Guan-Ming Ke

Respiratory Adenoviral Infections in Children: A Study of Hospitalized Cases in Southern Taiwan in 2001–2002

Adenoviruses account for 5-10 per cent of respiratory illnesses in children. To analyse the clinical features and the temporal frequency in acute adenoviral respiratory infections in hospitalized children in southern Taiwan, a total of 4333 children who were admitted to the Department of Pediatrics, Kaohsiung Municipal Hsiaokang (KMHK) Hospital, with clinical evidences of acute respiratory infections between January 2001 and December 2002 were studied. Adenoviruses were isolated from 317 patients with an isolation rate of 7.67 per cent. Serotype analysis was performed by polymerase chain reaction (PCR) and/or PCR-restriction fragment length polymorphism (PCR-RFLP) in 186 specimens. In 2001, adenovirus type 4 was found in the majority (57 per cent), followed by type 1.5.6 (15 per cent), type 2 (13 per cent), type 14 (8 per cent), type 3 (5 per cent), and type 7 (2 per cent). In 2002, type 3 became the major type (46 per cent), whereas the previously predominant type 4 decreased to 6 per cent, and type 7 increased from 2 to 19 per cent. The symptoms and signs included fever (98.7 percent), cough (77.6 per cent), abnormal breathing sounds (crackles and/or wheezing 23.3 per cent), abdominal pain (18.9 per cent), vomiting (21.8 per cent), and diarrhea (25.2 per cent). The mean duration of fever was 4.8 days (range 0-19 days). In the 186 cases in whom serotypes were analysed, pharyngitis and tonsillitis (47.8 per cent) were the most common presentation, followed by pneumonia (25.2 per cent), bronchitis (12.9 per cent), and pharyngoconjunctival fever (PCF) (7.6 per cent). Children between 4 and 8 years old were the most common group of patients with respiratory adenoviral infections. Our patients all had good prognosis. This adenoviruses molecular epidemiological study provides information that helps physicians in clinical differential diagnosis and treatment of respiratory adenoviral infection in children in southern Taiwan.

Molecular epidemiology of Coxsackievirus B3.

Molecular epidemiological characteristics are needed to understand the impact of Coxsackievirus B3 (CV-B3) infection, since no CV-B3 genotyping literature is available. Twenty-nine CV-B3 Taiwan strains obtained from 1992 to 2005 were analyzed. A phylogenetic tree was constructed based on the 290 nucleotide sequence of the VP1 gene of Taiwan isolates and in 91 other CV-B3 GenBank sequences. Five genotypes (GI-GV) were depicted. The GI, GII, and GIII were dominant in America and Europe, whereas GIV and GV were prevalent in Asia. In Taiwan, a transient outbreak of GIV occurred in 2000, while GV has been the main genotype circulating since 1992. Patient age ranged from 0.1 to 81 months (median, 4.3 months). The male:female ratio was 1.9:1. More than 60% (17/29) of cases involved children younger than 1 year. Half of them contracted respiratory tract infection (12/24). Nine of the 24 (37.5%) cases with available medical records had central nervous system (CNS) involvement. Eight of the nine patients were younger than 3 months. The CV-B3 has evolved and circulated for the past 60 years. Although the nucleotide sequence of the VP1 is highly variably, amino acids were relatively conserved within the same genotype of CV-B3. CNS infections were not associated with a specific strain or genotype. The CV-B3 poses a significant health threat to children younger than 1 year, especially those younger than 3 months old.

Secular trend of genome types of respiratory adenovirus type 3 during 1983–2005: a study from Taiwan

Genome type analysis of adenovirus type 3 (Ad3) in Taiwan identified four types (Ad3a, Ad3a2, Ad3a1, Ad3–7) during 1983–2005. Ad3a was the major type during 1983–1999, while Ad3a2 was the predominant type from 2001 to 2005. Phylogenetic analysis of the hexon gene of 23 isolates revealed that most Ad3a2 and Ad3–7 isolates belonged to one cluster, and most Ad3a isolates to the other cluster. The clinical manifestations included respiratory tract infections, acute gastroenteritis, hand-foot-and-mouth disease, febrile convulsion and pharyngoconjunctival fever. In conclusion, Ad3a2 has replaced Ad3a as the most common genome type in Taiwan since 2001.

MOLECULAR EPIDEMIOLOGY OF DENGUE VIRUS SEROTYPE 2 IN THE TAIWAN 2002 OUTBREAK WITH ENVELOPE GENE AND NONSTRUCTURAL PROTEIN 1 GENE ANALYSIS

The genetic relationships among dengue virus serotype 2 (DEN‐2) isolates from the Taiwan 2002 epidemic were studied by sequence analysis of the envelope (E) and nonstructural protein 1 (NS1) genes. A 0–0.4% divergence among 10 isolates revealed an epidemic strain in the outbreak. Phylogenetic study demonstrated that the 2002 Taiwan isolates were of the Cosmopolitan genotype, which is different from the Asian 1 and Asian 2 genotypes of Taiwan DEN‐2 isolates from 1981 to 1998 and the American/Asian genotype of 2005 Taiwan isolates. Although grouping results from both E and NS1 gene sequence analyses were the same, the usage of the NS1 gene as a sequence analysis target has not been validated for the lower bootstrap support values of branches in the phylogenetic tree. Our result showing the same genotype changes in Taiwan and Philippines isolates suggests strain transfer of DEN‐2 to nearby countries resulting in the same trend of genotype change.

Phylogenetic Study of Dengue-3 Virus in Taiwan with Sequence Analysis of the Core Gene

Dengue virus serotype 3 (dengue‐3) has been classified into five genotypes (I–V) by phylogenetic analysis based on different viral genes. To investigate the genetic variability and evolutionary character of the dengue‐3 isolates in southern Taiwan from 2005 to 2006, we analyzed the 290 nucleotides of the core (C) gene of 12 dengue‐3 isolates and compared them with the published C gene sequences of global dengue‐3 strains available in GenBank, including four isolates from 1998 and one isolate from 1999, from Taiwan. The dengue‐3 viruses from 2005 to 2006 were not from continuous spread of an epidemic strain or re‐emergence of the 2005 strains in the 2‐year period because there was a 5.4–6.2% difference in the 290 nucleotides of the C gene and different genotypes between the 2005 and 2006 strains. Most of the nucleotide changes, compared with a prototype dengue‐3 virus, H87, occurred in the third codon position and were non‐synonymous mutations occurring naturally in the C gene. In addition, there was no consistent difference in the 290 nucleotides of the C gene between eight dengue fever and two dengue hemorrhagic fever isolates from 2006. The phylogenetic analysis indicates that the isolates from the 1998, 1999 and 2006 Taiwan dengue‐3 epidemics are phylogenetically related and belong to genotype III. It was noted that the 2005 Taiwan dengue‐3 isolates belong to another genotype. This molecular epidemiology study of dengue‐3 viruses in Taiwan helps to elucidate whether there is a continuation of outbreaks in consecutive years, re‐emergence of endemic dengue virus, or introduction of strains from other countries.

Comparison of Nucleotide Sequence of P2C Region in Diabetogenic and Non-Diabetogenic Coxsackie Virus B5 Isolates

Enteroviruses are environmental triggers in the pathogenesis of type 1 diabetes mellitus (DM). A sequence of six identical amino acids (PEVKEK) is shared by the 2C protein of Coxsackie virus B and the glutamic acid decarboxylase (GAD) molecules. Between 1995 and 2002, we investigated 22 Coxsackie virus B5 (CVB5) isolates from southern Taiwan. Four of these isolates were obtained from four new‐onset type 1 DM patients with diabetic ketoacidosis. We compared a 300 nucleotide sequence in the 2C protein gene (p2C) in 24 CVB5 isolates (4 diabetogenic, 18 non‐diabetogenic and 2 prototype). We found 0.3‐10% nucleotide differences. In the four isolates from type 1 DM patients, there was only 2.4‐3.4% nucleotide difference, and there was only 1.7‐7.1% nucleotide difference between type 1 DM isolates and non‐diabetogenic isolates. Comparison of the nucleotide sequence between prototype virus and 22 CVB5 isolates revealed 18.4‐24.1% difference. Twenty‐one CVB5 isolates from type 1 DM and non‐type 1 DM patients contained the PEVKEK sequence, as shown by the p2C nucleotide sequence. Our data showed that the viral p2C sequence with homology with GAD is highly conserved in CVB5 isolates. There was no difference between diabetogenic and non‐diabetogenic CVB5 isolates. All four type 1 DM patients had at least one of the genetic susceptibility alleles HLA‐DR, DQA1, DQB1. Other genetic and autoimmune factors such as HLA genetic susceptibility and GAD may also play important roles in the pathogenesis in type 1 DM.