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Background Accurate, rapid, and early diagnosis of dengue virus (DENV) infections is essential for optimal clinical care. Here, we evaluated the efficacy of the quantitative real-time PCR (qRT-PCR)-LightMix dengue virus EC kit for DENV detection using samples from a dengue outbreak in Taiwan in 2015. Methods Sera from patients with suspected DENV infection were analyzed and compared using the LightMix kit, a Dengue NS1 Ag + Ab Combo kit for detection of NS1 antigen and DENV-specific IgM and IgG antibodies, and an “in-house” qualitative DENV-specific RT-PCR assay. Results A total of 8,989, 8,954, and 1581 samples were subjected to NS1 antigen detection, IgM and IgG detection, and LightMix assays, respectively. The LightMix assay yielded a linear curve for viral loads (VL) between 102 and 106 copies/reaction, and the minimum detection limits for DENV serotype 1 (DENV1) and DENV2, DENV3, and DENV4 were 1, 10, and 100 focus forming units (FFU)/mL, respectively. There was 88.9% concordance between the results obtained using the NS1 antigen combo kit and by LightMix analysis, and the diagnostic sensitivity and specificity of the two methods were 89.4 and 100%, and 84.7 and 100%, respectively. Notably, fatal cases were attributed to DENV2 infection, and 79.5% (27/34) of these cases occurred in patients ≥ 71 years of age. Among these older patients, 82.3% (14/17) were NS1/IgM/IgG (+/-/-), exhibiting VLs between 106–109 copies/mL, which was markedly higher than the rate observed in the other age groups. Conclusions The LightMix assay was effective for early diagnosis of DENV infection. Our data indicate that high VLs during primary infection in elderly patients may be a positive predictor for severe illness, and may contribute to high mortality rates., Author Summary The LightMix dengue virus EC qRT-PCR assay is effective for early diagnosis of DENV infection. High viral loads during primary infection in elderly patients may comprise a positive predictor for severe illness, and may contribute to high mortality rates.

Human adenoviruses (HAdVs) are important causes of respiratory infections in children. They usually cause mild upper respiratory symptoms, but they can also produce severe pneumonia and other complications. The aims of this retrospective study were to better define the molecular epidemiology of respiratory adenoviruses circulating in Taiwanese children during 2002 and 2013, detect reinfections and co-infections, and characterize the clinical features and laboratory findings according to the causative genotypes. We collected a representative sample of 182 isolates of adenoviruses from 175 children during the 12-year study period. The most prevalent species was HAdV-B genotype 3 (HAdV-3) (92/182, 50.5%) followed by HAdV-C (HAdV-2) (38/182, 20.9%). A single outbreak of HAdV-E (6/182, 3.3%) was noted in 2007. The mean age of children with adenovirus infections was 3.7 ± 2.0 years, with a slight predominance of males (53.1%). Children with HAdV-B tended to be older, had more lower respiratory tract infections, gastrointestinal symptoms, and a higher rate of hospitalization than those with HAdV-C (P

A large outbreak of aseptic meningitis occurred from April to November 2001 in Taiwan. Of the 1,130 enterovirus-infected patients, echovirus 30 (E30) infection was diagnosed in 188 (16.6%), with the patients having various clinical manifestations including aseptic meningitis (73.9%), young infant fever (6.9%), respiratory symptoms or herpangina (13.3%), or others (5.9%). The majority of the E30-infected patients were between 3 and 10 years old. Of the 264 E30 strains identified, 94.3, 71, and 67.4% were isolated from RD, MRC-5, and A549 cells, respectively. Primary isolation of E30 required mean times of 3.7 days for RD cells and 4.1 days for MRC-5 and A549 cells. Among all E30-positive patients, virus was most frequently isolated from throat swab specimens (85.2%) and, to a lesser extent, stool (76.4%) or cerebrospinal fluid (70.1%) specimens. The virus isolates were initially identified as echovirus 4 (E4) on the basis of immunofluorescence staining with anti-E4 and anti-E30 (Bastianni prototype) monoclonal antibodies. However, upon performance of the neutralization test, E30-specific reverse transcription-PCR, and sequencing of the VP1 gene, the results identified these isolates as E30, not E4, indicating that the reagent used to type E30, which is produced with the Bastianni strain as the immunogen, is inadequate for the identification of recent E30 isolates in Taiwan. Phylogenetic analyses of the VP1 genes of these isolates showed that their sequences differed from those of E30 isolates from the GenBank database by 9.1 to 25.2%, suggesting that this outbreak was caused by a new variant strain of E30 introduced into Taiwan in 2000 that resulted in the widespread aseptic meningitis epidemic in 2001.

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.

In 2006, an outbreak of aseptic meningitis was noted in Taiwan. From January to October 2006, a total of 3283 specimens collected from patients with viral infection, including 173 cerebrospinal fluid (CSF) samples, were examined for virus isolation and identification. Overall, 339 enterovirus (EV)-positive cases were identified by virus culture: echovirus 18 (E18) formed the majority (27.4 %, 93 cases), followed by coxsackievirus B2 (13.8 %, 47 cases) and coxsackievirus A2 (10.8 %, 37 cases). The manifestations of the 93 E18 cases were aseptic meningitis (44.1 %), viral exanthema (23.6 %), acute tonsillitis (15.1 %), acute pharyngitis (14.0 %), acute gastritis (11.8 %), herpangina (7.5 %) and bronchopneumonia (5.3 %). Of 107 E18 isolates identified, 100, 62.5 and 19 % were obtained following culture in RD, MRC-5 and A549 cells, respectively. E18 was identified most frequently from throat swabs (67.2 %) and less frequently from stool samples (15.9 %) and CSF (16.8 %). The detection rate of E18 was 78.2 % from CSF, 50 % from stool samples and 22.9 % from throat swabs. Phylogenetic relationships among the E18 strains were examined. Analysis of the partial VP1 gene showed 3.7–23.8 % variation in sequence compared with sequences from GenBank and, notably, the amino acid change V152S was detected in a protruding loop within the VP1 protein. These results indicate that a genetic variant of E18 was circulating and caused an outbreak of aseptic meningitis in Taiwan in 2006.

The present study examined the association of specific virus infections with acute respiratory tract conditions among hospitalized and outpatient children in a subtropical country. A total of 2,295 virus infections were detected in 6,986 patients between 1997 and 1999, including infections caused by respiratory syncytial virus (RSV) (1.7%), parainfluenza virus (2.0%), influenza B virus (2.6%), adenovirus (4.0%), herpes simplex virus type 1 (4.4%), influenza A virus (5.5%), and enterovirus (12.7%). There were 61 mixed infections, and no consistent seasonal variation was found. One or more viruses were detected among 24.8% of hospitalized patients and 35.0% of outpatients. The frequencies and profiles of detection of various viruses among in- and outpatients were different. The occurrence of enterovirus infections exceeded that of other viral infections detected in 1998 and 1999 due to outbreaks of enterovirus 71 and coxsackievirus A10. RSV was the most prevalent virus detected among hospitalized children, whereas influenza virus was the most frequently isolated virus in the outpatient group. Most respiratory viral infections (39.3%) occurred in children between 1 and 3 years old. RSV ( P < 0.025) and influenza A virus ( P < 0.05) infections were dominant in the male inpatient group. In addition, most pneumonia and bronchiolitis (48.4%) was caused by RSV among hospitalized children less than 6 months old. Adenovirus was the most common agent associated with pharyngitis and tonsilitis (45.5%). These data expand our understanding of the etiology of acute respiratory tract viral infections among in- and outpatients in a subtropical country and may contribute to the prevention and control of viral respiratory tract infections.