Differential diagnosis of the infection caused by wild-type or CD2v-deleted ASFV strains by quantum dots-based immunochromatographic assay.

African swine fever (ASF), a highly contagious and lethal disease, poses a tremendous threat and burden to the swine industry worldwide. Lack of available vaccines or treatments leaves rapid diagnosis as the key tool to control the disease. Quantum dots (QDs) are unique fluorescent semiconductor nanoparticles, highly versatile for biological applications. In this study, we developed a quantum dots-based fluorescent immunochromatographic assay (QDs-FICA) using CD2v as the diagnosis antigen to detect ASFV antibodies. The titre of the test strip was 1 : 5·12 × 105 . In addition, the strip was highly specific to anti-ASFV serum and had no cross-reaction with CSFV, PPV, PRRSV, PCV-2, PRV and FMDV. Moreover, a comparative test of 71 clinical samples showed that the coincidence rate was 85·92% between the test strip and the commercial ELISA kit (coated with p30, p62 and p72). The QDs-FICA can be used to detect ASFV antibodies, which is meaningful for the surveillance, control and purification of ASF.

Quantification of soya-based feed ingredient entry from ASFV-positive countries to the United States by ocean freight shipping and associated seaports.

African swine fever virus (ASFV) can survive in soya-based products for 30 days with T ½ ranging from 9.6 to 12.9 days in soya bean meals and soya oil cake. As the United States imports soya-based products from several ASFV-positive countries, knowledge of the type and quantity of these specific imports, and their ports of entry (POE), is necessary information to manage risk. Using the data from the International Trade Commission Harmonized Tariff Schedule website in conjunction with pivot tables, we analysed imports across air, land and sea POE of soya-based products from 43 ASFV-positive countries to the United States during 2018 and 2019. In 2018, 104,366 metric tons (MT) of soya-based products, specifically conventional and organic soya bean meal, soya beans, soya oil cake and soya oil were imported from these countries into the United States via seaports only. The two largest suppliers were China (52.7%, 55,034 MT) and the Ukraine (42.9%, 44,775 MT). In 2019, 73,331 MT entered the United States and 54.7% (40,143 MT) came from the Ukraine and 8.4% (6,182 MT) from China. Regarding POE, 80.9%-83.2% of soya-based imports from China entered the United States at the seaports of San Francisco, CA, and Seattle, WA, while 89.4%-100% entered from the Ukraine via the seaports of New Orleans, LA, and Charlotte, NC. Analysis of five-year trends (2015-2019) of the volume of soya imports from China indicated reduction over time (with a noticeably sharp decrease between 2018 and 2019), and seaport utilization was consistent. In contrast, volume remained high for Ukrainian soya imports, and seaport utilization was inconsistent. Overall, this exercise introduced a new approach to collect objective data on an important risk factor, providing researchers, government officials and industry stakeholders a means to objectively identify and quantify potential channels of foreign animal disease entry into the United States.

Antiviral drugs targeting endosomal membrane proteins inhibit distant animal and human pathogenic viruses.

The endocytic pathway is a common strategy that several highly pathogenic viruses use to enter into the cell. To demonstrate the usefulness of this pathway as a common target for the development of broad-spectrum antivirals, the inhibitory effect of drug compounds targeting endosomal membrane proteins were investigated. This study entailed direct comparison of drug effectiveness against animal and human pathogenic viruses, namely Ebola (EBOV), African swine fever virus (ASFV), and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A panel of experimental and FDA-approved compounds targeting calcium channels and PIKfyve at the endosomal membrane caused potent reductions of entry up to 90% in SARS-CoV-2 S-protein pseudotyped retrovirus. Similar inhibition was observed against transduced EBOV glycoprotein pseudovirus and ASFV. SARS-CoV-2 infection was potently inhibited by selective estrogen receptor modulators in cells transduced with pseudovirus, among them Raloxifen inhibited ASFV with very low 50% inhibitory concentration. Finally, the mechanism of the inhibition caused by the latter in ASFV infection was analyzed. Overall, this work shows that cellular proteins related to the endocytic pathway can constitute suitable cellular targets for broad range antiviral compounds.

Electrochemical investigations for COVID-19 detection-A comparison with other viral detection methods.

Virus-induced infection such as SARS-CoV-2 is a serious threat to human health and the economic setback of the world. Continued advances in the development of technologies are required before the viruses undergo mutation. The low concentration of viruses in environmental samples makes the detection extremely challenging; simple, accurate and rapid detection methods are in urgent need. Of all the analytical techniques, electrochemical methods have the established capabilities to address the issues. Particularly, the integration of nanotechnology would allow miniature devices to be made available at the point-of-care. This review outlines the capabilities of electrochemical methods in conjunction with nanotechnology for the detection of SARS-CoV-2. Future directions and challenges of the electrochemical biosensors for pathogen detection are covered including wearable and conformal biosensors, detection of plant pathogens, multiplexed detection, and reusable biosensors for on-site monitoring, thereby providing low-cost and disposable biosensors.

Development of a real-time PCR assay for detection of African swine fever virus with an endogenous internal control.

Real-time PCR assays are highly sensitive, specific and rapid techniques for the identification of ASF virus (ASFV) (Section 3.8, OIE Terrestrial Manual, 2019). Although an ASFV p72 gene-based real-time PCR assay (a.k.a. the Zsak assay) (Journal of Clinical Microbiology, 2005, 43, 112) has been widely used for ASFV detection, several more ASFV whole genome sequences have become available in the 15 years since the design of the Zsak assay. In this study, we developed a new ASFV p72 gene-based real-time PCR after analysis of all currently available sequences of the p72 gene and multiplexed the new assay with a modified Zsak assay aiming to have a broader coverage of ASFV strain/isolates. To reduce false-negative detections, porcine house-keeping gene, beta actin (ACTB), was applied as an internal control. Eight ACTB sequences from the GenBank and 61 partial ACTB sequences generated in this study, and 1,012 p72 sequences from the GenBank and 23 p72 sequences generated at FADDL, were used for ACTB and ASFV primer and probe designs, respectively, to ensure broader host and ASFV coverage. Multiplexing ACTB in the reaction did not affect ASFV amplification. The multiplex assay was evaluated for strain/isolate coverage, sensitivity and specificity. The in silico analysis showed high ASFV strain/isolate coverage: 98.4% (978/994) of all p72 sequences currently available. The limit of detection (LOD) was 6 plasmid copies or 0.1-1 TCID50 /ml of ASFV isolates per reaction. Only targeted ASFV isolates and the viruses in the positive clinical samples were detected, indicating that the assay is highly specific (100% specificity). The test results of 26 ASFV isolates with different country origins showed that this newly developed multiplex assay performed better than the Zsak assay that has been widely accepted and used worldwide, indicating that it may be used as an alternative assay for ASFV detection.