Detection of SARS-CoV-2 Genome for over 100 Days after COVID-19 Onset.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), is spreading globally. Generally, the viral genome becomes undetectable within a couple of weeks after infection. Herein, we report a case of long-term detection of the SARS-CoV-2 genome in the same individual for 106 days. Whole genome sequencing was performed on specimens taken at the onset of the disease and 2 months after onset, and the B.1.1.7 lineage was detected in both samples. A comparison of the full-length sequences revealed a single-base difference and no amino acid mutations. This is the first case in Japan where the virus was detected over a long period, and the full-length sequences were compared.

Detection of Respiratory Viruses during the Early Phase of the Coronavirus Disease 2019 Pandemic in Ibaraki and Gunma Prefectures, Japan.

Respiratory infections are common, and the most common causative agent is a virus. Therefore, routine surveillance of respiratory viruses is useful in the case of novel viral diseases such as coronavirus disease 2019 (COVID-19). In this study, to clarify the kind of virus involved in suspected cases of COVID-19 in the early stages of the pandemic, we attempted to detect various respiratory viruses in 613 specimens that tested negative for severe acute respiratory syndrome coronavirus 2 using reverse transcription polymerase chain reaction. As a result, viruses were detected in 59 (9.6%) patients. In addition, human rhinovirus (HRV), human metapneumovirus (HMPV), human respiratory syncytial virus, and human parechovirus were detected in 29, 25, 3, and 2 patients, respectively. Although this study was conducted over a short period of time and not all specimens were tested, these results indicate that various respiratory viruses, especially HRV and HMPV, can be detected even during the early stages of the COVID-19 pandemic. Because various respiratory viruses maintain a constant effect during the outbreak of the newly emerged pandemic, systematic surveillance of respiratory viruses is needed during the normal period to make good use for clinical and public health.

A Longitudinal Study on Enteric Virus Contamination in Bivalves along the Coast of Ibaraki Prefecture, Japan.

ABSTRACT: During the 2014 to 2018 seasons, we conducted a longitudinal study involving enteric virus surveillance in bivalves, including natural oysters and clams harvested in Ibaraki Prefecture, Japan. Some norovirus (NoV) contaminations were detected in natural oysters, whereas no enteric virus was found in clams. NoVs detected in oysters were of the genotypes GII.4 and GII.6, both of which are closely related genetically to the NoV strains prevalent in humans. We found low level of enteric virus contamination in bivalves collected along the coast of Ibaraki Prefecture. The possibility of food poisoning caused by these viruses appears low, and few cases of infectious disease have been observed in the surrounding area. The harvest timing was more related to contamination quantity than the harvest area in many enteric viruses. Our results highlight that contamination of bivalves by enteric viruses may depend upon the prevalence of human diarrhea and illness.

Development of Monoclonal Antibodies and Antigen-Capture ELISA for Human Parechovirus Type 3.

Human parechovirus type 3 (HPeV3) is an etiologic agent of respiratory diseases, meningitis, and sepsis-like illness in both infants and adults. Monoclonal antibodies (mAbs) can be a promising diagnostic tool for antigenic diseases such as virus infection, as they offer a high specificity toward a specific viral antigen. However, to date, there is no specific mAb available for the diagnosis of HPeV3 infection. In this study, we developed and characterized mAbs specific for HPeV3 capsid protein VP0. We used cell-free, wheat germ-synthesized viral VP0 protein for immunizing BALB/c mice to generate hybridomas. From the resultant hybridoma clones, we selected nine clones producing mAbs reactive to the HPeV3-VP0 antigen, based on enzyme-linked immunosorbent assay (ELISA). Epitope mapping showed that these mAbs recognized three distinct domains in HPeV3 VP0. Six mAbs recognized HPeV3 specifically and the other three mAbs showed cross-reactivity with other HPeVs. Using the HPeV3-specific mAbs, we then developed an ELISA for viral antigen detection that could be reliably used for laboratory diagnosis of HPeV3. This ELISA system exhibited no cross-reactivity with other related viruses. Our newly developed mAbs would, thus, provide a useful set of tools for future research and ensure HPeV3-specific diagnosis.