The RNA helicase DDX3 promotes IFNB transcription via enhancing IRF-3/p300 holocomplex binding to the IFNB promoter.

The human DEAD-box protein 3 (DDX3) has been reported as a positive regulator and functions in the induction of type I interferon signaling. We elucidated the function of DDX3 in the positive regulation of IFNB production in non-pDC cells. We found that DDX3 regulates virus-induced activation of IFNB at the level of IRF-3. However, it does not affect conventional innate signaling, including IRF-3 phosphorylation, dimerization, or nuclear translocation of IRF-3, but has some downstream events after IRF-3 phosphorylation. Co-immunoprecipitation analyses revealed that DDX3 interacts with IRF-3 through its DNA-binding domain and promotes IRF-3-mediated IFNB promoter activation. DDX3 does not affect the formation of the IRF-3/p300/CBP complex. Instead, ChIP and EMSA assay revealed that DDX3 promotes the recruitment of IRF-3 and transcriptional co-activator p300/CBP to the IFNB promoter. The ATP binding pocket of DDX3 is involved in this association and is essential for the transcriptional activation. Taken together, our study demonstrates that DDX3 plays an important role in guiding a transcription factor complex formed by antiviral signaling to the target gene promoter.

Detection and genetic characterization of porcine astroviruses in piglets with and without diarrhea in Thailand.

Porcine astrovirus (PAstV) is widely distributed and highly prevalent among pigs, nevertheless its clinical significance remains unclear as it can be detected in both diarrheic and in healthy pigs. Information about the prevalence, clinical significance and molecular characterization of PAstV in Thailand is not available. This study investigated the prevalence of PAstV in 488 fecal samples collected from piglets with and without diarrhea in 28 pig farms in northern and central parts of Thailand using RT-PCR. The overall prevalence of PAstV infection was 6.5% (32/488), of which 21/251 (8.4%) were in diarrheic and 11/237 (4.6%) were in healthy pigs. Of 32 positive samples, 46.9% were positive for PAstV alone whereas 53.1% were co-infected with porcine group A rotavirus (PRVA). A phylogenetic analysis of the partial RNA-dependent RNA polymerase/capsid genes revealed two lineages of PAstV strains detected in this study. PAstV4 was the most dominant genotype (92%), followed by PAstV2 (8%). This study revealed for the first time that PAstV4 and PAstV2 were circulating in Thailand with PAstV4 as the most dominant genotype in pig herds in northern and central parts of Thailand.

Comparative Evaluation of Norovirus Infection in Children with Acute Gastroenteritis by Rapid Immunochromatographic Test, RT-PCR and Real-time RT-PCR.

Immunochromatographic (IC) test for norovirus detection is a rapid and simple detection method. This study evaluated the sensitivity and specificity of a recent version of R-Biopharm RIDA®QUICK Norovirus IC assay for norovirus detection in fecal specimens from children hospitalized with acute gastroenteritis. Fecal specimens were tested by IC kit in comparison with gold standard reverse transcription polymerase chain reaction (RT-PCR) and real-time RT-PCR. The IC kit showed high sensitivity and specificity comparable with PCR-based methods. None of false positive and false negative was found and the assay did not cross-react with other gastroenteritis viruses. The IC assay could detect genogroup I.5 (GI.5) and a wide range of genotypes in the GII noroviruses including GII.3, GII.4, GII.6, GII.7, GII.14, GII.15, GII.21, and also newly emerging GII.17 norovirus. In conclusion, this norovirus IC kit could be an alternative choice for rapid screening or a quick diagnostic tool for norovirus detection in fecal specimens of acute gastroenteritis patients.

Detection and characterization of Aichi virus 1 in pediatric patients with diarrhea in Thailand.

Kobuvirus is a newly discovered virus that belongs to the Kobuvirus genus in Picornaviridae family, which comprised of three species including Aichivirus A, Aichivirus B, and Aichivirus C. The kobuvirus isolated from human has been classified as Aichi virus 1 and belongs to Aichivirus A species. The present study aimed to assess the epidemiology and to perform molecular characterization of Aichi virus 1 in children admitted to hospitals with acute gastroenteritis in Chiang Mai, Thailand. A total of 923 fecal specimens collected from January, 2011 to December, 2013 were screened for the presence of Aichi virus 1 by RT semi-nested PCR. Out of 923 fecal specimens tested, Aichi virus 1 was detected with the prevalence of 2.6% (24/923). Of these, 0.3% (3/923) was genotype A and 2.3% (21/923) were genotype B. It is interesting to note that the genotype A showed the nucleotide sequence closely related to the Aichi virus reference strain isolated from sewage in Tunisia, while genotype B was most closely related to other human Aichi virus B reference strains. The results suggest that Aichi virus 1 of both genotypes A and B are circulating in pediatric patients in Thailand. J. Med. Virol. 89:234-238, 2017. © 2016 Wiley Periodicals, Inc.

Molecular detection and characterization of picobirnaviruses in piglets with diarrhea in Thailand.

Picobirnavirus (PBV) is a small, bi-segmented, double-stranded RNA virus. Taxonomically, the genus Picobirnavirus belongs to the Picobirnaviridae family. PBV infects a wide range of hosts and causes opportunistic infections, but its role in diarrheal disease remains unclear. To determine the prevalence and genetic diversity of porcine PBVs in Northern Thailand, 380 fecal samples collected from diarrheic and non-diarrheic piglets, raised in 22 pig farms, were tested for the presence of PBV. Reverse-transcription PCR (RT-PCR) was performed using primer sets specific to the RNA-dependent RNA polymerase (RdRp) gene. PBV was detected in 86 of 265 (32.5%) diarrheic piglets and in 26 of 115 (22.6%) non-diarrheic piglets. All the PBV strains detected in this study belonged to genogroup I and a high proportion of PBV-positive piglets were co-infected with group A rotavirus (RVA) and bocavirus (BoV). Phylogenetic analysis of representative genogroup I strains revealed remarkably high similarity between strains; these formed a monophyletic cluster with 97-100% sequence identity in the RdRp gene. The strains were also closely related to genogroup I PBV Chinese porcine strain. The findings indicate that PBV infection is common in piglets with and without diarrhea in Northern Thailand.

Complete genome analysis of a rare G12P[6] rotavirus isolated in Thailand in 2012 reveals a prototype strain of DS-1-like constellation.

Species A rotaviruses (RVAs) are a major cause of severe diarrhea in children worldwide. G12 RVA detection is currently increasing and has been reported from many countries around the world. However, few studies have reported whole genome sequences of G12 RVAs. In the present study, the complete genome sequence of a G12P[6] RVA strain (RVA/Human-wt/THA/CMHN49-12/2012/G12P[6]) detected in a stool sample from a child with acute gastroenteritis in 2012 in Thailand was analyzed. In the CMHN49-12 strain, all genome segments had a DS-1-like backbone: G12-P[6]-I2-R2-C2-M2-A2-N2-T2-E2-H2 indicates that it is most likely the prototype strain of G12P[6] with a DS-1-like genotype constellation. Based on a Bayesian evolutionary analysis of VP7 nucleotide sequence, G12 RVA strains reported previously from Thailand during the period of 2007-2012 could be divided into 3 clusters, indicating that they originated from at least 3 different ancestral G12 strains. The evolutionary rate of G12 calculated by Bayesian Markov Chain Monte Carlo analysis indicated that the nucleotide substitution rate of G12 was 1.11×10(-3) mutations/site/year. The finding of a G12P[6] RVA possessing a DS-1-like backbone provides insights into the evolution of global G12 RVAs.

Great genetic diversity of rotaviruses detected in piglets with diarrhea in Thailand.

A total of 491 fecal specimens collected from diarrheic piglets in Thailand from January 2011 to March 2014 were screened for group A rotavirus by RT-PCR assay. The G and P genotypes of the detected rotaviruses were determined by multiplex PCR or nucleotide sequencing. Group A rotaviruses were detected in 113 out of 491 (23.0 %) fecal specimens. A wide variety of G-P genotype combinations were identified, and G4P[13] was the most prevalent genotype combination (29.2 %), followed by G4P[23] (14.1 %), G5P[23] (11.5 %), G4P[6] (9.7 %), G3P[23] (7.0 %), G5P[13] (6.1 %), G3P[13] (4.4 %), G3P[6] (2.7 %), and G5P[6] (2.7 %). In addition, the other G-P combinations were also detected at a low percentage, including G3P[19], G4P[7], G9P[19], G9P[23], G9P[7], G4P[19], and G11P[13] strains. This study indicated that group A rotaviruses are a common causes of diarrhea in piglets and a great diversity of G and P genotype combinations are circulating in piglets in Thailand.

Detection and characterization of a novel human parechovirus genotype in Thailand.

Human parechoviruses (HPeV), member in the family Picornaviridae, cause respiratory symptoms primarily in infants and young children. Currently, 16 genotypes have been described based on phylogenetic analysis of VP1 sequences, all of which have a global distribution. The purpose of this study was to investigate the prevalence and genotype distribution of HPeV in Thailand. A total of 171 fecal specimens collected during October 2012 to May 2013 from children with diarrhea in Chiang Mai, Thailand were investigated for HPeV by RT-PCR and sequence analysis. HPeVs were found in 3 out of 171 (1.8%) fecal specimens tested. Of these, one was HPeV1 which is commonly detected in children with gastroenteritis and another one was uncommon HPeV14 genotype. Most interestingly, the sequence of the third HPeV positive sample (CMH-N185-12) did not cluster with any of the known 16 genotypes and therefore is proposed as a candidate HPeV genotype 17.

SAffold viruses in pediatric patients with diarrhea in Thailand.

Saffold virus (SAFV) is a newly discovered human virus which is classified into the genus Cardiovirus of the family Picornaviridae. A total of 608 fecal specimens collected during January 2012 to December 2013 from children with diarrhea in Chiang Mai, Thailand were investigated for SAFV by RT-nested PCR and sequence analysis. Of these, nine out of 608 (1.5%) were positive for SAFVs and four genotypes were identified, SAFV1, SAFV2, SAFV3, and SAFV4. SAFV mono-infection was found in five cases (CMH-S038-12, CMH-S071-12, CMH-S102-12, CMH-N029-12, and CMH-S048-13), while co-infection with other viruses causing diarrhea was observed in four cases (CMH-S021-12, CMH-S115-12, CMH-N048-13 and CMH-N103-13). This study provides more information about the genetic background of SAFV circulating in pediatric patients with diarrhea in Thailand.

Detection of diarrheal viruses circulating in adult patients in Thailand.

A total of 332 fecal specimens collected during January-December 2008 from adult patients with diarrhea were screened for group A and C rotaviruses, noroviruses GI and GII, sapovirus, Aichi virus, human parechovirus, enterovirus, adenovirus and astrovirus by RT-multiplex PCR. The detection rate for diarrheal viruses was 4.2 %. Adenovirus and enterovirus were equally detected as the most predominant viruses, with prevalence of 1.2 %, followed by Aichi virus (0.9 %) and norovirus GII (0.6 %). Mixed infection with norovirus GII and human parechovirus was also detected (0.3 %). This study provides epidemiological data for a wide variety of diarrheal viruses circulating in adult patients with diarrhea in Chiang Mai, Thailand.

Molecular detection and characterization of Aichivirus A in adult patients with diarrhea in Thailand.

Viral gastroenteritis is a common public health problem that causes morbidity and mortality worldwide. Recently, new viruses causing gastroenteritis have been identified. Among these, Aichivirus has also been proposed as a causative agent of gastroenteritis in human. Most studies have been conducted in infants and children, the information in adults is limited. Therefore, the purpose of this study was to investigate the epidemiology and molecular characterization of Aichivirus in adult patients with diarrhea. A total of 332 fecal specimens collected from January to December 2008 were screened for the presence of Aichivirus by reverse transcription-PCR (RT-PCR) method. Out of 332 fecal specimens tested, Aichivirus was detected with the prevalence of 0.9% (3/332). The data indicate that the prevalence of Aichivirus in adults was as low as those reported in children in Thailand. Phylogenetic analysis of the VP1 sequence revealed that one Aichivirus belonged to genotype A, while other two Aichiviruses were genotype B. In conclusion, this study provided the molecular epidemiological data of Aichivirus circulating in adult patients with diarrhea at low prevalence and the viruses were genetically variable as both genotypes A and B were found in this population.

Genetic diversity and novel combinations of G4P[19] and G9P[19] porcine rotavirus strains in Thailand.

Several epidemiological studies reported the detection of rotavirus strains bearing unusual combinations of genetic background of human and porcine rotaviruses. This observation supports the hypothesis of interspecies transmission of rotaviruses in humans and pigs. The aims of this study were to investigate the genotypes and molecular characteristics of rotaviruses in piglets with diarrhea in several farms from two provinces in Thailand. A total of 207 fecal specimens collected from diarrheic piglets were screened for the presence of groups A, B, and C rotaviruses. Group A rotaviruses were detected in 41 out of 207 (19.8%) fecal specimens tested. A wide variety of G-P combination rotavirus strains were detected in this study. The G4P[6] was identified as the most prevalent genotype (39.0%), followed by G4P[23] (12.2%), G3P[23] (7.3%), G4P[19] (7.3%), G3P[6] (4.9%), G3P[13] (4.9%), G3P[19] (4.9%), G9P[13] (4.9%), G9P[19] (4.9%), G5P[6], and G5P[13] each of 2.4%. Furthermore, G5 and G9 in combinations with P-nontypeable strains were also found at each consisting of 2.4% (n=1) of the collection. It was interesting to note that among diversified porcine rotavirus strains, novel combinations of G4P[19] and G9P[19] strains were detected for the first time in this study. Nucleotide sequences of VP4 and VP7 of these strains were closely related to human rotaviruses reported previously. The data implies that these porcine rotaviruses were probably generated in nature from the reassortment between the viruses of human and porcine origin. This study provides valuable epidemiological information and molecular characteristics of porcine rotaviruses circulating in piglets with diarrhea in northern Thailand.