Rapid identification of human adenovirus types 3 and 7 from respiratory specimens via multiplex type-specific PCR

Development of Rapid and Visual Nucleic Acid Detection Methods towards Four Serotypes of Human Adenovirus Species B Based on RPA-LF Test

Objectives

Human adenoviruses (HAdV) are classified as 7 HAdV species, and some serotypes in species B like HAdV 3, HAdV 7, HAdV 21, and HAdV 55 caused severe symptoms, even fatalities. Patients may be misdiagnosed and inadequately treated without reliable and practical methods for HAdV serotyping. Developing rapid, sensitive, and specific diagnostic methods for HAdV is critical.

Methods

Detection methods were established based on a recombinase polymerase amplification (RPA) assay and lateral flow (LF) test. Specific target sequence was screened, targeting which, primers and probes were designed, synthesized, and screened for establishing assay with high amplification efficiency. Primer or probe concentrations and amplification time were optimized. Detection limit, sensitivity, and specificity were evaluated. Results and Conclusions. Simple, sensitive, and specific RPA-LF methods for detection of four serotypes of HAdV together or separately were established, which had detection limits of 10 to 280 copies/reaction comparable to real-time PCR without recognizing other pathogens. The sensitivity and specificity were >92% and >98%, respectively, evaluated by limited clinical samples. The detection can be completed in 25 min without requirement of any instrument except a constant temperature equipment, showing superior detection performance and promising for a wide use in the field and resource-limited area.

The novel antiviral properties of brassicasterol against human adenovirus

Aim: To investigate whether brassicasterol has inhibitory effects against adenovirus (AdV). Materials & methods: The antiviral effects of brassicasterol against AdV 3 and 7 were tested in human airway epithelial cells. Brassicasterol cytotoxicity was assessed by WST-1 assay. AdV DNA was quantified by qPCR. Results: Brassicasterol inhibited AdV 3 and 7 infection of airway epithelial cells in a dose-dependent manner. Similarly, brassicasterol also inhibited AdV 3 and 7 production in infected cells. No apparent cytotoxicity of brassicasterol was detected. Further study showed that brassicasterol inhibited AdV DNA replication, but had no impact on viral entry of cells and viral genome import to nucleus. Conclusion: Brassicasterol exerts anti-AdV effects probably through the inhibition of viral DNA replication.

Adenoviromics: Mining the Human Adenovirus Species D Genome

Human adenovirus (HAdV) infections cause disease world-wide. Whole genome sequencing has now distinguished 90 distinct genotypes in 7 species (A-G). Over half of these 90 HAdVs fall within species D, with essentially all of the HAdV-D whole genome sequences generated in the last decade. Herein, we describe recent new findings made possible by mining of this expanded genome database, and propose future directions to elucidate new functional elements and new functions for previously known viral components.

Detection and Molecular Typing of Human Adenoviruses Associated with Respiratory Illnesses in Kerala

Adenoviruses are responsible for approximately 5-10% of acute respiratory infections globally. However, there are a limited number of reports on the types of circulating respiratory human adenoviruses (HAdV) in India. We detected HAdV in the post-mortem specimens of a young child who died as a result of an acute febrile illness. To retrospectively investigate the circulating adenovirus types in the Alappuzha region, samples (n = 235) collected from patients with influenza-like illnesses who participated in the influenza surveillance program were screened for HAdV. Fourteen samples were identified as positive for adenovirus by PCR analysis. Adenovirus was isolated from 3 of the 14 PCR-positive samples cultured using HEK-293 cell lines. The viral strains isolated in the study were from children between 6 and 10 years of age. The isolates were identified as adenovirus species C and E. Sequencing analysis of the fiber gene and a BLAST search revealed that 2 of the isolates were type HAdV-C2, and the third isolate was a HAdV-E4. A fiber gene sequence-based phylogenetic tree showed that the HAdV-E4 isolate was similar to the Japanese HAdV-E4 strain, whereas the HAdV-C2 isolates formed a distinct cluster. Respiratory infections due to HAdV-E4 are generally observed in adults; this study is the first to demonstrate the involvement of the HAdV-E4 strain in respiratory illnesses in children.

High-incidence of human adenoviral co-infections in taiwan

Background

Respiratory infections caused by adenovirus (HAdV) are common year round. Recently, a significant increase of adenoviral infections was observed in Taiwan.

Objective

To understand the prevalence and molecular epidemiology of respiratory adenovirus circulating in Taiwan for the past decade.

Study Design

One hundred and twenty-six human adenoviruses, isolated between 2002 to 2011, were characterized via DNA sequencing of the hexon and fiber genes. The nucleotide sequences were then compared by phylogenetic analysis.

Results

HAdV-B3 accounted for 64.3% (81/126) and peaked almost every year, whereas the sequences of hexon and fiber genes of HAdV-B3 were highly conserved in different years. A high incidence of co-infection of adenoviruses was observed (19.0%, 24/126); HAdV-B3 co-infected with HAdV-C2 was the most common combination (58.3%, 14/24). An additional interesting finding of repeated infection was noted in 10 children, all of whom showed first infection with adenovirus species HAdV-C, followed by species HAdV-B or HAdV-E.

Conclusions

HAdV-B3 was the predominant type of respiratory adenovirus circulating in Taiwan over the past ten years. This merits further attention for vaccine development. Furthermore, the observed high-incidence of adenoviral co-infections along with repeated infections found in our study provides important epidemiological insights into adenovirus infections.

Diagnosis of pneumococcal empyema using immunochromatographic test on pleural fluid and serotype distribution in Korean children

To evaluate the diagnostic value of immunochromatographic test (ICT) on pleural fluid in diagnosing pneumococcal empyema in children and to determine pneumococcal serotypes, 62 exudative parapneumonic effusions from Korean children were tested with culture, ICT for S. pneumoniae, pneumococcal autolysin polymerase chain reaction (PCR), and subsequent sequencing. Of the 62 patients, culture was positive in 3 patients only (4.8%). Pneumococci were identified in 13 samples (21.0%) by sequencing-confirmed PCR and ICT, respectively. When pneumococcal empyema was defined by either positive culture or sequence confirmation, the sensitivity of ICT was 76.9% (10/13) and the specificity of ICT was 93.9%. Eight of 10 patients with positive ICT and culture-negative results had a history of prior antibiotics use, whereas none of the culture-proven cases had. Serotypes of PCR-positive samples were determined by multiplex PCR assays. Multiplex PCR detected serotypes 19A (6), 1 (1), 14 (1), 34 (1), and untypable (4). ICT on pleural fluid is a relatively sensitive and highly specific method for diagnosis of pneumococcal empyema, especially in children given prior antibiotics.

The association of newly identified respiratory viruses with lower respiratory tract infections in Korean children, 2000-2005

Background. This study was performed to evaluate the associations of newly recognized viruses, namely, human metapneumovirus (hMPV), human coronavirus (HCoV)–NL63, and human bocavirus (HBoV) with lower respiratory tract infections (LRTIs) in previously healthy children.

Methods. To determine the prevalences of 11 viruses—respiratory syncytial virus (RSV), adenovirus, rhinovirus, parainfluenza viruses (PIVs) 1 and 3, influenza viruses A and B, hMPV, HCoV, HCoV-NL63, and HBoV—among infants or children with LRTIs, in association with their epidemiologic characteristics, we performed multiplex reverse-transcriptase polymerase chain reaction on nasopharyngeal aspirates obtained from 515 children 5 years old with LRTIs during the period 2000–2005.

Results. Viruses were identified in 312 (60.6%) of the 515 patients. RSV was detected in 122 (23.7%), HBoV in 58 (11.3%), adenovirus in 35 (6.8%), PIV-3 in 32 (6.2%), rhinovirus in 30 (5.8%), hMPV in 24 (4.7%), influenza A in 24 (4.7%), PIV-1 in 9 (1.7%), influenza B in 9 (1.7%), and HCoV-NL63 in 8 (1.6%). Coinfections with 2 viruses were observed in 36 patients (11.5%). Twenty-two patients (37.9%) infected with HBoV had a coinfection. Bronchiolitis was frequently diagnosed in patients who tested positive for RSV, PIV-3, or rhinovirus, whereas influenza A, PIV-1, and HCoV-NL63 were commonly found in patients with croup. The age distributions of patients with viral infections differed; notably, RSV was responsible for 77% of LRTIs that occurred in infants 3 months old. The number of hMPV infections peaked between February and April, whereas the number of HCoV-NL63 infections peaked between April and May.

Conclusions. This study describes the features of LRTIs associated with newly identified viruses in children, compared with those associated with known viruses. Additional investigations are required to define the role of HBoV in LRTI.