Establishment of a new method for rapid detection of SARS-CoV-2 by visual LAMP (without nucleic acid extraction)

A new type of coronavirus (SARS-CoV-2) infection caused acute or fatal pneumonia. The virus is another coronavirus that is transmitted from animal to human and capable of transmitted from human to human, following the severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS CoV). In order to control the epidemic as soon as possible, there is an urgent need, for rapid detection and confirmation of infected patients. In this study, according to the SARS CoV-2 whole genome published in GenBank as target gene, LAMP Desiner 2.0 software was used to screen efficient and highly specific combinatorial loop primers. The amplification characteristics of Bst 4.0 DNA polymerase relys RNA as template for DNA synthesis. Viral RNA-positive test results showed that 5 to 20 copies of virus nucleic acid could be detected. The inactivated virus was directly used as amplification template for clinical detection. The amplified nucleic acid molecules are combined with OG (Orange-Green) dye. Positive samples are green and negative samples are orange yellow.. The established SARS-CoV-2 one-step visual constant temperature rapid detection method realizes rapid detection of nucleic acids with high sensitivity. This study provides a new method for SARS-CoV-2 detection.

Development of a TaqMan loop-mediated isothermal amplification assay for the rapid detection of pigeon paramyxovirus type 1.

Pigeon paramyxovirus-1 (PPMV-1) is a strain of Newcastle disease virus (NDV) that has adapted to infect pigeons and poses a constant threat to the commercial poultry industry. Early detection via rapid and sensitive methods, along with timely preventative and mitigating actions, is important for reducing the spread of PPMV-1. Here, we report the development of a TaqMan loop-mediated isothermal amplification assay (TaqMan-LAMP) for rapid and specific detection of PPMV-1 based on the F gene. This system makes use of six novel primers and a TaqMan probe that targets nine distinct regions of the F gene that are highly conserved among PPMV-1 isolates. The results showed that the limit of detection was 10 copies µL-1 for PPMV-1 cDNA and 0.1 ng for PPMV-1 RNA. The reaction was completed within 25 min and was thus faster than conventional RT-PCR. Moreover, no cross-reactions with similar viruses or with peste des petits ruminants virus (PPRV) or NDV LaSota vaccine strains were observed under the same conditions. To evaluate the applicability of the assay, the TaqMan-LAMP assay and a commercial RT-PCR assay were compared using 108 clinical samples, and the concordance rate between two methods was found to be 96.3%. The newly developed PPMV-1 TaqMan-LAMP assay can therefore be used for simple, efficient, rapid, specific, and sensitive diagnosis of PPMV-1 infections.

Animal coronaviruses and SARS-CoV-2.

COVID-19 is a highly contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It has rapidly spread to 216 countries and territories since first outbreak in December of 2019, posing a substantial economic losses and extraordinary threats to the public health worldwide. Although bats have been suggested as the natural host of SARS-CoV-2, transmission chains of this virus, role of animals during cross-species transmission, and future concerns remain unclear. Diverse animal coronaviruses have extensively been studied since the discovery of avian coronavirus in 1930s. The current article comprehensively reviews and discusses the current understanding about animal coronaviruses and SARS-CoV-2 for their emergence, transmission, zoonotic potential, alteration of tissue/host tropism, evolution, status of vaccines and surveillance. This study aims at providing guidance for control of COVID-19 and preventative strategies for possible future outbreaks of zoonotic coronavirus via cross-species transmission.