Molecular Epidemiology of Enteric Viral Infection in Children of Northern Taiwan

• Main Authors: Shih Yen Chen, 陳世彥
• Other Authors: C. H. Chiu
• Format: Others
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/80414091646714801306

博士 === 長庚大學 === 臨床醫學研究所 === 97 === Abstract (英文摘要) Viral gastroenteritis composed of 70% -80% of acute gastroenteritis (AGE) in children that accounts for several clinical syndromes including diarrhea, vomiting, dehydration and even death. Among these viral pathogens, rotavirus remains the leading cause of AGE; rotavirus caused an estimation of 600,000 deaths in children annually, nevertheless other viruses also play a role, such as norovirus, and adenovirus. The specific aims of this propose is as following described: (1). Detection of viral pathogens from fecal specimens of AGE by using RT-PCR (Rotavirus, Astrovirus and NLVs), DNA PCR (Adenovirus). (2). To correlate clinical manifestations of AGE patients with their etiological results. (3). Phylogenetic analysis of these enteric viruses. Fecal specimens from these hospitalized AGE patients in Chang Gung Children’s Hospital were randomly collected since April of 2004 to January of 2007 and their clinical manifestations were followed up. Extraction of the viral nucleic acid was carried out and the RT-PCR reaction for RNA viruses and PCR reaction for DNA virus were performed. The etiological results were correlated with clinical manifestations of AGE patients by statistical analysis. Besides, the rotavirus positive and norovirus positive PCR products were purified and determined their DNA sequence by DNA autosequencer. The sequences obtained were aligned with other sequences (rotavirus or norovirus) published in the GenBank/EMBL by using the ClustalW program and constructed a phylogenetic tree by using the neighbor-joining method. Viral etiologies can be identified in most hospitalized pediatric patients (81.7%) with AGE by molecular methods and rotavirus is the most common cause for a more severe disease. In addition, AGEs due to mixed enteric pathogens infections are not uncommon in hospitalized patients and rotavirus takes the most important role in not only mixed viral infection but also in viral and bacterial co-infection. Among these enteric pathogens, we found that norovirus is a significant and emerging cause of acute gastroenteritis other than rotavirus in children and was associated with a higher rate of convulsion in young children than previously recognized. Norovirus GGII/4 strain compromised majority of genotypeable norovirus strains and also among the strains responsible for convulsions. We identified rotavirus G1, G2, G3, and G9 as the major four genotypes circulating in northern Taiwan during the study period. When compared with rotavirus strains isolated in Taiwan before, all our strains showed slow evolution except in G2 strains. Based on this study, we have four major conclusions. (1). The disease burden and severity of AGE in children are different from virus to virus. By molecular methods, a better etiological identification can be achieved. (2). AGEs caused by multiple enteric pathogens are not rare in hospitalized patients in Taiwan and rotavirus takes the most important role. (3). Norovirus infection was associated with a higher rate of convulsion in young children than previously recognized. In view of the high extra-intestinal morbidity, the development of a norovirus vaccine is of paramount importance. (4). The immune response elicited by a pentavalent rotavirus vaccine that demonstrated against gastroenteritis might be sufficient to control the infections caused by most of rotavirus strains circulating in Taiwan.