Hour-Young Chen

Sentinel Hospital Surveillance for Rotavirus Diarrhea in Taiwan, 2001–2003

We examined the epidemiological profile of rotavirus infection among children hospitalized for diarrhea in Taiwan, to assess the burden of this disease. From 1 April 2001 through 31 March 2003, children <5 years old with gastroenteritis admitted to 4 sentinel hospitals were enrolled in a surveillance study and had stool specimens tested for the presence of rotavirus, enteric adenovirus, and the bacterial pathogens for which routine screening is performed. For 52% of patients, a recognized enteric pathogen was identified, including rotavirus (43% of patients), bacteria (11%), enteric adenovirus (2.5%), and a mixture of pathogens (3.9%). Rotavirus was detected year-round, but great month-to-month variability made it difficult to identify a distinct seasonal pattern. Rotavirus disease was most common among children 7-23 months old, but the rate of rotavirus detection varied little between the youngest and oldest age groups. The novel strain P[8]G9 was detected most commonly (37% of strains), followed by strains P[8]G1 (31%), P[4]G2 (10%), P[8]G3 (9.3%), and P[8]G4 (3.7%). Rotavirus infection is the most important cause of diarrhea among hospitalized children in Taiwan, and a rotavirus vaccination program for young children might significantly reduce this problem.

Molecular Epidemiology of G9 Rotaviruses in Taiwan between 2000 and 2002

ABSTRACT Since the mid-1990s, novel G9 rotaviruses have been detected in many countries, suggesting that G9 is a globally important serotype. The molecular epidemiology of G9 rotaviruses in Taiwan from 2000 to 2002 was investigated in this study. G9 rotavirus first appeared in 2000 with 4 cases and constituted 33.8% and 54.8% of the rotavirus-positive samples in 2001 and 2002, respectively. These G9 strains belonged to P[8]G9, subgroup II, and long electropherotype, except one belonged to P[4]G9, subgroup II, and short electropherotype. Nucleotide sequencing and phylogenetic analysis of 52 Taiwanese G9 rotaviruses showed that the VP7 genes shared a high degree of identity to overseas G9 rotaviruses detected after 1993 and that the VP8* portions of the VP4 genes were more closely related to those of local rotaviruses of other G types. The two P[8]G9 strains with high nucleotide identities in the VP7 and the partial VP4 genes, 01TW591 of Taiwan from 2001 and 95H115 of Japan from 1995, varied in four genes, genes 2, 3, 7, and 8, which was revealed by RNA-RNA hybridization. Representative strains for different RNA patterns were also analyzed in the partial VP2 and VP3 genes; the nucleotide identities were high between Taiwanese G9 strains and local G3 or G2 strains. These results suggested that Taiwanese G9 rotaviruses possibly had evolved through reassortment between overseas G9 strains and circulating rotaviruses of other G types.

Do centrally obese Chinese with normal BMI have increased risk of metabolic disorders

BACKGROUND:Body mass index (BMI) and waist circumference are highly correlated. One or the other predicts the metabolic syndromes better, depending on characteristic of the population studied, such as age, gender, and ethnicity. We examined the impact of isolated central obesity, isolated BMI elevation, and the combined type of obesity on metabolic disorders, in order to shed lights on the strategy of obesity screening.METHODS:The study subjects were Chinese aged 20 or above residing in Taiwan. Their data were derived from two large-scale studies: the Nutrition and Health Survey in Taiwan (NAHSIT 1993–1996) and the Cardiovascular Disease Risk Factor Two-township Study (CVDFACTS, 1994–1997). In evaluating the relations between obesity and health risks, the cut-points of BMI (≥24 kg/m2 for overweight) and waist circumference (≥80 cm for women and ≥90 cm for men) recommended by Department of Health in Taiwan for Taiwanese people were used to define various types of obesity.RESULTS:We found that there was a small but nontrivial proportion (1.7% for men and 4.0% for women) of Taiwanese people for whom BMI was in the normal range but their waist circumferences were above normal. These people were at a higher risk of developing metabolic syndromes than those with isolated BMI elevation. Their risks were close to that of the combined type.CONCLUSIONS:In order to screen out high-risk obese individuals, isolated centrally obese subjects should not be overlooked. Therefore, we recommend to assess waist circumference in parallel to, not just sequential to the measurement of BMI in Chinese.

Antigenic Divergence of Bordetella pertussis Isolates in Taiwan

ABSTRACT In recent studies, antigenic divergence has been observed in Bordetella pertussis circulating isolates. We collected 80 Bordetella pertussis isolates in Taiwan from 1998 to 2004 and analyzed them using a combination of pulsed-field gel electrophoresis (PFGE) and sequencing of the ptxS1 and prn genes. The incidence of pertussis increases every 3 years, and most of the isolates prevalent since 1998 have expressed nonvaccine ptxS1A and prn2 alleles. Through PFGE analysis, all isolates could be classified into four major groups, and the incidence of these groups exhibited a correlation with the prn allele expressed by the isolates. We found that PFGE is more discriminative than gene sequencing, since it could divide the isolates expressing the prn2 allele into two groups: one group circulating from 1998 to 2001 and another group circulating from 2001 to 2004. The transition between the two groups in 2000 coincided with an outbreak of 326 cases. This research indicates that the antigenic divergence of B. pertussis circulating isolates has evolved over time in Taiwan. Such information will have implications for vaccine policy in Taiwan.

Phylogenetic analysis and sequence comparisons of structural and non-structural SARS coronavirus proteins in Taiwan

Abstract Taiwan experienced a large number of severe acute respiratory syndrome (SARS) viral infections between March and July 2003; by September of that year, 346 SARS cases were confirmed by RT-PCR or serological tests. In order to better understand evolutionary relationships among SARS coronaviruses (SCoVs) from different international regions, we performed phylogenetic comparisons of full-length genomic and protein sequences from 45 human SCoVs (including 12 from Taiwan) and two civet SCoVs. All the Taiwanese SARS-CoV strains which associated with nosocomial infection formed a monophyletic clade within the late phase of the SARS epidemic. This Taiwanese clade could be further divided into two epidemic waves. Taiwan SCoVs in the first wave clustered with three isolates from the Amoy Gardens housing complex in Hong Kong indicating their possible origin. Of the 45 human SCoVs, one isolate from Guangdong province, China, exhibited an extra 29-nucleotide fragment between Orf 10 and Orf 11—similar to the civet SCoV genome. Nucleotide and protein sequence comparisons suggested that all SCoVs of late epidemic came from human-to-human transmission, while certain SCoVs of early epidemic might have originated in animals.

Molecular Epidemiology of Severe Acute Respiratory Syndrome–Associated Coronavirus Infections in Taiwan

Abstract Background In 2003, Taiwan experienced a series of outbreaks of severe acute respiratory syndrome (SARS) and 1 laboratory-contamination accident. Here we describe a new phylogenetic analytical method to study the sources and dissemination paths of SARS-associated coronavirus (SARS-CoV) infections in Taiwan Methods A phylogenetic analytical tool for combining nucleotide sequences from 6 variable regions of a SARS-CoV genome was developed by use of 20 published SARS-CoV sequences; and this method was validated by use of 80 published SARS-CoV sequences. Subsequently, this new tool was applied to provide a better understanding of the entire complement of Taiwanese SARS-CoV isolates, including 20 previously published and 19 identified in this study. The epidemiological data were integrated with the results from the phylogenetic tree and from the nucleotide-signature pattern Results The topologies of phylogenetic trees generated by the new and the conventional strategies were similar, with the former having better robustness than the latter, especially in comparison with the maximum-likelihood trees: the new strategy revealed that during 2003 there were 5 waves of epidemic SARS-CoV infection, which belonged to 3 phylogenetic clusters in Taiwan Conclusions The new strategy is more efficient than its conventional counterparts. The outbreaks of SARS in Taiwan originated from multiple sources

Detection of a novel bunyavirus associated with fever, thrombocytopenia and leukopenia syndrome in Henan Province, China, using real-time reverse transcription PCR.

A novel bunyavirus associated with fever, thrombocytopenia and leukopenia syndrome (FTLS) was discovered in Henan Province, China. Here, we report the development of an assay for this novel bunyavirus based on real-time reverse transcription PCR (RT-PCR). The assay exhibited high sensitivity and specificity without cross-reactivity towards 13 other viruses that cause similar symptoms. To evaluate the performance of this assay in detecting clinical samples, we analysed 261 serum samples from patients in Henan Province between 2007 and 2010. Of these samples, 91.95 % were bunyavirus positive. Compared with serological assays, the real-time PCR assay was much more sensitive in identifying infected patients 1 to 7 days after the onset of symptoms.

Seven integrated influenza surveillance systems in Taiwan

Background: Influenza surveillance in recent decades in Taiwan showed that the major virus isolates were A/Hong Kong/68-like (H3N2), A/England/42/72-like (H3N2), A/Taiwan/1/86 (H1N1), A/Texas/36/91-like (H1N1), A/Taiwan/112/96 (H1N1), and A/Taiwan/118/96 (H1N1) based on passive virologic surveillance before 1999. Materials and methods: To prevent the potential public health threat of a newly emerged influenza A strain like H5N1 in Hong Kong, seven surveillance systems have been established in Taiwan since 1999, including severe case reporting, sentinel physician, contract-laboratory, poultry market, domestic avian, wild bird and pig surveillance. Scientific exchanges and possible public health actions are discussed in regular meetings during the winter season. Results: The isolation rates of influenza A virus were higher among ducks than chickens in both domestic avian and market surveillance systems. Ten subtypes of influenza A virus can be found in migrating wild birds, which may serve as a reservoir for the genetic and antigenic changes of the virus. The H6 subtype was isolated from both wild birds and market surveillance systems. Pig surveillance found that H3 occurred more in the winter, whereas H1 appeared predominantly in the summer. Human virologic surveillance also demonstrated summer and winter peaks. Market surveillance in Taipei showed H6, H4, and H3 subtypes isolated from ducks only. Sentinel physician surveillance experience has taught us the importance of involving local clinics, particularly in farm areas. The traditional passive physician reporting surveillance provided limited information and it was replaced by severe case reporting. Most elderly physicians in Taiwan did not like to report influenza even after implementation of direct electronic reporting through a worldwide web system. More modern technology will be applied to increase the timeliness and representativeness of influenza surveillance in preparing for future pandemics. Conclusion: Integration of animal and human influenza surveillance systems in the high population density in Taiwan serves as a model in the efforts of global influenza surveillance to detect newly emerged influenza virus strains via several channels, particularly useful in detecting severity of cases and inter-species transmission.