and human origin, respectively. Notably, the remaining two genes, VP6 and NSP5, of the 2014 strains appeared to have originated from locally circulating DS-1-like G2P[4] human rotaviruses. Thus, the 2014 strains were assumed to be multiple reassortment strains as to DS-1-like intergenogroup reassortant, bovine, bovine-like human, human, and/or locally circulating DS-1-like G2P[4] human rotaviruses. Overall, the great genomic diversity among the DS-1-like intergenogroup reassortant strains seemed to have been generated through additional reassortment events involving animal and human strains. Moreover, all the 11 genes of three of the 2014 strains, NP-130, PCB-656, and SSL-55, were very closely related to those of Vietnamese DS-1-like G8P[8] strains that emerged in 2014-2015, indicating the derivation of these DS-1-like G8P[8] strains from a common ancestor. To our knowledge, this is the first report on full genome-based characterization of DS-1-like G8P[8] strains that have emerged in Thailand. Our observations will add to our growing understanding of the evolutionary patterns of emerging DS-1-like intergenogroup reassortant strains.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0165826PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5089778PMC
June 2017

Predominant prevalence of human rotaviruses with the G1P[8] and G8P[8] genotypes with a short RNA profile in 2013 and 2014 in Sukhothai and Phetchaboon provinces, Thailand.

J Med Virol 2017 04 7;89(4):615-620. Epub 2016 Sep 7.

Department of Virology and Parasitology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan.

Of 2,754 stool specimens collected from children with acute gastroenteritis during 2013-2014 in Sukhothai and Phetchaboon provinces, Thailand, 666 (24.2%) were positive for rotavirus A (RVA) in polyacrylamide gel electrophoresis (PAGE). The G and P types of all RVA-positive specimens were determined by semi-nested RT-PCR. G1P[8] (56.5%) was most prevalent, followed by G2P[4] (22.1%). Unusual G8P[8] human RVAs (HuRVAs) were detected at a high frequency (20.0%). Interestingly, 171 of the 376 G1P[8] HuRVAs and all of the 133 G8P[8] HuRVAs showed a short RNA pattern in PAGE. Thus, it was shown that the properties of HuRVAs have been markedly unusual in recent years in Thailand. J. Med. Virol. 89:615-620, 2017. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/jmv.24669DOI Listing
April 2017

Vertical transmission of Indian Ocean Lineage of chikungunya virus in Aedes aegypti and Aedes albopictus mosquitoes.

Parasit Vectors 2016 Apr 23;9:227. Epub 2016 Apr 23.

Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.

Background: The re-emergence of chikungunya (CHIK) fever in Thailand has been caused by a novel lineage of chikungunya virus (CHIKV) termed the Indian Ocean Lineage (IOL). The Aedes albopictus mosquito is thought to be a primary vector of CHIK fever in Thailand, whereas Ae. aegypti acts as a secondary vector of the virus. The vertical transmission is believed to be a primary means to maintain CHIKV in nature and may be associated with an increased risk of outbreak. Therefore, the goal of this study was to analyze the potential of these two Thai mosquito species to transmit the virus vertically and to determine the number of successive mosquito generations for the virus transmission.

Methods: Two-hundred-and-fifty female Ae. aegypti and Ae. albopictus mosquitoes were artificially fed a mixture of human blood and CHIKV IOL. Mosquito larvae and adults were sampled and screened for CHIKV by one-step qRT-PCR. LLC-MK2 cell line was used to isolate CHIKV in the mosquitoes each generation. The virus isolate was identified by immunocytochemical staining and was confirmed by sequencing. Both mosquito species fed on human blood without CHIKV and uninfected LLC-MK2 cells were used as controls.

Results: Aedes aegypti and Ae. albopictus mosquitoes were able to transmit CHIKV vertically to F5 and F6 progenies, respectively. The virus isolated from the two mosquito species caused cytopathic effect in LLC-MK2 cells by 2 days post-infection and immunocytochemical staining showed the reaction between CHIKV IOL antigen and specific monoclonal antibody in the infected cells. DNA sequence confirmed the virus transmitted vertically as CHIKV IOL with E1-A226V mutation. No CHIKV infection was observed in both mosquito species and LLC-MK2 cells from control groups.

Conclusions: The study demonstrated that Ae. aegypti and Ae. albopictus mosquitoes from Thailand are capable of transmitting CHIKV IOL vertically in the laboratory. Our results showed that Ae. albopictus is more susceptible and has a greater ability to transmit the virus vertically than Ae. aegypti. This knowledge would be useful for risk assessments of the maintenance of CHIKV in nature, which is crucial for disease surveillance, vector control and the prevention of potential CHIKV epidemics.
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http://dx.doi.org/10.1186/s13071-016-1505-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4842298PMC
April 2016

Circulation of HIV-1 Multiple Complexity Recombinant Forms Among Female Sex Workers Recently Infected with HIV-1 in Thailand.

AIDS Res Hum Retroviruses 2016 07 19;32(7):694-701. Epub 2016 Apr 19.

4 Research Institute of Microbial Diseases, Osaka University , Osaka, Japan .

The circulating subtype distribution of HIV-1 has not been well characterized in female sex worker (FSW) populations in Thailand. To understand the mechanisms and interrelationships of epidemics involving FSWs in Thailand, we performed a large molecular epidemiological study of FSWs aged 25 years with recently acquired HIV-1 infections. The samples were collected in 2005, 2007, 2009, and 2011 in 38 provinces, representing every region of Thailand. After gag (p24), pol (pro-RT), and env (C2/V3) were sequenced, comprehensive genome analysis was performed. Genetic subtypes were determined in 159 plasma samples. The percentage of circulating recombinant forms (CRFs) CRF01_AE (90.6%) predominated, while subtype B (1.3%), other CRFs (1.9%), and unique recombinant forms (URFs) (6.2%) were identified as minor populations. Interestingly, the unique recombinant nature of these HIV-1 strains was verified in 10 specimens, indicating the presence of new forms of HIV-1 intersubtypes G/A, C/B, AE/B/C, and AE/B with different recombination breakpoints. Subtype B has contributed to these new generations of unique CRF01/B recombinants, especially in the pol (RT) gene, in which the template switching of the RT genomes occurred during reverse transcription. These results imply that the several unique recombinant viruses circulating in Thailand were probably generated in the population or introduced from neighboring countries. Our study helps clarify the patterns of viral transmission and define transmission pathways in Thailand.
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http://dx.doi.org/10.1089/AID.2015.0371DOI Listing
July 2016

Reassortment of Human and Animal Rotavirus Gene Segments in Emerging DS-1-Like G1P[8] Rotavirus Strains.

PLoS One 2016 4;11(2):e0148416. Epub 2016 Feb 4.

Department of Virology and Parasitology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan.

The emergence and rapid spread of novel DS-1-like G1P[8] human rotaviruses in Japan were recently reported. More recently, such intergenogroup reassortant strains were identified in Thailand, implying the ongoing spread of unusual rotavirus strains in Asia. During rotavirus surveillance in Thailand, three DS-1-like intergenogroup reassortant strains having G3P[8] (RVA/Human-wt/THA/SKT-281/2013/G3P[8] and RVA/Human-wt/THA/SKT-289/2013/G3P[8]) and G2P[8] (RVA/Human-wt/THA/LS-04/2013/G2P[8]) genotypes were identified in fecal samples from hospitalized children with acute gastroenteritis. In this study, we sequenced and characterized the complete genomes of strains SKT-281, SKT-289, and LS-04. On whole genomic analysis, all three strains exhibited unique genotype constellations including both genogroup 1 and 2 genes: G3-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 for strains SKT-281 and SKT-289, and G2-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 for strain LS-04. Except for the G genotype, the unique genotype constellation of the three strains (P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2) is commonly shared with DS-1-like G1P[8] strains. On phylogenetic analysis, nine of the 11 genes of strains SKT-281 and SKT-289 (VP4, VP6, VP1-3, NSP1-3, and NSP5) appeared to have originated from DS-1-like G1P[8] strains, while the remaining VP7 and NSP4 genes appeared to be of equine and bovine origin, respectively. Thus, strains SKT-281 and SKT-289 appeared to be reassortant strains as to DS-1-like G1P[8], animal-derived human, and/or animal rotaviruses. On the other hand, seven of the 11 genes of strain LS-04 (VP7, VP6, VP1, VP3, and NSP3-5) appeared to have originated from locally circulating DS-1-like G2P[4] human rotaviruses, while three genes (VP4, VP2, and NSP1) were assumed to be derived from DS-1-like G1P[8] strains. Notably, the remaining NSP2 gene of strain LS-04 appeared to be of bovine origin. Thus, strain LS-04 was assumed to be a multiple reassortment strain as to DS-1-like G1P[8], locally circulating DS-1-like G2P[4], bovine-like human, and/or bovine rotaviruses. Overall, the great genomic diversity among the DS-1-like G1P[8] strains seemed to have been generated through reassortment involving human and animal strains. To our knowledge, this is the first report on whole genome-based characterization of DS-1-like intergenogroup reassortant strains having G3P[8] and G2P[8] genotypes that have emerged in Thailand. Our observations will provide important insights into the evolutionary dynamics of emerging DS-1-like G1P[8] strains and related reassortant ones.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0148416PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4742054PMC
July 2016

Emergence and Characterization of Unusual DS-1-Like G1P[8] Rotavirus Strains in Children with Diarrhea in Thailand.

PLoS One 2015 5;10(11):e0141739. Epub 2015 Nov 5.

Department of Virology and Parasitology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan.

The emergence and rapid spread of unusual DS-1-like G1P[8] rotaviruses in Japan have been recently reported. During rotavirus surveillance in Thailand, three DS-1-like G1P[8] strains (RVA/Human-wt/THA/PCB-180/2013/G1P[8], RVA/Human-wt/THA/SKT-109/2013/G1P[8], and RVA/Human-wt/THA/SSKT-41/2013/G1P[8]) were identified in stool specimens from hospitalized children with severe diarrhea. In this study, we sequenced and characterized the complete genomes of strains PCB-180, SKT-109, and SSKT-41. On whole genomic analysis, all three strains exhibited a unique genotype constellation including both genogroup 1 and 2 genes: G1-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2. This novel genotype constellation is shared with Japanese DS-1-like G1P[8] strains. Phylogenetic analysis revealed that the G/P genes of strains PCB-180, SKT-109, and SSKT-41 appeared to have originated from human Wa-like G1P[8] strains. On the other hand, the non-G/P genes of the three strains were assumed to have originated from human DS-1-like strains. Thus, strains PCB-180, SKT-109, and SSKT-41 appeared to be derived through reassortment event(s) between Wa-like G1P[8] and DS-1-like human rotaviruses. Furthermore, strains PCB-180, SKT-109, and SSKT-41 were found to have the 11-segment genome almost indistinguishable from one another in their nucleotide sequences and phylogenetic lineages, indicating the derivation of the three strains from a common origin. Moreover, all the 11 genes of the three strains were closely related to those of Japanese DS-1-like G1P[8] strains. Therefore, DS-1-like G1P[8] strains that have emerged in Thailand and Japan were assumed to have originated from a recent common ancestor. To our knowledge, this is the first report on whole genome-based characterization of DS-1-like G1P[8] strains that have emerged in an area other than Japan. Our observations will provide important insights into the evolutionary dynamics of emerging DS-1-like G1P[8] rotaviruses.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0141739PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4634990PMC
June 2016

Whole Genomic Analysis of an Unusual Human G6P[14] Rotavirus Strain Isolated from a Child with Diarrhea in Thailand: Evidence for Bovine-To-Human Interspecies Transmission and Reassortment Events.

PLoS One 2015 30;10(9):e0139381. Epub 2015 Sep 30.

Department of Virology and Parasitology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan.

An unusual rotavirus strain, SKT-27, with the G6P[14] genotypes (RVA/Human-wt/THA/SKT-27/2012/G6P[14]), was identified in a stool specimen from a hospitalized child aged eight months with severe diarrhea. In this study, we sequenced and characterized the complete genome of strain SKT-27. On whole genomic analysis, strain SKT-27 was found to have a unique genotype constellation: G6-P[14]-I2-R2-C2-M2-A3-N2-T6-E2-H3. The non-G/P genotype constellation of this strain (I2-R2-C2-M2-A3-N2-T6-E2-H3) is commonly shared with rotavirus strains from artiodactyls such as cattle. Phylogenetic analysis indicated that nine of the 11 genes of strain SKT-27 (VP7, VP4, VP6, VP2-3, NSP1, NSP3-5) appeared to be of artiodactyl (likely bovine) origin, while the remaining VP1 and NSP2 genes were assumed to be of human origin. Thus, strain SKT-27 was found to have a bovine rotavirus genetic backbone, and thus is likely to be of bovine origin. Furthermore, strain SKT-27 appeared to be derived through interspecies transmission and reassortment events involving bovine and human rotavirus strains. Of note is that the VP7 gene of strain SKT-27 was located in G6 lineage-5 together with those of bovine rotavirus strains, away from the clusters comprising other G6P[14] strains in G6 lineages-2/6, suggesting the occurrence of independent bovine-to-human interspecies transmission events. To our knowledge, this is the first report on full genome-based characterization of human G6P[14] strains that have emerged in Southeast Asia. Our observations will provide important insights into the origin of G6P[14] strains, and into dynamic interactions between human and bovine rotavirus strains.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0139381PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4589232PMC
June 2016

Tuberculin Skin Test and QuantiFERON(®)-TB Gold In-Tube Test for Diagnosing Latent Tuberculosis Infection among Thai Healthcare Workers.

Jpn J Infect Dis 2016 May 7;69(3):224-30. Epub 2015 Aug 7.

Division of Infectious Diseases, Faculty of Medicine, Thammasat University.

A cross-sectional study was conducted on the performance of the tuberculin skin test (TST) and QuantiFERON(®)-TB Gold In-Tube test (QFT-IT) for detecting latent tuberculosis infection among Thai healthcare workers (HCWs). Each HCW underwent both the TST and QFT-IT during the annual health screening. Among the 260 HCWs enrolled, the median age was 30 years (range 19-60 years), 92% were women, 64% were nurses and nurse assistants, 78% were Bacillus Calmette Guérin vaccinated, and 37% had previously taken the TST. Correlation between TST reaction size and the interferon-γ level was weak (r = 0.29; P < 0.001). Of the HCWs, 38% and 20% had a reactive TST and a positive QFT-IT, respectively. Using QFT-IT positivity as a standard for latent tuberculosis diagnosis, the cut-off for TST reactivity with the best performance was ≥13 mm with a sensitivity, specificity, false positivity, and false negativity of 71%, 70%, 30%, and 29%, respectively (area under the curve 0.73; P < 0.001). The independent factor associated with a false reactive TST was a previous TST (adjusted odds ratio 1.83; P = 0.04). Our findings suggest that the QFT-IT may be the preferred test among HCWs with previous TST. In settings where the QFT-IT is not available, appropriate cut-offs for TST reactivity should be evaluated for use among HCWs.
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http://dx.doi.org/10.7883/yoken.JJID.2015.181DOI Listing
May 2016

Comparative field efficacy of newly developed formulations of larvicides against Aedes aegypti (L.) (Diptera: Culicidae).

Southeast Asian J Trop Med Public Health 2013 Sep;44(5):753-60

Department of Entomology University of California, Riverside, USA.

Aedes aegypti (L.) is known as vector of dengue and chikungunya fever. Larvicides are used to control this vector. We evaluated the efficacy of newly developed formulations of larvicides to control Ae. aegypti under field conditions for 24 weeks post single application. Mosdop P and Mosdop TB containing diflubenzuron (2% and 40 mg/tablet, respectively) as the active ingredient, were applied at a dosage of 0.1 mg a.i./1 and Mosquit TB10, Mosquit TB100 and Temecal containing temephos (1%, 10% and 1%, respectively) as the active ingredient were applied at a dosage of 1 mg active ingredent (a.i.) to 200 liter water storage jars. Two water regimens were used in the jars: in one regimen the jar was kept full of water all the time and in the other regimen a full jar had half the volume removed and refilled weekly. The larvicidal efficacy was reported as the level of inhibition of emergence (IE%) calculated based on the pupal skins in the jars versus the original number of larvae added. Mosdop P, Mosdop TB, Mosquit TB10, Mosquit TB100 and Temecal showed complete larvicidal efficacy (100% IE) in the constantly full jars for 16, 17, 14, 20 and 13 weeks posttreatment, respectively; in the jars where half the volum of water was replaced weekly, the larvicides had complete larvicidal efficacy (100% IE) for 19, 20, 17, 24 and 15 weeks post-treatment, respectively. The five larvicide regimens evaluated in this study are effective for controlling Ae. aegypti larvae.
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September 2013

An outbreak of foodborne botulism in Surat Thani Province, Thailand, 2012.

Jpn J Infect Dis 2013 ;66(4):353-4

National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand.

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http://dx.doi.org/10.7883/yoken.66.353DOI Listing
February 2014

Multicenter validation of fully automated capillary electrophoresis method for diagnosis of thalassemias and hemoglobinopathies in Thailand.

Southeast Asian J Trop Med Public Health 2011 Sep;42(5):1224-32

Clinical Research Center, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand.

Thalassemias and hemoglobinopathies are highly prevalent in Thailand and other Southeast Asian countries. Accurate and precise separation of hemoglobin types, together with reliable quantitation, are essential for differential diagnosis of these diseases. Presented in this study is a multicenter validation of a fully automated capillary electrophoresis (CE) method for hemoglobin separation and quantitation involving four reference laboratories in Thailand. Analytical performance characteristics, including precision and accuracy were compared with existing validated HPLC and LPLC methods using 412 blood samples from unrelated subjects. Coefficient of variance of Hb A2 quantitation was 1.80-2.86, 1.26-5.13 and 1.08-6.66% for within run, between run and interlaboratory comparison, respectively. Results of Hb A2 and Hb F quantitated by the CE method correlates well with those of the two comparative methods (r = 0.98-0.99). The CE method correctly determined the genotypes (thalassemias and hemoglobin variants) of all blood samples tested. The major advantage of the CE system is its ability to separate and quantitate Hb A2, Hb E, Hb F, Hb H and Hb Bart's, which are important parameters required for diagnosis of thalassemias and hemoglobinopathies.
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September 2011

Validation of osmotic fragility test and dichlorophenol indophenol precipitation test for screening of thalassemia and Hb E.

Southeast Asian J Trop Med Public Health 2005 Nov;36(6):1538-42

National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand.

The strategy for screening of thalassemia and Hb E by a combination of osmotic fragility (OF) test and dichlorophenol indophenol precipitation (DCIP) test was validated with 436 unrelated Thai subjects. Hemoglobin (Hb) typing, Hb A2 quantitation, PCR and DNA sequence analysis were used as confirmatory methods for diagnosis of thalassemia and hemoglobinopathy. The sensitivity and specificity of this strategy was 100% and 79.7%, respectively. The results assessed by two medical scientists were exactly the same with 93.3% accuracy in comparison with the confirmatory methods. A combination of OF and DCIP has been shown to be a reliable, rapid, simple and sensitive strategy for screening thalassemia and Hb E in the Thai population.
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November 2005