Evaluation of SARS-CoV-2 quantification from oropharyngeal swabs, nasopharyngeal swabs, and naso-oropharyngeal swabs: A cross-sectional study

The current naso-oropharyngeal swab for SARS-CoV-2 detection faces several problems, such as waste issues and its use for quantitative studies. This study aimed to evaluate the total RNA and viral loads from different upper respiratory tract swabs types and whether SARS-CoV-2 quantification can use the current internal control for normalization. This cross-sectional study collected positive specimens with single oropharyngeal or nasopharyngeal swabs and naso-oropharyngeal swabs. The samples were extracted, tested with qualitative RT‒PCR, and then tested with quantitative RT‒PCR. The RNA eluate was measured for the total RNA concentration. The total RNA concentration, viral load, and RNaseP Ct values were collected and analysed statistically. The positive results came from 41 oropharyngeal swabs, 34 nasopharyngeal swabs, and 36 naso-oropharyngeal swabs. The total RNA increased significantly from oropharyngeal swabs to nasopharyngeal swabs to naso-oropharyngeal swabs. Significant differences in RNaseP Ct values between groups and their correlations with total RNA were found. In addition, the increase in the total RNA and the RNaseP Ct values were unrelated to the viral load. The physical features in the naso-oropharyngeal area and the swabbing procedures could affect the total RNA but not the viral load. However, since the virus particles could present inside and outside human cells, the increase in collected human cells may not always be followed by the viral load increase. Normalization using the RNaseP Ct value became unnecessary due to the factors mentioned above. Therefore, a careful approach is needed in viral load studies of swab specimens.

In vitro broad-spectrum antiviral activity of MIT-001, a mitochondria-targeted reactive oxygen species scavenger, against severe acute respiratory syndrome coronavirus 2 and multiple zoonotic viruses

The COVID-19 pandemic caused by SARS-CoV-2 becomes a serious threat to global health and requires the development of effective antiviral therapies. Current therapies that target viral proteins have limited efficacy with side effects. In this study, we investigated the antiviral activity of MIT-001, a small molecule reactive oxygen species (ROS) scavenger targeting mitochondria, against SARS-CoV-2 and other zoonotic viruses in vitro. The antiviral activity of MIT-001 was quantified by RT-qPCR and plaque assay. We also evaluated the functional analysis of MIT-001 by JC-1 staining to measure mitochondrial depolarization, total RNA sequencing to investigate gene expression changes, and immunoblot to quantify protein expression levels. The results showed that MIT-001 effectively inhibited the replication of B.1.617.2 and BA.1 strains, Zika virus, Seoul virus, and Vaccinia virus. Treatment with MIT-001 restored the expression of heme oxygenase-1 (HMOX1) and NAD(P)H: quinone oxidoreductase 1 (NqO1) genes, anti-oxidant enzymes reduced by SARS-CoV-2, to normal levels. The presence of MIT-001 also alleviated mitochondrial depolarization caused by SARS-CoV-2 infection. These findings highlight the potential of MIT-001 as a broad-spectrum antiviral compound that targets for zoonotic RNA and DNA viruses, providing a promising therapeutic approach to combat viral infection.

Etiological agent and clinical characteristics of haemorrhagic fever with renal syndrome in the southern Republic of Korea: a genomic surveillance study

OBJECTIVES

High incidences of haemorrhagic fever with renal syndrome (HFRS) have been reported in the southern Republic of Korea (ROK). A distinct southern genotype of Orthohantavirus hantanense (HTNV) was identified in Apodemus agrarius chejuensis on Jeju Island. However, its association with HFRS cases in southern ROK remains elusive. We investigated the potential of the southern HTNV genotype as an etiological agent of HFRS.

METHODS

Samples from 22 patients with HFRS and 193 small mammals were collected in the southern ROK. The clinical characteristics of patients infected with the southern HTNV genotype were analysed. Amplicon-based MinION sequencing was employed for southern HTNV from patients and rodents, facilitating subsequent analyses involving phylogenetics and genetic reassortment.

RESULTS

High-throughput sequencing of HTNV exhibited higher coverage with a cycle of threshold value below 32, acquiring nearly whole-genome sequences from six patients with HFRS and seven A. agrarius samples. The phylogenetic pattern of patient-derived HTNV demonstrated genetic clustering with HTNV from Apodemus species on Jeju Island and the southern Korean peninsula, revealing genetic reassortment in a single clinical sample between the M and S segments.

DISCUSSION

These findings imply that the southern HTNV genotype has the potential to induce HFRS in humans. The phylogenetic inference demonstrates the diverse and dynamic characteristics of the southern HTNV tripartite genomes. Therefore, this study highlights the significance of active surveillance and amplicon sequencing for detecting orthohantavirus infections. It also raises awareness and caution for physicians regarding the emergence of a southern HTNV genotype as a cause of HFRS in the ROK.

Consideration of the Cycle Threshold Values from Real-Time RT-PCR SARS-CoV-2 Interpretation for the Clinicians: Analysis of 339 Positive Cases from a Referral Laboratory in Jakarta, Indonesia

BACKGROUND

real-time RT-PCR was recommended by WHO for COVID-19 diagnosis. The cycle threshold (Ct) values were expected to have an association with clinical manifestation. However, the diagnostic modalities such as quantitative molecular detection and virus isolation were not yet available for the routine test. This study has been conducted to analyze the relationship between the Ct values of qualitative rRT-PCR and the clinical manifestation and to describe the factors determining the result.

METHODS

from March to April 2020, specimens were sent to our laboratory from different healthcare centers in Jakarta. The patient's characteristic and clinical manifestation were extracted from the specimen's epidemiology forms. The specimens extracted and tested using rRT-PCR, and the Ct value were collected. The data were analyzed using the appropriate statistic test.

RESULTS

from 339 positive results, the mild to moderate case was 176 (52%) and the severe cases was 163 (48%). Female was dominant in the mild to moderate cases (58%), while the male was prevalent in the severe cases (60%). The median age for mild to moderate case was 35 years old and severe cases was 49 years old. Statistical analysis found relationship between both group with gender (p = 0.001) and age (p < 0.001), but not with the Ct value.

CONCLUSION

many variables in specimen sampling and processing could affect the Ct value result. In addition, the disease's severity was depended with the host immune response, regardless the number of virus. There was suggested no significant difference between the Ct values of mild-moderate and severe COVID-19, and thus should not be loosely interpreted.

Preliminary report of COVID-19 testing: experience of the clinical microbiology laboratory Universitas Indonesia, Jakarta, Indonesia

Indonesia first reported SARS-CoV-2 in March 2020. From March to April, clinical microbiology laboratory Universitas Indonesia in Jakarta received 4617 specimens with 12.6% positivity rate and 22% asymptomatic case. The result of this study could give an early picture of Indonesia’s COVID 19 outbreak situation.