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: 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 01/2015; 87(1). DOI:10.1002/jmv.23984 · 2.22 Impact Factor
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ABSTRACT: Human adenoviruses (HADVs) comprise at least 54 types and cause a wide spectrum of respiratory tract infections; early diagnosis and epidemiological monitoring of HADV infections requires a rapid and sensitive assay. The use of a real-time polymerase chain reaction (PCR) assay was evaluated with one set of in-house designed primers for respiratory adenoviral infections. The assay was first validated by detecting successfully 6 representative types and 100 clinical isolates. A concomitant prospective surveillance of viral aetiology using conventional cultures and PCR assays in 160 febrile children with acute respiratory tract symptoms was conducted between May 2010 and July 2011. Viral aetiologies were confirmed in 72 (45%) cases using conventional cultures, including 51 adenoviral infections. The concordance between the real-time PCR and culture was good (Kappa = 0.94), and two additional culture-negative adenovirus infections were identified. During the study period (January 2011), an adenoviral community epidemic occurred. Adenovirus B3 was the predominant type in this epidemic (69.8%), followed by C2 (5.7%), C1 (5.7%), C5 (1.9%), E4 (1.9%), C6 (1.9%), F41 (1.9%), and 4 unclassified species C (7.5%). Significantly prolonged duration of fever (>5 days), higher leukocyte counts, higher neutrophil counts, and higher C-reactive protein levels were in the adenoviral infected group (n = 53, P < 0.001), compared with the non-adenoviral infected group (n = 107). In conclusion, this in-house real-time PCR is capable of detecting adenoviral respiratory infections of various types in children; and patients with adenoviral aetiology suffered from more severe clinical manifestations. J. Med. Virol. © 2014 Wiley Periodicals, Inc.Journal of Medical Virology 06/2014; DOI:10.1002/jmv.23940 · 2.22 Impact Factor
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ABSTRACT: Background: Adenovirus (AdV) causes respiratory infection; recent observations suggest that some subtypes have more ability to develop fatal disease. AdV infection has been associated with co-infection with human bocavirus (HBoV). We analysed the frequency of AdV infection, its subtypes and the presence of co-infection with HBoV, as well the clinical characteristics of such co-infection in Mexican paediatric immunosuppressed (IP) and non-immunosuppressed patients (non-IP) diagnosed with pneumonia. Methods: A total of 5185 nasopharyngeal swabs from two groups of children with pneumonia, one IP and the other non-IP, were analysed for the detection of AdV by immunofluorescence and confirmed by PCR and culture. HBoV was identified by PCR. Positive samples for AdV and AdV/HBoV were typed using PCR sequencing, the clinical characteristics of the AdV/HBoV co-infection were analysed. Results: Thirty-seven of the 5185 (0.71%) samples were positive for AdV, of those 27/37 (73%) were detected in non-IP and 10/37 (27%) in the IP group. Twelve were typed as follows: 9/12 (75%) as Species B1 subtype 3, of those 8/9 (88.9%) in non-IP and 1/9 in the IP group. One of twelve AdV2 subtype B11a was identified in one non-IP and the remaining two out of 12 successfully typed, were identified as Species C subtypes 2 and 6 in the group of non-IP. The presence of both AdV and HBoV1 in co-infection was observed in 2/37 (5.4%) non-IP with a syndrome like influenza. Conclusions: In this 5 year analysis of samples from non-IP and IP hospitalized paediatric patients with a diagnosis of pneumonia, a low incidence of AdV was found. B1 was the most frequent subtype and frequently found in non-IP, and two cases of co-infection AdV/HBoV1 were detected in two non-IP with a influenza-like syndromes. This is the first report of HBoV and AdV co-infection in Mexico. The frequency of AdV and HBoV co-infection was lower than that reported in other populations.Clinical laboratory 01/2014; 60(8). DOI:10.7754/Clin.Lab.2013.130449 · 1.08 Impact Factor