Tuan Anh Nguyen - Academia.edu (original) (raw)
Papers by Tuan Anh Nguyen
Journal of Medical Virology, 2005
An outbreak of acute gastroenteritis consisting of 57 cases occurred in a mental health care faci... more An outbreak of acute gastroenteritis consisting of 57 cases occurred in a mental health care facility in Takasaki city, Japan during 6th February and 27th March 2002. A total of 18 fecal specimens collected from 17 residents and one member of the medical staff during this outbreak were tested for the presence of viral enteropathogens by RT-PCR and latex agglutination. Group A rotavirus and sapovirus were detected in 5 out of 18 fecal specimens (55.6%). To our knowledge, this is the first finding of an outbreak of gastroenteritis associated with co-circulation of different kinds of viruses such as group A rotavirus and sapovirus. All of group A rotaviruses were typed further as P[4]G2 strains. Both rotavirus and sapovirus were subjected to molecular analysis by sequencing. It was noteworthy that all rotaviruses and sapoviruses had high homologies, respectively, to each other and sapoviruses presented a potential novel sapovirus genogroup I (GI) genotype, which was obviously different from any GI genotypes (GI-a, b, c, and d). The outbreak associated with these viruses spread gradually from dormitory to dormitory, suggesting a spread by person-to-person contact, although investigation on the route of transmission of the outbreak is lacking. The findings confirm the presence of group A rotavirus and sapovirus are important in acute gastroenteritis among adults in Japan. J. Med. Virol. 75:475–481, 2005. © 2005 Wiley-Liss, Inc.
Journal of Medical Virology, 2008
Sequence analysis of the capsid gene of Aichi viruses was performed on 12 strains detected in Jap... more Sequence analysis of the capsid gene of Aichi viruses was performed on 12 strains detected in Japan, Bangladesh, Thailand, and Vietnam during 2002–2005. The phylogenetic tree constructed from 17 nucleotide sequences of the capsid gene of the strains studied and reference strains demonstrated that Aichi virus strains clustered into two branches. A classification of Aichi viruses based on the capsid gene was proposed, in which lineage I consists of the Aichi virus strains detected from Japan, Thailand, Vietnam, and Germany, and lineage II includes Bangladeshi strains and a Brazilian strain. J. Med. Virol. 80: 1222–1227, 2008. © 2008 Wiley-Liss, Inc.
Journal of Medical Virology, 2004
Fecal specimens from 517 infants and young children admitted to the Civil Karachi Hospital, Dow M... more Fecal specimens from 517 infants and young children admitted to the Civil Karachi Hospital, Dow Medical College, Karachi city, Pakistan with acute gastroenteritis from 1990 to 1994 were collected and screened by RT-PCR for human astrovirus (AstV), norovirus (NV), and sapovirus (SV). The specific epidemiological data for illness caused by these viruses in Pakistan are not available. AstV, NV, and SV were detected in 58, 51, and 17 of 517 fecal specimens, and this represented 11.2, 9.9, and 3.2%, respectively. An outbreak of gastroenteritis attributable to AstV serotype 1 was identified during September and October 1990. Moreover, one specimen with a triple mixed infection between AstV (serotypes 1 and 3) and NV GII was found. NV and SV were subjected to molecular analysis by sequencing. One of the sequenced specimens positive for SV turned out to be similar to a strain tentatively called a genogroup IV. The result underscores the importance of these viruses in association with acute gastroenteritis in Karachi city, Pakistan. J. Med. Virol. 73:256–261, 2004. © 2004 Wiley-Liss, Inc.
Journal of Medical Virology, 2010
Sequence and phylogenetic analyses of the rotavirus VP7 gene were performed on 52 human G2 and G4... more Sequence and phylogenetic analyses of the rotavirus VP7 gene were performed on 52 human G2 and G4 strains isolated in Japan, China, Thailand, and Vietnam during 2001–2003. All genotype G2 strains included in the study clustered into lineage II of the phylogenetic tree, together with the majority of global G2 strains detected since 1995. The amino acid substitution at position 96 from aspartic acid to asparagine was noted among the emerging or re-emerging G2 rotavirus strains in Japan, Thailand, and Vietnam during 2002–2003. Genotype G4 strains detected in Vietnam grouped into lineage Ia of the phylogenetic tree, whereas Japanese G4 strains clustered in lineage Ic which included emerging G4 strains from Argentina, Italy, Paraguay, and Uruguay. It is noteworthy that an insertion of asparagine was found at position 76 in all the Japanese strains and that its presence might be involved in the emergence of G4 rotavirus in Japan during 2002–2003. J. Med. Virol. 82: 878–885, 2010. © 2010 Wiley-Liss, Inc.
Journal of Medical Virology, 2007
Nucleotide and amino acid sequences of the VP8☆ gene of five Vietnamese P[6] rotavirus strains de... more Nucleotide and amino acid sequences of the VP8☆ gene of five Vietnamese P[6] rotavirus strains detected from hospitalized patients with acute gastroenteritis were analyzed and compared with other human and porcine P[6] rotaviruses. It is of interest that these strains had greatest identity with two Italian porcine rotavirus strains, 134/04-10 and 134/04-11. To our knowledge, these five Vietnamese rotaviruses are the rare P[6] rotavirus strains belonging to lineage I that cluster into sublineage Ic with porcine rotaviruses, and not into sublineage Ia, as other human P[6] rotaviruses have done so far. Sequence analysis of the VP7 gene of these P[6] rotavirus strains was also performed. The results showed that the Vietnamese G9P[6] strain had high similarity with other human G9 rotaviruses, confirming a human–animal reassortant virus, whereas other three G4P[6] strains had best identity with porcine G4 rotavirus strains, suggesting interspecies transmission of rotavirus between porcine and humans. This result provides the important data on molecular characteristics of Vietnamese rotaviruses, and highlights interspecies transmission events of rotaviruses in Vietnam as well as in Asia. J. Med. Virol. 79:1959–1965, 2007. © 2007 Wiley-Liss, Inc.
Journal of Medical Virology, 2007
A molecular epidemiological study on common diarrheal viruses was conducted in Ho Chi Minh City, ... more A molecular epidemiological study on common diarrheal viruses was conducted in Ho Chi Minh City, Vietnam between October 2002 and September 2003. Fecal samples were collected from 1,010 hospitalized children with acute gastroenteritis. Those samples were screened for groups A, B, and C rotavirus, adenovirus, genogroups I and II norovirus (NoV), sapovirus (SaV), and human astrovirus (HAstV) by RT-multiplex PCR, and the positive specimens were characterized further by ELISA, nested PCR, or sequencing. Among the diarrheal viruses detected, group A rotavirus was the most common, with a proportion of 67.4%, whereas NoV GII, adenovirus, SaV, and HAstV were also found in 5.5, 3.2, 0.8, and 0.6%, respectively. It is noteworthy that the group C rotavirus was first reported in Vietnam, with a proportion of 0.5% in this study. Fifty-six of 1,010 (5.5%) samples were found positive with more than one viral agent, in which 25 samples contained both group A rotavirus and NoV GII. Group A rotavirus could be identified throughout year with the peaks in both the dry and rainy season, whereas other viruses prevailed mainly in the rainy season. G-typing for the group A rotavirus showed that genotype 1 was still the most prevailing (33.0%), but interestingly, serotype 9 was emergent and became the third most common rotavirus G-type in these samples (13.7%). The four most common G–P combinations globally, G1P[8], G2P[4], G3P[8], and G4P[8] were found in 46.8% of rotavirus-positive samples, and it is of interest that one unusual rotavirus G9P[19] strain was first detected in Vietnam. The majority of NoV strains belonged to GII/4, and SaV strains mainly clustered with the Manchester strain (GI/1). Twenty-seven out of 32 adenovirus strains were identified as serotype 41. All HAstVs belonged to genotype 1. The results indicated clearly the impact of viral agents causing gastroenteritis and the importance of vaccination against diarrhea in Vietnam. J. Med. Virol. 79:582–590, 2007. © 2007 Wiley-Liss, Inc.
Journal of Clinical Virology, 2007
Background: Diarrhea, over the years, has killed millions of people and continues to be a major t... more Background: Diarrhea, over the years, has killed millions of people and continues to be a major threat in Bangladesh. Objectives: To determine the incidence of norovirus infection in infants and young children with acute gastroenteritis in Dhaka City, Bangladesh and to determine the genogroup and genotype in norovirus-positive stool specimens. Study design: Fecal specimens were collected from infants and children with acute gastroenteritis in Dhaka City, Bangladesh from October 2004 to September 2005, and examined for norovirus by reverse transcription-polymerase chain reaction. Results: Noroviruses were detected in 41 of 917 fecal specimens. Molecular analysis of norovirus was carried out by sequencing methods. Only norovirus GII/4 strains were detected during this study. The dominant genotype throughout the study period was GII/4. Norovirus infections were most commonly observed in winter and rainy seasons in Dhaka City. The common clinical symptoms in norovirus-infected patients were diarrhea (90%), vomiting (75%) and abdominal pain (46%). Conclusions: This is the first epidemiological research of norovirus in Bangladesh. Norovirus is an important enteropathogen responsible for viral gastroenteritis among infants and children in Bangladesh.
Journal of Medical Virology, 2007
The distribution of rotavirus G-types in the world appears to be changing, especially with the em... more The distribution of rotavirus G-types in the world appears to be changing, especially with the emergence of G3 and G9 in many countries. Sequence analysis of the VP7 gene was performed on the 27 human G3 rotavirus strains isolated in China, Russia, Thailand, and Vietnam during 2001–2004. All the strains studied were clustered into the same branch of the phylogenetic tree. The comparison of the G3 deduced amino acid sequences between the studied Chinese strains and the strains circulating in China during 1986–1992 showed a wide range of amino acid substitutions (up to 13 amino acids in the VP7 antigenic regions). The two considerable changes both from aspartic acid to asparagine were located at positions 96 in antigenic region A and 213 in antigenic region C. Those amino acid substitutions of the Chinese G3 strains might involve in the emergence of G3 rotavirus in China during 2001–2003. J. Med. Virol. 79:1611–1616, 2007. © Wiley-Liss, Inc.
Journal of Medical Virology, 2007
Sapovirus, a member of the family Caliciviridae is one of the major causative agents of viral gas... more Sapovirus, a member of the family Caliciviridae is one of the major causative agents of viral gastroenteritis affecting all age group. Sapovirus was detected in 25 of 917 stool specimens from infants and children with acute gastroenteritis in a Children Hospital in Dhaka City, Bangladesh during 2004–2005. All fecal specimens were examined for sapovirus by reverse transcription-polymerase chain reaction. Molecular analysis of sapovirus was carried out by sequencing methods. Sapovirus detected in this study was clustered into only one distinct genogroup I. Sapovirus GI/1 was predominant, followed by GI/2 and accounted for 92% (23 of 25) and 8% (2 of 25), respectively. The results clearly indicated that sapovirus infections were observed most commonly in the autumn to winter seasons (September to January) in Dhaka City. The common clinical symptoms of sapovirus infected patients were dehydration (88%), vomiting (76%), and abdominal pain (60%). This is the first report of sapovirus in Bangladesh. J. Med. Virol. 79:633–638, 2007. © 2007 Wiley-Liss, Inc.
Journal of Medical Virology, 2008
A molecular epidemiological study on common diarrheal viruses was conducted in a children's hospi... more A molecular epidemiological study on common diarrheal viruses was conducted in a children's hospital in Ho Chi Minh City between December 2005 and November 2006. Fecal samples were collected from 502 pediatric patients with acute gastroenteritis, and were screened for eight types of viral agents. Human astroviruses (HAstVs), which were detected with a prevalence of 13.9%, became the second most frequent viral enteropathogen. Although detected in both dry and rainy seasons, the majority (92.8%) of HAstVs in this study were found in the rainy season. Patients aged between 6 and 23 months were found to be more infected from astrovirus when compared to other age groups. The ratio between boys and girls was 2.3:1. The overall mean severity score of astrovirus positive patients was 11.8 ± 2.45. The mean severity score of the inpatients was statistically higher than that of the outpatients; however, there was no difference in severity scores between the age groups observed. The clinical manifestations of astrovirus infections among the Vietnamese children were diarrhea, vomiting, fever, coughing, and coryza. All of the detected astroviruses belonged to genotype 1. The phylogenetic tree clearly indicated that HAstVs-1 worldwide could be classified into four different lineages, in which, Vietnamese astroviruses and other recently isolated strains from other countries clustered into the distinct lineage, 1d. These results provide important information on astrovirus infections among Vietnamese children. J. Med. Virol. 80:298–305, 2008. © 2007 Wiley-Liss, Inc.
Journal of Virological Methods, 2008
The efficiency of immunochromatography and commercial enzyme-linked immunosorbent assay (ELISA) k... more The efficiency of immunochromatography and commercial enzyme-linked immunosorbent assay (ELISA) kit (Denka Seiken Co. Ltd., Tokyo, Japan) were evaluated for rapid detection of norovirus (NoV) from stool specimens. A total of 503 stool specimens collected from infants and young children who suffered from acute gastroenteritis were tested for NoV by the NoV-immunochromatography kit, Denka ELISA kit, and by a monoplex RT-PCR method. The NoV-immunochromatography revealed 78.9% sensitivity, 96.4% specificity, and 92.4% efficiency with the monoplex RT-PCR method. The Denka ELISA kit had a sensitivity of 90.4%, specificity of 96.4%, and an efficiency level of 95%. The findings indicate that the newly developed NoV-immunochromatography kit provides the specificity equal to that of the Denka ELISA kit, even through the sensitivity of detection was lower. However, the advantage of the NoV-immunochromatography kit is less time consuming and simpler. The data show that both the Denka ELISA and the NoV-immunochromatography kits may be used as an alternative method for screening of NoV in stool samples.
Journal of Medical Virology, 2005
A total of 276 fecal specimens collected from infants and children admitted to hospital with acut... more A total of 276 fecal specimens collected from infants and children admitted to hospital with acute gastroenteritis in Ho Chi Minh City, Vietnam from October 2002 to September 2003, were tested for the presence of enteroviruses by RT-PCR and virus isolation. Enteroviruses were detected in 27 patients by RT-PCR corresponding to 9.8%. However, only four enterovirus strains could be isolated by cell culture with two different cell lines CaCo2 and Vero, showing specific cytopathic effect (CPE). The results clearly indicate that RT-PCR is a sensitive, specific assay to investigate the true burden of acute gastroenteritis due to enteroviruses in clinical fecal specimens. In the present study, enteroviruses were identified throughout the year except in May and the highest number was in December. Enteroviruses were subjected to molecular analysis by sequencing. It was found that enterovirus strains detected were classified further into two distinct genetic clusters (I, II) and demonstrated the great genetic diversity among them. Based on genetic analysis, 5′ noncoding region (5′ NCR) sequences suggested the predominant presence of Vietnamese enteroviruses with the greatest similarities to coxsakieviruses (51.9%) and echoviruses (29.6%). Interestingly, two of the sequenced specimens of enteroviruses were similar to a new strain called enterovirus 74. This report is the first detection of enteroviral infection in feces from infants and children admitted to hospital with acute gastroenteritis in Vietnam. J. Med. Virol. 77:257–264, 2005. © 2005 Wiley-Liss, Inc.
Journal of Medical Virology, 2004
A total of 236 fecal specimens collected from infants and children with gastroenteritis in Maizur... more A total of 236 fecal specimens collected from infants and children with gastroenteritis in Maizuru city, Japan from July 2002 to June 2003, were tested for the presence of rotaviruses, noroviruses, sapoviruses, astroviruses, and adenoviruses by RT-PCR, PAGE, RPHA, and latex agglutination methods. Among diarrheal viruses detected, group A rotavirus was the most prevalent (32.2%; 76 of 236) followed by norovirus GII (21.2%; 50 of 236), group C rotavirus (10.2%; 24 of 236), adenovirus (3.8%; 9 of 236), sapovirus (2.5%; 6 of 236), astrovirus (1.3%; 3 of 236), and norovirus GI (0.8%; 2 of 236), respectively. It is noteworthy that group C rotavirus infection was apparently confined only within the period of 5 months (December 2002 through April 2003). This pattern of infection implied that the outbreak of group C rotavirus in these patients, which was the first outbreak of gastroenteritis attributed to group C rotavirus in Maizuru city. Moreover, about half (12 of 24) of group C rotavirus infected cases were confined to infants and young children less than 3 years old. Another interesting feature of the study was the demonstration of the mixed infections with group C rotavirus and group A rotavirus, as well as group C rotavirus and norovirus GII in 20.8% (5 of 24) and 8.3% (2 of 24), respectively. This is the first report of gastroenteritis associated with the mixed infections with group C rotavirus and other viral enteropathogens such as norovirus. The results indicate that group C rotavirus could infect not only older children and adults but also infants and young children under 3 years old. J. Med. Virol. 74:173–179, 2004. © 2004 Wiley-Liss, Inc.
Pediatrics International, 2004
Acute gastroenteritis is one of the most common diseases in humans, and continues to be a signifi... more Acute gastroenteritis is one of the most common diseases in humans, and continues to be a significant cause of mortality and morbidity worldwide. Recently the estimates of mortality associated with diarrhea declined, however the majority of deaths still occur in developing countries and thus urgent intervention is needed for the prevention of these diseases. In Asian countries it is very important to study the distribution, transmission and characteristics of prevalent viruses in order to produce viral vaccines. The viruses which cause gastroenteritis are primarily from four distinct families - group A rotaviruses, caliciviruses, enteric adenoviruses and astroviruses. Rotavirus is a common virus that causes severe gastroenteritis in children <5 years of age. The reassortant viruses with animal virus, or directly animal viruses are isolated in humans. The future development of a safe and effective vaccine against rotavirus, along with the expansion of understanding of the distribution of types in Asia and an availability of rapid diagnostic tests, could reduce mortality and might be able to prevent severe gastroenteritis. Calicivirus is a causative virus of acute gastroenteritis in children and has been known to contaminate food causing viral outbreaks affecting people of all ages. Recently, the understanding of calicivirus and the improvement of detection techniques has increased the total frequencies of diarrheal viruses. For the future control and prevention of diarrheal diseases it is necessary to examine the molecular epidemiology of caliciviruses as well as rotaviruses.
Infection Genetics and Evolution, 2010
Journal of Medical Virology, 2007
Over the last decade, rotavirus G1 has represented the most common genotype worldwide. Since 2000... more Over the last decade, rotavirus G1 has represented the most common genotype worldwide. Since 2000, the prevalence of rotavirus G1 has decreased in some countries such as Japan and China. To monitor the trend of the VP7 encoding gene of rotavirus G1, we performed a sequence analysis of 74 G1 rotavirus strains isolated in Japan, China, Thailand, and Vietnam during the period from 2002 to 2005. The phylogenetic tree showed that all of the studied G1 strains from the four countries clustered into lineage III, the same as the majority of the G1 strains isolated in China and Japan in 1990 and 1991. Examination of the deduced amino acid sequences of the G1 strains from China and Japan revealed an amino acid substitution at position 91 (Asn instead of Thr) in antigenic region A when compared to the G1 strains isolated in China and Japan in 1990, 1991, and global reference strains. For the G1 strains from Thailand and Vietnam, there were three amino acid substitutions, not belonging to any antigenic regions. The study showed that there have been no considerable changes of human rotavirus G1 isolated in Japan, China, Thailand, and Vietnam. Further studies need to be carried out for a better understanding of why such changes in the prevalence of rotavirus G1 occur in these countries. J. Med. Virol. 79:1009-1016, 2007. © 2007 Wiley-Liss, Inc.
Journal of Medical Virology, 2005
A total of 921 fecal specimens collected from 44 infants in a day care center in Tokyo, Japan dur... more A total of 921 fecal specimens collected from 44 infants in a day care center in Tokyo, Japan during June 1999 to July 2000 were tested for the presence of sapovirus by reverse transcription-polymerase chain reaction (RT-PCR). Of 88 fecal specimens from infants with acute gastroenteritis, 2.3% (2) were found to be positive for sapovirus. Twenty-two of 833 (2.6%) fecal specimens collected from asymptomatic infants were also infected with this virus. Another interesting feature was the demonstration of high incidence of sapovirus infection (95.5%, 21 of 22) identified in a single day care center, which was not due to viral shedding after the latest acute gastroenteritis. Sapovirus was subjected to genetic analysis by sequencing. Up to 4 of 24 sapoviruses (16.7%) were clustered into genogroup IV known as a rare group. Remarkably, majority (79.2%, 19 of 24) of sapovirus isolates detected in this study turned out to present one novel sapovirus genotype tentatively called GI/8. It was noteworthy to point out that the GI/8 sapovirus infection was apparently confined only within the period of 9 weeks (44th through 52nd weeks). This pattern of infection implied the outbreak of asymptomatic GI/8 sapovirus infection in these subjects. The findings clearly indicate genogroup I sapovirus can be classified into eight genotypes. This is the first report to underscore that sapovirus pathogen causes not only clinical manifestations of acute gastroenteritis but also asymptomatic infection in infants in day care centers in Japan. J. Med. Virol. 77:595–601, 2005. © 2005 Wiley-Liss, inc.
Journal of Affective Disorders, 2006
Background: Major Depressive Disorder (MDD) becomes increasingly prevalent during adolescence and... more Background: Major Depressive Disorder (MDD) becomes increasingly prevalent during adolescence and is associated with substantial psychiatric comorbidity and psychosocial impairment. The marked behavioral heterogeneity evident among adolescents with MDD suggests the possibility of distinct subtypes. This study was designed to determine whether family psychiatric histories differ between groups of MDD adolescents defined by the presence or absence of severe behavioral disinhibition. Methods: Adolescents with MDD (n = 71) completed the Buss-Durkee Hostility Inventory-Adapted, Adolescent Aggressive Incidents Interview (AAII), Measure of Aggression, Violence, and Rage in Children, Diagnostic Interview Schedule for Children, Suicidal Ideation Questionnaire-JR., Suicidal Behavior Inventory, and Reynolds Adolescent Depression Scale. Parents completed the Family Informant Schedule and Criteria, Children's Affective Liability Scale, AAII, and a partial DISC. Behavioral disinhibition (BD) measures were used to assign adolescents to MDD + BD (n = 41) and MDD À BD (n = 30) groups. Results: The MDD + BD group had a higher prevalence of drug use disorders in biological fathers than the MDD À BD group. The MDD + BD group also had higher proportions of paternal second degree relatives with alcohol use disorders, drug use disorders, and psychiatric hospitalizations, and a higher proportion of maternal second degree relatives with antisocial personality disorder. Limitations: Limitations include reliance on single informants for family psychiatric histories and the failure to distinguish between child-and adolescent-onset depression. Conclusions: Family psychiatric histories differentiated MDD adolescents grouped by the presence or absence of behavioral disinhibition, suggesting possible etiologic mechanisms. Further research on subtypes or comorbid presentations may assist in the development of targeted treatment strategies. D
Accounting and Finance, 2004
The present study examines the impact of the announcement of special dividends for a sample of Au... more The present study examines the impact of the announcement of special dividends for a sample of Australian companies over the period July 1989 to June 2002. The risk-adjusted price reaction to special dividend announcements from the day before the announcement to the day after the announcement (day −1 to day 1) is positive and statistically significant, averaging 3.67 per cent. Initial special dividend announcements (4.68 per cent) led to stronger price reaction than special dividend announcements that follow an earlier special dividend (1.51 per cent) in the previous year. The magnitude of price reactions to special dividend announcements is statistically related to the size of the special dividend, the existence of prior special dividend announcements, abnormal cash flow for the year ended after the special dividend announcement, the existence of dividend reinvestment plans (DRP) versus non-DRP, and a preannouncement effect. Finally, we found strong support for the information content/signalling hypothesis for special dividend announcements that do not participate in DRP and limited support for those associated with DRP.
The present research evaluated the corrosion and inhibition performances of steel-mortar samples ... more The present research evaluated the corrosion and inhibition performances of steel-mortar samples with various levels of NaCl and corrosion inhibitors admixed in fresh mortar (0.05M DGP, 0.5M SN, and 0.05M DMEA). FESEM, EDX and XPS were used to analyze the fracture surfaces of the steel-mortar interfacial region for samples exposed to various time periods of ponding by 3% NaCl solution. The admixing of NaCl and the corrosion inhibitors in fresh mortar altered the morphology and microstructure of the hardened mortar at the steel-mortar interfacial region. The admixing of the corrosion inhibitors in fresh mortar increased the risk of carbonation of cement hydrates at the steel-mortar interfacial region, but partially displaced chloride ions. Chloride (either admixed or ingressed) and the admixed corrosion inhibitors facilitated the formation of different cement hydrates and affected chloride binding.at the steel-mortar interfacial region, all of which may affect the steel corrosion and its inhibition.
Journal of Medical Virology, 2005
An outbreak of acute gastroenteritis consisting of 57 cases occurred in a mental health care faci... more An outbreak of acute gastroenteritis consisting of 57 cases occurred in a mental health care facility in Takasaki city, Japan during 6th February and 27th March 2002. A total of 18 fecal specimens collected from 17 residents and one member of the medical staff during this outbreak were tested for the presence of viral enteropathogens by RT-PCR and latex agglutination. Group A rotavirus and sapovirus were detected in 5 out of 18 fecal specimens (55.6%). To our knowledge, this is the first finding of an outbreak of gastroenteritis associated with co-circulation of different kinds of viruses such as group A rotavirus and sapovirus. All of group A rotaviruses were typed further as P[4]G2 strains. Both rotavirus and sapovirus were subjected to molecular analysis by sequencing. It was noteworthy that all rotaviruses and sapoviruses had high homologies, respectively, to each other and sapoviruses presented a potential novel sapovirus genogroup I (GI) genotype, which was obviously different from any GI genotypes (GI-a, b, c, and d). The outbreak associated with these viruses spread gradually from dormitory to dormitory, suggesting a spread by person-to-person contact, although investigation on the route of transmission of the outbreak is lacking. The findings confirm the presence of group A rotavirus and sapovirus are important in acute gastroenteritis among adults in Japan. J. Med. Virol. 75:475–481, 2005. © 2005 Wiley-Liss, Inc.
Journal of Medical Virology, 2008
Sequence analysis of the capsid gene of Aichi viruses was performed on 12 strains detected in Jap... more Sequence analysis of the capsid gene of Aichi viruses was performed on 12 strains detected in Japan, Bangladesh, Thailand, and Vietnam during 2002–2005. The phylogenetic tree constructed from 17 nucleotide sequences of the capsid gene of the strains studied and reference strains demonstrated that Aichi virus strains clustered into two branches. A classification of Aichi viruses based on the capsid gene was proposed, in which lineage I consists of the Aichi virus strains detected from Japan, Thailand, Vietnam, and Germany, and lineage II includes Bangladeshi strains and a Brazilian strain. J. Med. Virol. 80: 1222–1227, 2008. © 2008 Wiley-Liss, Inc.
Journal of Medical Virology, 2004
Fecal specimens from 517 infants and young children admitted to the Civil Karachi Hospital, Dow M... more Fecal specimens from 517 infants and young children admitted to the Civil Karachi Hospital, Dow Medical College, Karachi city, Pakistan with acute gastroenteritis from 1990 to 1994 were collected and screened by RT-PCR for human astrovirus (AstV), norovirus (NV), and sapovirus (SV). The specific epidemiological data for illness caused by these viruses in Pakistan are not available. AstV, NV, and SV were detected in 58, 51, and 17 of 517 fecal specimens, and this represented 11.2, 9.9, and 3.2%, respectively. An outbreak of gastroenteritis attributable to AstV serotype 1 was identified during September and October 1990. Moreover, one specimen with a triple mixed infection between AstV (serotypes 1 and 3) and NV GII was found. NV and SV were subjected to molecular analysis by sequencing. One of the sequenced specimens positive for SV turned out to be similar to a strain tentatively called a genogroup IV. The result underscores the importance of these viruses in association with acute gastroenteritis in Karachi city, Pakistan. J. Med. Virol. 73:256–261, 2004. © 2004 Wiley-Liss, Inc.
Journal of Medical Virology, 2010
Sequence and phylogenetic analyses of the rotavirus VP7 gene were performed on 52 human G2 and G4... more Sequence and phylogenetic analyses of the rotavirus VP7 gene were performed on 52 human G2 and G4 strains isolated in Japan, China, Thailand, and Vietnam during 2001–2003. All genotype G2 strains included in the study clustered into lineage II of the phylogenetic tree, together with the majority of global G2 strains detected since 1995. The amino acid substitution at position 96 from aspartic acid to asparagine was noted among the emerging or re-emerging G2 rotavirus strains in Japan, Thailand, and Vietnam during 2002–2003. Genotype G4 strains detected in Vietnam grouped into lineage Ia of the phylogenetic tree, whereas Japanese G4 strains clustered in lineage Ic which included emerging G4 strains from Argentina, Italy, Paraguay, and Uruguay. It is noteworthy that an insertion of asparagine was found at position 76 in all the Japanese strains and that its presence might be involved in the emergence of G4 rotavirus in Japan during 2002–2003. J. Med. Virol. 82: 878–885, 2010. © 2010 Wiley-Liss, Inc.
Journal of Medical Virology, 2007
Nucleotide and amino acid sequences of the VP8☆ gene of five Vietnamese P[6] rotavirus strains de... more Nucleotide and amino acid sequences of the VP8☆ gene of five Vietnamese P[6] rotavirus strains detected from hospitalized patients with acute gastroenteritis were analyzed and compared with other human and porcine P[6] rotaviruses. It is of interest that these strains had greatest identity with two Italian porcine rotavirus strains, 134/04-10 and 134/04-11. To our knowledge, these five Vietnamese rotaviruses are the rare P[6] rotavirus strains belonging to lineage I that cluster into sublineage Ic with porcine rotaviruses, and not into sublineage Ia, as other human P[6] rotaviruses have done so far. Sequence analysis of the VP7 gene of these P[6] rotavirus strains was also performed. The results showed that the Vietnamese G9P[6] strain had high similarity with other human G9 rotaviruses, confirming a human–animal reassortant virus, whereas other three G4P[6] strains had best identity with porcine G4 rotavirus strains, suggesting interspecies transmission of rotavirus between porcine and humans. This result provides the important data on molecular characteristics of Vietnamese rotaviruses, and highlights interspecies transmission events of rotaviruses in Vietnam as well as in Asia. J. Med. Virol. 79:1959–1965, 2007. © 2007 Wiley-Liss, Inc.
Journal of Medical Virology, 2007
A molecular epidemiological study on common diarrheal viruses was conducted in Ho Chi Minh City, ... more A molecular epidemiological study on common diarrheal viruses was conducted in Ho Chi Minh City, Vietnam between October 2002 and September 2003. Fecal samples were collected from 1,010 hospitalized children with acute gastroenteritis. Those samples were screened for groups A, B, and C rotavirus, adenovirus, genogroups I and II norovirus (NoV), sapovirus (SaV), and human astrovirus (HAstV) by RT-multiplex PCR, and the positive specimens were characterized further by ELISA, nested PCR, or sequencing. Among the diarrheal viruses detected, group A rotavirus was the most common, with a proportion of 67.4%, whereas NoV GII, adenovirus, SaV, and HAstV were also found in 5.5, 3.2, 0.8, and 0.6%, respectively. It is noteworthy that the group C rotavirus was first reported in Vietnam, with a proportion of 0.5% in this study. Fifty-six of 1,010 (5.5%) samples were found positive with more than one viral agent, in which 25 samples contained both group A rotavirus and NoV GII. Group A rotavirus could be identified throughout year with the peaks in both the dry and rainy season, whereas other viruses prevailed mainly in the rainy season. G-typing for the group A rotavirus showed that genotype 1 was still the most prevailing (33.0%), but interestingly, serotype 9 was emergent and became the third most common rotavirus G-type in these samples (13.7%). The four most common G–P combinations globally, G1P[8], G2P[4], G3P[8], and G4P[8] were found in 46.8% of rotavirus-positive samples, and it is of interest that one unusual rotavirus G9P[19] strain was first detected in Vietnam. The majority of NoV strains belonged to GII/4, and SaV strains mainly clustered with the Manchester strain (GI/1). Twenty-seven out of 32 adenovirus strains were identified as serotype 41. All HAstVs belonged to genotype 1. The results indicated clearly the impact of viral agents causing gastroenteritis and the importance of vaccination against diarrhea in Vietnam. J. Med. Virol. 79:582–590, 2007. © 2007 Wiley-Liss, Inc.
Journal of Clinical Virology, 2007
Background: Diarrhea, over the years, has killed millions of people and continues to be a major t... more Background: Diarrhea, over the years, has killed millions of people and continues to be a major threat in Bangladesh. Objectives: To determine the incidence of norovirus infection in infants and young children with acute gastroenteritis in Dhaka City, Bangladesh and to determine the genogroup and genotype in norovirus-positive stool specimens. Study design: Fecal specimens were collected from infants and children with acute gastroenteritis in Dhaka City, Bangladesh from October 2004 to September 2005, and examined for norovirus by reverse transcription-polymerase chain reaction. Results: Noroviruses were detected in 41 of 917 fecal specimens. Molecular analysis of norovirus was carried out by sequencing methods. Only norovirus GII/4 strains were detected during this study. The dominant genotype throughout the study period was GII/4. Norovirus infections were most commonly observed in winter and rainy seasons in Dhaka City. The common clinical symptoms in norovirus-infected patients were diarrhea (90%), vomiting (75%) and abdominal pain (46%). Conclusions: This is the first epidemiological research of norovirus in Bangladesh. Norovirus is an important enteropathogen responsible for viral gastroenteritis among infants and children in Bangladesh.
Journal of Medical Virology, 2007
The distribution of rotavirus G-types in the world appears to be changing, especially with the em... more The distribution of rotavirus G-types in the world appears to be changing, especially with the emergence of G3 and G9 in many countries. Sequence analysis of the VP7 gene was performed on the 27 human G3 rotavirus strains isolated in China, Russia, Thailand, and Vietnam during 2001–2004. All the strains studied were clustered into the same branch of the phylogenetic tree. The comparison of the G3 deduced amino acid sequences between the studied Chinese strains and the strains circulating in China during 1986–1992 showed a wide range of amino acid substitutions (up to 13 amino acids in the VP7 antigenic regions). The two considerable changes both from aspartic acid to asparagine were located at positions 96 in antigenic region A and 213 in antigenic region C. Those amino acid substitutions of the Chinese G3 strains might involve in the emergence of G3 rotavirus in China during 2001–2003. J. Med. Virol. 79:1611–1616, 2007. © Wiley-Liss, Inc.
Journal of Medical Virology, 2007
Sapovirus, a member of the family Caliciviridae is one of the major causative agents of viral gas... more Sapovirus, a member of the family Caliciviridae is one of the major causative agents of viral gastroenteritis affecting all age group. Sapovirus was detected in 25 of 917 stool specimens from infants and children with acute gastroenteritis in a Children Hospital in Dhaka City, Bangladesh during 2004–2005. All fecal specimens were examined for sapovirus by reverse transcription-polymerase chain reaction. Molecular analysis of sapovirus was carried out by sequencing methods. Sapovirus detected in this study was clustered into only one distinct genogroup I. Sapovirus GI/1 was predominant, followed by GI/2 and accounted for 92% (23 of 25) and 8% (2 of 25), respectively. The results clearly indicated that sapovirus infections were observed most commonly in the autumn to winter seasons (September to January) in Dhaka City. The common clinical symptoms of sapovirus infected patients were dehydration (88%), vomiting (76%), and abdominal pain (60%). This is the first report of sapovirus in Bangladesh. J. Med. Virol. 79:633–638, 2007. © 2007 Wiley-Liss, Inc.
Journal of Medical Virology, 2008
A molecular epidemiological study on common diarrheal viruses was conducted in a children's hospi... more A molecular epidemiological study on common diarrheal viruses was conducted in a children's hospital in Ho Chi Minh City between December 2005 and November 2006. Fecal samples were collected from 502 pediatric patients with acute gastroenteritis, and were screened for eight types of viral agents. Human astroviruses (HAstVs), which were detected with a prevalence of 13.9%, became the second most frequent viral enteropathogen. Although detected in both dry and rainy seasons, the majority (92.8%) of HAstVs in this study were found in the rainy season. Patients aged between 6 and 23 months were found to be more infected from astrovirus when compared to other age groups. The ratio between boys and girls was 2.3:1. The overall mean severity score of astrovirus positive patients was 11.8 ± 2.45. The mean severity score of the inpatients was statistically higher than that of the outpatients; however, there was no difference in severity scores between the age groups observed. The clinical manifestations of astrovirus infections among the Vietnamese children were diarrhea, vomiting, fever, coughing, and coryza. All of the detected astroviruses belonged to genotype 1. The phylogenetic tree clearly indicated that HAstVs-1 worldwide could be classified into four different lineages, in which, Vietnamese astroviruses and other recently isolated strains from other countries clustered into the distinct lineage, 1d. These results provide important information on astrovirus infections among Vietnamese children. J. Med. Virol. 80:298–305, 2008. © 2007 Wiley-Liss, Inc.
Journal of Virological Methods, 2008
The efficiency of immunochromatography and commercial enzyme-linked immunosorbent assay (ELISA) k... more The efficiency of immunochromatography and commercial enzyme-linked immunosorbent assay (ELISA) kit (Denka Seiken Co. Ltd., Tokyo, Japan) were evaluated for rapid detection of norovirus (NoV) from stool specimens. A total of 503 stool specimens collected from infants and young children who suffered from acute gastroenteritis were tested for NoV by the NoV-immunochromatography kit, Denka ELISA kit, and by a monoplex RT-PCR method. The NoV-immunochromatography revealed 78.9% sensitivity, 96.4% specificity, and 92.4% efficiency with the monoplex RT-PCR method. The Denka ELISA kit had a sensitivity of 90.4%, specificity of 96.4%, and an efficiency level of 95%. The findings indicate that the newly developed NoV-immunochromatography kit provides the specificity equal to that of the Denka ELISA kit, even through the sensitivity of detection was lower. However, the advantage of the NoV-immunochromatography kit is less time consuming and simpler. The data show that both the Denka ELISA and the NoV-immunochromatography kits may be used as an alternative method for screening of NoV in stool samples.
Journal of Medical Virology, 2005
A total of 276 fecal specimens collected from infants and children admitted to hospital with acut... more A total of 276 fecal specimens collected from infants and children admitted to hospital with acute gastroenteritis in Ho Chi Minh City, Vietnam from October 2002 to September 2003, were tested for the presence of enteroviruses by RT-PCR and virus isolation. Enteroviruses were detected in 27 patients by RT-PCR corresponding to 9.8%. However, only four enterovirus strains could be isolated by cell culture with two different cell lines CaCo2 and Vero, showing specific cytopathic effect (CPE). The results clearly indicate that RT-PCR is a sensitive, specific assay to investigate the true burden of acute gastroenteritis due to enteroviruses in clinical fecal specimens. In the present study, enteroviruses were identified throughout the year except in May and the highest number was in December. Enteroviruses were subjected to molecular analysis by sequencing. It was found that enterovirus strains detected were classified further into two distinct genetic clusters (I, II) and demonstrated the great genetic diversity among them. Based on genetic analysis, 5′ noncoding region (5′ NCR) sequences suggested the predominant presence of Vietnamese enteroviruses with the greatest similarities to coxsakieviruses (51.9%) and echoviruses (29.6%). Interestingly, two of the sequenced specimens of enteroviruses were similar to a new strain called enterovirus 74. This report is the first detection of enteroviral infection in feces from infants and children admitted to hospital with acute gastroenteritis in Vietnam. J. Med. Virol. 77:257–264, 2005. © 2005 Wiley-Liss, Inc.
Journal of Medical Virology, 2004
A total of 236 fecal specimens collected from infants and children with gastroenteritis in Maizur... more A total of 236 fecal specimens collected from infants and children with gastroenteritis in Maizuru city, Japan from July 2002 to June 2003, were tested for the presence of rotaviruses, noroviruses, sapoviruses, astroviruses, and adenoviruses by RT-PCR, PAGE, RPHA, and latex agglutination methods. Among diarrheal viruses detected, group A rotavirus was the most prevalent (32.2%; 76 of 236) followed by norovirus GII (21.2%; 50 of 236), group C rotavirus (10.2%; 24 of 236), adenovirus (3.8%; 9 of 236), sapovirus (2.5%; 6 of 236), astrovirus (1.3%; 3 of 236), and norovirus GI (0.8%; 2 of 236), respectively. It is noteworthy that group C rotavirus infection was apparently confined only within the period of 5 months (December 2002 through April 2003). This pattern of infection implied that the outbreak of group C rotavirus in these patients, which was the first outbreak of gastroenteritis attributed to group C rotavirus in Maizuru city. Moreover, about half (12 of 24) of group C rotavirus infected cases were confined to infants and young children less than 3 years old. Another interesting feature of the study was the demonstration of the mixed infections with group C rotavirus and group A rotavirus, as well as group C rotavirus and norovirus GII in 20.8% (5 of 24) and 8.3% (2 of 24), respectively. This is the first report of gastroenteritis associated with the mixed infections with group C rotavirus and other viral enteropathogens such as norovirus. The results indicate that group C rotavirus could infect not only older children and adults but also infants and young children under 3 years old. J. Med. Virol. 74:173–179, 2004. © 2004 Wiley-Liss, Inc.
Pediatrics International, 2004
Acute gastroenteritis is one of the most common diseases in humans, and continues to be a signifi... more Acute gastroenteritis is one of the most common diseases in humans, and continues to be a significant cause of mortality and morbidity worldwide. Recently the estimates of mortality associated with diarrhea declined, however the majority of deaths still occur in developing countries and thus urgent intervention is needed for the prevention of these diseases. In Asian countries it is very important to study the distribution, transmission and characteristics of prevalent viruses in order to produce viral vaccines. The viruses which cause gastroenteritis are primarily from four distinct families - group A rotaviruses, caliciviruses, enteric adenoviruses and astroviruses. Rotavirus is a common virus that causes severe gastroenteritis in children <5 years of age. The reassortant viruses with animal virus, or directly animal viruses are isolated in humans. The future development of a safe and effective vaccine against rotavirus, along with the expansion of understanding of the distribution of types in Asia and an availability of rapid diagnostic tests, could reduce mortality and might be able to prevent severe gastroenteritis. Calicivirus is a causative virus of acute gastroenteritis in children and has been known to contaminate food causing viral outbreaks affecting people of all ages. Recently, the understanding of calicivirus and the improvement of detection techniques has increased the total frequencies of diarrheal viruses. For the future control and prevention of diarrheal diseases it is necessary to examine the molecular epidemiology of caliciviruses as well as rotaviruses.
Infection Genetics and Evolution, 2010
Journal of Medical Virology, 2007
Over the last decade, rotavirus G1 has represented the most common genotype worldwide. Since 2000... more Over the last decade, rotavirus G1 has represented the most common genotype worldwide. Since 2000, the prevalence of rotavirus G1 has decreased in some countries such as Japan and China. To monitor the trend of the VP7 encoding gene of rotavirus G1, we performed a sequence analysis of 74 G1 rotavirus strains isolated in Japan, China, Thailand, and Vietnam during the period from 2002 to 2005. The phylogenetic tree showed that all of the studied G1 strains from the four countries clustered into lineage III, the same as the majority of the G1 strains isolated in China and Japan in 1990 and 1991. Examination of the deduced amino acid sequences of the G1 strains from China and Japan revealed an amino acid substitution at position 91 (Asn instead of Thr) in antigenic region A when compared to the G1 strains isolated in China and Japan in 1990, 1991, and global reference strains. For the G1 strains from Thailand and Vietnam, there were three amino acid substitutions, not belonging to any antigenic regions. The study showed that there have been no considerable changes of human rotavirus G1 isolated in Japan, China, Thailand, and Vietnam. Further studies need to be carried out for a better understanding of why such changes in the prevalence of rotavirus G1 occur in these countries. J. Med. Virol. 79:1009-1016, 2007. © 2007 Wiley-Liss, Inc.
Journal of Medical Virology, 2005
A total of 921 fecal specimens collected from 44 infants in a day care center in Tokyo, Japan dur... more A total of 921 fecal specimens collected from 44 infants in a day care center in Tokyo, Japan during June 1999 to July 2000 were tested for the presence of sapovirus by reverse transcription-polymerase chain reaction (RT-PCR). Of 88 fecal specimens from infants with acute gastroenteritis, 2.3% (2) were found to be positive for sapovirus. Twenty-two of 833 (2.6%) fecal specimens collected from asymptomatic infants were also infected with this virus. Another interesting feature was the demonstration of high incidence of sapovirus infection (95.5%, 21 of 22) identified in a single day care center, which was not due to viral shedding after the latest acute gastroenteritis. Sapovirus was subjected to genetic analysis by sequencing. Up to 4 of 24 sapoviruses (16.7%) were clustered into genogroup IV known as a rare group. Remarkably, majority (79.2%, 19 of 24) of sapovirus isolates detected in this study turned out to present one novel sapovirus genotype tentatively called GI/8. It was noteworthy to point out that the GI/8 sapovirus infection was apparently confined only within the period of 9 weeks (44th through 52nd weeks). This pattern of infection implied the outbreak of asymptomatic GI/8 sapovirus infection in these subjects. The findings clearly indicate genogroup I sapovirus can be classified into eight genotypes. This is the first report to underscore that sapovirus pathogen causes not only clinical manifestations of acute gastroenteritis but also asymptomatic infection in infants in day care centers in Japan. J. Med. Virol. 77:595–601, 2005. © 2005 Wiley-Liss, inc.
Journal of Affective Disorders, 2006
Background: Major Depressive Disorder (MDD) becomes increasingly prevalent during adolescence and... more Background: Major Depressive Disorder (MDD) becomes increasingly prevalent during adolescence and is associated with substantial psychiatric comorbidity and psychosocial impairment. The marked behavioral heterogeneity evident among adolescents with MDD suggests the possibility of distinct subtypes. This study was designed to determine whether family psychiatric histories differ between groups of MDD adolescents defined by the presence or absence of severe behavioral disinhibition. Methods: Adolescents with MDD (n = 71) completed the Buss-Durkee Hostility Inventory-Adapted, Adolescent Aggressive Incidents Interview (AAII), Measure of Aggression, Violence, and Rage in Children, Diagnostic Interview Schedule for Children, Suicidal Ideation Questionnaire-JR., Suicidal Behavior Inventory, and Reynolds Adolescent Depression Scale. Parents completed the Family Informant Schedule and Criteria, Children's Affective Liability Scale, AAII, and a partial DISC. Behavioral disinhibition (BD) measures were used to assign adolescents to MDD + BD (n = 41) and MDD À BD (n = 30) groups. Results: The MDD + BD group had a higher prevalence of drug use disorders in biological fathers than the MDD À BD group. The MDD + BD group also had higher proportions of paternal second degree relatives with alcohol use disorders, drug use disorders, and psychiatric hospitalizations, and a higher proportion of maternal second degree relatives with antisocial personality disorder. Limitations: Limitations include reliance on single informants for family psychiatric histories and the failure to distinguish between child-and adolescent-onset depression. Conclusions: Family psychiatric histories differentiated MDD adolescents grouped by the presence or absence of behavioral disinhibition, suggesting possible etiologic mechanisms. Further research on subtypes or comorbid presentations may assist in the development of targeted treatment strategies. D
Accounting and Finance, 2004
The present study examines the impact of the announcement of special dividends for a sample of Au... more The present study examines the impact of the announcement of special dividends for a sample of Australian companies over the period July 1989 to June 2002. The risk-adjusted price reaction to special dividend announcements from the day before the announcement to the day after the announcement (day −1 to day 1) is positive and statistically significant, averaging 3.67 per cent. Initial special dividend announcements (4.68 per cent) led to stronger price reaction than special dividend announcements that follow an earlier special dividend (1.51 per cent) in the previous year. The magnitude of price reactions to special dividend announcements is statistically related to the size of the special dividend, the existence of prior special dividend announcements, abnormal cash flow for the year ended after the special dividend announcement, the existence of dividend reinvestment plans (DRP) versus non-DRP, and a preannouncement effect. Finally, we found strong support for the information content/signalling hypothesis for special dividend announcements that do not participate in DRP and limited support for those associated with DRP.
The present research evaluated the corrosion and inhibition performances of steel-mortar samples ... more The present research evaluated the corrosion and inhibition performances of steel-mortar samples with various levels of NaCl and corrosion inhibitors admixed in fresh mortar (0.05M DGP, 0.5M SN, and 0.05M DMEA). FESEM, EDX and XPS were used to analyze the fracture surfaces of the steel-mortar interfacial region for samples exposed to various time periods of ponding by 3% NaCl solution. The admixing of NaCl and the corrosion inhibitors in fresh mortar altered the morphology and microstructure of the hardened mortar at the steel-mortar interfacial region. The admixing of the corrosion inhibitors in fresh mortar increased the risk of carbonation of cement hydrates at the steel-mortar interfacial region, but partially displaced chloride ions. Chloride (either admixed or ingressed) and the admixed corrosion inhibitors facilitated the formation of different cement hydrates and affected chloride binding.at the steel-mortar interfacial region, all of which may affect the steel corrosion and its inhibition.