Δευτέρα 12 Σεπτεμβρίου 2022

Rapid and reliable inactivation protocols for the diagnostics of emerging viruses: the example of SARS‐CoV‐2 and monkeypox virus

alexandrossfakianakis shared this article with you from Inoreader

ABSTRACT

The emergence and sustained transmission of novel pathogens are exerting an increasing demand on the diagnostics sector worldwide, as seen with the ongoing SARS-CoV-2 pandemic and the more recent public health concern of monkeypox virus (MPXV) since May 2022. Appropriate and reliable viral inactivation measures are needed to ensure the safety of personnel handling these infectious samples.

In the present study, 7 commercialized diagnosis buffers, heat [56°C and 60°C], and sodium dodecyl sulfate detergent [SDS; 2.0%, 1.0%, and 0.5% final concentrations] were tested against infectious SARS-CoV-2 and MPXV culture isolates on Vero cell culture. Cytopathic effects were observed up to 7 days post-inoculation and viral load evolution was measured by semi-quantitative PCR.

WHO recommends an infectious titer reduction of at least 4 log10. As such, the data show efficacious SARS-CoV-2 inactivation by all investigated methods, with >6.0 log10 reduction. MPXV inactivation was also validated with all investigated methods with 6.9 log10 reduction, although some commercial buffers required a longer incubation period to yield complete inactivation.

These results are valuable for facilities, notably those without BSL-3 capabilities, that need to implement rapid and reliable protocols common against both SARS-CoV-2 and MPXV.

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Development of a multi‐recombinase polymerase amplification assay for rapid identification of COVID‐19, Influenza A and B

alexandrossfakianakis shared this article with you from Inoreader

Abstract

Background

The coronavirus disease 2019 (COVID-19) pandemic caused extensive loss of life worldwide. Further, the COVID-19 and influenza mix-infection had caused great distress to the diagnosis of the disease. To control illness progression and limit viral spread within the population, a real-time reverse-transcription PCR (RT-PCR) assay for early diagnosis of COVID-19 was developed, but detection was time-consuming (4-6 h).

Methods

To improve the diagnosis of COVID-19 and influenza, we herein developed a recombinase polymerase amplification (RPA) method for simple and rapid amplification of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19 and Influenza A (H1N1, H3N2) and B (influenza B). Genes encoding the matrix protein (M) for H1N1, and the hemagglutinin (HA) for H3N2, and the polymerase A (PA) for Influenza B, and the nucleocapsid protein (N), the RNA-dependent-RNA polymerase (RdRP) in the open reading frame 1a b (ORF1ab) region, and the envelope protein (E) for SARS-CoV-2 were selected, and specific primers were designed. We validated our method using SARS-CoV-2, H1N1, H3N2 and influenza B pseudovirus standards and RNA samples extracted from COVID-19 and Influenza A/B (RT-PCR-verified) positive patients.

Results

The method could detect SARS-CoV-2 pseudovirus standard DNA quantitatively between 102 and 105 copies/mL with a log linearity of 0.99 in 22 min. And this method also be very effective in simultaneous detection of H1N1, H3N2 and influenza B. Clinical validation of 100 cases revealed a sensitivity of 100% for differentiating COVID-19 patients from healthy controls when the specificity was set at 90%.

Conclusion

These results demonstrate that this nucleic acid testing method is advantageous compared with traditional PCR and other isothermal nucleic acid amplification methods in terms of time and portability. This method could potentia lly be used for detection of SARS-CoV-2, H1N1, H3N2 and influenza B, and adapted for point-of-care (POC) detection of a broad range of infectious pathogens in resource-limited settings.

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Assessing transmission risks and control strategy for monkeypox as an emerging zoonosis in a metropolitan area

alexandrossfakianakis shared this article with you from Inoreader

Abstract

Objective

To model the spread of Monkeypox (MPX) in a metropolitan area for assessing the risk of possible outbreaks, and identifying essential public health measures to contain the virus spread.

Methods

The animal reservoir is the key element in the modelling of a zoonotic disease. Using a One Health approach, we model the spread of the MPX virus in humans considering potential animal hosts such as rodents (e.g., rats, mice, squirrels, chipmunks, etc.) and emphasize their role and transmission of the virus in a high-risk group, including gay and bisexual men-who-have-sex-with-men (gbMSM). From model and sensitivity analysis, we identify key public health factors and present scenarios under different transmission assumptions.

Findings

We find that the MPX virus may spill over from gbMSM high-risk groups to broader populations if efficiency of transmission increases in the higher-risk group. However, the risk of outbreak can be greatly reduced if at least 65% of symptomatic cases can be isolated and their contacts traced and quarantined. In addition, infections in an animal reservoir will exacerbate MPX transmission risk in the human population.

Conclusion

Regions or communities with a higher proportion of gbMSM individuals need greater public health attention. Tracing and quarantine (or "effective quarantine" by post-exposure vaccination) of contacts with MPX cases in high-risk groups would have a significant effect on controlling the spreading. Also, monitoring for animal infections would be prudent.

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