Detection of Five Rash-Associated Viruses Using Multiplex Real-Time PCR during 2006^|^ndash;2011

Virus detection of measles-negative cases in Gyeonggi Province, South Korea, from 2017 to 2019

To investigate viruses in measles-negative cases, 221 measles-suspected samples collected in Gyeonggi Province, South Korea were tested using a real-time PCR assay. Rubella virus was not detected. However, 11 cases of parvovirus B19 (5.0%), 47 cases of human herpesvirus 6 (21.3%), 25 cases of human herpesvirus 7 (11.3%), and one case of co-infection with parvovirus B19 and human herpesvirus 7 were confirmed, as were eight cases of co-infection with human herpesvirus 6 and human herpesvirus 7. This study showed that parvovirus B19, human herpesvirus 6, and human herpesvirus 7 should be considered by physicians for the diagnosis of measles-suspected patients.

Simultaneous and rapid detection method for measles and rubella using single-tube multiplex real-time quantitative RT-PCR

Patients with measles or rubella infections manifest acute onset fever accompanying systemic exanthema, which are clinically difficult to be distinguish. Rapid diagnosis and differentiation of such epidemic viral diseases is essential to prevent outbreaks. We developed a single-tube multiplex real-time PCR assay for these indistinguishable viruses. We used previously-reported primer settings, with a slight modification of reporter dye, and applied to multiplex Taqman real-time PCR by cobas z480 (Roche Molecular Systems, Inc.). Consequently, the assay could detect 10 copies/10 μl of measles and rubella with coefficient of variations of 11.2% and 21.8%, respectively. Strengths of our methodology include simplicity of operation, short measurement time (2 h), uses of internal control (confirming a run of PCR), and quantitative measurement with high sensitivity. Both measles and rubella currently cause social outbreaks in Japan. We hope that our single-tube multiplex assay contributes to an early diagnosis, leading to an appropriate infection control measure and prevention of epidemics.

A method for detecting rash and fever illness-associated viruses using multiplex reverse transcription polymerase chain reaction

In this study, a new multiplex RT-PCR method for detecting various viral genes in patients with rash and fever illnesses (RFIs) was constructed. New primer sets were designed for detection of herpes simplex viruses 1 and 2 (HSV1 and 2), and Epstein-Barr virus (EBV). The newly designed and previously reported primer sets were used to detect 13 types of RFI-associated viruses by multiplex RT-PCR assay systems. Moreover, to eliminate non-specific PCR products, a double-stranded specific DNase was used to digest double-stranded DNA derived from the templates in clinical specimens. RFI-associated viruses were detected in 77.0% of the patients (97/126 cases) by the presented method, multiple viruses being identified in 27.8% of the described cases (35/126 cases). Detected viruses and clinical diagnoses were compatible in 32.5% of the patients (41/126 cases). Sensitivity limits for these viruses were estimated to be 10¹ -10³ copies/assay. Furthermore, non-specific PCR products were eliminated by a double-stranded specific DNase with no influence on sensitivity. These results suggest that this method can detect various RFI-associated viruses in clinical specimens with high sensitivity and specificity.

A Novel High-Throughput Method for Molecular Detection of Human Pathogenic Viruses Using a Nanofluidic Real-Time PCR System

Human enteric viruses are recognized as the main causes of food- and waterborne diseases worldwide. Sensitive and quantitative detection of human enteric viruses is typically achieved through quantitative RT-PCR (RT-qPCR). A nanofluidic real-time PCR system was used to develop novel high-throughput methods for qualitative molecular detection (RT-qPCR array) and quantification of human pathogenic viruses by digital RT-PCR (RT-dPCR). The performance of high-throughput PCR methods was investigated for detecting 19 human pathogenic viruses and two main process controls used in food virology. The conventional real-time PCR system was compared to the RT-dPCR and RT-qPCR array. Based on the number of genome copies calculated by spectrophotometry, sensitivity was found to be slightly better with RT-qPCR than with RT-dPCR for 14 viruses by a factor range of from 0.3 to 1.6 log₁₀. Conversely, sensitivity was better with RT-dPCR than with RT-qPCR for seven viruses by a factor range of from 0.10 to 1.40 log₁₀. Interestingly, the number of genome copies determined by RT-dPCR was always from 1 to 2 log₁₀ lower than the expected copy number calculated by RT-qPCR standard curve. The sensitivity of the RT-qPCR and RT-qPCR array assays was found to be similar for two viruses, and better with RT-qPCR than with RT-qPCR array for eighteen viruses by a factor range of from 0.7 to 3.0 log₁₀. Conversely, sensitivity was only 0.30 log₁₀ better with the RT-qPCR array than with conventional RT-qPCR assays for norovirus GIV detection. Finally, the RT-qPCR array and RT-dPCR assays were successfully used together to screen clinical samples and quantify pathogenic viruses. Additionally, this method made it possible to identify co-infection in clinical samples. In conclusion, given the rapidity and potential for large numbers of viral targets, this nanofluidic RT-qPCR assay should have a major impact on human pathogenic virus surveillance and outbreak investigations and is likely to be of benefit to public health.

Human parechovirus infections and child myositis cases associated with genotype 3 in Osaka City, Japan, 2014

Human parechovirus (HPeV) infects humans early in life and typically causes asymptomatic or mild diseases such as gastrointestinal and respiratory illness but sometimes leads to more serious consequences in neonates and young infants. In 2014, we detected HPeV from 38 patients by real-time reverse transcription-PCR in Osaka City, Japan, and 33 HPeV strains were genotyped based on their VP1 sequences. HPeV genotype 3 (HPeV-3) was the most prevalent and accounted for 22 cases (66.7%) followed by nine HPeV-1 (27.3%), one HPeV-2 (3.0%) and one HPeV-4 (3.0%). Phylogenetic analysis revealed that detected HPeV-3 strains were divided into three genetically distinct groups. One was characterized by a novel single amino acid deletion mutation at the N terminus of the 2A protein as well as the VP1 sequence, whereas the others were closely related to HPeV-3 strains detected in Japan in either 2008 or 2011. These HPeV-3 groups were detected from patients with various symptoms including three myositis cases. Recent papers have demonstrated that HPeV-3 was the aetiological agent for epidemic myalgia exclusively among adults from Yamagata Prefecture in Japan. Here, we provide clinical details and episodes of three myositis patients including an adult and two children in Osaka City, Japan. Our results suggest that HPeV-3 is a causative agent of myositis not only in adults but also in children.