Advances in Virology

Due to the coronavirus disease 2019 (COVID-19), researchers all over the world have tried to find an appropriate therapeutic approach for the disease. The angiotensin-converting enzyme 2 (ACE2) has been shown as a necessary receptor to cell fusion, which is involved in infection due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It is commonly crucial for all organs and systems. When ACE2 is downregulated via the SARS-CoV-2 spike protein, it results in the angiotensin II (Ang II)/angiotensin type 1 receptor axis overactivation. Ang II has harmful effects, which can be evidenced by dysfunctions in many organs experienced by COVID-19 patients. ACE2 is the SARS-CoV-2 receptor and has an extensive distribution; thus, some COVID-19 cases experience several symptoms and complications. We suggest strategy for the potential protective effect of ACE2 to the viral infection. The current review will provide data to develop new approaches for preventing and controlling the COVID-19 outbreak.

Background. In 1995, the hepatitis B vaccine in South Africa was incorporated into the childhood expanded programme of immunization. We report on immunity gaps of laboratory-based hepatitis B virus (HBV) among patients in public facilities in Gauteng Province from 1st January 2014 to 31st December 2019. Methodology. We analyzed HBV serological data extracted from the National Health Laboratory Services Central Data Warehouse (NHLS CDW). A descriptive analysis was performed for hepatitis B surface antigen (HBsAg), antibodies to HBV core (anti-HBc) total, anti-HBc IgM, and antibodies to HBV surface antigen (anti-HBs) according to annual distribution, age groups, and sex. Results. The HBsAg positivity rate was 7.0% (75,596/1,095,561; ): 7.4% (96,532/944,077) in the 25 years and over age group and 4.0% (358/9,268 and 325/10,864) in the under 5 and 13–24 year age groups. The positivity rates of the other HBV serological markers were as follows: anti-HBc total was 37.0% (34,377/93,711; ), anti-HBc IgM was 2.4% (5,661/239,237; ), and anti-HBs was 37.0% (76,302/206,138; ). Naturally acquired HBV immunity was detected in 25.7% (11,188/43,536) of patients in the 25 years and over age group, and 9.7% and 8.2% (113/1,158 and 541/6,522) among those under 5 years and 13–24 year age group, respectively (). Vaccine-induced immunity was 56.6% (656/1,158) in children under 5 years and 10.2% (4,425/43,536) among those 25 years and above (). Fifty-six percent (29,404/52,581) of patients were HBV seronegative; predominantly among patients in the 13–24 year age group (60.6%; (3,952/6,522)) and 25 years and over (56.3% (24,524/43,536)) (). Conclusion. The HBV infection seroprevalence remains high in South Africa, with Gauteng province having high intermediate endemicity. However, the HBV immunity gap has shifted from younger children to older children and adults.

SARS-CoV-2 is a novel coronavirus that causes a potentially fatal respiratory disease known as coronavirus disease (COVID-19) and is responsible for the ongoing pandemic with increasing mortality. Understanding the host-virus interaction involved in SARS-CoV-2 pathophysiology will enhance our understanding of the mechanistic basis of COVID-19 infection. The characterization of post-transcriptional gene regulatory networks, particularly pre-mRNA splicing, and the identification and characterization of host proteins interacting with the 5′ and 3′UTRs of SARS-CoV-2 will improve our understanding of post-transcriptional gene regulation during SARS-CoV-2 pathogenesis. Here, we demonstrate that either SARS-CoV-2 infection or exogenous overexpression of the 5′ and 3’UTRs of the viral genomic RNAs, results in reduced mRNA levels possibly due to modulation of host cell pre-mRNA splicing. Further, we have investigated the potential RNA-binding proteins interacting with the 5′ and 3′UTRs, using in-silico approaches. Our results suggest that 5′ and 3′UTRs indeed interact with many RNA-binding proteins. Our results provide a primer for further investigations into the UTR-mediated regulation of splicing and related molecular mechanisms in host cells.

Since its discovery at the end of 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly evolved into many variants, including the subvariant BA.2 and the GKA clade. Genomic clarification is needed for better management of the current pandemic as well as the possible reemergence of novel variants. The sequence of the reference genome Wuhan-Hu-1 and approximately 20 representatives of each variant were downloaded from GenBank and GISAID. Two representatives with no track of in-definitive nucleotides were selected. The sequences were aligned using muscle. The location of insertion/deletion (indel) in the genome was mapped following the open reading frame (ORF) of Wuhan-Hu-1. The phylogeny of the spike protein coding region was constructed using the maximum likelihood method. Amino acid substitutions in all ORFs were analyzed separately. There are two indel sites in ORF1AB, eight in spike, and one each in ORF3A, matrix (MA), nucleoprotein (NP), and the 3′-untranslated regions (3′UTR). Some indel sites and residues/substitutions are not unique, and some are variant-specific. The phylogeny shows that Omicron, Deltacron, and BA2 are clustered together and separated from other variants with 100% bootstrap support. In conclusion, whole-genome comparison of representatives of all variants revealed indel patterns that are specific to SARS-CoV-2 variants or subvariants. Polymorphic amino acid comparison across all coding regions also showed amino acid residues shared by specific groups of variants. Finally, the higher transmissibility of BA.2 might be due at least in part to the 48 nucleotide deletions in the 3′UTR, while the seem-to-be extinction of GKA clade is due to the lack of genetic advantages as a consequence of amino acid substitutions in various genes.

SARS-CoV-2 is a major public health problem worldwide. Since its emergence, several diagnostic kits have been developed to ensure rapid patient management. The aim of our study is to check the performance of the new Moroccan SARS-CoV-2 detection kit: MAScIR SARS-CoV-2 M 2.0. The following parameters were studied: repeatability, reproducibility, analytical specificity, analytical sensitivity, and comparison with the GeneFinder™ COVID-19 Plus RealAmp Kit. In addition, an external quality evaluation comprising five specimens was carried out as part of an international program for the external quality evaluation of sublaboratories of the WHO and the Laboratory Office of the National Institute of Hygiene of Morocco. The results of all parameters studied showed an analytical performance that complied with the requirements of the method verification/validation protocol adopted by the Central Laboratory of Virology and met the recommendations of COFRAC (French Accreditation Committee). During the current study, the sequencing of some randomly selected positive samples was performed, among which the carriers of the Alpha variant, the Delta variant, and the Omicron variant were detected. These results allowed us to deduce that this kit was valid for detecting these three variants.

Rift Valley fever virus (RVFV) is a high-priority zoonotic pathogen with the ability to cause massive loss during its outbreak within a very short period of time. Lack of a highly sensitive, instant reading diagnostic method for RVFV, which is more suitable for on-site testing, is a big gap that needs to be addressed. The aim of this study was to develop a novel one-step reverse transcription loop-mediated isothermal amplification (RT-LAMP) method for the rapid detection of RVFV. To achieve this, the selected RVFV M segment nucleotide sequences were aligned using Multiple Sequence Comparison by Log-Expectation (MUSCLE) software in MEGA11 version 11.0.11 program to identify conserved regions. A 211 pb sequence was identified and six different primers to amplify it were designed using NEB LAMP Primer design tool version 1.1.0. The specificity of the designed primers was tested using primer BLAST, and a primer set, specific to RVFV and able to form a loop, was selected. In this study, we developed a single-tube test based on calorimetric RT-LAMP that enabled the visual detection of RVFV within 30 minutes at 65°C. Diagnostic sensitivity and specificity of the newly developed kit were compared with RVFV qRT-PCR, using total RNA samples extracted from 118 blood samples. The colorimetric RT-LAMP assay had a sensitivity of 98.36% and a specificity of 96.49%. The developed RT-LAMP was found to be tenfold more sensitive compared to the RVFV qRT-PCR assay commonly used in the confirmatory diagnosis of RVFV.