Clinical severity of respiratory adenoviral infection by serotypes in Korean children over 17 consecutive years (1991-2007).
ABSTRACT Human adenoviruses (HAdVs) are important causes of acute respiratory tract illness in children.
To evaluate the risk factors for severe respiratory HAdV infections and the temporal change in case-severity in relation to HAdV types.
From January 1991 to December 2007, respiratory HAdV infections of Korean children requiring hospitalization or an emergency room visit were included. An episode of HAdV infection requiring an intensive care unit stay, use of mechanical ventilation and/or death was designated as a severe infection. The medical records were reviewed retrospectively.
A total of 428 respiratory HAdV infections were included in the clinical analysis. The mean age of patients was 2.6 years. The most frequent diagnosis was a lower respiratory tract infection (312/428, 72.9%), and 44% of respiratory HAdV infections occurred in patients with underlying co-morbidities. Fifteen percent of clinical events resulted in severe HAdV infections with a case-fatality rate of 5.1%. HAdV types 7 and 8 were associated with severe infections, after adjusting for co-morbidity and the age of patients (adjusted OR 8.5 and 15.1, respectively, by a logistic regression model). The case-severity of HAdV-7 associated with lower respiratory tract infections has decreased over time, coinciding with the decreasing size of subsequent epidemics after a large outbreak (P for trend = 0.003).
HAdV types 7 and 8 were independent risk factors for severe respiratory HAdV infections. In addition, the overall severity of HAdV-7 associated lower respiratory tract infections has shown a decreasing trend, which may reflect increasing level of herd immunity.
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ABSTRACT: Lower respiratory tract infections (LRTI) caused by adenovirus can be severe with resultant chronic pulmonary sequelae. More than 50 serotypes have been recognized; however, the exact association of serotype with clinical phenotype is still unclear. There have been no reports on the adenovirus serotype pattern in Hong Kong, and their relationships with disease manifestations and complications are not known. Clinical and epidemiological data on 287 children (<6 years old) admitted with adenovirus respiratory infections from 2001 to 2004 were reviewed. Common presenting symptoms included fever (97.9 %) and cough and rhinitis (74 %). Extra-pulmonary manifestations were present in 37.3 %. The clinical picture mimicked bacterial infection for its prolonged high fever and neutrophilic blood picture. Forty-two patients (14.6 %) had LRTI, either pneumonia or acute bronchiolitis, but none had severe acute respiratory compromise. Children aged 1 to 2 years old were most at risk for adenovirus LRTI (adjusted p = 0.0165). Serotypes 1 to 7 could be identified in 93.7 % of the nasopharyngeal specimens, with serotypes 2 and 3 being the most prevalent. Different serotypes showed predilection for different age groups and with different respiratory illness association. The majority of acute bronchiolitis (71.4 %) were associated with serotype 2 infection, and this association was statistically significant (p < 0.0001). Serotype 3 infection accounted for over half of the pneumonia cases (57-75 %) in those aged 3-5 years old. Only one patient developed mild bronchiectasis after serotype 7 pneumonia. Children aged 1 to 2 years old were the at-risk group for adenovirus LRTI, but respiratory morbidity was relatively mild in our locality. There was an apparent serotype-respiratory illness association.European Journal of Pediatrics 08/2013; · 1.91 Impact Factor
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ABSTRACT: The human adenovirus (HAdV) types most commonly found in respiratory samples belong to HAdV species C (HAdV-C1, -C2, -C5, and -C6) and to HAdV species B (HAdV-B3 and -B7). Several studies in South America have shown the association between severe respiratory infections and subspecies B1. The aim of this study was to identify the adenovirus types associated with acute lower respiratory tract infections in children, found as single or coinfections, throughout a 12-year period. All samples that tested positive for adenovirus by immunofluorescence assay from January 1999 to December 2010 were typed by evaluating a set of four viral genes (E1A, VA, hexon and fiber). Quantitative PCRs for HAdV-B and HAdV-C species were performed to compare the viral load found in single infections and coinfections. From a total of 743 HAdV, 654 (88%) were single infections and 89 (12%) coinfections. From the 654 single HAdV infections, members of four species were present: species B (n=492, 75.23%), species C (n=138, 21.1%), species E (n=19, 2.91%), and species D (n=5, 0.76%). Only members of species B (n=109, 57.67%) and species C (n=80, 42.33%) were detected in coinfections. HAdV-B7 and HAdV-B3 were the most prevalent types (n=308, 36.54%; n=230, 27.28% respectively) and HAdV-C1, -C2, -E4, -C5, -C6, -D8, -B11, -B14 and -B21 were also detected. Viral loads for species C viruses were higher in single infections than in coinfections (p<0.01), whereas the opposite was observed for species B viruses (p<0.0001). This study provides a thorough description of adenovirus circulation and diversity in Buenos Aires in a 12-year period. The high proportion of coinfections found in this work shows that this phenomenom might be more common than expected.Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology 12/2011; 53(2):145-50. · 3.12 Impact Factor
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ABSTRACT: An outbreak of upper respiratory tract infections associated with human adenovirus (HAdV) occurred on a national scale in Korea from September to December 2010, following a major H1N1 influenza pandemic. Data from the Korea Influenza and Respiratory Surveillance System (KINRESS) showed an unusually high positive rate accounting for up to 20% of all diagnosed cases. To determine the principal cause of the outbreak, direct polymerase chain reaction (PCR) amplification followed by sequence analysis targeting parts of the hexon gene of HAdV was performed. Serotypes of 1,007 PCR-diagnosed HAdV-positive samples from patients with an acute upper respiratory tract illness were determined and epidemiological characteristics including major aged group and clinical symptoms were analyzed. The principal symptom of HAdV infections was fever and the vulnerable aged group was 1-5 years old. Based on sequence analysis, HAdV-3 was the predominant serotype in the outbreak, with an incidence of 74.3%. From the beginning of 2010 until May, the major serotypes were HAdV-1, 2, and 5 (70-100%) in any given period. However, an outbreak dominated by HAdV-3 started between July and August and peaked in September. Phylogenetic analysis revealed that there was no genetic variation in HAdV-3. The results demonstrated that an outbreak of upper respiratory illness followed by H1N1 influenza pandemic in Korea was caused mainly by emerged HAdV-3. J. Med. Virol. © 2014 Wiley Periodicals, Inc.Journal of Medical Virology 06/2014; · 2.37 Impact Factor