Phylogeographic and genetic characterization of porcine circovirus type 2 in Taiwan from 2001-2017.

Porcine circovirus type 2 (PCV2) is an important pathogen that causes significant economic losses in the swine industry worldwide. Five major PCV2 genotypes have been identified, including PCV2a, PCV2b, PCV2c, PCV2d, and PCV2e. To investigate the prevalence and phylodynamics of the different PCV2 genotypes in Taiwan, 214 PCV2 ORF2 sequences from Taiwan and other countries were analyzed. Genotypic differences were observed among PCV2a, 2b, and 2d at amino acid position 89 in ORF2, with isoleucine (I), arginine (R), and leucine (L), respectively. Similar to other countries, a genotypic shift was also observed in Taiwan, where the predominant genotype shifted from PCV2b to 2d after 2010. The estimated nucleotide substitution rate of Taiwanese strains in the ORF2 region was 8.467 × 10-4 substitutions per site per year. This rapid evolution rate of PCV2 may lead to the genotypic shift observed in Taiwan. The times to the most recent common ancestor (TMRCA) for PCV2a, -2b, and -2d-2 was dated to 1970, 1992 and 2004, respectively. Thus, the PCV2a, -2b, and -2d genotypes were already present in Taiwan before the introduction of the PCV2 vaccine.

Phylodynamic and Genetic Diversity of Canine Parvovirus Type 2c in Taiwan.

Canine parvovirus type 2c (CPV-2c) emerged in 2000 and is known for causing a more severe disease than other CPV-2 variants in puppies. In 2015, the emerging CPV-2c variant was isolated in Taiwan and it subsequently became the predominant variant. To trace the evolution of Taiwanese CPV-2c, we compared complete VP2 genes of CPV-2c from Taiwan and sequences obtained from GenBank. The evolutionary rate of CPV-2c was estimated to be 4.586 × 10-4 substitutions per site per year (95% highest posterior density (HPD) was 3.284-6.076 × 10-4). The time to the most recent common ancestor (TMRCA) dated to 1990 (95% HPD: 1984-1996) and 2011 (95% HPD: 2010-2013) for the CPV-2c variant and Taiwanese isolates, respectively. The CPV-2c variant isolated from Taiwan was clustered with CPV-2c from China. This phylogenetic clade began to branch off in approximately 2010 (95% HPD was 3.823-6.497). Notably, two unique mutations of Taiwanese CPV-2c were found, Q383R and P410L. In summary, this is the first report on the genome evolution of CPV-2c in Taiwan, revealing that this CPV-2c variant shares a common evolutionary origin with strains from China. The demographic history inferred by the Bayesian skyline plot showed that the effective population of CPV-2c increased until 2006 and then slowly declined until 2011.

Surveillance of upper respiratory infections using a new multiplex PCR assay compared to conventional methods during the influenza season in Taiwan.

OBJECTIVES: To improve diagnosis as part of laboratory surveillance in Taiwan, influenza-like illness (ILI) surveillance was conducted using a new multiplex PCR assay (FilmArray) and the results compared to those of conventional methods The study was performed during the winter months. METHODS: Throat swabs from patients with an ILI presenting to physicians in sentinel practices were collected during the 2016-2017 influenza season. RESULTS: A total of 52 samples tested positive by FilmArray Respiratory Panel. Forty percent were influenza A virus, and subtype H3N2 virus was the major epidemic strain. However, nearly 60% of ILI cases seen at sentinel sites were caused by non-influenza pathogens. The results of the FilmArray assay and cell culture were identical, and this assay was more sensitive than a rapid influenza diagnostic test. Genetic analyses revealed new influenza A H3N2 variants belonging to a novel subclade 3C.2a2. CONCLUSIONS: The FilmArray assay facilitates urgent testing and laboratory surveillance for common viral and bacterial respiratory pathogens. This study demonstrated the use of a highly sensitive assay using clinical samples that is feasible for application worldwide. This may lead to an increased rate of diagnosis of viral infections and to improved patient outcomes, and in particular to a reduction in the overuse of antibiotics and antivirals.

Inflammatory myofibroblastic tumors of the pancreas in children: A case report and literature review.

INTRODUCTION: Inflammatory myofibroblastic tumors are an uncommon neoplasm, which are very rarely located in the pancreas. Clinically and radiologically, this rare pancreatic tumor presents as an abdominal mass lesion that mimics other pancreatic tumors, and should therefore be considered in the differential diagnosis of pancreatic tumors. CLINICAL FINDINGS AND DIAGNOSIS: The 15-year-old boy complained of abdominal pain over the left upper quadrant with intermittent fever for 7 days. Abdominal sonography revealed one cystic lesion with a hyperechoic component in the left upper quadrant of the abdomen. Surgical excision was performed and postoperative findings indicated a pancreatic tail tumor. The pathology indicated inflammatory myofibroblastic tumors. To our knowledge, this patient is a unique case as the tumor was located in the pancreatic tail only, sparing the body. INTERVENTIONS AND OUTCOMES: The patient underwent tumor resection and segmental resection of the transverse colon with simple closure. The patient had no evidence of disease recurrence at 3 years follow-up. CONCLUSION: Inflammatory myofibroblastic tumors of the pancreas in children are extremely rare. Surgical excision is the standard treatment, and corticosteroids use in children need more large-scale studies.

Phylodynamic Characterization of an Ocular-Tropism Coxsackievirus A24 Variant.

Recent phylodynamic studies have focused on using tree topology patterns to elucidate interactions among the epidemiological, evolutionary, and demographic characteristics of infectious agents. However, because studies of viral phylodynamics tend to focus on epidemic outbreaks, tree topology signatures of tissue-tropism pathogens might not be clearly identified. Therefore, this study used a novel Bayesian evolutionary approach to analyze the A24 variant of coxsackievirus (CV-A24v), an ocular-tropism agent of acute hemorrhagic conjunctivitis. Analyses of the 915-nucleotide VP1 and 690-nt 3Dpol regions of 21 strains isolated in Taiwan and worldwide during 1985-2010 revealed a clear chronological trend in both the VP1 and 3Dpol phylogenetic trees: the emergence of a single dominant cluster in each outbreak. The VP1 sequences included three genotypes: GI (prototype), GIII (isolated 1985-1999), and GIV (isolated after 2000); no VP1 sequences from GII strains have been deposited in GenBank. Another five genotypes identified in the 3Dpol region had support values >0.9. Geographic and demographic transitions among CV-A24v clusters were clearly identified by Bayes algorithm. The transmission route was mapped from India to China and then to Taiwan, and each prevalent viral population declined before new clusters emerged. Notably, the VP1 and 3Dpol genes had high nucleotide sequence similarities (94.1% and 95.2%, respectively). The lack of co-circulating lineages and narrow tissue tropism affected the CV-A24v gene pool.

Spatial Temporal Dynamics and Molecular Evolution of Re-Emerging Rabies Virus in Taiwan.

Taiwan has been recognized by the World Organization for Animal Health as rabies-free since 1961. Surprisingly, rabies virus (RABV) was identified in a dead Formosan ferret badger in July 2013. Later, more infected ferret badgers were reported from different geographic regions of Taiwan. In order to know its evolutionary history and spatial temporal dynamics of this virus, phylogeny was reconstructed by maximum likelihood and Bayesian methods based on the full-length of glycoprotein (G), matrix protein (M), and nucleoprotein (N) genes. The evolutionary rates and phylogeographic were determined using Beast and SPREAD software. Phylogenetic trees showed a monophyletic group containing all of RABV isolates from Taiwan and it further separated into three sub-groups. The estimated nucleotide substitution rates of G, M, and N genes were between 2.49 × 10(-4)-4.75 × 10(-4) substitutions/site/year, and the mean ratio of dN/dS was significantly low. The time of the most recent common ancestor was estimated around 75, 89, and 170 years, respectively. Phylogeographic analysis suggested the origin of the epidemic could be in Eastern Taiwan, then the Formosan ferret badger moved across the Central Range of Taiwan to western regions and separated into two branches. In this study, we illustrated the evolution history and phylogeographic of RABV in Formosan ferret badgers.

Age-dependent distribution of the atopic phenotype and allergen sensitization among asthmatic children in southern Taiwan.

BACKGROUND: Asthma is divided into atopic and non-atopic phenotypes. The percentages of atopic asthma and allergen sensitization in patients of different ages have not been well studied. OBJECTIVE: To determine the percentage distribution of atopic and non-atopic phenotypes in different age groups of asthmatic children, and investigate the distribution of specific IgE to different allergens when stratified by age group in southern Taiwan. METHOD: We conducted this hospital-based, retrospective, cross-sectional study in southern Taiwan between 2004 and 2006. Asthmatic children aged 3 to 18 years who were diagnosed according to the Global Initiative for Asthma guidelines were enrolled. The MAST-CLA system was used to detect 36 allergen-specific IgEs. RESULTS: A total of 620 asthmatic children were divided into three groups: preschool (3-6 years old, n=360), school-aged (7-12 years old, n=213), and adolescent (13-18 years old, n=41) children. The atopic and non-atopic phenotypes were observed in 54.8% and 45.2% of the asthmatic children, respectively. The atopic phenotype was observed in 45.6%, 65.7%, and 80.5% of the preschool, school-aged and adolescent groups, respectively. The percentages of the atopic phenotype were significantly different when stratified by age group (p<0.001), and there was a positive trend of percentage distribution. The percentages of sensitization to aeroallergens were significantly different and observed in 44.0%, 65.7%, and 80.5% of the preschool, school-aged and adolescent groups, respectively (p<0.001). There were positive trends between age groups and prevalence rates of sensitization to the main aeroallergen and other aeroallergen groups, but not to each allergen of the seafood or other food allergen group. CONCLUSIONS: A trend of an increasing percentage of the atopic phenotype when stratified by age group was found in asthmatic children in southern Taiwan. Aeroallergens contributed more to pediatric asthma than food allergens. The prevalence of sensitization to aeroallergens increased with increasing age when stratified by age group.

Phylodynamic reconstruction of the spatiotemporal transmission and demographic history of coxsackievirus B2.

BACKGROUND: Studies regarding coxsackievirus (CV) tend to focus on epidemic outbreaks, an imbalanced topology is considered to be an indication of acute infection with partial cross-immunity. In enteroviruses, a clear understanding of the characteristics of tree topology, transmission, and its demographic dynamics in viral succession and circulation are essential for identifying prevalence trends in endemic pathogens such as coxsackievirus B2 (CV-B2). This study applied a novel Bayesian evolutionary approach to elucidate the phylodynamic characteristics of CV-B2. A dataset containing 51 VP1 sequences and a dataset containing 34 partial 3D(pol) sequencing were analyzed, where each dataset included Taiwan sequences isolated during 1988-2013. RESULTS: Four and five genotypes were determined based on the 846-nucleotide VP1 and 441-nucleotide 3D(pol) (6641-7087) regions, respectively, with spatiotemporally structured topologies in both trees. Some strains with tree discordance indicated the occurrence of recombination in the region between the VP1 and 3D(pol) genes. The similarities of VP1 and 3D(pol) gene were 80.0%-96.8% and 74.7%-91.9%, respectively. Analyses of population dynamics using VP1 dataset indicated that the endemic CV-B2 has a small effective population size. The balance indices, high similarity, and low evolutionary rate in the VP1 region indicated mild herd immunity selection in the major capsid region. CONCLUSIONS: Phylodynamic analysis can reveal demographic trends and herd immunity in endemic pathogens.

Molecular Epidemiology and Phylogenetic Analysis of Human Adenovirus Caused an Outbreak in Taiwan during 2011.

An outbreak of adenovirus has been surveyed in Taiwan in 2011. To better understand the evolution and epidemiology of adenovirus in Taiwan, full-length sequence of hexon and fiber coapsid protein was analyzed using series of phylogenetic and dynamic evolution tools. Six different serotypes were identified in this outbreak and the species B was predominant (HAdV-3, 71.50%; HAdV-7, 15.46%). The most frequent diagnosis was acute tonsillitis (54.59%) and bronchitis (47.83%). Phylogenetic analysis revealed that hexon protein gene sequences were highly conserved for HAdV-3 and HAdV-7 circulation in Taiwan. However, comparison of restriction fragment length polymorphism (RFLP) analysis and phylogenetic trees of fiber gene in HAdV-7 clearly indicated that the predominant genotype in Taiwan has shifted from 7b to 7d. Several positive selection sites were observed in hexon protein. The estimated nucleotide substitution rates of hexon protein of HAdV-3 and HAdV-7 were 0.234×10-3 substitutions/site/year (95% HPD: 0.387~0.095×10-3) and 1.107×10-3 (95% HPD: 0. 541~1.604) respectively; those of the fiber protein of HAdV-3 and HAdV-7 were 1.085×10-3 (95% HPD: 1.767~0.486) and 0.132×10-3 (95% HPD: 0.283~0.014) respectively. Phylodynamic analysis by Bayesian skyline plot (BSP) suggested that using individual gene to evaluate the effective population size might possibly cause miscalculation. In summary, the virus evolution is ongoing, and continuous surveillance of this virus evolution will contribute to the control of the epidemic.

Exploring the benefits of growing bioenergy crops to activate lead-contaminated agricultural land: a case study on sweet potatoes.

Phytoremediation is the most environmentally friendly remediation technology for heavy metal contaminated soil. However, the phytoremediation approach requires a long time to yield results, and the plants used must be economically profitable to maintain the sustainability of the process. Because high levels of bioethanol can be produced from sweet potatoes, an experiment was conducted by planting sweet potatoes in a lead-contaminated site to observe their growth and lead-uptake capacity, thereby enabling the evaluation of the phytoremediation efficiency of sweet potatoes. The lead content in the soil was approximately 6000 mg kg(-1), and the phytoavailable Pb content was 1766 mg kg(-1). Three starch-rich sweet potato varieties, Tainung No. 10 (TNG-10), Tainung No. 31 (TNG-31), and Tainung No. 57 (TNG-57), were used in the experiment. The results indicated that TNG-10, TNG-31, and TNG-57 had fresh root tuber yields of 94.5, 133.0, and 47.5 ton ha(-1) year(-1), produced 9450, 13,297, and 4748 L ha(-1) year(-1) of bioethanol, and removed 2.68, 7.73, and 3.22 kg ha(-1) year(-1) of lead, respectively. TNG-31 yielded the highest bioethanol production and the highest lead removal in the lead-contaminated site. Therefore, implementing phytoremediation by planting TNG-31 would decrease lead content and generate income, thereby rendering the sustainable and applicable activation of contaminated soil possible.

Phytoremediation of lead using corn in contaminated agricultural land­an in situ study and benefit assessment.

Phytoremediation is an environmentally friendly and economically feasible remediation technology for mitigating soil contamination in agricultural lands. However, phytoremediation can be a slow process, and for highly contaminated soils this approach would require hundreds to thousands of years to meet soil environmental quality standards. Such a long period of phytoremediation is relatively unfeasible without economic revenue from crop production. This study involves growth of corn in plots of lead-contaminated agricultural land with Pb concentrations of about 6000 mg/kg. Our results showed that Bright Jean No. 7 corn was highly tolerant to lead, as evidenced by minimal effects on its growth and biomass production. Annually, each hectare of corn could produce up to 93.4 tons of dry matter and removed up to 7.2 kg of lead. The corn biomass grown on such contaminated fields could be used as a bioenergy fuel, and each hectare of corn biomass could produce 1545 GJ of thermal energy every year, which is equivalent to the heat from combustion of 57 tons of hard coal. The lead content in the corn kernel was less than the EU standard limit for animal consumption. Each hectare could produce approximately 25 tons of corn grains for animal feed per year, and the remaining parts of the plant could be used as the bioenergy fuel to generate heat energy equivalent to 40 tons of hard coal.

Molecular epidemiologic and clinical characteristics of influenza B-associated complications among hospitalized patients during an outbreak in Taiwan.

OBJECTIVES: To study the resurgence of influenza B/Yam in Taiwan and summarize clinical findings of influenza B-associated complications among hospitalized patients, in particular the link between clinical and molecular epidemiologic characteristics. METHODS: Clinical information and isolates were collected through the national surveillance system of the Taiwan Centers for Disease Control. Potential risk factors associated with severe illness were analyzed. Antigenic and genetic analysis of representative hemagglutinin (HA) nucleotide sequences was performed. RESULTS: Of 326 patients admitted to the intensive care unit (ICU), 63.2% were aged ≤18 years or ≥65 years and 12.9% were adults aged 19-49 years. Most of the cases had underlying medical conditions before admission, and more fatal cases had chronic medical conditions than those who convalesced in the ICU. Results of the phylogenetic analysis showed that the majority of isolates from fatal cases in Taiwan were in group 2 (represented by B/Massachusetts/2/2012-like) rather than group 3, which was the predominant group of strains circulating in other Asian countries. CONCLUSIONS: Our findings suggest a regional trend of influenza B viruses and showed that new phylogenetic lineages and antigenic variants emerging in neighboring countries were likely to be the progenitors of the epidemic strains in the following seasons.

Molecular epidemiology and phylodynamics of the human respiratory syncytial virus fusion protein in northern Taiwan.

BACKGROUND AND AIMS: The glycoprotein (G protein) and fusion protein (F protein) of respiratory syncytial virus (RSV) both show genetic variability, but few studies have examined the F protein gene. This study aimed to characterize the molecular epidemiology and phylodynamics of the F protein gene in clinical RSV strains isolated in northern Taiwan from 2000-2011. METHODS: RSV isolates from children presenting with acute respiratory symptoms between July 2000 and June 2011 were typed based on F protein gene sequences. Phylogeny construction and evaluation were performed using the neighbor-joining (NJ) and maximum likelihood (ML) methods. Phylodynamic patterns in RSV F protein genes were analyzed using the Bayesian Markov Chain Monte Carlo framework. Selection pressure on the F protein gene was detected using the Datamonkey website interface. RESULTS: From a total of 325 clinical RSV strains studied, phylogenetic analysis showed that 83 subgroup A strains (RSV-A) could be further divided into three clusters, whereas 58 subgroup B strains (RSV-B) had no significant clustering. Three amino acids were observed to differ between RSV-A and -B (positions 111, 113, and 114) in CTL HLA-B*57- and HLA-A*01-restricted epitopes. One positive selection site was observed in RSV-B, while none was observed in RSV-A. The evolution rate of the virus had very little change before 2000, then slowed down between 2000 and 2005, and evolved significantly faster after 2005. The dominant subtypes of RSV-A in each epidemic were replaced by different subtypes in the subsequent epidemic. CONCLUSIONS: Before 2004, RSV-A infections were involved in several small epidemics and only very limited numbers of strains evolved and re-emerged in subsequent years. After 2005, the circulating RSV-A strains were different from those of the previous years and continued evolving through 2010. Phylodynamic pattern showed the evolutionary divergence of RSV increased significantly in the recent 5 years in northern Taiwan.

Exploring the molecular epidemiology and evolutionary dynamics of influenza A virus in Taiwan.

The evolution and population dynamics of human influenza in Taiwan is a microcosm of the viruses circulating worldwide, which has not yet been studied in detail. We collected 343 representative full genome sequences of human influenza A viruses isolated in Taiwan between 1979 and 2009. Phylogenetic and antigenic data analysis revealed that H1N1 and H3N2 viruses consistently co-circulated in Taiwan, although they were characterized by different temporal dynamics and degrees of genetic diversity. Moreover, influenza A viruses of both subtypes underwent internal gene reassortment involving all eight segments of the viral genome, some of which also occurred during non-epidemic periods. The patterns of gene reassortment were different in the two subtypes. The internal genes of H1N1 viruses moved as a unit, separately from the co-evolving HA and NA genes. On the other hand, the HA and NA genes of H3N2 viruses tended to segregate consistently with different sets of internal gene segments. In particular, as reassortment occurred, H3HA always segregated as a group with the PB1, PA and M genes, while N2NA consistently segregated with PB2 and NP. Finally, the analysis showed that new phylogenetic lineages and antigenic variants emerging in summer were likely to be the progenitors of the epidemic strains in the following season. The synchronized seasonal patterns and high genetic diversity of influenza A viruses observed in Taiwan make possible to capture the evolutionary dynamic and epidemiological rules governing antigenic drift and reassortment and may serve as a "warning" system that recapitulates the global epidemic.

Phylodynamics and molecular evolution of influenza A virus nucleoprotein genes in Taiwan between 1979 and 2009.

BACKGROUND: Many studies concentrate on variation in the hemagglutinin glycoprotein (HA) because of its significance in host immune response, the evolution of this virus is even more complex when other genome segments are considered. Recently, it was found that cytotoxic T lymphocytes (CTL) play an important role in immunity against influenza and most CTL epitopes of human influenza viruses were remarkably conserved. The NP gene has evolved independently in human and avian hosts after 1918 flu pandemic and it has been assigned a putative role as a determinant of host range. METHODS AND FINDINGS: Phylodynamic patterns of the genes encoding nucleoprotein (NP) of influenza A viruses isolated from 1979-2009 were analyzed by applying the Bayesian Markov Chain Monte Carlo framework to better understand the evolutionary mechanisms of these Taiwanese isolates. Phylogenetic analysis of the NP gene showed that all available H3 worldwide isolates collected so far were genetically similar and divided into two major clades after the year 2004. We compared the deduced amino acid sequences of the NP sequences from human, avian and swine hosts to investigate the emergence of potential adaptive mutations. Overall, selective pressure on the NP gene of human influenza A viruses appeared to be dominated by purifying selection with a mean d(N)/d(S) ratio of 0.105. Site-selection analysis of 488 codons, however, also revealed 3 positively selected sites in addition to 139 negatively selected ones. CONCLUSIONS: The demographic history inferred by Bayesian skyline plot showed that the effective number of infections underwent a period of smooth and steady growth from 1998 to 2001, followed by a more recent rise in the rate of spread. Further understanding the correlates of interspecies transmission of influenza A virus genes from other host reservoirs to the human population may help to elucidate the mechanisms of variability among influenza A virus.

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.

Clinical and genetic analysis of Human Bocavirus in children with lower respiratory tract infection in Taiwan.

BACKGROUND: Human Bocavirus (HBoV) is a likely etiologic agent of acute respiratory disease in children. The prevalence of this virus has been studied in several sites worldwide. We conducted the first clinical and molecular study of HBoV in Taiwan at the Centers for Diseases Control, Taiwan. OBJECTIVES: To investigate the genomic and epidemiologic profiles of HBoV infection in Taiwan. STUDY DESIGN: Throat swabs or nasopharyngeal aspirates were obtained from hospitalized pediatric patients with acute lower respiratory tract infections. Specimens negative for other respiratory viruses by molecular screening were examined for HBoV. RESULTS: HBoV was the only virus detected in 30 (5.6%) of 531 samples. Of these positive cases, 56.7% were from children less than 2 years old. Two groups of HBoV co-circulated in Taiwan during the study. Results of evolutionary networks evaluation suggest that HBoV might have had an opportunity for interbreeding of viruses and genetic recombinations among the different genes. CONCLUSION: HBoV may have circulated in Taiwan for some time and it appears to be one of the etiological agents responsible for lower respiratory tract infection in children.

Characterization of the epidemic influenza B viruses isolated during 2004-2005 season in Taiwan.

To characterize the antigenic and genetic relationships of influenza B viruses isolated during the 2004-2005 season, a total of 11,707 clinical respiratory samples were tested of which 1572 (13.5%) were positive for influenza (463 type A and 1109 type B influenza). Of the type B viruses, 348 isolates collected in different parts of Taiwan were further analyzed. Viruses belonging to both influenza B lineages, B/Yamagata/16/88 (B/Yam) and B/Victoris/2/87 (B/Vic) were detected, although an increasing number of B/Vic lineage isolates was obtained as the season progressed. Recent B/Vic-lineage isolates were found to have additional amino acid substitutions compared to isolates from previous seasons, indicating that viruses of this lineage continue to evolve significantly and may have the capacity to become the dominant influenza B viruses worldwide. Results presented in this report demonstrate that antigenically and genetically distinct viruses within both B/Vic and B/Yam lineages co-circulate and that reassortment among these two lineages occurs frequently contributing to the genetic diversity of the circulating strains.

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.